Broken Head Stud...Now What?

[Wayne 962]

Originally posted by john walker's workshop
i just fixed an '83 that had one outer stud broken and it sounded like several were broken when you accelerated. surprised to find just one. best fix it now or damage will result from the head beating on the cylinder every time it fires. aluminum is soft you know.

While I agree with this statement, 3.0 heads are pretty common, so the overall damage is relatively limited...

-Wayne

[Grady Clay]

JL,

“…the clutch that was done the summer before i purchased the car. The transmission and motor were both rebuilt between '93 and '94. I remember, i was less concerned about the age, because in those 10 years, they both the engine and the transmission only saw about 15,000mi. Also, both were rebuilt by Gary Fairbanks, who is aparently a big deal in the area, though i personally could not tell you. Included on the reciept is documentation of new rings, pistons, cylinders, chains and sprokets AND...12 dilivar studs.”

GREAT!

Please scan and post the invoices. We can help you interpret them. The Dilvar studs may have been the best choice 13 years ago but not now. The important issue will be what new P&Cs, what was done to the heads, what other parts replaced, etc. Regardless of the broken head stud, you may have a great, 15K engine and trans.

George (Pelican aigel) is correct. You can easily fix this problem and you will have great 911SC running gear. Play the “poor college student “to the hilt, just don’t let anyone see the underside beautiful machinery. Put off the body, paint and interior. Just preserve what you have.


A plan is coming together.

Inspect for leak at head-to-cylinder interface. Measure cranking compression and cylinder leak. This will give you some quantitative information about the engine. Not only will it tell you if there is an existing compression leak but you will gain some insight about the condition of the heads.

Drain the oil and inspect the sump screen. Cut the oil filter apart. These will give you some indication if there is anything circulating in the oil system. It is better to find that now than with the engine half disassembled.

The Forum members will be able to help you interpret the prior invoices. Again this is important to know what to expect.

Buy
Dempsey, Wayne R. How To Rebuild & Modify Porsche 911 Engines, MBI, St. Paul, 2003.
and
Anderson, Bruce Porsche 911 Performance Handbook, 2nd Ed. MBI, Osceola, 1996.
and
Bentley Publishers, Porsche 911SC Service Manual, Bentley, Cambridge, 2000.
and
Porsche parts catalog PET (Porsche P/N 000.043.400.05).
and
Porsche Technical Specifications, 78, 79, 80, 81 WKD.422.720 (~$10 on ebay).
and
Find someone locally with a Porsche Workshop Manual, Vol 1-6 (’65-’83).

Using the above resources, make yourself a plan. That should include a parts list with sources and cost. A list of necessary tools is important. Post them here for review and suggestions. You have hundreds here who are experienced and skilled.

Join your local PCA. Just like Pelican there are many who will help and loan tools.

Show your parents your resources, plan and your determination to complete the project promptly. Organize your work area. You will need light, heat, workspace, engine stand, engine yoke, floor jack(s), jack stands, something to clean parts in, compressed air, etc. Keeping your parts organized is paramount. Have a Pelican party for engine removal.

Organize with a shop to remove the old cylinder head studs and broken part, chasing the threaded holes and installing new studs. They will need an oxy-acetylene torch, the stud extractor tool (Snap-On CG500-2 and collet), whatever to remove the broken stud, Loctite cleaner and thread chaser (not tap). The new studs need to be installed with Loctite and at the correct height.

While compression and leak tests will give you an indication, you won’t know the exact condition of the valves, seats, and guides until you inspect them. Shop now for who you want to do the inspection and repair (if necessary).

There is some controversy about the type of valve stem seals. The trade-off is a softer seal that passes some oil but preserves the valve guides better compared to a tighter seal at the expense of prematurely worn guides.

I agree with George (Pelican aigel), take the P&Cs off still assembled and don’t disturb the rings. With 15K mi on new P&Cs and rings, they should be perfect.

Don’t get ahead of yourself by lighting into the engine before you are ready.

I’m sure others can add to this.


BTW, where are you in school? What year? What engineering major (if you have one yet)?

