www.the351cforum.com

Walter Malik very respected builder and he mentions 2% losses is what he sees. Frank Merkyl I know personally and runs some 2000hp bbf stuff and is pushing to be the first guy to put c6 in 7 second range very knowledgeable builder. I beleive what they say, valve set typically in .006-008 range hot to cold. Frank himself has been in my shop so i tend to believe what he tells me. I had mentioned to Dragboss that the expansion coefficient of supracast is measured at 150 f so if running a engine at 160f which i do does the bock even see 150? Likely not with the dissipation rate of aluminum so its very likely it doesn't expand as expected. However its here nor there. The bottom line is Dragboss will make more hp just from cubes alone, then he's adding cam which is more power, and best of all less weight. So the famed 69 cougar is going to be even faster than ever with a new state of art cleveland block! Trackboss! How can you beat that?

You can't. He's going to make more power and go faster for sure. Less nose weight might make the wheels stand higher . He's in the situation where he needs an aftermarket block, the only c block available in the states right now is the trackboss in alloy. I can't fault him for trying it.

This isn't apples to apples, but, when we ran Super late models with alloy 400 sbc, our builder specced 0 lash when cold. After running hot laps on a new build(water temp of 200-220), I'd check the lash again and we'd always be around 14-16 thou, which is where the builder spec'd it to be.

I'm happy that both of you are willing to be the test mules for trackboss. I hope they work out. But if I ever go through the 2 stock blocks I have, I'll go with a track boss in cast. I don't need the alloy, I'm just not interested in the weight savings.

Steve, I would say that's a true statement if it weren't for the fact that I dyno a lot of my engines at the 150-170°F temp range (to simulate drag race conditions) and the lash still grows.

Remember, that the thermal expansion coefficient of Supracast is over twice that of cast iron and pretty much tied with 356T6. Dragboss said that he's seeing .006" lash growth from cold to hot on his current engine at the temperatures that he's running, which is spot on to what I see with cast iron block/aluminum head combinations here.

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Brent Lykins, Lykins Motorsports
www.lykinsmotorsports.com
brent@lykinsmotorsports.com

Brent I know the properties of the supracast and cast. But that doesn't mean they expand as far as the test modules. Why is you cannot except our findings? Did we do it wrong? Did we actually set the lash at .012 and it was .036???No! It is what it is! Ive talked to Dragboss he sets his .006 cold and resets when warm. Usually dead on he says. I don't do it that way i have already mentioned. I set at specified lash and warm engine up. As i said before only a few need adjustment not all. Which tells me its by no means a unified expansion rate. Done this a hundred times at least. Im fine with what you believe. I'll keep building the test motor tb1 and report. You can take for what you like. It is interesting that on 460 ford all aluminum engines they get 2-3 more though than i on lash. Makes sense cause supracast expands less.

How do you set lash again?

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Brent Lykins, Lykins Motorsports
www.lykinsmotorsports.com
brent@lykinsmotorsports.com

Running mates evo

I don't know what that means, but I was mainly referring to how you set cold/hot, etc.

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Brent Lykins, Lykins Motorsports
www.lykinsmotorsports.com
brent@lykinsmotorsports.com

Well the only time I would ever set cold is during assembly of course after that always hot.

Steve.k
Man you dont have to apologize, like I said, I dont take internet talk too personal unless someone just flat out cusses me out. If that were the case then I would prefer someone going through the messenger that way any shit talking can stay off the main threads and keep this forum as clean as possible. Your right, there are alot of knowledgable people on the other forum but I pretty much still remember how George and a few others treated Brent and they are just a problem. Anyways thankfully Brent opened this forum and life is history Heck I didnt even know the other forum was still up and going. Its been a few years since I looked at it and I never see any updated post or pictures. Oh well, im out of this conversation cause you guys defiantly know more about this aluminium vs iron stuff than I do. I didnt realize aluminium blocks could be so problematic with the expansion. I still would say a iron vs aluminium 408 with the same rotating assembly from the 408 instead of the 427 would settle some things but I understand the reasoning not too do it.
-Matt

Several years ago I built a 582 Chevy with an aluminum block and heads for a customer with a jet boat. The lash changed close to .015 from cold to hot on the dyno at 185 degrees. After I had run the engine I just checked the valves cold and I gave the customer a cold setting which worked good in the boat.

I've built a few Ford 4.6 engines using the factory aluminum block and supposedly they grow enough to really effect the main bearing clearance. I shot for .001-.0015 cold clearance and it worked out fine.

A friend of mine who does a lot of big Ford engines in aluminum blocks that are really tall told me that his engines sometimes end up with negative lash when they are cold. It doesn't seem to hurt anything because the compression ratio is high enough that it starts right up anyway.