1983 911SC with Broken Head Studs
 

I am a new member to the Porsche Family. And soon to be one that is sleeping on the sofa.

I purchased a 1983 911sc in December, 2005. The car has a pretty good service record and had 130,000 miles. Prior to the purchase, I checked around and found a Porsche mechanic that came under good reference from several friends and I am happy with them. I had a pretty thorough PPI performed on the car, which checked out well, with the exception of an oil leak at the base gasket of the #6 cylinder. The mechanic suggested that I have the seller correct the problem prior to purchase or reduce the sale price of the car. The seller paid my mechanic to correct the problem. From what I understand this involved removal of the cylinders and heads on the #6 side and replacement of the gasket, and rebolt and torqing of the cylinders and heads on this side (forgive me, I'm not much of a mechanic). The seller paid $4,000 for this work along with some other items identified in the PPI.

I asked the mechanic about the condition of the head studs (thanks to previous postings on this web site). In addition to torqing the studs on the #6 side of the engine, he checked torque on each of the head studs on the other bank of 3. Everything seemed fine.....until today. I took the car into the mechanic with a new popping/clapping sound from the exhaust. Interestingly the sounds was only noticeable in 2nd gear. He inspected the car and discovered 3 broken head studs (2 on the one side of the engine and 1 on the other). It has only been 3-1/2 months since the PPI and purchase and I have only put 1,200 miles on the car. Prior to purchase, I had always known that this issue could be a problem and rear its head at some time in the future. 3-1/2 months is not what I expected. Also, I should note that I really haven't pushed the car very hard, typically shifting at 4500 rpm. I was just surprised?? Is this how this problem typically occurs? When I have the work done, should I have all of the studs replaced? Dilavar? Steel? Is this a once in a 60,000 mile issue?

Any advice would be most appreciated.
Rick:(

Well if you use the new dilavars you'll see them last longer than 60k, they are much improved over the older design (been redesigned quite a few times). However the general consensuse on this board is replacing them with steel, or going to aftermarket (arp ,supertec ,raceware). I got a killer deal on a new set of dilavar on my rebuild so i took it. 100k miles is a long time for someone who like to tinker (chances are i'll crack open the engine before it breaks for some stupid reason or another). In your case i think it's more of a personal call. Steel is cheap and doesn't break, but also doesn't have the thermal expansion properties of aluminum. As i said, your call.

"The seller paid $4,000 for this work along with some other items identified in the PPI."

I hope for that much money the transmission was rebuilt as part of the deal!

There's a way to replace base gaskets and studs without separating the heads and the cam towers; from the bill it appears this mechanic doesn't use that approach.

Steel or Dilavar will work. If it were my SC I'd go with the new Dilavar but there are people who refuse to use it.

I don't know if you have any recourse but it seems unlikely that 3 studs would break in such a short time. I also don't understand a "reputable" mechanic taking one of these engines that far down and not replacing the bottom studs (at least on the side he had apart).

You have to replace all the studs on the bottom row. I recommend steel. You should be able to get used steel studs or a new set. I used old ones that my machine shop had from previous rebuilds.

Where are you located. Maybe we can recommend a good shop. You can also attempt this job yourself if you are so inclined.

-Andy

all the studs could have been replaced for about $2000 when it was apart. hopefully something worthwhile was repaired for $4K.

Wow. Lot's of good information.

Nothing was done with the 915 transmission, though that would have been nice. Shifting is a little notchy but still pretty good and feels even better when car is warmed up.

I am located in Valley Forge, PA. Any suggestions on shops would be most appreciated. Also, when they tear down and rebuild, it sounds like this will last me for a good while. Is there any additional work that you would recommend at the same time. I know that is a general question but are there any known areas of problem with the SCs? Valve guides? Rings? etc. Compression and leakdown tests were pretty good when I bought.

Here's the big question:
How difficult is the job? Any special tools required asside from a motor stand. I did check the rebuild section of Pelican under tools and didn't see anything too specialized. Am pretty good with my hands but have never done anything like this mechanically, though I have friends that are mechanics on other cars...Doable or am I dreaming?
Rick

Some of the guys in PA should chip in, but I question what was done for $4K. You can do this yourself, the board will help. If you decide to go the route of paying someone to work on your vehicle, I'd go to a different shop. I could be very wrong (I'm overdue at being wrong today so this might be the time) but I have a poor feeling about your current shop.

Oh, and enjoy the couch! I don't get that lucky. I'm usually sent out back to sleep with the horses in their barns...