Best,
Grady

[aigel]

It was getting late yesterday and I read right over the info you had on the mileage. If the engine indeed has had major work 15k miles ago and from a reputable shop, you chances are very high that you can do this for much under 3k and end up with an engine that will be great for many years to come.

George

[JLGarbanzo]

Well, im off to make some phonecalls. My parents left for work this morning before i woke up, so i havent had a chance to speak with them since my last posts.

Grady,
I will be a senior Mechanical Engineering major and Carnegie Mellon in Pittsburgh.

[Grady Clay]

JL,

Small world. I graduated from CMU in ’68, EE & Economics. I’m a Pike.


"...before i woke up...."
Aah, students home for the summer.... sleep 'til noon.

Best,
Grady

[sammyg2]

Quatrorunner asked "Can you replace all the studs if none are broken? Like one at a time while the engine is together and gasp in the car? Hmmm."

it is nearly impossible to change a head stud on one of these engines without pulling the cylinder. One guy on this board said he removed a broken stud with a chisel, but he must have been a magician.

There really isn't a good way to grab or turn the stud whether it is broken or not because they are shrouded by the cylinders and heads.
Even if you could, they are locktited in and are a bear to get loose without heat in the right places.

So the answer is no, you can't change the studs with the engine together or in the car. The engine needs to be pulled out of the car and the cam towers/heads and cylinders have to come off to remove the old head studs.

[JLGarbanzo]

Grady,
It is a small world. I’m a KDR (we've had the old ZBT since '85). I think the house was even something else when you were there. I have a few good friends that are Pikes. Do you still head back for Spring Carnival?

To tell you the truth, I was prepping the car to drive back to Pittsburgh for the early fall when the weather is nice. I’m glad I found this before making the 500 mile trek out there.

[quattrorunner]

Thanks Sammy,
And again, sorry for the hijack.

[Grady Clay]

JL,

I have been attending on-line and helping (money)
with the fire engine. See, I didn’t get wet this year.

Since classes start the 28th, you have some decisions to make right now.

Regardless of the 911SC, do you need (or just want) a car
your senior year? Several choices: Buy a beater that is
suitable to go to Pittsburgh and back. Sell the SC and
buy a nice daily. Park the SC and bum a ride to school.
If you don’t have a cylinder-to-head leak you could take
the SC to school, just go slow uphill in a lower gear and
accept the risk. Take your cell, AAA card and have a back-
up plan.

I still think my prior recommended plan is valid.
You will end up with:
1978 911SC coupe, S/R?
Interior needs work.
Paint needs work.
Never crashed.
Minimal rust (galvanized body).
Complete engine rebuild with new P&C, Fairbanks 15K ago,
fresh valve job, new cylinder studs, invoices for $zzzz
Updated tensioners and more.
Fresh 915 rebuild 15K ago, receipts for $xxxx.
Recent clutch 500 mi, $xxxx.
Short shift kit.
CIS works really great.
Koni shocks all around.
Upgraded sway bar.
Large front mounted oil cooler.
SSI...

This is starting to sound like a “no brainer” to fix it yourself.
You can continue fixing and still be below a sale price. You
can sell it and make money. You can buy another with
great body, paint and interior but distressed mechanicals
and swap running gear. Or even more possibilities.

I recommend you get the information resources I listed. You
are going to want to have all the diagnostic info next week.
You need to put some highway miles on the car if the head
isn’t leaking.

If you are going to park it, you need to convince your parents
that the 911SC can live in the garage. What are the winter
environmental conditions in the garage? Remove the catalytic
converter and install a pipe and a junk muffler. Drain the gas
and put in 5 gallons unleaded aviation fuel (or motor home
storage fuel) with a quart of Marvel Magic Mystery Oil. Run
it until the exhaust smokes. Park it and remove the battery.

If you have time put in fresh brake fluid and flush/bleed the
brakes.

When you go to restart the engine, start with the oil gas mix
just long enough to get it running. Siphon out the mix and
put in highest octane unleaded. Drive carefully until it quits
smoking. Reinstall the catalytic converter and your good
muffler and put on some careful highway miles.

Now you are ready for your engine adventure.


BTW, send me your e-mail address to gradyclayathotmaildotcom.

