7:1 > 8:1

[siii8873]

I am having some work done on my 7:1 head at a motor shop. I'm thinking of having it shaved to 8:1 at same time. What amount would need to be shaved off to make this conversion. Is there a head overall thickness to shoot for? Any info would help.
thanks
Bob

[albersj51]

I think .00001" is what you need to remove. This thread should have all you need.

http://siteground237.com/~gunsandr/showthread.php?450-shav-n-me-head&highlight=Head

Jason

[jac04]

I think .00001" is what you need to remove.
I think you may have three too many zeros in there.

[albersj51]

I think you may have three too many zeros in there.

Youre right, I just pulled it from that post. Its a thousandths of an inch, .001", IIRC

[Apis Mellifera]

One hundred thousandths of an inch (0.100)...nearly 1/8th of an inch.

[albersj51]

Thank God I'm not an engineer or we'd all be screwed. :)

[Walker]

Uuuummmhhhhh. 0.100 is one tenth not one one hundredth or one one thousandth. 1/10. I am a retired algebra teacher and I would have failed any student that gave me that kind of answer (sorry Apis).

Art

[Apis Mellifera]

Obviously you aren't familiar with how these sorts of things are measured by machinists. Re-bores and surfacing (using the kings measure) are measured by thousandths (of an inch); just as drills are typically by 64ths. "Boring 20 over" , for example, is 20 thousandths. I may have failed your algebra test, but the machine shop will know exactly what to do if he asks them to take 100 off that head. Conversely, he could ask them to remove X if 2(a+b)=X and a=0.02 and b=0.03.

I didn't set the industry standard; I just follow it.

[mongoswede]

I am having some work done on my 7:1 head at a motor shop. I'm thinking of having it shaved to 8:1 at same time. What amount would need to be shaved off to make this conversion. Is there a head overall thickness to shoot for? Any info would help.
thanks
Bob

keep in mind that you will need different length push rods to go with your shaved head.

[LR Max]

keep in mind that you will need different length push rods to go with your shaved head.

I disagree. I've had my cylinder head shaved twice (shaved such that I've had to remove a touch of material from the water pump housing because the cyl head was touching it!) and I still run the stock push rods. No problems.

Only thing is make sure you've got the valves adjusted properly. Or if you are like me and can't adjust a valve to save your life, find someone who can and take it to them :thumb-up:. Otherwise it'll all be for nothing!

[TeriAnn]

If anyone is interested I have a FAQ web page covering this subject.

http://www.expeditionlandrover.info/landRoverFAQ/FAQ_head.htm (http://www.expeditionlandrover.info/landRoverFAQ/FAQ_head.htm)