Back in the old days guys used to shave the head on their engine to increase the compression ratio. Does anyone know of any shops that still do this? How do you calculate the increase in compression ratio based on the amount ground off? It would be the same formula used when installing a thicker head gasket to decrease to CR.

The reason I'm asking is that I might very soon have access to a bargain on a vk45. This is the 4.5 litre V-8 from Infiniti. It has only been around a couple of years, and I haven't been able to find any aftermarket performance parts for it.

Any other suggestions?

 

That's just shaving/milling the head; you can also deck the block for the same effect.

The best way to change compression is to use high compression pistons, b/c when you mill the head, there's no going back.

Any good machine shop will be able to mill your head for you. You calculate the compression just like you would w/ a thicker head gasket; take how much was shaved, figure how much displacement from each cylinder that will take away, and go from there.

 

milling the head affects cam timing too since the head is closer to the crank and the timing belt has a shorter distance to travel...you can also use a thinner head gasket though...

 

If you use a reasonable amount of milling, it won't affect things much. A set of adjustable cam gears, if there are any for that motor, can fix that easily.

Just don't go over the factory specs for milling.