Boy, a 911SC at school! I had a ’50 Ford we used to
chase the Buggy through Schenley Park. Yes we won
back then also. Hehe.


Ever try and drift a ’50 Ford? Don’t.

Best,
Grady

[Duckworth]

So it's official - you'd rather not drop in a 3.2 motor and be done with it ? ?

Uhmm, it's your decision and the above drawn out proposals are useful -but I still think you're passing up a great opportunity to scrap (for now) that 3 litre motor and be out from under that popped motor.

Not to mention - a much better 911 experience than the 3.0 can ever bring you.

A small loan on the amount of a 3.2 would entail you signing off on perhaps 6 G$. Yes, it's a chunk of change but a short stint at 'Jack In the Box' for 3 -4 months part time would have that paid in short order (no pun).

Phil
___________

'80 928
'82 Targa - sold

[aigel]

Originally posted by Duckworth
So it's official - you'd rather not drop in a 3.2 motor and be done with it ? ?

Done with what?

3.2 engines break studs just as quickly as 3.0 engines. They have the same studs in there. All they have going for them is that they are a few years younger and just starting to pop studs.

Why would you recommend replacing a documented 15k mile engine with a used high mileage 3.2? It is obvious that JLGarbanzo has long surpassed your abilities, as he tamed the beast and his CIS is running great, while you gave up and went to a "modern" fuel injection where you better keep a spare DME in the glove compartment.

George

[Duckworth]

You may have missed my point......

Think about it - there you are in the sound comfort of that 3.6 motor...and never happier that your CIS days are all behind you -

Honestly, if you were reliving your college days in that SC and popped the motor, what would be your 'choice' out of that nightmare ?

1) Keep driving it - with a watchful eye.

2) Spend one or more calendar year (rebuild) without a driver.

3) Part time work : nights as a security guard to pay for a 70K 3.2 complete motor and otherwise ready to 'drop' right in.



Plenty of 3.2 motors reach 200K without broken studs. How many times in the last year on this board have you heard of an '84 - 89 car with snapped studs ? Yeah, it happens but his odds are darn good that it wont.

[JLGarbanzo]

Regardless of the 911SC, do you need (or just want) a car your senior year? Several choices: Buy a beater that is
suitable to go to Pittsburgh and back. Sell the SC and
buy a nice daily. Park the SC and bum a ride to school.
If you don’t have a cylinder-to-head leak you could take
the SC to school, just go slow uphill in a lower gear and
accept the risk. Take your cell, AAA card and have a back-
up plan.

I guess i didnt make it all clear. Taking the car to school was going to be a fun little luxury. I have always had an Infiniti I30 to get back and forth to campus. Shadyside isnt too far, but im lazy and i would end up skipping more classes than i already do.

I was prepping the car to take it down for the fun of the first few weeks of school. First long weekend i was going to drive it home and swap back.

[JLGarbanzo]

This also means that i have the time to take it slow, read, and do it right. I am in no rush.

[Duckworth]

Taking the car to school was going to be a fun little luxury. I have always had an Infiniti I30 to get back and forth to campus. ...JL Garbonzo

Son, it's up to you which way you choose to sort out the problem....just surprised you have no? interest in a 3.2 swap which solves most of your problems with many fewer headaches.

You may have constructed teardown plans already and that's Ok. Just offering an alternative, that's all. The beauty of dropping in a 3.2 is that you can forget about putting any money into that 3.0 litre case - which you probably will once you get inside and see what else it needs.....

If you've followed this board long you'll see that most SC owners with bad motors don't usually wish to rebuild their motors with high miles - when there are many nice used motors just 'waiting' to drop in there.


...... ........

__________

'80 928
'82 targa - sold

[Bobboloo]

Maybe you should back up and re-read the thread. He doesn't have a high mileage 3.0 in need of a rebuild. He has a rebuilt 3.0 with 15k miles and a broken head stud. Big difference.

Since the motor has been rebuilt there is no reason to rebuild it provided that the documentation checks out. He just needs to replace the dilivar head studs.

