Let's have a discussion. IS .040 over to much for a boosted motor?
 

So as some of you know. My block took some scaring and I am considering boring it out to .040 over. I have heard an entire fleet of sides on this. Some say no issues what so ever. Others say NO WAY. Yet I have yet to see any FACTUAL reason why nor has anyone showed any proof of issues w .040 over. Let's have this discussion. I already have another stock block on the way to me. I may just punch that block to .020 over and run or maybe I will run this 1 at .040 over. I would LOVE to hear some ideas or better yet proof as to what is so dangerous and why YES or why NOT. I've spoken with a few machine shops local and abroad. There does not seem to be a general consensus. To those against. The idea I am getting is either A: the sleeve is too thin and will crack (yet no one seems to know of a cracked sleeve of any kind under 8-900whp) or B: it will cause more heat on the coolant and cause cooling issues. I would love to have and more so hear from those more knowledgable than I.

Dooooo ittttttt!!!!!!!!

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For comparison sake. How minute even .040 is. And it's this much from the circumference of the cylinder. It's not like it's all in 1 spot.

Personally "no leg to fall on" I would say the difference between .020 and .040 is so small I would do it if it was my motor. The sleeves are plenty thick to loose .040" in circumference and still boost it.

I had my motor .04 over for my wiseco pistons (for extra thermal expansion of low silicone in my pistons+original hp goals). Anything more and you're pushing it but it should be fine for your application.

They have been doing SBC blocks and a ton of others, .030" and .060" for 50 years.

Are SBC closed decked motors?

True, it's also 50+ year old Technology and is a Sand Casted Block.

Meaning, that the Cores used in the Sand Casting Process can shift or move as much as .060" or more.

.030" over is the first size available back then. Then .060", and then .090"

SBC machining has nothing to do with vq35. The vq35 has thinner aluminum sleeves. The concern here is not removing too mach material, and compromising the strength of the sleeves (especially with open deck).

These is No Cencern here.......

You Build your Motors You way, I'll Build them mine.....

Pay no attention to the man behind the curtain.

Here you go again

Nobody even knows what you're talking about.


LSX and SBC machining clearances for sleeves are different than VQ35 clearances. As in how much you can take out of one sleeve is different than the other.

You do this kind of thing a lot man. I'm not upset, and I don't think anyone else is, but you find really weird and non-nonsensical ways to buttheads on here.

Well Happy Holidays to You Man........