Quench/Squish.. what are you running?

[grimreaper]

Last bit of the build. It seems most have posted .8-1mm on the 7m. guys with 2jz's say 1.5mm is optimal for them. Who has played with it and how did it re act?

anyone know stock?

anyone know "optimal" ?

 

[NashMan]

you really don't wana run a thick head gasket on the 7m stock spec is pretty much the best you will ever get


i still wounder were the 1.5j's and that stuff = too

 

[grimreaper]

^ somewhat why i was asking, The shop is fly cutting the tops of the pistons to get the deck height all the same and to cut down on the size of the gasket being used. I cant remember what they said stock squish was though.

Ya I'm very curious to know where the na-t guys fall as well.. Not to mention a lot seem to missmatch the 2jzgte pistons with ge head etc..

 

[Nick M]

IJ probably has that stuffed in his noggin someplace...

 

[grimreaper]

We'll I'm looking at about .048" or 1.2mm of quench with a static compression ratio of 8.7:1 or right around there (dont have my notes in front of me). This is with a 1.6mm HG. Shop said stock is in the .045-.050" range. Any body have any input as to how helpful say .040" of quench would be compared to .048"?

 

[Nick M]

I don't think having it a little tighter is going to help. Especially since I know you are going well above factory boost levels. You should have more than adequate effect at the stock levels.

 

[87M-GTE]

Read this
http://www.supramania.com/forums/showthread.php?97552-Head-Gasket-thickness-selection

Sam

 

[grimreaper]

decent read but the normal to much quench is bad, to little is bad etc..no details.
My head and pistons have all been cc'ed and piston potrusion is known and accurate. No point in adding this and subtracting that when you have accurate measurements. I'd expect a lot guys to go this route after getting a head rebuilt/decked. My head is still at 40cc in each chamber. pistons are 15.75-15.85 cc. I have had mine decked twice by me and once by the previous owner. Also had a full valve job a few years back. Any time the heads getting worked on your changing the combustion chamber size and shape. My head is a good example of why adding what you removed doesnt always work out.

I would think more people would pay to get accurate measurments. You can always do it yourself as well but keep in mind GIGO. I chose to pay a bit more since I'm not into "trial mode" on this motor.

---------- Post added at 08:58 PM ---------- Previous post was at 08:50 PM ----------

I don't think having it a little tighter is going to help. Especially since I know you are going well above factory boost levels. You should have more than adequate effect at the stock levels.

good point, the machinest wanted more then .040" for a buffer given the cars intended use. A new to me issue of tolerance stack was another reason.