AFM delete means turning off a feature that can shut down some cylinders to save gas. It changes how the engine runs, and it can also affect whether the car still meets emissions rules.
Jasper engines is a company that rebuilds and sells replacement engines. Here they’re mentioned in a discussion with tuners about what’s legal when changing engine settings.
HP Tuners is a company/toolset used by mechanics and enthusiasts to adjust a car’s computer settings. In this episode it’s mentioned in the context of engine modifications and diagnostics.
CARB and the EPA are U.S. agencies that set emissions rules. If you change something on a car, you may need certified parts or a legal tune so it doesn’t violate emissions laws.
Line boring is a machine-shop process that re-machines a long, straight hole so parts line up correctly again. It’s often used when something has worn out or been damaged.
Term
crinchef bearing housing failures
This sounds like a specific problem where the bearing area in the engine housing fails. The host is saying it’s something they’re seeing more often in certain modern diesel setups.
Oversized OD bearings are bigger bearings used to fix wear in the engine’s bearing area. Mechanics use them when the housing is worn so the new bearing can fit tightly and work correctly.
Spray welding of shafts is a way to rebuild a worn metal shaft by adding material back onto it. Afterward, the part is machined to the correct size so it can work like new.
Oversizing journals means the bearing surface on a shaft is rebuilt and made slightly bigger than factory. Then the matching bearing surfaces are chosen to fit that new size.
A pressure transducer is a sensor that measures pressure and turns it into an electrical reading. It lets you get more accurate data about what’s happening inside the engine.
A compression gauge measures how much pressure the engine cylinders build. It’s a diagnostic tool that helps you spot problems like worn rings or valve sealing issues.
Valve guides are parts inside the engine head that help the valve move straight up and down. They also help the valve stay aligned so it seals well, and they help carry heat away from the valve.
Valve train is the set of parts that opens and closes the engine valves. If valve guides aren’t right, the valves can’t move and seal correctly, which affects engine performance and wear.
An interference fit is a tight press-fit where the parts are made to be slightly too tight so they lock together. With valve guides, that tight fit helps them stay put and do their job of alignment and heat transfer.
JB Weld is a strong epoxy used for metal repairs. The point here is that it’s not a substitute for the correct press-fit and machining needed for valve guides, because the part can still wear out or move.
The valve seat is the “landing spot” in the engine head where the valve seals when it’s closed. If that seal isn’t perfect, gases can slip past and the engine can start running poorly and wearing parts out faster.
Thermal load just means “heat stress.” When the engine burns fuel, the valve gets extremely hot, and that heat can gradually damage or wear the valve and its guide.
Mechanical loads are the “push and pull” forces from the moving parts in the valve train. If those forces are higher or the valve moves faster, the guide can wear faster.
Overhead cam means the camshaft sits in the top of the engine head. That layout can change how the valve train parts work together and where the forces go.
Rocker ratio is a geometry setting in the valve train that changes how the cam’s motion turns into valve lift. If the valve lifts/moves differently, it changes the stresses on the guide and stem.
A valve stem seal helps keep oil from leaking into the combustion chamber where it can burn. It also helps ensure the valve stem still gets enough lubrication so it doesn’t grind and wear out.
The Chevrolet Spin is a small family vehicle that can carry people and cargo. The podcast mention about valves is about parts inside the engine that help control airflow. If those parts wear out, the engine can run less smoothly.
Valve rotation means the valve isn’t just moving straight up and down—it also turns a bit. That helps even out wear, but deposits and heat cycles can still cause problems.
Oil consumption means the engine is using oil faster than it should. If oil gets into the wrong places (like around the valve), it can burn and cause smoke.
A supercharger is a device that squeezes more air into the engine. That can make more power, but it also changes engine operating conditions compared with older naturally aspirated setups.
A turbocharger is a device that forces more air into the engine using exhaust gases. More air can mean more power, but it also changes how the engine runs and heats up.
Vacuum-to-boost describes how the engine’s intake pressure can go from “sucking” (vacuum) to “pushing” (boost) depending on throttle and load. That changes how hard the engine is working and can affect heat and lubrication.
Hot tank cleaning is like soaking engine parts in a heated cleaning bath. Here, the concern is that it can wash out special oil/lubricant that was put into the part during manufacturing.
John Deere is a well-known company that makes tractors and other heavy equipment. The hosts mention a John Deere technical bulletin as an example of how cleaning can affect valve guide lubrication.
Porosity means the material has tiny internal holes. Those holes can hold oil and then release it later, which matters for how well the valve guide lubricates the valve stem.
Powdered metal is made by pressing metal powder into a shape and then heating it so it sticks together. It can also create tiny spaces that can help hold oil for lubrication.
Graphite flake is a form of carbon found in some iron materials. In this discussion, it’s mentioned as a type of dry particle that can influence how the material behaves and how lubrication is retained.
The BMW M3 is a fast, performance version of a BMW sedan. It’s built to accelerate quickly and handle well. It might be mentioned in an engine discussion because its engine parts and maintenance can involve more specialized components.
A valve seal is a rubber/metal seal that helps keep oil from getting where it shouldn’t—like into the combustion chamber. It helps control how much oil reaches the valve stem.
A reciprocating test machine is a lab setup that moves a component back and forth to simulate real engine motion. Here, it’s used with pressure and vacuum to measure how much oil migrates through a valve guide/valve stem assembly.
