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iTrader: (1)

Yea , no im confused because i have 66cc heads and 6cc valve reliefs and my compression was to high for 93 @ 26 degrees of timing .

02*C5

iTrader: (1)

If you are going to use an online calculator use this one. http://golenengineservice.com/calc/calccr.htm. I did a little searching and this calculator has everything you need to make sure it gives correct information. Let me know how it works out for you.

Beau@SDPC

iTrader: (14)

there is one piece left out from alot of the CR calculators if you want a very true reading. that one does not use deck height, rod length, compression height, or height from top of piston to first ring land. all of those things will factor in as well.

this one is a little more inclusive, plus gives good info on piston speed and how elevation and boost will effect CR. http://www.zealautowerks.com/

Isolde

iTrader: (4)

This is horrifying, stating a given static compression as being okay or not, without specifying your elevation above sea level. It makes a huge difference. When I moved up here from Florida, I was able to add more than a full ratio of static compression, and even so switch from premium unleaded to regular unleaded. The thing that remains constant is that 200 psi cranking compression is fairly safe on 91 octane. But for a given engine and a given cam, you'll need more static compression the higher you go to get 200 psi.

Beau@SDPC

iTrader: (14)

My V6 engine was 190 psi all stock.....i would not try to confuse CR with cranking compression.

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iTrader: (1)

Thats why i ask the op for cam specs , because untill you have them , your pissin in the wind .

The bigger duration the cam is , the higher you can run static compression , the smaller duration the cam is the higher the dynamic is going to be which means you will have to drop static.

NemeSS

iTrader: (127)

i run 11.3:1 n 91 octane. higher scr allows for longer duration cams on pump gas. although i could have gone as high as 11.6:1 with current cam. but would have required to mill more than .030 from head. too much for oe heads

Chrome355z

iTrader: (1)

People run 200hp shots all the time on pump gas. It's all in the tune. Running higher octane is not that much different then pulling timing. Higher octane basically burns slower which in effect is the same as pulling timing. (generalization)

02*C5

iTrader: (1)

Its true what you have stated but then you are pulling timing and adding timing and after a while it gets old IMO.

MBC Racing

iTrader: (3)

Gives me the exact same number....12.0749
Now, if i put in +.01, I get 11.4 But since the piston is above the deck, it says to put in (-)

Looks like I am back in the 12:1 range......

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iTrader: (1)

Run a big *** cam and you will be fine ,, hehe

A 248/252 or so will drop your dynamic to tolerable levels.

MBC Racing

iTrader: (3)

No valve reliefs won't like that duration much........

MBC Racing

iTrader: (3)

If I use a stock MLS 6.0L gasket, it looks like I will be back in the 11.7 range.
That is if the thickness is .055.

Can someone please explain the quench stuff to me? I read about .o35, but why does GM use .055 and .058 gaskets stock on LS1's?

Thanks!

Isolde

iTrader: (4)

I'm pretty sure I know this one. In the early '80s, GM was building a lot of iron-headed SBCs with the pistons about 0.025" in the hole, and steel-shim head gaskets about 0.020" thick. But they were working on giving the Corvette aluminum heads. Steelshims didn't work, and MLS wasn't even an option. By the time they made a composite work the way they liked, it was 0.051" thick. Great, now they had a proven thing that would survive. It survived the warranty period, but it also survived into the days of our LSx.
GM realized that 0.076" quench was too much, yet they were stuck with 0.051" thick head gaskets, so they designed the LS to have the pistons out of the cylinders about 0.008" . And that gives 0.043", which is safe but not excessive.

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iTrader: (1)

The duration will be fine but you will need like a .575/.578 lift

PREDATOR-Z

My MLS 6.0 is .052 crushed.
Quench= Crushed gasket thickness - piston deck height
If your pistons are .010 out of hole, then with MLS 6.0 GM, your quench would be .042 (which is good)

And .050 lifts have almost nothing to do with PTV. Max lift occurs at or near BDC while contact with valve is at or near TDC (usualy 10* BTDC to 10* ATDC) <= Danger zone.

MBC Racing

iTrader: (3)

I understand what quench is, just not finding out what exactly is the best number.... does it differ between lsx iron and alum blocks as far as what works better do to how heat affects things?

If my old 236/236 .550 cam is not bent, I am going to try to use it to determine piston to valve clearance. If you guys were guessing or know.... what is the biggest you think would work?

How about any of the sponsors that sell cams and gaskets and stuff..... what do you sell that will work form my application???
thanks

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iTrader: (1)

I would put that .550 lift cam in , clay a piston and set one of the heads on the motor and roll it over by hand so that you know for sure exactly what your dealing with .

Any thing less and you wont know Exactly what your numbers are .

Beaflag VonRathburg

iTrader: (176)

Reread post 36 by PREDATOR-Z.

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iTrader: (1)

I said Exactly .