4drgl

Hmmm, now that's interesting!! Now this gets the wheels turning!

If I shaved the heads a bit... how much hp would I yield? How much shaving needs to be done?? I do have access to a local machine shop!

I know there's lots of variables here... but 220 hp is modest! Any help I can give her while I'm in there that doesn't add a huge fortune to my bill I'm game for!

Mrmerlin

well take off the minimum amount to make the heads flat
Note the more you take off the heads the more you change the water bridge angles at some point you will then be machining this part to fit the heads
See the WSM for exact machining info as there are limits for cutting the heads.
Also make sure to have a valve job done with new valve seals, no need to have leaky valve going back into your fresh rebuild.
Block drains are under where the #3/ #7 exhaust ports would be on the block its a 13mm head with a sealing ring under the head

Tom928

Not trying to hyjack the thread, but what headgaskets to use?
I am going to have to replace the head gaskets on my 81.
I hear that there are no improvements to the original Porsche gaskets. Do we still use them?
I noticed that Carl (928 motiorsports) has a improved set for all years.
Has anyone tried these?

Cheers,

Mrmerlin

you should be good to go with the Elring gaskets that come in the rebuild kit.
IIRC the gaskets Carl made are suggested for boosted engines,
but the Elring gaskets will work for a normal rebuild

hacker-pschorr

+1

The stock gaskets are holding up just fine in my supercharged 81 with 17psi of boost.

My next enigne will have an MLS / Cometic gasket. When I did my head job that wasn't an option. For a stock engine, stock gaskets are perfect.

goodspeed928

Change your coolent!

tveltman

Any reason not to go with MLS just in case it becomes a boosted engine in the future?

GregBBRD

Always new.

4drgl

I have considered boosting it... However will not have that kind of funding for several years... so elring is good enough for me. Lasted 30 years... with new gaskets it'll be good for 5-10 more.

I'm just looking for oem goodness and some add ons... maybe an extra hp or two!! Nothin crazy for a while... Got too many projects in the hopper. Just want it to be in good repair and running excellent!

I will replace the stud nuts tho!

blown 87

Yes, it is a gamble on if they will leak, or just seep or be dry.

I would go with the stock gaskets if I had no plans of supercharging at a high boost level.

GlenL

I suggest this as well. Bumping the CR is "free" hp until you need to get racing gas to have peace-of-mind. Like 10 hp going from 10 to 11. Not worth the hassle.

BC

Crap.

chewy8000

Just an FYI don't be surprised if your headgasket leaks after all this. Mine did... and I followed everything by the book with extra precaution.

I'm not sure what happened but my heads were freshly rebuilt and machined perfectly by a well respected machinest who has done a bunch of 928's. I had to do the whole headgasket thing twice and it's fine now with some aviation permatex. I'm thinking the block might be warped. I'll wait til it blows up under boost and start my euro 5.0L conversion.

hacker-pschorr

How long ago did you do the intstall of those gaskets? There was a bad batch some time ago.

chewy8000

3 or 4 years ago?