i nead to no what the compression shoud be on a 95 12 VALVE

 

16 -17:1

 

I think 16:1

 

pretty sure all 12v's are 17.5:1

 

thats why i gave it some room to be wrong.

 

Compression ratio is 17.5:1 on our engines. Compression check at cranking rpms should be around 350 psi.

 

It's alot. That's why when you turn off the key, they come to a screeching halt so quick.

 

i always wondered is that with full boost or with out boost???

 

I'm curious how much more compression non i/c had over i/c blocks

 

From the B series Operation and Maintenance manual the 6B is 18.5:1, the 6BT is 17.5:1, and the 6BTA is 16.5:1

 

Heh and my truck comes out low in compression. Even with a freshening.

 

Compression ratio is a function of total volume vs. swept volume, it does not change based on boost. Cylinder pressure on the other hand is affected by everything including the weather and what color underwear you are wearing.

 

i raised my compression a couple points at most with a .006" milling of the head and a standard gasket. starts just as fast as it did prior. i might be off topic slighty, but it's related to compression i guess

 

it wouldnt raise a couple points from .006 milled off. see's how theres only the little volume from the valve area your shrinkin you would be LUCKY if it raised .01 of a point.

 

If anything, raising compression will aid in cold starting behavior. Ever notice how pulling trucks and tractors start on gobs and gobs of ether? It's cause they're running gasser compression ratios. By nature, a compression-ignition engine needs 'compression' to start and run. The higher the better, to a point, of course, as far as starting and running is concerned.