Planned correctly and with some experienced help by his side at critical times this can be done efficiently and inexpensively. The actual time it takes to do this job isn't really that much. It's the unexpected snags and lack of organization that cost you time wise.

Buying a used 3.2 will bring it's share of issues not the least of which is the conversion process. It's a lot more envolved than just pulling the 3.0 and plugging in the 3.2. The 3.2 motors were built with the dilivar studs as well and therefore are prone to the same failures. Add to that the issue of premature valve guide wear and doesn't look like such a good proposition.

My feelings are that considering his obvious mechanical abilities exhibited fixing the CIS this head stud problem will be no problem.

Besides, there's nothing like hands on experience to teach you something. His parents have to appreciate that. It's like tuition free school.


P.S.
JL, When you get the motor broken down to the shortblock minus the pistons and cylinders, or as some here would call it the bottom end, you might want to take it to a shop that has some experience removing studs in this type situation. This way you can avoid one of those unexpected snags. Besides the money you save on the tools to remove the studs will pay for the job.

Also, read up on the procedures for removing the exhaust. Those exhaust studs are brittle and can break very easily.

[Grady Clay]

JL,

Pelican duckworth is correct, you should consider all possible options. I think he missed that you already have a 15,000 mile fully rebuilt 3.0SC with new P&Cs and done by a reputable professional. The engine simply has a broken head stud.

OK, the I30 takes the pressure off. Take some flattering pictures to school with you for Show ‘n Tell.

Your parts count for this project is going to be fairly low. Wayne’s engine book has a good list pp. 71-75 and BA’s book p. 120 and a good check list p. 131-133. Needless to say these cover complete overhauls so you will only need top-end stuff.

Both books have tool lists; BA p. 128 and WD p. 115. Be frugal. Some are absolutely essential and others just make the job easier. Avail yourself of loaned tools.

You will need some more bits ‘n pieces that are not engine parts. CV joint gaskets, bolts and Schnorr washers come to mind. This will be a good opportunity to thoroughly clean your engine, trans, chassis and suspension in and under this area. Removing the oil tank for cleaning and painting is worthwhile.

Keep your “while you are there” list to a minimum. There are a few things worthwhile. The chain tensioners could benefit from the inexpensive seal kits. This might be the time to replace the engine cooling fan and housing with the larger one. Moving the fuel pump and filter to the front cross member has benefit and costs almost nothing. We can find lots of things for you to do “while you are there.”

Scout around at home and in Pittsburgh for the salvage yards and shops with “junk” piles. It is nice to use old fittings to make seals for the fuel and oil lines when apart. No doubt you can occasionally score some goody (a pair of 8x16 Fuchs?)

When manipulating the fuel lines and wiring, be gentle. Everything is pushing 30 years old.


Send me your e-mail address to gradyclayathotmaildotcom.

Best,
Grady

[Duckworth]

Since the issue of the batches of Dilivar studs has been known for many years - the 15K "rebuild" gives me some pause....Anyone who gets an engine back from a shop and 15K later "witnesses a length of stud fall out of the rocker cover" must have misgivings as to the integrity of the rebuild.

Maybe you should back up and re-read the thread. He doesn't have a high mileage 3.0 in need of a rebuild. He has a rebuilt 3.0 with 15k miles and a broken head stud. ...Bobboloo

Yes, I saw that...Anyone read or hear of the factory carreras with only 15K snapping their studs around 85 - 90 years ? That's less than 3 months of driving for some around Los Angeles. Would be interesting to know if that has occured. My impression was that Porsche at one time used factory 'steel' studs even though Dilivar was the preferred product in the aftermarket.

______________

'80 928
'82 targa - sold

[aigel]

Head studs in corrosive climates can go very quickly independant of mileage. There is nothing strange about it.

George

[Won]

Originally posted by Grady Clay
Are there any signs of leakage (black or oil) between the head and cylinder?

Reading this thread has got me concerned a little, haven't opened the valve covers to confirm broken studs (probably).

cylinder 1:


2:


couldn't get to 3, here's 4:


5 was like 2, 6:


Is this the leak from loose cylinders? I scrapped off some of the black stuff when I was replacing an oil return tube last week, hence the clean spots for 4 and 6.