Matching head volumes

[ChrisBennet]

Hi everyone,
If I want to make my 911 heads CC the same how/where should I remove material?
TIA,
Chris
P.S. I accidently posted this to the 911 list instead of the engine list. Sorry Wayne.

[kstylianos]

Chris,

How different are the volumes from one head to another? Is this going to be a blueprinted race engine where you want the CR's for all C's as close as possible?

This is just some ideas to get the juices flowing. I'm thinking possibly fly cut the base and the inner sealing surface to get your desired CC's.....funky math involved to determine amount of material to remove due to the head profile, or trial and error. This will also reduce your piston dome to head clearance.

If the heads have already been fly cut and the piston dome to head clearances are pretty much consistent from cylinder to cylinder, maybe recessing the valves a little bit to increase the CC's? Don't think removing material from the domed head surface will be an easy task as you'd probably want to disturb its profile, unless you can take an equal amount off from the whole concave surface.


I'm not offering advice, just throwing out some ideas........Hopefully others will chime in on the pro/cons.

[Type961]

Hi,
A way I work is to change volume of chambers which have the lowest CC by grinding around the spark. This helps combustion propagation.
Don't touch the piston dome or any profile, this should decrease squish effect...

regards,
Luc

[ChrisBennet]

Thanks Luc!