An annular groove is a circular channel cut around a part. In valve-related components, the shape of grooves can affect how oil is guided and controlled.
Centerless grinding is a way to precisely shape a metal part using abrasive wheels. It’s used to get very accurate dimensions on round parts like valve guides.
Net diameter is the final “correct size” a part is supposed to be. The machining steps described are used to get the valve guide close to that exact inner diameter.
Tooling marks are the marks left on metal by the cutting tools. Sometimes they’re just incidental scratches, but sometimes they’re actually part of the design.
A carbon trap area is a spot in the valve guide designed to catch soot and carbon. Diesel engines make more soot, so this helps prevent buildup from causing problems.
Paraffin is a wax. In this kind of manufacturing, it’s used because it melts at a relatively low temperature, so it can be removed during processing without damaging the rest of the part.
Powder metal is a way to make parts by compressing metal powder into a shape first, then processing it so it becomes a solid part. It can behave differently than cast metal when you machine or run it in an engine.
Here, particulates refers to tiny abrasive particles that can form or be carried in the lubrication/combustion environment. The speaker’s point is that these particles can attack softer guide materials (like certain bronze/copper alloys), accelerating wear.
Ultrasonic measurement uses sound waves to check what’s going on inside a part. Here it’s used to see whether two pieces are truly in full contact or if there’s a gap/transition between them.
A thermal barrier is anything that makes it harder for heat to move through. Adding another layer can keep heat from getting where it needs to go, which can affect how long parts last.
High-speed steel reamers are metal-cutting tools. The host is saying they’re fine for some guide materials, but for powder-metal guides the guide’s harder particles can make the tool perform poorly.
Guide honing is a finishing step that makes the inside of the valve guide the right size and smoothness. It helps the valve move correctly and reduces wear.
A chip is the tiny shaving of metal that a cutting tool removes. The host is saying the guide is made slightly small so the right tool can cut it to the final size properly.
PCD is diamond used for cutting tools. It’s used when the job is too hard or abrasive for normal cutting tools, so the tool can keep cutting instead of wearing out quickly.
Depth of cut is how deep the tool goes into the metal each pass. The host is saying there’s a good range that helps the tool cut cleanly instead of just dragging and smearing.
A profilometer measures how rough or smooth a surface is. The host is saying powder-metal surfaces can have tiny pores, which can confuse the measurement.
A Napier ring is a particular shaped ring feature used in some tooling. The point is that tool geometry can require specific lubrication or cutting technique.
A machining center is a precision machine (often computer-controlled) that cuts metal. Here it matters because the machine’s coolant can help clear chips away.
A seat and guide machine is the equipment used to machine the valve seat and the valve guide. It helps the shop cut them accurately so the valve fits and seals correctly.
Stem to guide clearance is the small gap between the valve stem and its sleeve. It’s set so the valve can move freely without rubbing too hard or letting oil leak.
The head gasket seals the connection between the engine block and the cylinder head. Tightening everything down can slightly warp the head, which can affect how the valve seats line up.
Concentricity means the valve parts are centered on the same axis. If they’re not, the valve can end up rubbing unevenly and sealing less effectively.
LIVE
Rob Munro: Chuck, what's happening, man? What's going on?
Chuck Lynch: Rob has it in the great north country!
Rob Munro: You were gonna say great white north. I know that's what you wanted to say But now things in the great white north are not looking so white anymore. It's looking pretty good good this way. So you Hey, man, are you are you a big soccer fan? You know the June we got June here So June is the FIFA soccer big shitting happening here in North America. Are you a big fan?
Chuck Lynch: I can't say I'm a big fan. I played a bit when I was in the Marine Corps ⁓ because I was around the right crowd,
Rob Munro: Well, the rest of the world says football. I know we in North America say soccer, but I kind of wish it was more like football. mean, that would make it actually more interesting for me because if you had like a 250 pound guy coming from center field to plow the guy over that's kicking the ball around. Now that would be more like my kind of sport. I think I could get into it.
Chuck Lynch: Yeah, or hockey you just you know, it just starts throwing punches before speaking of hockey. You know, it's it's that time of year too, right?
Rob Munro: Yeah. June is playoff season, exactly. It's hockey time. So you know what? I'm glad I don't have to look at buying a ticket because it's a little out of my tax bracket. But I heard the tickets are pretty expensive for some of that stuff. But maybe I'll just catch a game or two on TV just to kind of say that I did. I think that's the plan.
Chuck Lynch: Yeah, I'm probably there with you. Yeah, I heard some crazy hotel cost in, you know, the area out there. So that's just that's just the hotel. Then you got all the other things and the game tickets and stuff. Yeah. Spendy spending.
Rob Munro: Yeah. Right? Exactly. Yeah, spendy spendy. And now I know you you're kind of a bit of a history buff. And I know you, you always send us little like in the mornings and stuff. For those of you that are listening, Chuck's really good at sending us little things on email at work.
And, you know, he'll look into different things that happened back in, you know, the early 1900s or, you know, stuff like that. So Chuck, share with us what goes on in June that you know of this kind of brings us back into a little bit of a history moment.
