They’re talking about very early car racing—when cars first started being raced competitively. The point is that racing happened almost immediately after cars appeared.
Jasper is a company that rebuilds engines and sells them as remanufactured units. In this episode, they’re part of a discussion about engine tuning and emissions legality.
HP Tuners makes tools used to tune a car’s computer. The hosts mention it because it’s used for engine changes like disabling certain factory functions.
AFM is a system that can shut off some cylinders to save fuel. An “AFM delete” means you disable that feature, so the engine runs on all cylinders instead.
Line boring is a precision machining step that makes a long, straight hole the right size and alignment. It’s often used when engine or bearing surfaces get worn or damaged.
CARB and the EPA are the U.S. agencies that set emissions rules. If a modification is “certified,” it means it’s been approved to meet those rules so it can be legal to use.
Oversized bearings are bigger than the original ones so they can fit correctly after the housing has been worn or machined. It helps the bearing sit properly again.
This is when the metal “seat” that holds a bearing gets damaged or worn out. Once that happens, the bearing can’t fit correctly and the engine can start running poorly.
A pressure transducer is a sensor that measures pressure and turns that measurement into an electrical signal. It’s useful for getting accurate readings inside an engine instead of guessing.
A compression gauge measures how much pressure the engine builds in each cylinder. If compression is low, it can point to sealing problems like valves not seating correctly.
Valve guides are small metal sleeves inside the engine head that help the valve move smoothly and stay aligned. They also help move heat away from the valve so it doesn’t overheat.
A stem seal is a small seal that helps keep oil from leaking past the valve stem into the engine’s cylinders. Less oil leakage usually means less smoke and better efficiency.
EMD is a company known for locomotive engines. Here it’s used as an example of a valve-guide design so listeners can compare how different engines handle valve guidance.
An interference fit is when the guide is slightly larger than the hole it goes into, so it must be pressed in and the parts grip tightly. For valve guides, that tight fit is important for heat transfer and for preventing the guide from moving in the head.
The valve seat is the surface the valve seals against when it’s closed. If the seal isn’t right, the valve can wear out faster and sealing can get worse.
Thermal load is the heat-related stress the valve guide experiences from combustion. The speaker describes how a large portion of heat is transferred from the valve face to the seat, while the remaining heat flow contributes to guide temperatures and wear.
Overhead cam (OHC) describes an engine layout where the camshaft is located in the cylinder head. The speaker contrasts it with other valve-train setups, noting that direct-bucket designs can change how forces are transmitted to the valve system.
Rocker ratio is the mechanical advantage of the rocker arm in a valve train, affecting how cam lift becomes valve lift. It changes the forces and motion the valve stem experiences, which in turn influences guide loading and wear.
A piston ring is a sealing and friction-control ring on the piston that manages compression and oil control. The speaker uses it as an analogy for how fast and dynamically a rotating component can move under high-speed conditions.
The Chevrolet Spin is a family-oriented vehicle meant to carry people and cargo. It uses a normal engine that has small internal parts that help the valves open and close correctly. If those parts wear or behave differently, it can affect how the engine runs.
Term
torque plate home
“Torque plate honing” (as implied by the phrase) is a cylinder-head or block machining/finishing process done after tightening fasteners to simulate real operating distortion. It helps ensure the bore or mating surfaces have the correct geometry under clamping loads.
Dry scuffing is damage caused when metal surfaces slide with insufficient lubrication. In valve trains, inadequate oil between the valve stem and guide can lead to scuffing and accelerated wear.
Valve rotation is the controlled spinning of the valve as it opens and closes. This helps distribute heat and wear around the valve face and seat, but it also means the guide and stem see complex motion and loading.
A turbocharger is a forced-induction device that uses exhaust gas to spin a turbine, compressing intake air. The speaker links turbocharging to wider swings in manifold pressure (vacuum to boost), which affects engine operating conditions relevant to lubrication and wear.
A supercharger is a forced-induction device driven mechanically by the engine (typically via a belt or gears). It increases the amount of air entering the engine, which changes operating conditions like manifold pressure and how the engine manages heat and lubrication.
“Vacuum to boost” describes how manifold pressure can swing from below atmospheric pressure (vacuum) to above atmospheric pressure (boost) in forced-induction engines. Those swings change airflow and thermal conditions, which can influence how oil behaves and how components wear.
Graphite flake is a dry-lubricant additive found in some cast iron or composite materials. Graphite’s layered structure reduces friction, helping valve guides resist scuffing even when oil supply is limited.
Porosity means the material has lots of tiny internal holes. Those holes can hold oil or lubricant, and then release it when the part heats up and cools down.
