Broken head stud. Feeling sort of sick right now...
 

Bought this '83SC earlier this year. The PO put about 20k miles on it in 10 years. I bought it at 110k and I just turned over 117k today. It didn't have any broken head studs at 98k as reported by a Porsche dealership invoice. I removed the valve covers last week to have a look see and found the lower rear most stud on #4 was broken. The barrel nut and about 2" of stud were sitting in the head where the stud hole is. I bought this car with a leaky #3 hoping it was carbon under the valve (I paid a lower price because of this, and knew it going in.) A couple months ago it started making a burbling sound on launch, only under load. I thought it might be an exhaust leak, as it only happens between 2-3k rpm then goes away. But the last couple weeks its gotten worse. I had a very knowledgeable Porsche mechanic do a leakdown a couple weeks ago and here's what we found. We put new NGK plugs in at the same time.

Comp Leak
#1 180 6.5%
#2 185 5%
#3 170 31%
#4 165 13% (this is the one with broken stud)
#5 170 9%
#6 182 ? (we didn't bother doing the leakdown on this one based on good compression)

Today I went for what I thought might be my last drive of the year and the "paddle wheel" burbling sounds was worse than ever. I've read this is what a cylinder with a broken head stud sounds like. I'm also not experienced enough to know if its simply one of the gaskets in the cat or header going south. Some of those areas are pretty crusty and rusty. I'm planning on taking this in to my mechanic this week, but he also encourages me to post here. I'm the mechanical type, and want to work on this car as much possible, not only because it interests me, but also to save money obviously.

Probably hard to hear, but I made a little recording this afternoon. Its audible right at the beginning of the video. It makes the sound the "best" in second gear at around 20mph hitting the pedal at 2000rpm.

https://www.youtube.com/watch?v=WSDi6R5vsdY

This is my first 911, and I'm smitten with the car. It's unlike anything I've ever driven and I can't honestly see not owning one for the rest of my life. I was banking on a rebuild at some point, and had hoped to do it myself (I've built a 1776cc VW engine from scratch, so I've got at least some experience) but parking the car for a year or two while I gather parts and do the rebuild right (along with all the other stuff that needs attention) is giving me pause at this point. One summer of driving and I'm already dead in the water? Ugh. Not a fun thought.

http://forums.pelicanparts.com/uploa...1479692399.jpg

Read the workshop manual and buy Wayne's supplemental engine rebuild book.

Fast reading and you can get a glimpse into what's ahead if you DIY.

There's tons of help here and more than likely Pelucanites in your area if you fall into a rut.

I'm in the same boat as you... though with rust instead of engine. (Probably need a rebuild, but right now need to take nearly everything apart to clean and inspect).
My first 911... but to be honest, I bought it knowing this is what I need to do. And I'd feel much better to have done it all myself.

The good news is you have an excuse to spend time with the car over the winter? They are fun to work on, too!

3-4 months downtime for me when I found a broken stud within 2 months of buying the car.
Researched everything and did it all myself. (With the written knowledge base of this board)
New studs, new rings, used cams to replace the pitted ones I had, rocker re-grind and then some SSI's and some other goodies. More goodies since like EFI.

Not too tough on the bank account without the goodies. (Watch the slippery slope)

First time touching an air cooled engine.
That was the summer of 2011, still running strong 12,000 miles later. :)

At least it appears to have not broken off at the case....good news.....it will run like a red assed ape when done....

i've had the same experience after ca. half a year of ownership...i knew that a rebuild was coming, so now it's just done sooner rather than later. :) Good for another 30 years now...

i've had it done professionally, because although i can wrench a bit and do all of my maintenance...going into an engine and assessing all the wear etc...is for people with much more experience than me. The car was off the road for 2 months.

While you are in there: do the heads, valve guides, etc...re-ring if pistons and cylinders are still good (the one cylinder with broken heasdstud might have damage)...and i let the pro's open up the case, inspect the crank, polish it, and change out all the seals and bearings. Change all headstuds. I changed cam chains and guides as well, and you might consider hydraulic tensioners (mine already had those). Replcace all outside seals (triangle of death etc), check for airleaks in the CIS system while you can reach everything. I changed all exhaust studs as well. Clean up engine tin, etc...
All in, it was around 15.000USD for me...painfull but it's only money, right? :)

I started doing it myself, but by the time i was trying to pull the broken studs, i knew i was going in over my head. Bit the bullet, very happy now.

