My Porsche project...

[fanaudical]

I'm going to put all my project info in one thread starting with this one.

Quick synopsis:

I bought a 75 911 Targa very cheap when searching for a rebuild project. You certainly get what you pay for and I will attest that everybody's advice about spending more money up front to get a better car is certainly well founded. I have considered starting another thread entitled "Blatant lies of the previous owner..." with some wonderful "caveat emptor" examples, but that's just not nice.

Initial problems and discoveries are documented here:

Project Kickoff & Seeking Advice...

[fanaudical]

I finally separated the engine/trans yesterday. Here's my broken clutch fork:



You can see the broken piece of clutch fork and the throwout bearing retaining ring in the bottom of the bell housing. All the metal shavings are from the thrust washers getting chewed up by the pressure plate.

I also found that the case had one pulled transmission stud:



After removing the CIS, fan, alternator, and top engine shroud I found evidence of small mammals:



It appears that the oil cooler and cylinder cooling fins have been clogged closed for quite a while. This motor is obviously cooked.

Here's a few questions for interested experts:

- Given what I see of the motor, I'm looking for a 3.0L to drop in based on Grady's advice. Does anybody know if the 2.7 CIS works well on a 3.0 long block? Or is that a definite performance drop? (I'm looking to build a "street" car and keep things "stock" with minimal conversion issues.)

- Are there any clutch linkage upgrades I should be aware of to beef this up a bit? That original clutch fork sure looks wimpy.

Thanks for the help.

[fanaudical]

After doing some engine disassembly, I have to ask myself - WTF?

Previous owner had indicated that the engine was bone stock with no rebuild history. Up to now I had given the guy the benefit of the doubt (even with the massive oil leaks, broken clutch fork, and mammal residue). My attitude completely changed when I removed the timing chain covers and discovered the tensioner collars and "slipped" chain ramp:



At this point I concluded that the chain ramp was loose from a botched assembly, and was guessing that the oil leaks came from poor sealing on some rebuild.

My next indication of trouble was when I pulled the cylinder heads:



Those didn't look like 2.7 CIS pistons to me. The heads definitely look like 2.7 CIS heads:



I noticed as soon as I got the heads off that 2 of the cylinder had cracks on the bottom side where the fins split:



I also noticed some interesting pitting in the main bearing shells:



And one of the intermediate shaft bearings is worn down to the copper backing:




I spent some time tracking down part numbers to figure out what I have:

Case (one half) - 901.101.101.7R - mag case
Cylinders - Mahle 84ZD3 - 84mm Nikasil
Pistons - Mahle 84V53 - 84mm
Heads - 911.104.342.2R - 2.7 CIS
Cams - 911.105.143.00 & 911.105.144.00 - 2.7 CIS

I didn't find any broken rings, but did see evidence that the cylinders with low compression had a good amount of blow-by. I haven't gaged pistons/cylinders yet, but am guessing that the clearances are over spec on almost all of them.

My guess is that one of the previous owners toasted the engine at some point and had it rebuilt with used P&C's at some budget shop. Half the case bolts didn't have any sealant on them. The bolts with sealant had both blue and orange sealant. The sealing on the case flanges pulled away easily in places (case was oily when the sealant went on).

On the bright side, it does look like all the head stud inserts got put into the case.

Couple of questions for interested readers:

- Do you think my assessment of part numbers is correct?

- In your opinion - Is it worth rebuilding this motor with the 84mm (2.4L) P&C's? Or is it time to find a set of replacement cylinders or another motor?

- I'm guessing that the two cylinders with the cracks are not repairable (unless somebody has a different opinion?).

- Anybody have a gently-used 3.0L for sale near Portland, OR?

Any suggestions or alternate analysis here is appreciated. Thanks for the help.

[ratpiper71T]

If your cars a '75 the engine, well none of it is original. If those 84mm jugs fit the case, then the case as well is an early 2.4l engine 7r with 92mm spigots instead of later 2.7 98mm spigots, I think it is. On the bright side, I believe this case is more valuable to early car racers who want to build a small bore race motor. The pistons look like T pistons form a carbed or MFI engine

[James Brown]

What's the car look like? Any engine can be rebuilt even if you just reuse the breather cover and change the rest. But why, this engine has seen better days and nights. Would be easer to get a 3.0 from the parts page and call it good. You assessment of the engine seem to be good, the PO needs to be talked to sharply.

[fanaudical]

Thanks for the reply.

The car is in OK shape (see link up top for original thread with some body pics).

Ratpiper is right - that case has 92mm spigots - I didn't catch that last night. Looks like somebody swapped in a long block and kept the heads and CIS from the original 2.7L.

Looks like I have a nice stack of incompatible parts.

[fanaudical]

I thought I'd put an update out here since I haven't done so in a long time.

I have the engine totally disassembled. I was lucky enough to round up a set of new 2.7L P&C's and some nicely rebuilt heads. I'm soon to send out the case for some machine work. I had contemplating finding another case, but this one does seem to be in good shape and I think it's worth the machine work.

I got the gearbox apart this weekend to find that the ring and pinion are badly pitted, dog teeth on 3 & 4 are toast, and a broken spider on 1 & 2. The transmission wasn't nearly as scary as I thought once I got into it. Time to look for more parts or another transmission...

[fanaudical]

So much for keeping up with project updates...

Well, two years later, and progress. Engine is finally rebuilt and in the car, mated to a nicely rebuilt 915. Now I just have to finish a bunch of other stuff (drive-shaft rebuild, wiring issues, clutch adjustment, oil cooler....).

[James Brown]

1000% improvement, enjoy