Do you know where the stud broke along it's length?

Off the top of my head; besides common metric hand tools at least the following are needed to replace case to head studs: Floor jack and two jack stands, wheel chocks, oil line wrenches, dial indicator and holder, 80-1/2 on cam shaft holder tool, 3/8" and 1/2" drive torque wrenches, Sears Craftsman cam type stud remover, Snap-On stud remover/installer holder with 10 mm collet, 10 mm thread chasing tap, and ring compressor.

Thanks for the info on the tools. I don't know where the break occurred.

I did speak with the mechanic an hour ago. The studs that are damaged are the #2, 4 & 5 lowers. His price for the work is $6,000. This is for 24 dilivar studs, new upper and lower gaskets, headnuts, and washers. From the other posts that I have read, this seems high. What should it cost? Start to finish...

If I go for a second opinion, what is the likelihood of damaging other engine components (heads, etc.) by driving around with the broken studs? Also, would there be any noticeable signs if the situation gets worse.

Suggestions from PA members on good shops for a second opinion would be helfpul.
Rick

$6,000!

Seems like about twice as much as it should cost.

One can buy the tools I listed for between $800 and $1000 depending upon quality.

As long as there is only one stud broken per cylinder you likely have a few more miles left to drive it to other shops.

If it gets worse you will hear more noise.

Pelican Parts prices:

24 Nuts and 24 washers (unless these are in bad condition they can be reused): $138

24 OEM steel studs: $270

or 24 Dilavar OEM (993) studs: $492

Gasket kit: $232

I'm starting to see what you all mean.

Monday I am going to call around for some more estimates.

I haven't yet given up on the idea of doing the work myself.

Thank you all for the input. Its a painful situation but great to have a support network.
Rick :-)

P.S. I have a few other names of shops but am looking for references if anyone has a suggestion.

It seems that the studs that were not replaced but were re-torqued in the rebuild have all snapped now....

I found the best way to remove the studs on my engine was to weld nuts on the end of them. The welding heated up the studs enough to melt the loctite and of course they were easy to turn with nuts welded on them!

You don't need to touch the top row of studs. I used to ask if anyone had ever heard of a steel stud breaking. I don't ask anymore because one guy did reply that he had seen it. That is the only time I've ever heard of a non-dilivar stud breaking.

-Andy

Actually, none of the studs were replaced. All were retorqued. 2 of the bad studs are on the side of the engine that was not taken apart and 1 is one the side that received the work.

That is a good suggestion with the welding of the nuts. I don't have any welding equipment though. I was looking at 101 Projects for your 911 this evening and I noticed the section about how to loosen the loctite on the head studs, using a propane torch. How difficult is this? Is there any risk of overheating the case? and damaging the female threads in the case or breaking the studs??

I bought a cheap 199 dollar wire fed welder from Autozone. I've used it several times now. It works fine for jobs that don't require good welding. It works like crap if you want a good weld. The wire feeds too fast even on the slowest setting. It was worth it just for removing the studs though. I had never welded before I bought it. If I had to do it again I'd buy a better MIG welder for around 4-5 hundred from a place like Eastwood.

You can heat the studs with propane but MAPP gas works much better. You don't have to worry about overheating the case unless you use Oxy/Acetaline. I tried it this way but it was much slower and more difficult than the welding on of the nut solution. You can also weld nuts on the broken studs if there is enough sticking out.

Don't reem out the stud holes with a tap, you'll make them too loose.

-Andy

Thanks Andy! I will let you know how it goes.
Rick

Thanks Andy! I will let you know how it goes.
Rick

"Don't reem out the stud holes with a tap".

One uses a chasing or clean-out tap; it does not "ream" out the holes. It isn't a "cutting tap", there's a difference. Not cleaning out the threads in the case can make installing the new studs problematic.

find another mechanic. you can get a complete valve grind AND head studs around here for less than $4K. rip-off!

I spoke with two other mechanics today. I will receive a written quote from the one on monday. It sounds like it will be high as well but I don't have a sense how high yet. The other, who comes recommended from friends and various locations on the net, said that he could do the studs for $3,500 and could include new valve guides, if needed, for about $900. This is starting to sound better. He did mention that he would look at the condition of the valve heads when the engine is disassembled. I am assuming that valve head issues would show up on a leakdown test???
The leakdown tests on the PPI were:
5%, 8%, 5%, 6%, 4% and 5%. Would that give any indication of the condition of the valves. I am assuming that that tells me nothing about hte guids though??? The car has about 130K miles and I don't see any evidence in the service records that there was ever any valve work, aside from adjustment or guide replacement so I am assuming that needs doing.
Rick

You can still have worn out guides and get great leak down numbers. High oil consumption is one indicator or possible guide wear. 900 should cover head work and new guides and 12 new valves. So, if it only needs a grind and guides it should be closer to 600 I would think.

