Dealing with stuck cylinder head and exhaust nuts
 

Hello,

I am in the process of taking the engine apart on my 930 Turbo and thought that my experience of removing the cylinder head nuts might be useful to other people.

I soaked the nuts in WD40 first and used a good quality 10mm hex insert in a socket with a large handle and mostly this worked fine, except for two very stubburn nuts that simply would not move.

I tried tapping them on the top with a hammer (carefully) I tried heating them up and they still would not move.

Eventually the inside of the fastener got rounded off with my trying (this was an unhappy situation for me).

I tried to drill out the stud but found the metal was so hard that it was almost impossible to make any progress.

Eventually I did the following: -

I used a hacksaw blade to cut the top off the nut just above the washer. After about 45 minutes sawing this left me with a flat surface.

Then I carefully drilled two 5mm holes in the outside of the nut. I was then able to use a cold chisel to easily break the nut and hence I could remove the cylinder head.

This technique worked fine on two very stubburn nuts and I did not damage the cylinder heads at all. I plan to renew the studs in any case.

I had a similar issue with the exhaust studs, 6 came off with some WD40 and careful spanner work, 3 I used a nut splitter on and the last three 8mm allen nuts were corroded and rounded off before I even started. These three nuts were totally unaccessable so I opted to drill them off. The studs were hard but this technique worked fine and it has left me with enough stud left sticking out to remove then with some careful heating of the cyclinder head.

I hope this information is useful, if anybody has any other good tips for this type of problem then I would be pleased to hear them.

Best regards

Steve in the sunny UK!

Steve,
Greetings from dry, hot New Mexico.
I'll bet just cutting off the nuts with a hacksaw blade was a trying adventure. Not much room in there.
A dremel tool and 20 cutting disc's later, same result.
I wonder how to best protect against this happening again.
Anti-sieze compound on the threads?

Thanks for the post,

HI Try P119 for the head nuts (never had one not come undone, some have been very tight, with a large breaker bar to remove) and the gassaxe on the exhaust nuts, a good Allen key/sockets for the removal of the exhaust.
Reassemble with never-seez made by bostik in the USA for head and exhaust nuts

regards mike

Thanks for the posts and yes it is still nice and sunny here in the UK :-)

My exhaust nuts were very tight, I had a breaker bar almost 1 meter long and they still would not move. What is P119? Is this a special Porsche tool?

Regards
Steve

WD40 is nearly useless on rusty nuts. There are much better liquids out there for this task. Sounds like Mike's "P119" is one of them.
-Chris

Hello, Steve.

I'm sorry to hear you had so much trouble with these.

I can recall having some veery tight head nuts, but obviously never the trouble you had.

It is not unusual for the whole stud to come out with the nut still attached eitherIf the nuts rounded iside ..this suggests they were previously damaged..this has never happened to me.

I do use a soaking with plus gas or a special industrial goop I was given ..but mostly its just steady turning with a 2 foot bar..

Exhaust s are a whole'nother story...gas axe is often the most cost-effective..then weld a nut onto the stud and heat the head 'till the fins just start to melt, bathe with paraffin wax, reheat etc..

I reckon to get 10 out 0f every 12 out,,...drill the other two..

Kind regards
David

HI P119 is the cylinder head nut tool to remove the nuts, i have striped quite a lot of engines with the 2(since 1982 and still going strong) i have and unless the head nut is on to far( wrong washers, studs wrong length, heads/cylinders refaced) there is not a prob removing the head nuts.

regards mike

Hah!

What Mike is too modest to say is he has probably stripped more 91 motors than anyone in the uk..

Kind regards
David

I too had a hard time until I let them soak with PB blaster, available at our local auto parts stores. I repeatidly soaked them once per day for 5 days and they came off easy.

Good luck,

Alex

I thought some of you might find this interesting. There are sockets and spanners called "Metrinch". They are a clever design in that they put force only on the flats of the nut and not the corners. I am told that these tools are popular with people who do classic car restorations. The web link is:

http://www.metrinch.com

Sometimes these sockets and spanners can be found on EBay. It's a shame I found out about these after I had battled so hard to remove the exhaust nuts. Anyway I hadn't heard of them before so maybe this information will be of some use to some of you...

Best regards

Steve in the (still) sunny UK!