adrian_jaye

Can anyone confirm when you need to "skim the heads" (on any car not specifically P's)

scenarions

1> over heating
2> replacing head gasket
3> general work - maintenance
4> major overhaul work

if possible reasons why or why not

I'm sure I heard someone say that you need to generally

ta

adrian_jaye

bump
anyone ?

HughA44s

OK - I'll bite on this one. I had a 944 that was leaking compression into the coolant system and the coolant was shooting (burping) out the overflow tube. I had the head re-worked and skimmed and installed a new head gasket - no joy, still had the problem. I finally fixed it when I had the block and the head skimmed. On these cars, I think you need to have both done if possible.

xsboost90

i believe i had to have the oil pump housing mounted before they could skim the block so that it matched up correctly. Usually it is to correct warped heads or blocks. If you have the motor out rebuilding it i would do it, or if you head is warped. If not, i wouldnt do it just for no reason.

GlenL

If this is what's called "surfacing" around here and involves taking off as little material as possible (~0.002) then

1,3 and 4

I'll do it whenever the head is off the car. Makes the head perfectly flat and gives a perfectly clean surface. These both reduce the likelihood of having a head gasket leak.

sharky47

How many thousanths of an inch can you remove from a "new" head before it is considered unserviceable?

Jakerx

Sharkster, I think it's like 12 thousandths of an inch or something. My memory is fuzzy from back when I had it done.

spazegun2213

you can also compensate with a thicker or thinner head gasget. I built a 4.6L stroker from a jeep motor and had the head shaved almost a thousandth. I simply found a gasket that corrected for it and poof you have the compression ratio you want