compression ratio with .10 over HGs

[cub124]

hey everyone I was wondering if anyone knows what the compression ratio would be with .10 over head gaskets.

I know there is a few calculators for this online but they want the bore x stroke

If anyone knows the bore & stroke in inches that would be great! Thanks

-Kory

 

[tanman_2006]

I think that takes you to ~20:1 from 22:1

 

[cub124]

right now the compression ratio is 21.5:1 I also found the bore and stroke in inches, I should be able to figure it out now, hopefully ha. Bore x Stroke: 3.98 × 3.80 in

 

[tanman_2006]

Most people add .10 thicker gaskets to lower to 20:1 it might be a bit lower/higher but in that area. Are you doing this to a turbo engine or NA?

 

[cub124]

its for my 6.2 currently running a gm-8 but after some mods I'll be running the Holset HE351VE.
hopefully inter cooled but maybe not right away

Sorry I haven't had time to make a garage and signature yet!

 

[cub124]

alright I guess there is a few other measurements I need: Head Gasket Bore Diameter, Compressed Head Gasket Thickness, and one I can measure myself..unless someone knows it? Combustion Chamber Volume In CCs
Thanks

 

[MOcummins-farmboy]

ive got some .01 hg to run my 6.2 that im in the process of swapping on a 6.5 turbo. the block has already been decked but these will hopefully help bring the ratio back down alittle

 

[buddy]

If the block has been decked then the +.01" HG would be getting you back to stock CR.

Here is a calculator I made for these engines. It also tells you wha the effective Combustion Chamber volume is which is the volume at TDC, between the piston and the head and the insdide of the precombustion chamber.

http://www.thetruckstop.us/forum/showthread.php?25585-Anatomy-of-EGTs&p=343021&viewfull=1#post343021

Plug in your bore and stroke and current CR. The reason yours will be a little more than a typical 6.5 is that the 6.5 had slightly lower CR and the later model 6.5s came with larger volume pre-combustion chambers.

Depending on your model of 6.2, the stroke would be 3.82 in 599 blocks, because they used the same block and crank and the 6.5.

 

[cub124]

Thanks Buddy this helped a lot!! and my bad everyone I had a typo .10 should be .010 sorry! but .010 HGs without a decked bock should put you at 20:1

 

[cub124]

actually getting more technical it will turn out to be 20.45:1 with .010 over HGs

 

[buddy]

actually getting more technical it will turn out to be 20.45:1 with .010 over HGs

True, somewhere in that ballpark. It all depends on the inital CR assumption being correct. If you installed diamond precups (larger mouths, larger internal volume) into the heads it would bring the CR down a little and provide more throttle response.