Chuck Lynch: So yeah, June, there's a lot going on, know, of course, you know, we're... May is the Indy 500 and, you know, Memorial Day weekend and that's a huge thing for, especially as Hoosier guys like Steve and myself and...
but the world loves the Indianapolis Motor Speedway, you know. But when you get into June, you know, I think that's when we really kind of feel like it's summertime, right? And you you go back and you you look the it Steve and I joked about this in the in the past is like we built a car and then day two we had you know somebody else has got to build one and then we're going to race right.
So if you look at June 13th 1896 we had our first auto race and so Emile Lassure, I guess. ⁓ Throwing that out there. I'll probably offend some of our friends up in your part of the country. But anyway, was the first to drive across the finish line.
The first true documented automobile race. it makes you a lot of people probably didn't even realize we had cars in 1895.
Rob Munro: Wow. Yeah, and then who'd thought, you know, it's kind of like anything. Who'd have thought you'd actually race one and, yep, look where we've come. So that's pretty cool for sure.
Chuck Lynch: Yeah, that would have been a good Robert William skit, huh? You he was talking about, you know, the Scottish golf thing that is like, oh, two cars, let's race.
Rob Munro: Right? Yep. And I know you threw one here to me the other day, something about the first drive-in movie theater, you know, it was that happened in June back in 1933. You sent that one over. I got a kick out of that one because you know, that it's like, you know, 1933, did they even have back seats in 1933? Because I know what I'd be doing at the drive-in theater, right? So yeah.
Chuck Lynch: Yeah, I tell you what, if there wasn't, that's how it was originated.
Rob Munro: Exactly. Yeah. No, so, so lots going on. And when we talk about June, there's lots going on for us too. ⁓ you and I are, ⁓ busy, busy. And, ⁓ we got HPX expo in June and we'll have a crew there.
That's going to be in Charlotte, North Carolina. And that's June 2nd to 4th. So we got that going on. We got rank in college. We have our second regional of the year with AERA. and that's June 12th to 13th, as well as NACAT.
I'll be out at NACAT in Sacramento. It's now called the AEC, which is the Automotive Education Conference, and that's June 15th to 18th. So lots going on, and ⁓ I know you just came back. You were at Jasper here not that long ago for our first regional, and how was that?
Chuck Lynch: ⁓ it was great! Not to sound so repetitive, but it's just that when you can get face-to-face with your peers in the industry, you know, and share time, you know, the face-to-face time, can then all of the conversations break out.
We usually have... you know, good meals. Everybody just puts their guard down. They take an opportunity to learn, get people to come out and share some really great information. You know, we had a conversation between, you know, Jasper engines and HP tuners on the AFM delete type stuff, the diagnostics and...
the CARB and EPA certification programs that you know have been done to make sure that those products are legal in all 50 states. ⁓ So that was really good. Ken & Mettle did a great presentation on tooling for line boring.
I think everybody's pretty familiar with the lot of the modern mid-range diesels with the lighter oils and so forth, there's a lot of crinchef bearing housing failures, so oversized OD bearings. They talked about some tooling for that kind of stuff.
There were great demos. Dan Bagley, he did a great presentation on... bearings ⁓ to kind of go along with those, know, Lake Speed and Mark Mulberg, they collaborated and they talked surface finish and lubrication and a little bit on, you know, some modern...
⁓ big warranty issues that we're all aware of out there. So anyway, ⁓ I think everybody walks away with something, you know, that they can use in their shop, whether it's, you know, something they can physically employ in a machining practice or to protect them from something that might come in their door that they would have accepted and maybe they shouldn't.
you know, ⁓ sometimes... the knowledge of what not to mess with is what you can come away with and you you don't need to get into everything.
Rob Munro: know exactly. And you know what a great facility like for Jasper to open up their doors and allow everybody in ⁓ you know and to see that place. ⁓ You know I know you've got lots of history there you spent a lot of years there but when I went through I mean it's an eye-opener and you cannot help but come away you know like you said with the networking the camaraderie back and forth I mean just it's just a great facility and you know want to thank those guys.
for everything. They opened up their doors and they just they welcomed us and it was a first-class facility so very very good event for sure.
Chuck Lynch: Yeah, and I think whether you're a one-man shop or, you know, a big corporation or whatever, there's something to take away. And, you know, you can see some newer technologies like the spray welding of shafts, ⁓ know, from oversizing journals, seal surfaces, you know, just the all kinds of crazy technology type stuff, how the engines are tested and measuring.
flow and and how compression is measured and so forth and a lot of these things you know technology keeps driving things to a level that you know anyone can have a pressure transducer that they use in cylinder now i mean this is not reserved for the the formula one teams or anything of that nature there's stuff that you can order out of some online electronic stuff and build yourself ⁓ a very very accurate compression gauge so you can see things like that and if somebody had a cool idea and they built it in-house and so if they can do it you can do it so
Rob Munro: No, that is cool. That is, yeah, just like I say, you're only gonna, you gotta go face to face to see that kind of stuff. And I would encourage everybody, you know, we've got a couple more regionals coming up for this year. And if you can get out to ⁓ them, like I say, guaranteed Monday morning, when you get back in the shop, you're bringing something back with you, some knowledge, a contact, a phone number, something to help you out and apply to your shop right away. So. ⁓
Rob Munro: Speaking of that Chuck a little bit that's kind of what sort of got you started with this conversation that we're going to talk about today with valve guides I mean we've been taking a fair amount of calls lately with just some different questions about materials and how to size them and some different tips and tricks and that kind of stuff and you've put together a really good presentation for us today and I'm looking forward to that and I think valve guides are It's just one of those things you take for granted sometimes.
