What to expect: Rebuilding 80 3.0 Euro

[NEWFIE 69 911E]

Hi all,

Due to one broken head stud, I am preparing to rebuild the engine of my 1980 SC Euro (imported from Germany) this coming winter, and I'm wondering what to expect. Here are some details:

- 190K kilometers
- one broken head stud on #2. Broken stud that fell out measures 12.3 cm in length. Broken end was carbon-coated so it had broken some time ago
- engine never "opened"
- no oil leaks (usual seals and oil return tubes replaced)
- does not burn oil
- Tensioner and pop-off valve upgrades complete
- starts and runs perfectly, no smoke or strange noises
- driven approx 1,500 to 2,000 km per year

Some questions:

- Should I rebuild it now or drive it for the rest of this year? I discovered the broken head stud 3 years ago, and have driven approx 4,000 km since with no issues

- Checked some other posts; it appears that total stud length above base should = 13.5 cm. My broken stud is ~12.3 cm long, so I estimate that there is 1.2 cm left above the base. Is this enough to grab on to with vice-grips after heat?

- Can I get away with a top-end rebuild only? I don't drive it enough to justify spending big money. If so, what parts should I need? Is it likely that the heads will need work? Which studs should I order?

I've ordered Wayne's book, I've rebuilt engines before, and I have this great site and forum to help me, so I feel confident about doing this myself.

Any advice appreciated,

Thanks in advance,

[ninesixfour]

So let me get this straight; you've been driving it for 3 years with a broken stud, you don't rely on it for daily transportation, it doesn't leak or burn oil, it starts and runs perfectly...why bother? It takes a lot time, a lot of money (even if you DIY), and this motor sounds like it's in good shape overall. If you're just looking for a winter project then go for it, but otherwise I'd leave it be.

[NEWFIE 69 911E]

Originally Posted by ninesixfour

So let me get this straight; you've been driving it for 3 years with a broken stud, you don't rely on it for daily transportation, it doesn't leak or burn oil, it starts and runs perfectly...why bother? It takes a lot time, a lot of money (even if you DIY), and this motor sounds like it's in good shape overall. If you're just looking for a winter project then go for it, but otherwise I'd leave it be.

Yes, thanks, I understand your reasoning, and have been following the same train-of-thought for the last few years.

My main concern for wanting to rebuild is that I don't want to cause any damage to the head(s) that may cost more in the long-run. It seems that it should be OK as long as the head on #2 does not start leaking oil, or if I hear the tell-tale sound. I have read here that many people drive with one, or more, broken studs without issue.

[ninesixfour]

Originally Posted by NEWFIE 69 911E

Yes, thanks, I understand your reasoning, and have been following the same train-of-thought for the last few years.

My main concern for wanting to rebuild is that I don't want to cause any damage to the head(s) that may cost more in the long-run. It seems that it should be OK as long as the head on #2 does not start leaking oil, or if I hear the tell-tale sound. I have read here that many people drive with one, or more, broken studs without issue.

You're going to do the heads anyway when you rebuild, so it's a wash. Even if you damage one, a used one is about $150.

[NEWFIE 69 911E]

Originally Posted by ninesixfour

You're going to do the heads anyway when you rebuild, so it's a wash. Even if you damage one, a used one is about $150.

Thanks - excellent advice and info

[NEWFIE 69 911E]

So, I think I will keep driving it this summer and fall, and then decide if I want to rebuild the engine over the winter (November to May up here).

One question remains for now:

Checked some other posts; it appears that total stud length above the base should = 13.5 cm. The broken stud that fell out is ~12.3 cm long, so I estimate that there is 1.2 cm left above the base. Is this enough to grab on to with vice-grips after heat?

[ninesixfour]

Originally Posted by NEWFIE 69 911E

Checked some other posts; it appears that total stud length above the base should = 13.5 cm. The broken stud that fell out is ~12.3 cm long, so I estimate that there is 1.2 cm left above the base. Is this enough to grab on to with vice-grips after heat?