A hot tank is a heated cleaning bath used to degrease parts. Here, the concern is that it can wash out special lubricant that was put into the valve guide during manufacturing.
Powdered metal is made by compressing metal powder and then heating it so it bonds into a solid part. In this case, the internal structure can be designed to hold lubricant for the valve guide.
The BMW M3 is a fast, performance-focused BMW model. It’s designed to drive more aggressively than a regular BMW, with stronger engine and handling. People may talk about it when discussing the parts inside the engine that help it perform.
Term
cobalt tungsten
Cobalt tungsten is a very hard material used to make parts resist wear. In this context, it’s mentioned as an option for valve guide/seat surfaces that need to last under harsh conditions.
A valve seal is a small seal that keeps oil from getting where it shouldn’t around the valve. The episode’s point is that it affects how oil is metered and controlled, not just whether oil leaks.
It’s a lab device that repeatedly moves parts back and forth, like the engine does. In this case, it tests how oil passes through the valve guide so engineers can compare different designs.
Oil migration means oil slowly moves through tiny gaps or pores in a part. They test it because if oil can’t stay where it’s needed, the valve/guide area can run too dry.
A lubrication metering device is a part feature that controls the amount of oil that gets to where it’s needed. The point here is that the valve seal and guide work together to regulate oil supply.
An annular groove is a circular ring-shaped cut on a part. The shape and pattern of these grooves can help control how oil flows and gets metered to the valve area.
Centerless grinding is a way to precisely shape and smooth a cylindrical part. It’s used here as a step to get valve guides to the right size and finish.
Net diameter is the final intended size of the part. The process steps described are meant to bring the valve guide close to that exact inside diameter before finishing.
A carbon trap area is a built-in spot meant to catch carbon/soot. It’s especially relevant for diesels, which tend to build up more soot around the valve area.
Paraffin is a wax. In this kind of manufacturing, it’s used because it melts at a low temperature, so it can be removed quickly during processing to leave the part ready for the next steps.
Oil impregnation means soaking a porous metal part with oil so it can hold onto lubricant inside the material. That helps reduce wear where the part rubs during operation.
Powder metal is made by compressing metal powder into a shape and then heating it so it becomes solid. Because it starts as powder, the final part can behave differently than a cast part.
A burnishing tool is like a polishing/smoothing roller that presses on the metal surface. It can make the surface smoother and more durable, especially when the material is soft enough to respond well.
Ultrasonic measurement sends sound waves into a material and listens for how they travel. If two parts aren’t perfectly bonded or fully contacting, the sound travel pattern changes.
Surface finish means how smooth the metal surface is after machining. If it’s not smooth enough, two parts may not touch perfectly, which can change how heat and measurements behave.
Guide honing is a finishing step that uses abrasive tools to refine the inside of the valve guide. It helps get the right fit and a good surface so the valve moves correctly.
A chip is the tiny curled-off piece of metal that comes off when a tool cuts. The goal is to cut cleanly and remove material predictably, not just rub and smear it.
In machining, a lubricant (cutting fluid) is used to reduce friction while cutting. It can change how chips form and whether they get cleared out properly.
A reamer is a tool used to make a hole the right size very accurately. It can be used with or without lubricant, and that choice affects how chips behave during cutting.
A Napier ring is a feature found on some precision valve-guide tools. It helps create a particular cutting/measurement shape, which can change how you should use the tool.
Caterpillar is mentioned as an example of a valve part. The speaker is basically saying that mixing parts from different setups can cause problems because the geometry won’t match.
Stem to guide clearance is the small gap between the valve stem and the guide. That gap helps the valve move correctly, and getting it wrong can cause wear or sealing problems.
A seat and guide machine is a specialized tool used to machine the valve seat and valve guide areas. Using it correctly helps you get the valve surfaces aligned and sized properly.
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
June 13, 1896 and early racing set the stage before the conversation shifts into practical engine-building topics from a trade event. AFM delete comes up alongside emissions compliance and machining work like line boring. The core technical thread focuses on valve guides: how they maintain coaxiality, why proper interference fit and lubrication matter for heat transfer and scuff resistance, and how powdered-metal guides rely on retained lubricant that hot tanking can remove. Tooling, tolerances, and chip evacuation round it out.
The conversation covers a wide range of topics, including sports, historical events, industry events, and a detailed discussion on valve guides and their importance in engine performance and maintenance. The conversation delves into the intricate details of valve guide lubrication and manufacturing, covering topics such as materials, lubrication methods, and sizing techniques. It emphasizes the importance of valve seals and the science behind lubrication and valve guide manufacturing.
