[Tim Corcoran]

I always thought a true .000 deck height with a .040 head gasket was good practice for an efficient engine. My machinist recommends -.005 says zero with a .040 gasket is too close. I am using 6.8 Eagle rods and a 4.25 Scat forged crank and E-heads. I mocked it up yesterday with pistons in four corners and it's currently -.012, -.014, -014, -.015. What is your experience. Thanks.

[PAUL K]

We shoot for zero to .005 above the deck for a factory block build. Never had an issue.

[Tim Corcoran]

Originally Posted by PAUL K

We shoot for zero to .005 above the deck for a factory block build. Never had an issue.

With a .040 head gasket?

[PAUL K]

Originally Posted by Tim Corcoran

With a .040 head gasket?

Yes.....even an .039 occasionally

[Dragncar]

I went with zero and 1016s and all is good.

[steve25]

Getting to zero or better yet plus .005” gets more of the fuel out of narrow piston to bore gap and where it should be, in the chamber to be burned and not wash the lube oil out of the top of the bore over time.

[Tim Corcoran]

My machinist told me his recommended minimum is .050 and he said I should put them -.005. I told him to put them at .000 and he said OK. So I just wanted to confirm what I thought I already knew. Thanks for the confirmation. .000 deck will give me 13:1 and that is what I was shooting for. I had him mill .050 off of my heads and got the chambers down to 61cc's.

[aaronman]

https://www.enginelabs.com/engine-te...n%20the%20bore.

Thought this might be helpful. I would following your machinist recommmendations.

[bluegoat65]

I m actually .010 out with .060 head gasket on a factory block, running BME alum. rods, N/A motor, lol. No issues.

[Probird]

Originally Posted by bluegoat65

I m actually .010 out with .060 head gasket on a factory block, running BME alum. rods, N/A motor, lol. No issues.

I was just kissing the pistons with aluminum rods, zero deck, and a .060 gasket. I do have a small dome though. But I think it probably touched when it over revved breaking a rear end and bounced it off of the rev limiter. I run .075’s now.

[Tim Corcoran]

I have steel rods and Butler/Ross flat top pistons

[KEN CROCIE]

I agree with PK and Steve 25. I shoot for .030" piston to head clearance.

[77 TRASHCAN]

When Jon Kaase built his Engine Masters engine(s) he went .035 quench.

[KEN CROCIE]

BTW we ran a race engine with .027" clearance and had a very slight imprint of the cyl. head on the piston. I know where the limit is, by test.

[chiefbigb]

Some of my Mopar friends claim they run as much as .050 below deck with felpro gaskets similar thickness wise to what we use. They say numbers like that are common in their world.

[chiefbigb]

Unless you were building some type of class engine I would not invest the extra money in cutting that small amount for 0 deck. That's just my opinion on a bracket race engine. If you blew a head gasket and had to skim the deck later you would be glad you had some to cut.

[Dragncar]

My old 455 I did not deck it or line bore it. It lasted forever.
This last engine I did .000 deck it as its a higher effort pump gas engine. I wanted my quench the best I could.
But the block had hardly anything removed. You could see a spot where it barely cleaned up. One of the bores had a spot like that too.

[Skip Fix]

I might do 0.005 down just to give room for a clean up if you ever blow a head gasket.

[Tim Corcoran]

I appreciate all the feed back and advice on this. I believe it's quite difficult to get all the pistons at the exact point in relation to the deck. The closest I have is +.005 in one hole and I am using .040 Cometic MLS head gasket. So I will have .035 at the closest point static anyhow, at 6,500 RPM it will be somewhat closer. This make me a little nervous but according to some of you this is ideal. I suppose having this much piston to deck will improve VE.

[PAUL K]

If the shop has the proper tooling it is simple to set the deck exactly where you want it. Some shops don't have it. The old method was to mock assemble the four corner pistons, measure then cut.

I have a block now that is off by .009 (we didn't do the work) the simple fix is to use a .010 thinner gasket on the one side. Cometic offers several different sizes and sells their head gaskets in singles.