Arrrr! I have a broken head stud!

[smestas]

Recently my car has been showing some symptoms of a broken head stud. The first time I noticed anything was a few months ago when the car was leaking oil from the base of the cylinder head where it meets the case. Then it started to make a noise like the valves were pinging under load. I was hoping it just needed a valve job. From reading the BB I was afraid that that the noise was the heads clapping against something and a broken head stud as noted in other posts. So today I removed my lower right side valve cover and guess what rolled out? A picture is worth a thousand words.

I’m posting because I’m wondering what would be my options and least path of resistance to make a proper repair. I’m confident that I can do the job myself but I am on an extremely limited budget. So I’d like to ask what you guys think I should do to fix this and how to go about it. I have an excellent set of tools but none of the PORSCHE specific ones or anything to drop and stand a motor. How much am I in for dollars wise to do a proper repair?

I guess for starters I finally have to cave in and buy Wayne’s new book!

[brandett]

Simon,

I feel your pain, but if you are confident as you say, you can save lots of dollars doing the repair yourself.

Waynes books are a very good start and you will find step by step procedure to handle the task. You could go the easy way and only replace the broken stud along with the other Divilar studs. This will end up with some tools, a gasket set and new studs around $ 500 ( give or take some ). My cost is now approx $ 1000 as I went all the way and had one stud that i had to use EDM on...

So far the only special tool i bougth is the crow foot for the cam nut, but then i had a complete set of wrenches etc available.

Well, others will give you more info, good luck !

[avi8torny]

If it were me...pull the motor, disassmemble it down to the short block and plan on replacing all the studs on the exhaust side. If you can get this far with your repair, cracking the case and doing a rebuild of the bottom end is not that difficult at this stage. All the internals are probably fine, just have them cleaned and inspected. The real money is spent when you have to replace a crank, pistons, cylinders etc. If your parts are ok.....you're just talking seals, gaskets, hardware, some machine shop labor and your own time. Buying another used motor with an unknown history will probably cost you more in the end.

[Doug Zielke]

Simon,
Your situation replicates my own almost exactly.
You don't specify the mileage (and type) of the motor, but if the total is not too high, I would suggest you do a top-end rebuild.
That is what I did, and the motor is running superbly, without a doubt.

I can't begin to tell you how valuable Waynes new book will be for you. After studying it, you will find the confidence to D-I-Y. This will help you save some money, but you will also have more control over the work.

If you have specific questions I could help with, please e-mail, and I will do my best to give you some answers.

[Mike Kast]

Ok... this is what scares me about this board. I read limited budget and path of least resistance, and I'm hearing complete rebuild.
Does it make any sense to just change out one stud and keep driving? What is the cost of the minimum job to get the car back on the road opposed to a complete rebuild for someone who has never done either before? Time and money... even if it only got another 10 or 20,000 miles out of the car before he had to open it up again?

Does it make any sense to just change out one stud and keep driving?

I may be full of Bravo Sierra, and frequently am, but that's what I would do.

[Bob's Flat-Six]

Simon,
I had the studs done on my 80 SC and have felt the pain. The upside is a fairly bullet proof motor now that it's done.

But if bucks are tight, you could just keep driving it as you have been and maybe try tightning the good studs.
Or pull it down yourself and just do the minimum.

You might want to consider an engine swap down the road.

The 911 is so unique that it survives all it's faults and it has a few to be sure.
Cheers and good luck

[Joe Bob]

I had it done by a shop....3,000, but I also did a 964 cam upgrade and valve job as well as replacing all the studs.

[Doug Zielke]

Mark Wilson is certainly not full of BS when he suggests replacement of just 1 broken stud, but....
Your luck (or lack of it) may have another 1, 2, or more broken studs appear just as soon as you button up the motor. How many times do you want to drop the motor and reseal the top-end?

I did drive the 'Bomber a whole summer with 1 broken stud. Drove it quite hard as a matter of fact. I just retarded the ignition a few degrees to take some pressure off the cylinders. When I tore the motor down last winter, there was no additional damage as a result of my summer fun.

[Tyson Schmidt]

Well, I was going to tell you to dive right into it.

But after seeing that picture of your hand, I'm not sure you're experienced enough. You have all your original skin fer chrissakes!!!!!!

Well seriously, you know this is just the beginning. It'll start out as just one stud. Then the "while we're in there" disease will creep in and you'll have 964 cams, high compression pistons, ARP rod bolts, titanium spring retainers, etc, etc.

Nobody is immune. Just give in and budget yourself about 9 months and about 4 grand and that way you won't be disappointed. Buy Wayne's book and have fun!

