Porsche 928S 1981 (head gasket problems)
 

Hello,

A few months ago I bought my first 928. I joined the forum because I certainly will need some help/advice at some point. I have some technical background but I quickly noticed that the 928 can be complex. Before I have entirely restored a 1973 Ford Capri (know as a Mercury Capri in the States) but compared to a 928 this car was as simple as can be.

Now a small introduction about my 928. I bought it from a 75 year old man.
The last 6 years car almost didn't drove except 50m in his garden 2 times a year. The car came with almost no history except the stories from the old man. 10 years ago he changes many parts (radiator, bearings and syncros of manual gearbox, hydraulic valve lifters, all gaskets from the engine, wheel and axle bearings,...) I drove the car for 10 minutes and it drove and braked straight, no strange noises,... So I decided to believe him since the car was good enough (body, paint, interiour, no rust) for the price he asked.

After bringing the car home on a trailer I started the 928 in my garage and it smoked heavy from the exhaust, my first thought was condens in the exhaust but I noticed that the cooling water level droped.

So I decided to change the head gaskter together with the belt, timing belt, water pump and rollers. I'll post some pictures from the progression I make.

Rob Edwards was kind enough to do a Vin check and this was the result:

1981
C00- German market
G00000 - 5-speed

M058- Impact absorbers front and rear
I115 Cassette radio Blaupunkt Bamberg QTS Super Arimat 7639545 up to MY1981
M220 Locking differential 40%
M474- Sport shock absorbers
M494- Additional amp
M568- Tinted windshield and side glass

After reading some horror stories on this forum about removing the heads with the engine in the car, I decided to be stubborn and try to do it anyway :-D I'm halfway and I must say it is much work but doable.
Maybe because the previous owner changed the gaskets only 10 years ago
https://cimg2.ibsrv.net/gimg/rennlis...acd2a57cbf.jpg

Well it could be valve seals after all that time oh and welcome.There not so bad just take your time ask what you need to and enjoy. Ray

https://cimg6.ibsrv.net/gimg/rennlis...e68d29b052.jpg

Piston 6 looked "washed" so the problem must be there, No?

https://cimg7.ibsrv.net/gimg/rennlis...3faedc4a1b.jpg

The surfaces looked already pretty good without doing any cleaning

https://cimg9.ibsrv.net/gimg/rennlis...a05235d6d5.jpg

Should I have the heads checked or not? What is your opinion?

Yep sure could,you seem to be doing very well,I use cometic head gaskets but they are pricy and others here use ?rinze wrong spelling but maybe others will chime in soon. there are some real experts here so give i'm a bit. Ray

http://www.rosepassion.com/en/cat/po...f-seals/P21077

I was planning to buy this complete set. Hard to tell which brand they are.

Just went thru this myself. I opted to spend 500 to have the heads done and surfaced. My machinist told me they actually didn't need it but we didn't know that till afterward. Piece of mind, especially with the unknowns on this.

clean the block surfaces, then get a straight edge and check the deck height.

the heads may be able to be serviced with a piece of glass and some sand paper glued to it.
if the heads were already cut then this should be considered so the heads dont get too small.

Always hard to tell without looking at things first hand, but I see an area on the head gasket which coincides with an area on the head, that looks like a probable leak location past the fire ring.

Surfaces look quite good, and gasket looks way fresher than most, but I wonder if the block and head were checked for flatness, and surfacing done before installation ... maybe not.

Heads and block should be confirmed to be flat, before reassembly with new gaskets.

Ok thanks for the experienced look on the situation.
I'll take them to a machine shop to have them at least checked.

For a moment I was hesitating to take of the other head since I already found the problem.
But to be sure and to do the job good I'm going to change both head gaskets.

I already bought the auxilary belts, timing belt, rollers, water pump.
I'm planning to buy a complete gasket set and the 20 head studs.

Anything else I should consider changing?

spark plugs, air filter, fuel filter and injectors ( to the cheaper shorter mercedes ones) are already changed.

Yesterday evening I managed to take the other head off without any problem and there is nothing out of the ordinary visible.

This Evening I tried to screw the headstuds out of the block after having spayed enough penetration oil.
But the 2 nut method doens't work and I'm afraid to bend or break the stud.
Any tips? How have you guys done it before?
Maybe with a vice-grip closer to the bottom so there is less leverage to bend/break the stud?

Thanks in advance!