Top end only, or split the case...?
 

I have a 1969 911T with an '82 SC 3.0 case and an '87 3.2 top end. I do not know the exact pistons and rods, but it was claimed to be a 3.2SS. The cam towers and cams appear to be stock 3.2 (unless the cams were reground -- I have no reason to think that).

The engine runs terrific. I went from PMOs to a Motec ITB setup. It's a great street car, plenty of power for me, excellent all-around driver.

Issues:
1. Both sides I have small but constant oil leaks between the cam towers and the heads. I have investigated this over and over, and it's definitely NOT rocker arms, valve covers, nor oil return tubes. Several times I have carefully cleaned everything, checked with fluorescent dye in the oil. Leaks appear near cylinders #3 and #6. Only drips while running, but over the course of a couple of months, it starts to bake oil on my SSIs, and flings back onto the muffler and bakes on there.

2. I occasionally get a "mosquito fog" of blue smoke when idling. Not on start up, not often, but if the rear end is parked lower than the front, after starting I get a giant cloud of smoke at the first stoplight or two. Or if working on a warm idle in the driveway. Doesn't happen often. Suspect worn valve guides, though I don't get any smoke on a downhill decel test. Pictures of #4 oil fouled plug (about 1,000 miles on it) and exhaust valve #4. Exhaust valves are showing seepage around the valve guides, #4 particularly bad. At least one intake valve looking oily (can't recall which one). See pics below

3. I do have some oil leaking from the case parting line. Not a lot, but a few drops overnight. Annoying.

Leakdown:
1: 3%
2: 2%
3: 2%
4: 3%
5: 2%
6: 2%

Compression:
1: 175
2: 175
3: 180
4: 175
5: 180
6: 175

Oil consumption: have not been carefully tracking. Estimate about 1qt / 1,000 miles.

I would love to clean up the oil leaks. At some point, the heads look like they need to be rebuilt, with new valve guides, etc.

I know splitting the case is a lot more work, but feels like sooner or later I will want to fix the leaks at the case line.

Just in the planning phase, but trying to think ahead to the fall and winter. I will do most of the (non-machining) work myself, with help from a friend who has built a number of Porsche engines, from 356s to 2.2s to 3.0s to 3.2s.


So my questions are:
Valve guides appear to be a problem, yes?
Do it all at once (top and bottom end), or am I asking for trouble splitting the case?

Constructive advice welcome.

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a few more pics. exhaust valves...

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someone tried putting rtv near cylinder #6 to redirect oil off the heat exhangers. didn't work.

If you do have leaking from the case and it annoys you. As you have said it does I would split the case.

Obviously if your power level is about where you want it to be I would not suggest going ape.
However about 9:1 and a bit of a cam upgrade wont do you wrong at all.

What's your budget look? like things can get big fast.

That plug tells me the plug is either too cold or you are running too rich. What lambda did you tune to?

It's the only plug that looks like that. What the best way to show the lambdas -- scatter of tps vs lambda, or histogram?

Do you know how many miles on the bottom end already since last rebuild? If motor had a full rebuild last time with new bearings etc, you might just need top end. If you don’t know history from po then you might consider split it.

Unknown. Believe it's been over a decade since it was built from 3.0 to 3.2.

Some factors to consider:
Oil pressure - if it’s sub par split! Refresh mains and send out oil pump.
How are the threads in the case for the head studs? If no bueno there’s a good reason to split it.
Is your intermediate gear or distributor drive gear worn? If so … split! Im gear will knock when worn. You can peak at both to get a good look.
If you don’t split… doesn’t mean you can’t at least refresh con rod bearings. A lot of ppl forget this.
Check for gold in your oil .,, too much gold and you may want some new main bearings.

Daniel

Your puff of smoke at stoplights could be from many things. Classic sign of worn valve guides is smoke on overrun (coasting in gear, throttle closed).

Oil can pool in the muffler after sitting, as oil level rises in the engine sump, especially as you note, when parked for extended periods with rear lower than front. You’ll get smoke for a period of time as it burns off.

oil
 

Top end for sure, but I would check the triangle of death for oil leaks.....leaks there can migrate under the fiberglass shroud and easily look to be coming from #3 & #6 cylinders.....

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I should have said before: not coming from triangle. dry.