You you just pound them out, you pound them in and you're, you know, you're, off and running. But as you're going to see today, you've got a lot going on there and you're going to explain to us just, ⁓ just what to look out for.
Chuck Lynch: Alright, so just for reference here, so this is not something we're going to typically see in the heads that we're running through our shop. But this is like an EMD locomotive valve guide. So you know, it's got a stop that hits the head. They may or may not have a stem seal on it. So I just thought I would throw that in there too. We're going to do some slides, but this is the kind of the 3D component and ⁓ We'll get talking about some valve guides.
Rob Munro: I could take an eye out. Gotta be careful.
Chuck Lynch: Alright, so Rob, you're seeing my screen, right?
Rob Munro: I am. You're definitely, ⁓ slides look good. So I'll, ⁓ I'll let you fire away and I've got a few questions I think possibly as we go along, but, yeah, you just do your thing.
Chuck Lynch: Yeah, so you know, again, since it's a virtual, it's a little bit hard to get into some of the details and practices and stuff, but a slideshow definitely helps us get good visualization of what we're talking about.
So this is going to be kind of a 35,000 foot view of the subject and, you know, take notes and give us a call and we can chat further if you have a specific type of application question and so forth. It's something that's, you know, I'm a valve train guy.
I like the valve train stuff. And it's been one of the things that I've seen to be very challenging over time. And that's kind of because, you know, unlike cylinder homes, ⁓ you know, it's not very easy to just accommodate.
⁓ ⁓ big range and guide sizes with like you mentioned reaming tools How do you how do you ream it to size it or so? It's a little bit more difficult difficult. It's fairly costly to accommodate so We we have some bad practices.
We'll just go with that So Often an underappreciated component, the guide has very important tasks. So it guides the valve throughout the entire service life while maintaining coaxiality between the valve and the seat.
So ⁓ the guide is a guide. You've heard me say this all. We have to remember that the guide should guide the valve. It should guide where the seat gets machined. So if I'm going to rely on that to be such an important datum point, I need to make sure that the guide dimensionally, the ID is one dimension, know, diameter wise, that it's not got too much taper out around things of that nature because you can't machine from a poor datum point.
So if the idea of the guide is not very closely held to specification, the likelihood that you're going to generate a good seat, that it's going to be, you know, true and perpendicular to the spring pad and all.
There's a lot of controls that the guide has. ⁓ Cooling of the valve, you know, we're looking to get 70 to 75 percent of the valve heat out of the head of the valve through seat to valve head contact.
But the guide has a job of dissipating heat as well. So when you knock an old guide out or drill ring a guide out of a head, you need to make sure that you have the proper interference fit or the guides can move.
But you also have to have a bore that's not all scuffed up and torn that it can allow oil to go through. And if you don't have good interference, then you're not going to have good transfer. You can have excessively worn guides from doing things like, oh, I'll just put some, you know, I'm just going to make this up.
know, it's, oh, it's got some scratches in there and I'm going to throw some JB Weld in it or I'll do something to lock it in place. You know, okay, can it still do its job? Can it dissipate heat? Or you want to have, you know, guides wear out really quick because it can't provide that service.
⁓ being somewhat sacrificial by where the higher rate than the VALSTEM, they're still designed to last, you every we're upset if anything doesn't go 150,000 miles, right? There's some engines that, you know, people were like, oh, that thing is not broken until it's 110,000, you know.
So if you... to not maintain, you know, good sizing again, kind of my last point here, and you can't maintain a good alignment or concentricity between, you know, the valve and the seat. And there's a lot of things going on when you look at like a valve seat.
valve guide you know because the valve itself just the valve you're looking at you know the stem the head has to be perpendicular to and concentric to the stem the valve tip so there's a lot of things going on that ⁓ that you know can cause ⁓ early wear ⁓ misfires and so forth.
again, you just can't really state the importance of a guide enough, you know. And but again, I keep going back to a lot of times we just stick a valve in the guide and we kind of shake it and we say, okay, it's good or it's bad because it is expensive to get all the tools.
So we'll get into kind of the stresses on the valve guides. Again, the most significant loads on the guide are Thermal load due to combustion, ideally 75 % is transferred, as I said earlier, from the bow face to the seat.
The means, the balance goes to the guide. Mechanical loads and forces on the stem are basically impacted by the guide length and rocker ratio, know, lift. overhead cam stuff that has direct buckets take some of that out of the equation, but you have spring forces and the valve and open closing velocities and so forth.
I don't know if you've ever taken, I mean I'm sure anybody has done it, you you throw like a ball toward a funnel. There's some of those carnival games. You you throw that ball and it hits it and it spins around and tries to find itself and then goes down the hole.
So you have that kind of stuff going on. know, valves spin in the guide board. Valves are pushed from 12 to 6 because of rockers and whatnot. So the guide is getting those loads applied to it. ⁓ and if you already have concentricity issues that are kind of stacking against you or whatever, then you're going to see a lot more wear as you can see in this.
I don't know how well you can see the mouse, but on the ends they tend to bell mouth. That's where guides typically always wear the most. ⁓ This reduced area here is where you would put a valve stem seal.
