Bama99z

iTrader: (7)

Got another question. I have purchased a set of Cometic .040" gaskets for my build.
However after speaking with Wiesco today about my pistons they said that they will come out of the top of the bore about .010" due to my 6.125" rod length. How much clearence should I have. Wiesco suggested using the factory .050" head gaskets.
I just hate to waste the good Cometic gaskets.
What is ya"ll's thoughts?

Sales4@Texas-Speed

iTrader: (4)

We typically like to see a .035" quench value at the least. If the pistons are coming out of the hole .010 you are definitely underneath that value. I would see if there is a way to get some .045 gaskets to be safe.

JPH

iTrader: (2)

How much does the deck height grow/change when the motor is warmed up to temp?

Bama99z

iTrader: (7)

John, Thanks for letting me know. Sounds as if I will need to order me some more head gaskets. Actually Aaron has quoted me my rotating assembly and I will be ordering it in the next few days.

Sales4@Texas-Speed

iTrader: (4)

I will be honest and say we have never measured this. I talked to some of the guys in the back and we think it would expand but we don't know how much. I wouldn't expect more then .002-.003 in that respect, but don't quote me for truth.

PREDATOR-Z

First I would wait till shortblock is built then measure piston /deck height. Then I would assess if quench is too tight.
quench = .040 - piston deck height
.030 is still acceptable with Wiseco pistons if flat tops with reliefs.

TT427

iTrader: (1)

All iron .002, all alum .012 as a general rule...

bww3588

iTrader: (49)

This does not really apply unless your just talking general expansion rates.

The iron block will expand less upwards than the pistons expanding the same direction and heads the latter. With an iron block, the quench area would tighten up more than an aluminum block.

RezinTexas

I'm running 0.036", measured the height with the assembled shortblock cold, as suggested above. If you're unsure of your exact deck height, I suggest measuring yourself. These tools can be had on Jegs for cheap.

Sales4@Texas-Speed

iTrader: (4)

.012 would be a pretty large amount to have the deck move up...

TT427

iTrader: (1)

That would be deck and head. This is not something to figure for on quench. That will stay the stay the same or increase, not decrease. Just thinking along the lines of cold/hot lash for a sft. The proper thing to do is get the right gasket after measuring.

JPH

iTrader: (2)

Ok. I always wondered myself. But ya, I agree with .002-.003 would probably be that much in change.