First Time Rebuild '89 Carrera

[Tie Rod]

Had a sneaky suspicion all was not well. Needed to do a valve adjustment and oil change anyhow, so pulled the lower valve covers.

Let's see what we have behind door number 1.....



Sweet, a broken head stud!!

So, my plan is to drop it, tear it down and split the case. I'd like to return everything to spec and make it a leak-free, reliable engine. I may look into a cam profile change with exhaust, but for now I'd like to tear it apart and see what I am working with.

I have both of Wayne's books, a Bentley manual, Bruce Anderson's and the forum search feature. Still I will have questions for the masses.

[Ken911]

Well have fun it's not as hard as you would think, and a great learining experience.

[Tie Rod]

Step one complete. Engine and transmission came out rather nicely with only a few minor struggles. Didn't think the cruise control was gonna be my clock turner..... Frustrated, I turned to google since Bentley left me guessing and I was done in 2 minutes.

I found it really helpful to spend a little time finding the right balance point on the jack. It made the extraction much easier for the one man team.



Separated the trans and mounted the engine to the stand. It's the HF one I have seen used many times on these boards, but I have to admit I don't have a ton of confidence in it. Seems rather taxed. The penalty for failure is high!!

[OldTee]

How many miles on the engine. If less than 120K don't bother to split the case. If less than 90K don't do a rebuild at all. Fix the broken stud and go driving. Keep your money in the bank. Good chance you can go another 50k miles then do the top overhaul.

Not everybody will agree with me. Go slow.

[millhaus]

Rebuilding my 930 was one of the best things that I have ever done. It wasn't cheap and if ou do split the case find a good shop like Ollies to clean, check and machine everything back to spec.

Then with Waynes book it is like building legos. It really was easy but take your time, be patient and go slow. You only want to do it once.

Good luck.

[Tie Rod]

Thanks for the replies. As far was the engine goes, it has 109k miles.

Removing the exhaust was not the most fun I have had in a while. Most nuts were rusted solid. Many of the studs snapped even after a few days of soaking. A few of the barrel nuts were stripped from the start, so I had to modify a bolt extractor.



One had to be drilled out completely.



So with 5 broken exhaust studs, I think I am at least at a top-end rebuild. We shall see what other problems I come across or induce....

[Flat6pac]

In the last couple years I ve done several with 90+ K miles and all needed guides so heads in the shop is a good decision.
Bruce

[dkirk]

Tie Rod,

I did the same job you're facing on my '88 earlier this year. Here's a link to my diary:

3.2 Top End Overhaul – A Success Story

My engine had approximately the same mileage yours does. Valve guides and stem seals are usually necessary at this time. I elected not to split my case as oil pressure was to spec and engine appeared very clean internally.

This is a great winter project that I'm sure you'll enjoy! Take your time, take lots of pictures, and post often.

[ludvikagard]

Thanks for the replies. As far was the engine goes, it has 109k miles.



Removing the exhaust was not the most fun I have had in a while. Most nuts were rusted solid. Many of the studs snapped even after a few days of soaking. A few of the barrel nuts were stripped from the start, so I had to modify a bolt extractor.







One had to be drilled out completely.







So with 5 broken exhaust studs, I think I am at least at a top-end rebuild. We shall see what other problems I come across or induce....

For me, soaking has never "loosened" a bolt, but it helps when the it's already loose. Did You heat the nuts? Should be enough with propane. But even better with glowing red with map gas or oxy/acetylen.

[Brown747]

I just finished up replacing a broken stud (along with all lowers)on my 3.0 Hopefully you have enough stud remaining to get onto to remove. Here is a brief thread of my "studectomy"
Broken head stud defeated

[TibetanT]

How long is the broken stud?

Let's hope it isn't broken right at the case. Then, if it is, you would be better off replacing all of the lower dilavar studs with steel while you are down that far.

Good luck with the build and I look forward to the progress reports and pictures.

[ludvikagard]

Isn't he talking about exhaust studs?

And also on the picture of the broken head stud. It looks like it is the unbroken end of the stud You see on the picture. Makes me think: how did they manage to get the nut that far on to the stud? And how do you manage to torque it without being able to use hex spanner? Looks almost like the stud was not properly instslled, or, it has unscrewed itself from case and some previous owner put it back without torque? Or do I get it all wrong?? Something is strange is the head stud broken, or has the whole stud unscrewed itself without being broke off?

[Flat6pac]

Once the tension is released the head nut is free to move up and down the threads. Many times the broken stud, the nut, and the washer are free of eachother.
Bruce

[ludvikagard]

Thanks. Sounds like a logic cause. If I remember it right, the 4 broken ones in my 3.0 were in their original position on the stud when discovered.

[Tie Rod]

Yes, I would have to admit the "soaking" didn't really do much for me. I tried the propane and don't think I ever got it hot enough. Sometimes it is hard to tell if you are making good progress as the wrench turns or just beginning the shear. I wish I had a torch. I will have to add that to my wish list.

The head stud snapped a few inches up from the case, so I did get lucky there. The nut spun freely on the broken end. I am pretty sure it just migrated down after the failure. Thanks Brown747 for the "studectomy" procedure. I will see if I am a garage surgeon.

I agree that now is a good time to do the heads and valve guides to make sure everything is in proper spec. I'd rather deal with these things before they become a problem. Having a valve fail under power doesn't look it ever leads to anything good.

Dkirk, I had enjoyed that thread and now am very interested in some of your experiences. I too have Alusils. I decided after reading a few threads, yours included, one could take the pistons out for inspection and reuse. I am interested in your process. I assume they were carefully de-ringed, cleaned, measured and then reassembled in the exact place and orientation from which they came.

How much travel do I have left for this tensioner?


This side looks better


This was interesting. This is wear on the housing wall where it mates to the case. I am at a loss to understand how the chain could rub there if it is still on the sprockets. Both left and right sides had various marks like these.

[Tie Rod]

Is this normal for chain tensioner shaft/post?

[Flat6pac]

Wait til you see the intermediate shaft bearings....
The other marks on the chain box is from factory grinders cleaning sharp edges.
Bruce

[dkirk]

Tie Rod,

I never removed the pistons from the rods. A paper towel was wrapped around each piston for protection, and held in place with a rubber band. Leaving pistons on the rods does not hinder replacing head studs. Rotating the crankshaft to get pistons at TDC for the particular stud set your working on gives plenty of room for heating the case area with a torch. I did remove a top compression ring to measure ring end gap in that cylinder and found that it was right in the middle of the spec. As all cylinders and pistons appeared visually equal, I didn't check any other ring gaps.

With cross-hatch still evident in all cylinders plus no plating wear on the piston skirts, I saw no need to do any more detailed measurements. The oil control rings had some soft carbon present in the slots, and this was cleaned up using a brass brush and solvent without having to remove rings from the pistons.

[Tie Rod]

Well, slip slide and away....sticking with original plan to split case. Want to upgrade Rod bolts and evaluate internals so no surprises later.

So you mean these bearings.



#3 & #6 #6 has just about no sign of wear either side. The rest all show varying amounts.


It does appear that wear is higher on one side of the case as compared to the other.




So overall, is this considered good, average or bad? The engine only has 109K.

[porterdog]

Great pictures; can't wait to read the answer to your last question.