So This is going to be the combustion chamber side and that's typically where you're to see your highest amount of wear is combustion chamber side that's due to thermal expansion and so forth. I've got some better images of that.
So again, here's all of your kind of the dynamics and valve guide stresses that you're going to see. So you have combustion forces, gas forces that are trying to shove the valve through the seat. You still have that rotation.
much like a piston ring. I've seen some of the high-speed camera stuff ⁓ of recording the valve and you'd be amazed at how quickly that that valve might spin. A lot of the modern keepers where you have like that's got ⁓ three grooves in the keeper area, they don't lock like like a small block Chevy.
that actually acts as a rotator. So those the tapers on those locks ⁓ may lock in the retainer itself, but that bead area, the two valve collet pieces will come together and then those beads actually have clearance so the valve can actually rotate in there.
You have all those forces, so the valve can move around a good amount. ⁓ When you have those combustion forces moving on the seat, ⁓ you have the same things that will cause distortion in a block that will cause you to need to torque plate home.
Also, they're having an impact on the cylinder head too. So there's a lot of things that are causing stresses and movement that may cause the stem to rub against the guide and potentially cause wear. ⁓ Here's a little bit closer look at like the valve stem seal and we'll just briefly talk about valve stem seals aren't necessarily seals when usually if I think about sealing something off ⁓ what is your first thought?
Nothing leaks by it anymore, right? But valve stem seals in our jargon are actually regulators. So they control a metered amount of oil to go down the guide and into the stem to guide clearance to make sure that we don't have dry scuffing.
Again, here you see the valve rotation. The valves seem, they see really, really crazy variation in temperature range, right? So when you have a combustion event, the temperature soars, and then when you have a fresh charge of cool air coming through, you cool the head of the valve very quickly.
So a lot of times you get that that carbonizing on the valve, and that stuff will make its way up there and get into the stem to guide clearance as well. A little bit on what I was talking here, lubrication.
So valve guides ⁓ must have some lubrication between the stem and the guide to resist scuffing. The amount can't be so large that it enters the combustion chamber and becomes another source of fuel.
⁓ Oil consumption can be, you know, result in smoking. So oil enters a valve guide through gravity of course because a lot of times it's just being poured on top of the valve retainer, the locks, the keepers, all of the components and so it's going to try to make its way back down to the ⁓ crankcase.
⁓ Valve movements, so mechanically the valve is opened and closed by rocker arm, push rods, cam lift, blah, you know, the whole chain of events so that reciprocating action ⁓ you have surface finish in the valve stem so it grabs oil and tries to pull it into the combustion chamber in the surface finish kind of no differently than know, when in the cylinder bore finish you try to put the cross hatch in there, you try to hold oil in there.
Well, the valve stems have that ground finish that they can actually pull oil as they're being opened and closed. Angle has an impact on this both guide angle and the engine applications such as race engines, bus applications, and so forth.
differential so especially today I mean everything that we build's got either a supercharger or a turbocharger or something so we go we have these crazy extremes where we're going from you know vacuum to boost vacuum to boost used to with one a naturally aspirated you know we can get some very fairly high vacuum signals like at idle or so forth when the throttle plates nearly closed you get some high vacuum stuff but you know you can you can have all of that with these modern forced induction engines and then The lubrication can also be manufactured into the guide, and I've got a couple of slides on that that you can see some of that.
But you can put dry lubricants in the valve guide materials like the powdered metal products. And even the alloy products, so cast iron, you know, when you have graphite flake, well that's a dry lubricant.
That's why you can machine iron dry. It's got so much graphite in it that it's got built-in lubrication. But modern powder metal stuff, they actually submerge them in oil and through like some temperature.
control you have expansion contraction the stuff works like a like a wick so you can get oil that'll stay in it and then it'll as the temperature comes up then that lubrication will flow and then when the engine cools back down it ends up back in the porosity again and I know Anybody that's done very much work on an engine, know, so you try to get an old plug or something out and you take a torch and you put it to the engine block and you see it all the moisture rushing out of it.
So it's that same effect. It's just it's oil, you know, and we see that when we clean castings, right? ⁓
Rob Munro: It's funny you mentioned that, Chuck. ⁓ I just took a call here last week because we have a technical bulletin similar to this on some of the John Deere stuff about the member had questioned why they need to have the valve guides removed before they hot tank it.
And we have a technical bulletin. just goes to what you're mentioning here that those, you you'll pull the lubrication back out of those guides if you hot tank it. ⁓ Just like you said, it's pretty materials and porosity and everything can play a pretty big role.
Chuck Lynch: Yeah, so this is a you know some products from ⁓ Mala. There are some of these illustrations come from ⁓ a book that was shared with me, you when I used to work there. ⁓ But lubrication, valve guide ⁓ made of powdered metal materials, these center pores, you know, they heat this up and then they sink it.
But this is not because it's the the reaming fluid or something like that when they were manufacturing the guide. This is a test here to show so you can see the open porosities in the cross section of the material and then they've cross sectioned this guide here and then you apply heat and then sweating that lubricant.
And then they also do things again we mentioned dry particles in the iron like the graphite flake but with powdered metal. you can get really creative in the lubricants that you can put in. Do you want it to be copper, know, granules?
