what quench height do you run?

[Lavey Huffer]

what quench height do you run?

[poncho-pwr]

Okay, I'll bite sense noone else has. It depends on the engines intended use, what type of rods(steel or aluminum) and tight or loose bearing clearances among other things. I would say most pro builders use about a .035"-.040" quench height in a run of the mill steel rod engine and .055"-.060" in an aluminum rod deal that isn't being revved to the moon.

[Lavey Huffer]

thanks

[GofastRacer]

A lot of variables there but I make it as tight as I can for the application!..

[steelcomp]

I try and shoot for a final of .032-.035

[Lavey Huffer]

4340 h-beam rods 4340 crank .005 piston clearance .003+- main bearing

[Infomaniac]

.035 - .041
My pump gas blown deals have loose pistons (rock) so I put them .005 in the hole and run a .036 gasket.

[Taylorman]

Ive been reading about the same subject. From my reading i have gathered that .040 is about right. Question is, does it matter if you put the pistons further in the hole and use a thin gasket or not as far down with a thicker gasket?

[TIMINATOR]

No difference. We normally run the pistons out of the hole .005-.010 for hi-perf., and "0" for everything else. Put a dial indicator on the piston about 1/8" from the thrust side and see how much rock you can get. Everyone is real conservative on this. With aluminum rods on a 4.375 bore and .006 p/w clearance we have run .025 with no issues. This depends on skirt length and RPM, bearing clearances make almost no difference. Mock it up before you deck it and measure, leave a little extra for wear (you will get more piston/bore clearance). Make each of your own motors tighter until you see a light mark on the heads and then you know what you need for how you build them. Or just be safe and run them at "0" with a .038 like everybody else. TIMINATOR

[WannabeRacing]

Tim is right on. I am a little more conservative, and like too much unless it is a race application. In a flat, you just never know when you are going airborne and over-rev the deal.
But let me say one thing, having the piston in the hole too far is a problem. (Especially with gasoline.) You set that thing any further than .020 in a high compression deal or .025 in a pump gas, and the thing can find detonation real quick. So don't think that because you are sunk, that finding a cometic .027 and slapping it on is the answer. Take the slugs out and do it right.