Looking for writeup to replace head gaskets on s4
 

Hi, I am looking for a writeup on how to replace the head gaskets on a 928 s4 - preferably with the engine in the car.
Thanks
Dawid

Dawid,

I have not come across a definitive procedure pictorial like Dwayne's Magnum Opus for the timing belt /water pump job. There are videos on Youtube and various threads.

The desire to change out the heads without removing the motor is understandable and possible with the S4 motor and its head bolt configuration however the additional "buggeration" factor should be considered not to mention the words of those who have plenty of experience of such who invariably recommend pulling the motor [I AM NOT ONE OF THEM!].

When transplanting my 90S4 motor into my current 928 I was heavily involved in pulling the motor, refurbing the motor and installing it and all I can say is that you would do well to consider pulling the motor. This would be an excellent opportunity to do other jobs [as I did] like changing out the crank seals, upgrading the sump gasket and all the other maintenance work possibilities this opportunity presents.

Your choice at the end of the day

I would like to pull the engine but have a space issue. I have also already done the sump gasket, engine mounts and steering rack earlier this year - from underneath - so am very familiar with the buggeration factors.

I won't pretend to look forward to this, but hopefully taking my time and with help from everyone here I'll get this done.

The factory workshop manuals. Volume 1 is all about the engine.
http://www.ligeti.com/928/
Åke

The main thing is that you should make an informed decision aware of the pro's and cons of what you are proposing to undertake. I am sure the chaps on this list will give you all the help and encouragement you need as and when problems arise as invariably they will and do.

I have a feeling that 20 years is an appropriate time interval for head removal. The heads on my current 90S4 motor came off 17 years ago and were in perfect condition. Now I wonder what state they are currently in. Whereas I understand what is happening to the cylinder heads corrosion wise I am still trying to fathom out why the problem triggers. The popular belief that it is caused by lack of coolant change is invariably incorrect but needless to say if standard coolants are allowed to exhaust the chemical corrosion package the damage could be immense but when one sees severe damage to the heads and gaskets in the unsupported sections of the gasket head interface and yet no corrosion whatsoever in the water jacket and the head passages that for sure tells one that the coolant was not the problem, rather what happened to the coolant.

My guess is that you will find some corrosion damage to both the head[s] and the gasket[s]. The problem is the gap between the head and the gasket - this is not sealed and coolant seeps in and stagnates, the chemical corrosion package exhausts over time due to no flow and then the glycol breaks down to form organic acids mixed with water. Once this happens the passive film of the alloy breaks down and strange things start to happen the end result being a pitting corrosion type of attack. This phenomena [crevice corrosion] is not well known. The acids formed attack both the head and the gasket. Eventually they can nibble away at the fibrous gasket layer surrounding the fire rings. Once the problem reaches the fire rings they become vulnerable to galvanic corrosion and eventually the fire ring seal fails after corrosion preferentially nibbles away laterally at the cylinder head leading to fire ring seal failure.

If your head gasket has failed chances are this is what has happened - let's see what transpires.

To directly answer your question, yes, you can remove the heads with the engine in an S4 - I've done it in the past with no problems.

It is A LOT of extra work to pull the engine if you don't have a reason to do so.

Finally, I am not aware of any writeup, but overall it's not that difficult, just a lot of work.

It FEELS, like the hard part, is removing and reinstalling the cam gears/timing..everything is is simply bolts and washers...would that be correct?

And not counting R&R'ing the heads, an intake refresh is more a PITA than a head swap.

I've got a bad back...and I know exactly where it came from...pulling heads on 924 engines.
And those things were easy and quick to do.
However, I did many, many, back in the days.

Yeah, it is definitely possible to pull the heads in an S4, with the engine in the car.
I won't pull (or ask my guys to pull) a set of heads with the engine installed, in an S4.
Way to much bending over, for too many hours.
Sure, the job will be done and you will have saved a few hours, but a bad back is forever....

And at this point in time, 50% of the time, the engine will have to be removed for additional work, anyway.

I'm in the midst of putting my '88 motor back together. Here is a couple of mistakes you can learn from.

-Note the head numbers so you can note down which side is which. It is stamped by the exhaust ports. I wrote which was which on the heads but my marks were removed when the heads were serviced. So I guessed and got them backwards. I thought it would be ok, but the caps that hold the cams in place are machined to match the heads, and on my motor the races on the unused caps on the rear are degraded from the decay of the rubber plugs. So I cannot just swap all the caps with the heads.

-Do NOT skip the step of chasing the threads in the block. I did because I could not find a thread chaser for a reasonable price and did know I could make one. As I was doing the angle torque thing I was watching the actual torque value, and one of these things was not like the other. The torque value shot up much higher than the others as I tried to get the last 90 degrees. I think the threads jammed with gunk.

For these two reasons I am pulling the heads again and tossing a brand new set of head gaskets!
Other than that:
-Sunset has the gaskets for $71, which is a pretty good price. But make sure they have them in stock, because it is slow getting them from Germany.

-Get a good triple square tool.

-ArnnWorx has the cam alignment templates. Used to be 928MS, but not sure they exist any more. AW is cheaper anyhow. And they have a triple square tool, though maybe not the best.

Thanks for the tips, Karl.
What size triple square tool does the cam hats use? I saw in another thread that Greg suggest Hazet drives for quality, so I'll get that as well.
Also, can you remove the heads with the headers attached, or do they need to come of first?
Apparently 928 Motorsport has new owners, and they still advertise and list the cam alignment tool. I'll check out AnnWorx as well.

I did my valve covers and intake less than 500 km ago. Do not look forward to removing and replacing them again, but at least now I have experience.
If that is the hardest part of the job, it actually make me feel a bit better:)

My 87 S4 had hex bolts for the cam hats, so you probably won't need the triple square tool.
I've sent you a pm.

Cheers,
Gary.

guys - what is a triple square tool? About to do this job. Need tips and info. TIA

Not so much.
More special tricks than a New Orleans Whore.

Although Porsche says that the head bolts can be re-used, I'm pretty sure that they were talking about engine repairs during the warranty period....
(Otherwise, it would be dumb for Porsche to have massive amounts of these bolts in inventory, which they do.)
It's common to see these head bolts suffering from Hydrogen Embrittlement, which translates into: "Don't stretch as much as they originally did".
If all the bolts are still gold in color, you are generally in good shape. (Extremely rare at this point in time.)
If the bolts have become dark/some of the bolts have become dark, you need a new set.