[GeeTeeOh!]

Hi guys

How much can be removed from a 243 head before you run into probs with pushrods and valve to piston clearance?

I am planning to remove 1mm from my head. Is that too much?

Also, does anyone know of a shop that will be able to do that for me, pref in the Chicago area?


Regards

Rian
05M6

 

[juice12ufo]

Have you done DCR calcs? What are you basing the 1mm off of? Do you know what CR that will produce?

 

[ddawson]

Head milling usually goes from .010, .020 and .030 of an inch.

There is information on LS1tech that will give you the CR after a mill.

Or call Bob at Precision Motorsports and see what he thinks. He is a sponsor on the left.

http://www.ls1tech.com/forums/showpost.php?p=1740922&postcount=41

 

[GeeTeeOh!]

Thanks guys for the input.

1mm was really a guess.....i wanted higher compression, but did not really know where to start. I think a 0.02" milling job will do it.

Another option may be a thinner head gasket? I have heard some pros and cons about them...

Rian

 

[[email protected]]

Hey guys,

The most you really should go on stock ls heads is .025". You can calculate that for every .007 removed, you drop 1 CC on the heads. That means that you can drop almost 3 CC's to help bump compression. Those figures are based on what we call flat decking (or flat milling) which most shops do, it basically removes material across the entire deck evenly.

The other option is angle milling, which we use so long as the cam duration does not exceed 236 @ .050". This method allows us much bigger drops in CC's. For example, we take the 70 CC heads (317's from 6.0L trucks) and angle mill them, and can make them as small as 58CC's, depending on cam size.

It's best to decide your goals up front, and design the engine setup properly to get there. Gasket size is also a factor, but as long as you do the math up front, there should be no surprises.

Bob
727-233-1195