raise compression pros and cons

robbo1987*2.3*

Founding Member

Apr 22, 2002

445

0

17

varina, va

Dec 27, 2007

#1

• Dec 27, 2007

• #1

self explanatory, what are the pros and cons of raising the compression by shaving the head. How much should i have them take off if any at all?? MY buddy said he will do it for free and get all the factory cast markings or whatnot out of it.( polish??)
Need anything special to raise it or can i run the same setup that i have now but with the shaved head????

just curious because it is free to me

 

M

muskrat2.3

New Member

Jan 22, 2008

11

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0

Jan 24, 2008

#2

• Jan 24, 2008

• #2

The maximum you should take off is .150-inch, if the rocker rail to deck height is 3.800 inches. just make sure not to cut in to the intake bolt holes!!!!!

 

Red_LX

I’m not much help unless you’re looking for ****!

Founding Member

Nov 29, 1999

5,896

73

129

Morgantown, WV...where couches meet their doom

Jan 25, 2008

#3

• Jan 25, 2008

• #3

I hope this is on an n/a engine, not a turbo engine?

Probably the only real downside to shaving the head is that you kinda have to degree the cam and make new alignment marks, otherwise the cam timing will be wrong.

Oh, you also may have to run premium gas depending on how much you take off. Stock compression is 9:1.

 

Stinger

Founding Member

Jul 7, 2001

7,754

24

118

Basehor (Kansas City), KS

Jan 25, 2008

#4

• Jan 25, 2008

• #4

If you take off .150", you'll be running race fuel because your compression would be around 11:1.

You'll want to keep the compression in the mid-high 9's for pump fuel.

 

bhuff30

Founding Member

Dec 11, 2001

6,037

35

129

Olathe KS

Jan 30, 2008

#5

• Jan 30, 2008

• #5

You'll have to do the math for yourself. For every .007 you shave off, you remove 1cc from the combustion chamber.

I ran dish pistons and ended up shaving .090. I think it was around 10.5:1. I continued to run pump gas, 87 even, but the timing was probably backed off a bit. I don't remember well at the moment.

 

S

sahtt57

New Member

Feb 7, 2008

3

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0

Feb 7, 2008

#6

• Feb 7, 2008

• #6

robbo1987*2.3* said:

self explanatory, what are the pros and cons of raising the compression by shaving the head. How much should i have them take off if any at all?? MY buddy said he will do it for free and get all the factory cast markings or whatnot out of it.( polish??)
Need anything special to raise it or can i run the same setup that i have now but with the shaved head????

just curious because it is free to me

Click to expand...

Just be aware of the associated costs of the new tuning, and the fact it's going to be difficult to know exactly what compression you will end up having. There are also other ways to acheive a different compression ratio, each with different positives and negatives, such as different pistons, etc. Continue your research on the benefits and costs of higher compression on this auto forum search engine. You don't want any surprises in this game.