It’s $60+ for the bottom gasket set. Opening the bottom gives you access to knowledge and a reseal.
Intermediate shaft bearings,
Chain rails
Look at the mains. The mains get oil before the rods. If mains are clear of scratches,
That’s what you can expect inside the rod bearings so why open the rods.
You get a chance to power wash the case, who wants to rebuild a crusty case?
Then, you know what you own…
Bruce

+100 to this.

I rebuilt mine mostly due to oil leaks. From a performance standpoint I could have lived with it indefinitely, but the leaks and the fumes and the occasional puffs annoyed the eff out of me and why should my hobby car annoy me? It’s nice to know it’s all good for many years again, and dry. For now anyway. 😀

Agreed. I don't see myself doing the top end and not doing the bottom case. Thanks for the tip about the mains and rods. Very helpful.

same sentiment. i think of it as an only child, and i'm enjoying spoiling it.

You are 3/4 of the way there by the time you have torn the top end down. Engine out and top end teardown. A few hrs extra work to get to the bottom of the engine. As said previously.
I think the 3.2s had guide issues?
The cam box/heads is a critical seal area. May not have been done quite right.
While the heads are being done you can split the case and have it back together by the time the heads come back. Otherwise you can sit and twiddle your fingers with the case unsplit , still waiting for the heads to come back. And save $60 on gaskets.
Alan

I see comments above about taking apart the bottom end and looking at the main bearings but not the rod bearings. That would seem an odd choice.

I agree with splitting the case for sure. And feel it also wise to check the rod bearings.
The mains may be fine but I've seen more than once worn rod bearings despite that.
And you have the added advantage of replacing the rod bolts-never know if there's been an overrev!

I've seen a lot more worn out intermediate shaft bearings than rods and mains. It seems like every one has bearings down to the copper. And as mentioned above, the knocking noise that some don't even notice until it's fixed.

Bruce is speaking words of wisdom. Fix ALL of the leaks while you're this far into it. Order the Wrightwood gasket set, and for gawd's sake, use modern sealant on the case halves and cam housings.

Update:

I do not, in fact, have a short stroke 3.2, but a regular stroke (74.4) 3.2. This is news to me.

What I found:
Case: 1982 Carrera 3.0 (date mark 82 41)
Pistons: Mahle 3.2 (marked 95P36++)
Cylinders: Mahle 95mm (marked Mahle 95ZN1++).
Carrera 3.2 crankshaft (marked 930 014 09)
Connecting Rods: 3.2 (marked 930.103.121.2 R)
Heads: 3.2 (marked K1926R dated 7-87)
Cam Towers and cams: stock Carrera 3.2 (Left cam marked: 930 14710)
Oil pump: SC part (911.107.105.1R)

Overall condition is very good. Bearings look unmarred, crank looks excellent. I haven't pulled the rods off the crank so I haven't measured any rod journals yet. Oil pump looks like new. Upper head studs are steel, lower studs were replaced with newer porsche steel studs at some point. They look like new.

My friend thinks I should go to 98mm P&Cs to get to (about) 3.4L. My understanding is that I can have the cylinders bored out to 98 without a problem, and get some 98mm pistons with 9.5 or 9.8 compression. This should all bolt right in, correct? The whole setup is 3.2 from the crank to the cam towers (other than the SC distributor gear on the crankshaft, and the case of course).

Open to (constructive) thoughts on my 3.0 -> 3.2 -> 3.4 idea.

Lucky you!
what induction is on that motor? I might have missed it.. cis ?

I'm a bit new to this but have often wondered if CIS can run larger displacement.. ie, 3.4 or even 3.5?

If you do go the bigger piston route, I would try to get the pistons first, then send them with the cylinders so that they are bored, coated and honed to the correct clearance of the new piston.

The bigger motor can run a bigger cam... your new pistons will be good for valve clearance but your limitation will be the CIS (if you have it).
William Knight has a cam that might be suitable for this build.

Motec EFI Setup: Single Coil on Plug, Rasant ITBs and a 964 intake.

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If your oil pressure is good, don't split the case.

Otto,
haha!

Per my post above, the case has been split. I want to reseal it anyway. Glad I did.

Just waiting for my heads to come back from Walt's now...