Do you want it to be Teflon? You can get really, really creative as long as you know, because when you center materials, it's not like casting. So it doesn't... you can do relatively low temperature centering, but you can put stuff in there that you would burn up if you were doing a casting.
So you, you know, you take all these powder products and you put them in basically like paraffin so it'll stay in the net shape and there's going to be some material that melts at a low temperature which is your binder and this is this is true of any powdered metal product connecting rod your diamond honing stones this this process is going to be the same so they put it under pressure and heat and that binder will hold all the little particles together.
So you can have guides that I have and they do like valve seats. That's you'll hear ⁓ it's got cobalt tungsten m3 tools steel whatever so you can do the same with the guides or whatever. So it's just a it's very interesting product that you can do a lot of things with and it's what you do most of now.
Rob Munro: And it makes you realize just how important. I think we take sometimes the whole valve seal thing for granted. it only had O-rings on it. Well, we're going to throw a really good Vitan positive seal on now.
It's got to be better. ⁓ So it makes just what you're saying here about the valve seal plays a pretty important role on this whole lubrication thing and the way it controls the oil. Like I say, it's We've always taken the valve seal for granted, or at least I have, you know, so it's.
Chuck Lynch: Yeah and there's different categories or grades of oil flow that you always look at and so they have a reciprocating test machine where they can do pressure and vacuum on the valve guide assembly.
You know so they'll take the valve guide, the retainer, all that stuff and they grind the... they cut the head off the valve and they put it to a point and then they have a measuring cup under there and they measure how much oil migrates through.
Because again, the stuff can get really, really dry and you have to have some lubrication. So again, the whole valve seal notion is a little bit incorrect because it hits valve lubrication metering device.
And you see some that have an annular groove and they have a real fine pitch or a coarser pitch. You have stuff that's got multi-lip and there's... quite the science that goes into those and we've done some articles on those that it's pretty interesting what kind of bunny holes you can go down.
I mean if you're if you like to geek out on that type of stuff there's plenty of information out there on it. It's pretty neat but again we took usually we look at things from such a high level that like ⁓ it seals the seals the seal not necessarily.
Chuck Lynch: ⁓ So this is a little bit of what's going on when it comes to the manufacture of like a cast iron guide. So you do the casting and then the blank turning, then you got to pre-drill, you know, to get it a starter ID, and then you'll move to typically like heat treatment, ⁓ OV centerless grinding, then you drill, ream, whatever to get it close to the net diameter and usually those you might see some tooling marks in there.
Some tooling marks truly are only because the tool had to be pulled out and it made a scratch on the ID. You see a spiral through. There are a lot of valve guides that have very, very specific grooves in the ID and I remember a project cross-sectioning some guides and measuring and there were actually three different depth spirals.
And it was on, it was like a caterpillar application. And, you know, it had been having some issue with like the aftermarket part that wasn't made anywhere near like the original part. And so it had us to develop a new guide.
And you're like, really? Three different depths of groove inside of the guide. So then you got to think, well, the whole... notion of oversizing guides and so forth. Do you need to reintroduce that or do you change a material that can help?
So there's a lot that goes into that inside diameter. So yeah, don't take for granted that's just a tooling mark. It may have an actual purpose and then of course you got to machine the ends for the valve guide ID and OD in in the industrial diesel world, you'll see they have like a carbon trap area because diesels have a lot of soot.
So there's an area that it's like a counterbore that's cut into the guide that's usually toward the combustion chamber side. and it's a bit larger and I know that people have seen valves that actually have a scraper designed into me and where the underside of the valve head down below the neck will have a ⁓ funny shape and like a scraper to get rid of carbon buildup.
So again going back to there's always more than meets the eye. So if we we look at ⁓ cross-section of the material. This is kind of what your gray cast irons looks like. ⁓ You know, gray cast iron and then you see the matrix really really tightens up in the heat treated stuff.
powdered metal as I mentioned, so there's kind of some illustrations that show what I was talking about. So the powders, you know, it looks like you got mustard in there and copper, you know, so I don't know is this a cookie or is it a valve guide?
Looks pretty similar. So that recipe then it goes into pressing as I mentioned usually you always have some kind of inert stuff. Paraffin is used a lot. So it's got a low melting point. So and it, you know, but it recures and it's relatively solid at room temperature.
So you just put all the powders in and put the paraffin in. You smash it to the shape. Then you run it to the oven. The paraffin comes out really quick. And then that's going to be, again, it's got a low melting temp.
So the next lowest melting temp stuff would be the binder. basically glues it all together. Sometimes they're in there your kind of copper bronze world of materials. And again, this is very rudimentary and I see kinda, you know, in those elemental areas.
So we don't want to say, oh they're all stuck together with copper and bronze. I'm not saying that. It's usually a low melt point. of material to get that bond together. Here's the oil impregnation process, then the ODE grinding.
Again, no different than a cast guide. You know, have to make the ends, accept seals, starter edges, ⁓ directional orientation markings, whatever that case may be, scrapers. And here's an example of what know, the powdered metal kind of stuff would look like.
The cast materials, of course, we've talked about that a lot. You look at where their application and ranges are. The non-ferrous stuff, and I've had this question, know, hey, should I be using, you know, guidelines and diesel engines?
The non-fair stuff, know, your bronze, copper, phosphor bronze, those kind of alloys. The downside is particulate. know, because bronze guidelines can do very well in a hot rod diesel or whatever, but they may not.