Don't feel sick, feel challenged
 

You don't say where you live or whether you have a repair place or interest in DIY. If so, solicit some helpers, provide some incentive/beer and get busy. If you just want to bring the motor back to stock (I did) you can get it done complete for 5k +/- in a month or two if you're motivated. Its really mostly cleaning and planning. Actual wrenching is pretty minimal. Incredible resources that no other car on the planet enjoys on this forum. Get the motor out and apart in a few days, send some stuff out for refresh (heads). Get cleaning and before you know it its all back in hand for re-assembly. Just a little precision measuring there. The decision to do or not the bottom end is the most challenging of all. Buy all the right tools (there are just a few) and re-sell them when done. How I did it 70K miles ago, no regrets.

Thanks for the encouragement. I guess I have to decide how deep I want to go. #3 needs rings, and if I've got Alusil, then do I just replace the one P+C? That seems like a band aid. I want to drive this car for many years, so a full on rebuild seems like the smart move long term. I'm okay with working on the car, but pulling the engine every year or two to nickle and dime it does not sound fun.

You certainly won't "likely" pull it yearly unless the unthinkable continues to happen. I did pull mine a second time 2 years after rebuild due to a rubber clutch disc failure (did nothing to clutch the first time) but after you pull it once, its not horrible. Changed clutch on the floor with no special tools required and put it back in. 2 days of work spread over a week. That was 4 years ago, rebuild was 6 years ago. During rebuild, I chickened out and paid a guy to do the bottom end including rings, bearing, etc. for me which was the most costly single item of expense. (he told me that it showed little wear and would likely have lasted another 100+k miles). At that point, the engine is light enough that my wife and I could to hoist it into the Honda to bring it to a shop. At least the case sealing is now all new. Skip the bottom end ??

Pulling the engine is easy. If I had to I think I could do it in an hour, alone. with 2 people maybe even 20 minutes.

I rebuilt my engine using Wayne's book and the folks on the Engine Rebuilding Forum. It really was not that hard with all the help you get! I did send out my parts to be professionally checked and balanced, had my heads pro done, and took my sweet time, but man this thing screems now! and then there is the self satisfaction of having done it yourself. Worth it.

-m

You can do this yourself. No sweat. It's just a big bug engine with tighter tolerances. BUT. If you make a mistake you could ruin the engine. Read the books. Read the manual, read Wayne's stuff. Get on the Engine rebuild board at Pelican and make some friends. Read the forums. Read until you can do this stuff blindfolded. Then get three friends in the neighborhood to always be on call, or your wife, to be the third hand.

Yes, you'll be without your car for awhile, but you will have an experience unlike any other as you rebuild the engine. Do the whole thing. And while you are at it...

Welcome to the club. There is no 12 step program for us buddy, once you are a Porsche addict, always a Porsche addict.

Mine had Alusils and 80,000 miles.
No internal damage to cylinders or Pistons and re-ringed them successfully.
Many others have done the same.
I only re-ringed them as I broke an oil ring on re-assembly. (Grrrr...)

Keep it, pull it apart and see what you need. Re-ring is very doable, replace all head studs, and go on from there.

I started my top-end project because it was a bad oil-burner and found broken headstuds during tear-down. I loved doing this project:
http://forums.pelicanparts.com/porsche-911-technical-forum/729856-87-drop-top-drop-n-top-end.html

I too had alusil, and the oil rings were completely clogged with sludge. I had the cylinders professionally measured & honed and did a re-ring. I elected to leave the bottom end alone and don't regret it at all.

I find myself thinking of excuses to do another drop and tear-down, but my car runs great, doesn't burn or leak a drop of oil, so I guess I'll need to find another project car.

If you built a VW engine and you have some space and tools, you can do this. The engine forum is an invaluable resource, and there are some very helpful videos on Youtube that cover many aspects of this project. Embrace it!

Good luck,
GK

When I found my broken head stud on my 3.0 I faced the same situation.

If you truly love air/oil cooled engines, think Metzger and get a 3.6

The job is 95% cleaning. You can clean can't you?
I bought all the books and did the teardown and had a pro do the evaluations on parts and the assembly.
Enjoyable experience.

I removed the 3 heads and cam housing all together, saves a lot of time if you don't need to get into those parts.

Pistons can be slid out of cylinders far enough to remove the pins and then you never have to worry about the rings getting into trouble either.http://forums.pelicanparts.com/uploa...1479759551.jpg

Well, I know for sure now. Took the car in to my mechanic today and he identified a pretty obvious oil leak and exhaust leak coming right from where the head stud broke off. It was puffing and burbling in that area when revved as well. At this point we decided we're going to drop the engine, disassemble to the long block and start removing things to see what we're in for.

ouch.