[jason2guy]

i had the exact same stud break. a shop tore the engine down to that stud replaced just that stud, and that was 10K ago, no problems since.
so that is an option, but there is no telling if others will break soon after.
its sort of a gamble. if you have a garage where you can properly work on the engine, id say do it yourself.

[Wayne 962]

The fact of the matter is that these cars (and engines) are very expensive to work on and repair. In general, the words of advice I typically give are "do it right, or don't do it at all."

That said, broken head studs typically require a full rebuild. Why? There is usually at least one stud that you need to replace that will snap and not come out of the case. This will require you to drill or have it removed via EDM. Once you do this, the process will deposity tons of little metalic bits into the rest of your engine. Hence, the entire bottom needs to come apart.

If, and that's a big if, you're lucky, then you might be able to tear down the engine, remove all the studs, and reseal the top end. Not doing a valve job and not replacing gaskets on the top end would be very foolhardy. I recommend that the bottom end be refurbished, the case be cleaned, and the bearings replaced. Your pistons and cylinders may be worn out as well, or even worse, your head may be damaged beyond repair from the cylinder slapping against the head (was the case with my engine, and I only drove it 100 miles after hearing the noise).

So, can you do this repair inexpensively? Not if you're going to do the job right...

-Wayne

[Mike Kast]

I think I'd change one stud and acknowledge the fact I'm living on borrowed time. That way you can plan what to do next or if you want to keep the motor at all like Bob suggested. Changing everything because of a broken stud now when your not in the position too? Why not have changed everything before the stud broke? The logic being the studs could break at any time... Were all on borrowed time anyway aren't we?

[Mike Kast]

or... what Wayne said...lol... I haven't writen any books yet

[Early_S_Man]

The minimalist approach would require 12 new steel head studs for the bottom [exhaust] rows ...

911.101.172.00 STUD Available $10.87 ... total for 12 ea -- $130.44

And ... a top-end gasket set, Loctite 272 for the head studs, Loctite 518 to seal cam housing to heads, and a few specialized tools ...

Many people have related stories of how it was OK to continue to drive a car with one or more broken head studs ... but, I have always recommended against it! You would be risking further damage to the head/cylinder mating surface!!!

If a budget repair is the only way at the present time ... I strongly recommend parking the car until the minimalist repair can be done ... and then start saving for a complete rebuild down the road ...

[john walker's workshop]

what S man said! just doing the one would be dumb.

[stormcrow]

When I did my rebuild on my 78 SC Targa, I had four studs broken. I didn't even know it at the time until I did the rebuild. I would look at replacing the studs as a minimum if you don't want to tear the engine down. If you don't, you will mostlikely have more serious problems later that could run into bug bucks.

Steve

"A Porsche does more then just go fast in a straight line"

[Jadams1]

I had two broken dilivar head studs on mine. I replaced all 12 lower dilivar studs with steel ones, and put everything back together. Reused the rings, no machine work, new gaskets, cost around $300. When my engine needs to be rebuilt, I'll do a complete rebuild then. My engine had 107,000 miles on it when I did it in May of 2002. Everone says the 3.0L is the most bullet proof engine and can go over 200,000 miles. Well, that's what I plan on doing with mine. I met another Pelican BBS member at Hershey and he did the same thing. So it can be done for a minimal cost if your engine is in otherwise good shape.

[agabriel]

what about another used 3.0 or 3.2 engine?

That would be less than a rebuild - wouldn't it? Granted you don't know as much about it. If all the studs look good, it runs and you can get it cheap, you can sell your existing case to defer the cost. Is this reasonable?

Anthony

[kstylianos]

I wouldnt take the chance on a 3.0 swap unless you know that this new engine has had its head studs replaced.......you'd be right where you started.

I know this is not what what you want to hear, but I pulled my engine to fix some minor oil leaks, replace the clutch and add SSI's. Since the engine was out I found out I had the dilivar studs and a broken valve spring. I tore into the engine to replace all 12 head studs and had the heads redone, P/C's, rods and rockers checked for spec. When the engine comes back together, I KNOW it will be trouble free for the next 150K miles. If your engine has relatively low miles and looks good otherwise, I'd pull the top end, replace the studs (all 12) and at least get the P/C's and the heads inspected (cheap insurence) while they are out. Its hard to get this deep into a project and not get bitten by 'while you in theres', but at least get the top end components looked at. If I didn't I'd still be running w/ a broken intake valve spring and time bomb head studs....could have been looking at a much more expensive rebuild in the near future. Better to spend a little now and be safe than sorry later.

Of course, this pertains only if you decide to dive in and replace the studs. Many have run with a broken head stud for many miles and have not had any problems and addressed the issue when the time came for a rebuild. Just make sure the other studs are torqued to spec.