I didn't have any luck with vice grips, but did have good success with heat and a stud puller tool like the one described in the book. I bought a Titan brand from Northern Tool for about $35. The Snap-On one is pretty expensive. 1cm should be enough for it to grab onto.

[Brown747]

Did this a few days ago for a broken stud on #3.
Broken head stud defeated

[TibetanT]

+1 ^^ per Brown747....that IS the ticket for getting these babies out.

Good luck with your project.

[NEWFIE 69 911E]

Originally Posted by ninesixfour

I didn't have any luck with vice grips, but did have good success with heat and a stud puller tool like the one described in the book. I bought a Titan brand from Northern Tool for about $35. The Snap-On one is pretty expensive. 1cm should be enough for it to grab onto.

Excellent advice - thanks. Is this the stud puller you purchased:

Titan Stud Puller — 3/8in. Drive, Model# 16023 | Combination Wrenches | Northern Tool + Equipment

?

[lindemans]

I agree with your reasoning; if you don't stress it to the limits, you can probably cruise along quite OK, but I would surely fix it.
It can damage both head as well as the cilinder.

Quite a few specialists I talked to recommend a full tear down for big-end and crank bearings past 180.000 km.
I had my engine taken apart last year at 220.000 km due to worn piston rings and valve guides (oil consumption). I hesitated between doing top-end only or the full package. I am glad I went in full. Quite a few big-end bearings were really at "2 minutes to twelve" as they were worn through the hardened bearing surface already. Crank was still fine, but close to potentially getting damaged from the worn bearings.

So in your case: I would enjoy the rides and often check for any additional snapped headstud. Then at some point fully take it apart !

[ninesixfour]

Originally Posted by NEWFIE 69 911E

Excellent advice - thanks. Is this the stud puller you purchased:

Titan Stud Puller — 3/8in. Drive, Model# 16023 | Combination Wrenches | Northern Tool + Equipment

?

Yes it is. It worked well.

[flat6pilot]

Originally Posted by NEWFIE 69 911E

Excellent advice - thanks. Is this the stud puller you purchased:

Titan Stud Puller — 3/8in. Drive, Model# 16023 | Combination Wrenches | Northern Tool + Equipment

?

That's the one I use too. Good results on exhaust and intake studs which are probably much easier to pull out [then head studs] but this thing has a great bite to it.

[afterburn 549]

heat the H$LL out of the stud..maybe a couple cycles

[NEWFIE 69 911E]

Originally Posted by flat6pilot

That's the one I use too. Good results on exhaust and intake studs which are probably much easier to pull out [then head studs] but this thing has a great bite to it.

Thanks - just ordered this from Northern Tool and Equipment - preparing for my winter project

Thanks all for the advice. I'll be sure to post here when I start tearing the 3.0 down!

[NEWFIE 69 911E]

Update: Since I noted one broken head stud (a few years ago) I have been constantly listening for the "pop-pop" sound, and checking for new oil leaks.

Well, I still do not hear any "pop-pop", and the engine still runs great, but today I found a new oil leak on the cylinder with the broken stud:



Note my simple air injector plug.

My plan is to continue to drive the car for maybe 1,000 km total (unless I hear the "pop-pop") and then rebuild (top-end) over this winter.

Comments? Thanks,

[NEWFIE 69 911E]

Update: It is still winter where I live but I have not started the engine repair yet.

Of course, I'm hoping that the repair will be simple:

Replace all lower studs + gaskets and seals, machine one cylinder head (if sealing surface is damaged) and reassemble.

I'm hoping that I don't need to split the crankcase, but the oil pressure seems a little low. Suggestions?

[lindy 911]

Explain "a little low". At idle when warm it will show about a half bar and then 1 bar for each 1000 rpm (3 bar @ 3,000 rpm) is normal.

[NEWFIE 69 911E]

Thanks - at idle it is about 1/2 bar, and then just under 1 bar for each 1,000 rpm.

see image below:

[Flat6pac]

you cant machine one cylinder head, you have to do the group of 3 at least.
Bruce