First off, beautiful engine and I love your setup. I'm a little jealous. Very fortunate that you have a 3.2 crank. Must be nice to be that lucky. Lol.
From what I've gathered, you really don't want to go more than 98mm on the bore. So it'll put you up to 3.4L. Reason being, beyond 98mm, the forces are just too great for such little material that is left. Engines running more than 98mm bore are pretty strictly dedicated track cars and are broke down often. If I'm wrong here, somebody correct me but that is how I understand it.

2ndly, great read. I'm in a similar boat with my '82 911 SC. I'm slowly coming to the realization that I VERY likely will be splitting my case.

Circling back with an update.

The main issue was as suspected the valve guides were terribly worn, more on the intake than exhaust. Some had 0.5mm of valve to guide clearance.

I did a full tear down. Short block now back together with:

• New ARP rod bolts
• New small end bushings on the rods. Small ends were within spec but on the high side.
• All big ends right on spec.
• New Clevite rod bearings.
• Crank journals all within spec.
• New crank and intermediate bearings.
• #8 bearing replaced. Was within spec (barely) but had a definite wobble when installed and a visible north/south wear mark.
• New Supertec head studs (ouch, those are costly).
• Through bolts heads, washers and nuts were ceramic coated.
• New case studs.
• New timing chains.
• New bushings on all rocker arms. 9 of 12 were outside wear limit.

Received new Mahle forged 98mm 9.8:1 P&Cs from EBS. Sold my 95mm cylinders for more than I would have thought.

Just waiting for my reconditioned heads.

Sealing the case was surprisingly easy...if you don't count the 2 weeks of cleaning parts. Seriously, this should be called the Engine Parts Cleaning Forum.

I was blocked from buying Brakleen for a week on Amazon because I hit some hidden volume limit.

Update: She's back together as a 3.4L, and back on the road. 60 miles of break-in.

So far so good.


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Beautiful project, congrats.
Two thoughts:
I know it too late for this build but maybe it will help someone reading this post.
One of the great features of the Supertec head studs is the ability to install the piston/cylinder combination without dealing with the studs. Sliding the cylinders over the studs, then fighting with the clips can be maddening. You have easier access pin install and clips. It's generally good for 1.5 to 2 hrs of assembly time and less chance of losing a clip in the engine. [bing....oh shyt! where did that clip go?"

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My second thought is an easy one. It looks like you could move the clutch lever one full spline. If you can get the lever past zero fulcrum ( the center line) you'll fine that the clutch will release much smoother.
If you can, remove the cable spacer and rotate the lever one tooth.

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Henry,
Thanks for those tips. I read on another thread about the ability to put the studs on after the cylinders, but only after I installed things. I did not find putting the wrist pin clips in difficult at all using the Stomski tool, so no big deal.

I have the clutch arm at 90 degrees -- though the photo skews the view of that. I will see if I have enough threads to get one more spline to the rear (I assume you mean that direction?) and see if I notice the difference. She releases very smooth now, so this will be an interesting test.

By the way I went with your suggestions on the monster sealing thread (except I prefer Hondabond 4 on any paper gaskets other than the valve covers, which of course get no sealant) and so far not a leak to be found. Fingers crossed!

C

We also use a version of the Stromski tool but you have to be careful. The JE clips are larger than the Mahle clips used to design the Stromski tool. This tool was distorting the clips and leading the engine [clip engagement] issues.

Hondabond is made by Threebond so the product are the same. Using it on paper gaskets sounds reasonable. There is no "right" was just proven suggestions.

Can you explain this? I presume you mean install the P/C to the rod and then install the head studs?

Thanks.

Since Henry hasn't replied yet, let me try:
1. Assemble the case, but leave the head studs off.
2. Put the pistons and rings into the cylinders, but leave them out enough to access the wrist pins and circlips.
HINT: count and lay out the circlips and base gaskets before you start this part, so that you don't have anything "left over" and wondering whether you put all the circlips in the pistons!
3. Put one circlip in the "away" side of the piston.(and don't forget the base gasket on the cylinder bottom)
4. Line up the piston and connecting rod and insert the wrist pins, then install the "close" circlip.
5. Push the cylinder into the case bore.
6. Loosely install one head stud and nut or holder to keep the cylinder in place
7+. Repeat for the next cylinder, etc.

If you do it this way, you can lay the piston/cylinder off to the side of the case bore where you have more room to work and are less likely to drop or sproing! a circlip into the case. You can also stuff a rag into the case bore to prevent it from going in there.

After you have all the pistons installed and cylinders pressed into their bores, then install the head studs permanently.