And when people ask me that question, I usually say my biggest concern is particulates. So it gets in there and it just, it's gritty, sooty, nasty stuff that can eat those soft materials up. So you need a tougher thing.
Now why does the PM stuff have such a crazy range? Well... that recipe, you know, you can say, I got PM stuff that's really soft and it will not last up here. But it's such a broad statement to say I got PM guides, you know, cause like I know at one time and working like I had a list of 27 different guide options.
because of the different recipes. I haven't been... I've been out of that position for a while. So how many are there now? Double that? Who knows? But I would be inclined to say that yeah there's probably 50 different valve guide options in the powder metal classes.
Rob Munro: So Chuck, in saying that, and here's a question too that we used to always wonder, what's your feeling on, like on a gasoline engine for example, putting a bronze liner inside of a bronze guide?
Chuck Lynch: To put a... ⁓ with this... the bronze guideline is actually more of a copper. It's got a higher copper content. That's what gives it that great malleability to be able to run a burnishing ball or roller burnisher or whatnot.
So that you're stacking up layers of thermal distribution. Can people get by with it? People do. But sometimes you also, and I say this often, you don't know what you don't know. And if you don't know what the failure is going to look like, then you may blame it on something else.
Well, that's not my problem. It wasn't transferring heat from the seat and it's stuck in the guide. So it wasn't really the guide's fault. Was it or wasn't? I mean if we don't know what the failure is actually going to look like we might say that I've never had a problem with it.
So I think that once you you know we've talked about ultrasonic measurement of stuff you can take two of the same material cast iron sleeves put them together you know press one in the other and then when you measure the ultrasonic there's going to be a division there and acoustic velocity should be the same between sleeve A and sleeve B if they're the same material but there is that break in there because I you know I boarded it surface finishes get distance right so unless you had those absolutely full contact no no surface scratches from boring honing whatever so I know I'm getting a little bit off the topic there, but those are some of the things that you have to consider.
Surface finishes clearance. And so I don't like sticking any guide inside of a guide because it's just another thermal barrier. And those guidelines are a relatively soft material. again, but people, they do what they have to do sometimes.
Chuck Lynch: So guide sizing. Now this is the tough part. Sizing ⁓ cast iron leaves you with a lot more options. High-speed steel reamers still work. Coated reamers are very effective. Multi-fluid carbide ⁓ in iron.
You run dry. It just works great. Guide honing is a good primary, secondary, sometimes you use a single pass homes or you're familiar with single pass homes, right? That little thing that had like the wedge in it that Sonnen had and you set it up.
Once you got it set up, you can go bigger, but you can't really back it off. They tend to act funny after you back them up, but those things work great. ⁓ Powdered metal, it's tough. High-speed steel reamers don't work well.
at all usually because they put some hard particles in there. It works best if you're using like PCD polycrystalline diamond ⁓ coated stuff or a boring type insert. You need to make a chip. So I just took a call know last week and I know I've had this before but hey why do they ship me these things in their 40,000 or 1 millimeter undersize?
Because they want you to make a chip so you need a special reamer with a reduced pilot nose diameter and so forth to get in there and make a good chip when you're those guides. So people have been in a situation where like oh I can order a valve guide for this Iveco or 5.44 is another example.
I know that if you order them from a dealership, they're a millimeter undersized. And then they have a terrible time trying to find the tool because there's no, you know, OE service didn't set it up that there would be tools to be used out there because when they made the cylinder heads, they were in a big machining center, right?
So it just, it can get pretty challenging. But again, ideal ⁓ load or chip removal. know 10 to 20 thousandths depth of cut. So you know that's going to be 20 to 40 over chip load so it doesn't smear material.
Like I've seen the high-speed steel stuff basically weld itself in the guide board. And with the PM stuff it's hard to measure. It usually measures really really smooth. But you get some you know, it's got the when you open the pores and you're trying to measure it with a profilometer or something It falls off into the little cavities.
It's a bit difficult to measure but they're usually like rifle bore smooth very slick iron bores You know reaming stuff you see those in it like 60 to 100 there are a Which is not a great spec, but they they can be pretty rough but If you did have the opportunity to measure them, they're going to be pretty similar to your valve guide.
I mean your cylinder bore. So if you could use the same RPK, RVK, RK parameters, if you could actually get in there and measure that, that would be great. So if that helps you at all.
Rob Munro: Chuck, what's your opinion on using a lubricant when you're sizing? Like, are you a fan of that or are you more of a sizing dry or what's sort of your thoughts there?
Chuck Lynch: Well, typically the tooling manufacturer should really tell you that. ⁓ know, because bronze and so forth, the PEM type stuff, there's advantage to the lubricant. You can get by with an iron.
It actually may work against you because the way the chip loads up and if you're not flushing it, say if I want to dip my reamer in a lubricant. then ring the guide by hand. I probably wouldn't do that.
Keep it dry. Let the chips get evacuated by the tool. Otherwise, it's gonna stick to it. You know how cast iron is. You get a little bit of oil and it turns into a gritty paste. But it's a different story when you're doing bronze, bronze aluminum, phosphor bronze, those materials.