It makes sense to have the head work done while it is apart, if it needs any.

Cheers

Steel studs if you want to save money, Supertec studs if you want the best.
I wouldn't run Dilavar studs in a lawn mower engine.
The word should be stricken from the Porsche dictionary.
They were a bad idea when Porsche started using them and nothing has changed.
Of course this is just my opinion.

As for the cost of a top end, it all depends on the amount of work being performed. As this board clearly shows, there are many ways to perform a job. For some "while your in there" seems to inflate the cost. Compare apples to apples.
I would suggest that the shop that retorqued the head studs probably should not be working on Porsche 911 engines.
I would guess that they missed the broken studs because it's not likely that three studs broke in such a short period.

Thanks for the suggestion on the stud material.

Aside from the studs, the valve guides, and the valves are there any other common wear points or issues, common to the SCs that would warrant doing now. I want to keep it within reason cost wise but realize that now is the time to do these things...

Rick

p911sc i sent you a PM..... Hey Pelicans, Mobile going Mobile.. LOL

What was the final issue ????? Did you do a build or find anything to help you out??

Hi there, i'm just dooing a rebuilt on my 3.0 SC engine from 1980,
the car has approx. 220000 km on the clok.

When i removed the lower valve covers, i was choked!! 3 studs was broken in each side of the engine! one in every singel cylinder in the lower row. the broken parts was removed, except form one. the earlyer owner must have done that !! :-( i was in south france last summer, with some fast driving trough germany, but i have never observed any problems with the engine.. but i'm lucky i think - the cylinders seems to be ok condition! :-) just some black platted on no. 6 i direction where the bolt was missing.

Roslin

I'm going to find out for sure today if that is the problem on my 1980 SC. If it is, time to replace the studs.

Well I started the rebuild process yesterday. Disconnected the engine and lowered it onto a dolly. I have yet to separate it from the transmission . I couldn't pull them apart yesterday so I thought I should sleep on it before forcing it and risking something stupid. I am guessing that it is an alignment issue.

I will be back at it tomorow. Again the brethren in the Porsche family have come to the rescue with some good recommendations.

I have been taking pictures and am hoping to post them as the process moves along.

Rick

Did you disconnect the clutch fork?
On the 83 there are two arms that actuate the shaft that turns the clutch fork. The smaller of the two forks is held in place by a small snap ring. Remove the snap ring and the arm will fall off the shaft. At this point the shaft that holds the fork will rotate as you separate the trans from the engine.
Good luck.

Rick,

There are some tool you will need, the adaptor ring for mounting to a universal engine stand (made mine) and cam nut crow foot. I have an extra unused one if you are intrested, and cam chain adjustment thing. Both of Wane's books are also invalueable.

There are some shops in our area, Cyntex in West Chester and Performance just outside of Frazer; I have not used either so I can not recomend but they are willing to talk.

I am in the middle of a cam fix, I mean oil leak, so if you like to see any of it apart before you start to dig or I put it together this weekend you are more than welcome. My number 484 875 0130.

Jeff

Henry,
Thanks for the suggestion. I had disconnected and removed the clutch cable arms. My problem ended up being the result of a long day and not realizing that the transmission and engine were out of alignment. Today, I removed the rear wheels to get a better view and saw the problem. I jacked up the transmission and the engine slid very well. Incidentally, this experience led me to thinking about the difficulty of reinstalling the engine and mating the two with the transmission in the car, so before complete separation, I decided to remate the two and drop them together. I now have then both out of the car and separated. Success!

Jeff,
I would definitely be interested in what you are doing. I will call you tomorrow.
RIck

I want to put a closing note on the saga. Sunday August 20th I completed the rebuild. I am still dealing with some heat issues but am making progress and moving forward.

Anyway, it is great to have the car back on the road. As great as this is the knowledge I have gained from the project, the fun that I had in the process, and the friends that I made have contributed greatly to my enjoyment of the car.

I want to take this time to thank you all for being there, and taking the time to share your knowledge. It's priceless.
Thanks
Rick

Glad you are up and running! Way to go!

Cheers