80SC RoW rebuild: 8 broken lower head studs! 200K KM
 

Hi all,

As posted in the main forum over the years, I acquired my 1980 911SC Targa RoW 8 years ago (180K Kilometers at that time), and soon discovered 1 broken lower head stud. Despite opinions to the contrary, I decided to keeping driving it, paying attention to changes in engine noise.

I have driven and loved this car ever since, but last summer the tell-tale sound appeared and decided to stop driving it. Had hoped to rebuild the engine over the winter, but a broken ankle modified that plan!

Total mileage now = 200K Kilometers, engine never opened up before.

Thought I would post some images here because I'm sure I will be looking for advice, and some might be interested to see what damage can be caused by driving with broken studs :eek:

http://forums.pelicanparts.com/uploa...1469633803.jpg

Solo Extraction using motorcycle lift

http://forums.pelicanparts.com/uploa...1469633860.jpg

http://forums.pelicanparts.com/uploa...1469633958.jpg

Busy stable - one has to go!

http://forums.pelicanparts.com/uploa...1469634050.jpg

http://forums.pelicanparts.com/uploa...1469634114.jpg

Deep Creep is amazing - ZERO broken exhaust studs!http://forums.pelicanparts.com/uploa...1469634181.jpg

http://forums.pelicanparts.com/uploa...1469634224.jpg

Note number of broken lower studs!

http://forums.pelicanparts.com/uploa...1469634303.jpg

Heads from cylinders 1 to 3, after some gentle cleaning:
http://forums.pelicanparts.com/uploa...1469634329.jpg

Heads, so far, don't look too bad, one small nick where one of the head gaskets is broken. Will probably need fly-cutting of all heads on that side.

Presently on vacation - will be removing the other bank when I return.

Only 200K Kilometers on this car - engine never opened before - my plan is to not split the crankcase...

For those interested, OLD thread can be found here:

http://forums.pelicanparts.com/porsche-911-technical-forum/406265-one-broken-head-stud-2-drive-3.html

Sub'ed !

Thx for the tips.

Also,

Have Wayne's excellent book as reference :)

Since relatively low mileage, plan is to remove P&Cs together; hopefully can find a thread that outlines the best sequence.

Hi all.

Back from vacation and last night I removed the right bank of heads, the side with only 3 broken lower studs!

All went smoothly, and here is the outcome:http://forums.pelicanparts.com/uploa...1470444451.jpg
http://forums.pelicanparts.com/uploa...1470444498.jpg

The heads on this side seemed to have more or less the same amount of very slight erosion as the left bank. Most of the slight damage appears to be outside of where the head gasket sits. Is this normal?

In any event, I do plan to get the heads surfaces flycut, even if the damage is very minor.

All cylinders look good, with no scoring, except #5, which has one shallow score:

http://forums.pelicanparts.com/uploa...1470444740.jpg

http://forums.pelicanparts.com/uploa...1470444788.jpg

Should I be concerned about this? I was planning to leave the pistons in the cylinders as the engine has only 200K km. I drive this car less than 3,000 KM per year :)

Cylinder condition?
 

SmileWavy

Hi all,

Asking for some advice from the experts here please re condition of cylinder (above). Thanks!

If it was mine I'd re-ring it. See what caused that score, may be a broken ring. Why go thru all that work and not do it right?

Thanks! My only concern is re-ringing it as the cylinder is Alusil... ?:confused:

Oh, I missed that! At the minimum I would take the piston out on the scored one to see what is going on. Did it burn any oil?

Yes, thanks, I will attempt that!

No, it did not burn an excessive amount of oil. Only 124K miles... (~200K KM)
Best,
Tom

Latest status:

Heads removed from left tower in prep for shipping to machanist :)

http://forums.pelicanparts.com/uploa...1470795064.jpg

Then I would most likely do the same, keep the p and c's together except for that #5. Is the score deep enough to catch a finger nail? Off thread, I see you are on "the rock", neat place, I was there on my Harley a few years ago, was heading to St John's but decided to cut the trip short due to a hurricane coming up the coast. I'll be there again in Sept, coming across Quebec and Labrador then taking the ferry from Blanc Sablon to St Barbe then down to the ferry at Port aux Basques and work my way back home. Not on a Harley this time though, it wouldn't do well on the Lab 500 gravel, LOL.

Hi Boosted. Thanks, yes, the score can (just barely) catch a fingernail.

Your Road Trip sounds great! You should visit St. John's, and see my collection ;)

Best,
Tom

See what the rings look like on that #5, if not broken then I'd probably put them back in and run it. I might visit St John's, time permitting.

Update: 6 heads cleaned, packed and shipped to machinist in eastern Canada experienced with 911 aircooled engines :)

Next task: Remove P&Cs together and the n tackle removal of broken head studs!http://forums.pelicanparts.com/uploa...1471041227.jpg

Extraction of this broken head stud is going to be a challenge!!:eek::eek:

http://forums.pelicanparts.com/uploa...1471224781.jpg

SmileWavy

That is going to be a tough one. Can you get any bite at all with a pipe wrench?

I cleaned the stud with a dremel to bare clean metal. Then I put a big washer over it ,with the perfect size hole and then I did put a big nut M12 over it. Protect your case with fire resistant cloth and mig weld the nut on. Because of the gap between the stud and the nut you get a good and deep weld. The heat will help loosen the stud. This is how I did several of mine.

Thanks, I will try welding a nut on, or use a dremel to cut a slot for a screwdriver.

Did you have any issues welding a nut onto the stud?

Tom