Yeah. A lubricant usually is can be your friend. But again, I would talk to my tooling supplier and make sure that they haven't done something with the flutes. Because you take a look at... I know most of our listeners will know what a Napier ring is and they have that kind of hook.
So sometimes some of the things you can't see about a reamer in the tooling edge geometry may cause them to say, you need to do it like this. So... Typically, I think I would call the tech line of the who I bought the tools from and say, hey, tell me what I should do here.
Yeah, you don't want to go on my guidance on that. But my experience is try to do iron dry unless you got it in the machining center and you got a flooded coolant. And then I'm going to take advantage of that.
Let it wash all that junk away. But here we go. So that's pretty much it, what I have for the ⁓ slides here. you have any additional questions?
Rob Munro: Well, I was just going to make one comment. For those of you that are listening on the podcast and you're listening only, keep in mind that if you want to get more of a visual for what we're talking about today, all of our podcasts go onto our YouTube channel.
So again, if you want to put a bit of a visual with some of Chuck's slides, you can go right onto our website even, like the AERA website, and right at the top right-hand side, you'll see the YouTube icon.
You can just click that and it'll take you right to our YouTube channel. Great presentation, Chuck. It's funny how some of these parts, you know, we just take for granted. Like I said, we talked about valve guides, valve seals, but ⁓ there's a lot going on there.
Chuck Lynch: That's a fact and you know kind of just an illustration you know I see people post some of this stuff on and of course these parts don't go together you know I have an unfinished caterpillar valve in a EMD valve guide but just you know the rocker arm is it pushes the valve away and then it pulls back and it pushes it away and it pulls back so ⁓ when you're sizing your guides, try to get them as straight as possible.
Try to get those things as straight and round as possible. Taper is working against you and then when you put them on the Seat and Guide machine, you know, it just makes it that much more difficult to correct.
The... kind of the rule I typically share, you don't want more valve seat run out than you have stem to guide clearance. So if you you because there used to be an old rule it was basically a per a half a thousandth run out per inch of head diameter and or you know up to a thousandth but in our world a lot of times the performance intake valve we're going to have a thousandth clearance and the valve is two and a quarter two and three eighths in diameter So I'll run the stem guide clearance and then I'll have that kind of run out.
Well that means I'm definitely going to have flexing and so it's going to load the guide. So another illustration, you know the guides the valve in the seats way up here right? So if I have any tilt in the seat because anytime you're cutting seats they usually don't.
They're not off center. They usually tilt. I cut more on one side than the other so the valve seat's tilted. So now this valve is trying to match that tilt angle. What's it doing way down here? It's, you know, it's because the seat is here, it's tilting it over and rubbing the guide very heavily.
And then you take the distortion that you have by bolting the head over the head gasket and you get all that twisting and tweaking. So... Where I'm going with that, the closer you are to zero, the better.
So if I come off of my Seat and Guide machine pretty close to zero concentricity, then even with all those other factors and distortion and whatnot, I'm better. We're never going to be perfect. And O'Vincil and Barty said, ⁓ one the way to perfection you might pass excellence.
So yeah, are we ever going to be perfect? We're never going to get perfect. But if you, you know, get that stretch goal, you might be better.
Rob Munro: And it's funny, if you're chasing a concentricity issue, where's the first place you look? ⁓ must be something wrong with the machine. It's got to be the machine. It must be something. Well, maybe not. It's kind of the old saying garbage in, garbage out. Well, if you're not concentrating on that guide concentricity and where you're at, what results are you going to have when the end result's going to be a poor seat? yep. Exactly. No, that's right.
Chuck Lynch: Yeah, have to have a good datum point.
Rob Munro: Well, Chuck, appreciate you putting all the effort that you did into that. ⁓ Again, we try to do some of these technical podcasts just so that we can, it's all about education and ⁓ we always come away learning something so that we can apply it and appreciate your time on that.
Thanks again. It was a good presentation. If you want to see any of other podcasts and some of the other technical stuff that we've done, ⁓ we have, like I mentioned, we have a YouTube channel and some of our technical webinars and technical podcasts are on there.
It's a great place to go and you can just go out to our YouTube channel. We also ⁓ are always looking for feedback. So we have a website here for our podcast. It's EP podcast at AERA.org. So you can always let us know if there's Something you want Chuck to talk about it from a technical standpoint, or if you have some questions on the topic, by all means, just use that email address.
All of our podcasts are on the normal podcast streaming services. So you can just go out to Engine Professional Podcast and you'll be able to listen to all of them. And Chuck, you know what? I appreciate your time.
About this episode
The hosts connect tuning and legal compliance with hands-on cylinder-head repair, starting with an AFM delete conversation involving Jasper engines and HP Tuners and the CARB/EPA certification needed for legality in all 50 states. The rest of the discussion zooms in on valve guides: why proper interference fit matters, how valve stem seals meter oil to prevent dry scuffing, and how thermal load and forced-induction extremes stress the system. They also cover powdered-metal guide machining, tooling choices, and precision targets like concentricity and runout.
The conversation covers a range of topics, including sports, historical events, industry events, and technical discussions about valve guides and engine performance. It transitions from casual banter to more technical and industry-specific content, providing insights into various aspects of the automotive and engineering fields. The conversation delves into the modern lubrication methods for engine valve guides, the manufacturing process of valve guides, the materials and applications, guide sizing and lubrication, and the importance of valve guide quality and concentricity.
