Montychristo128

And just for the record no IMSB failure. All the bores are oval though and two are scored. Is this the new IMS???

Noz1974

There was a good write up about parts interchangeably by Autofarm I think, might be worth a read!

Montychristo128

Cool I will take a look. Really helpful thank you.

Porschetech3

Yes, they ARE the same !! I have a set ,pm me.

Montychristo128

Thanks Porschetech 3. Looking forward to the care package.

Block is on its way to LN for liners, we are on the road to recovery!!!

Porschetech3

Your Welcome !!Your rods are on the way.. Check your e-mail for tracking number.

docmirror

This primary failure mode surfaced in the 928 world with auto trans mostly in 86 and newer cars. Of course, the failure inducer was completely different as the torque of the engine would produce a twist shrink in the transaxle shaft. The take-up and release causes the pinch clamp on the flex plate to extend, and pushes the crank slowly into the thrust bearing and then the block.

In this case, either the driver rode the clutch all the time, or the clutch pre-load was out of spec and maintained forward pressure on the flywheel and crank. The debris found in the filter seems to be a mix of thrust bearing, and crank metal, with some other secondary swarf tossed in for good measure.

While a decent borescope would have discovered the cyl scoring, nothing short of disassembly would have discovered the thrust bearing issue. It was doomed to disassembly from the very start. A sad end to this engine. I don't think I would trust a crank exchange in this block unless it's checked very carefully. The crank thrust failure generates a lot of heat on the case journal. If it were brought up to spec, you could later suffer fretting of the case at the main journal surrounding web due to heat cycling from the slow thrust bearing torture(not 'superficial' at all).

I read a decent write up of a money-wise 996 owner who chose the Boxster engine swap and used a 3.2 from a Boxster S as I recall. The conversion sounded fairly straightforward with a few holes needed to be drilled somewhere for fitting the intake, or some other deal. Didn't sound like a rough job. The lower HP he advised was hardly noticeable, which makes sense as the difference was quite marginal. I'm not advocating it, but for the price of a Boxster S engine, vs a full rebuild, something to consider. Of course, the Boxster S engine would need very good evaluation before purchase, but the same can be said about the rebuild process as well.

Sorry, hope it has a happy ending whichever way you go.

Schnell Gelb

Boxster S 3.2 (no 3.4 in the Box as stock)engines are around the the same price as the 3.4 from the 996. 2.5 and 2.7 Box engines much cheaper but down on power for the O.P's. application
Call L.A. Dismantlers for more.
The real challenge is not price it is finding a good 3.4.Even a good 3.4 long block is difficult.3.2 different story.Much discussed in Search

docmirror

Oops, sorry and thank you. I will amend my post. I thought the 3.2 engine was significantly cheaper than the 3.4 in the used market? Haven't checked.

docmirror

Hmmm...

http://www.ebay.com/itm/01-Boxster-S...JY5E2h&vxp=mtr

http://www.ebay.com/itm/2001-Porsche...VYBBY6&vxp=mtr

22k miles, no core charge, $5k. This would be good to put in my car for DD use, and keep the 3.4 in wraps for resale some day:
http://www.ebay.com/itm/01-Boxster-S...1YeXLn&vxp=mtr

Montychristo128

My Engine builder is being extremely careful with everything, so I'm trusting we can get the old block back up and running, he has ideas for improving this particularly woeful single thrust bearing situation too and is using lessons from other 911 engines.

Just so there is no confusion regarding "clutch riding" I'm not the guilty one, as I drove it approx 900km's of its indicated 130K kms before it "failed".

I have to agree regarding PPI, it would never have picked up the thrust bearing failure, but probably would have spotted some of the other crap that's been done, a lesson learnt and clearly a warning to anyone else who buys one without a PPI.

I also have a horrible suspicion that the repairs carried out prior to purchase were to disguise this issue, but of course I'll never be able to prove it!

Flat6 Innovations

An extensive PPI could have detected this.. Debris in the oil is one way, part of the thrust shim in the oil sump is another... But just grabbing the crank pulley and thrusting it fore and aft is the quick way.

PPIs for these cars are a joke, its time that shops and dealers be held accountable for what they don't find. That said, an extensive PPI takes me all day, and costs over a thousand bucks.

docmirror

Yeah, the three places I called for a PPI wanted to focus on all the cosmetic and systems stuff. Like: "wipers, low speed - good. wipers, high speed - good, wipers, intermittent - good,,,". When I told them I wanted the sump plate taken off, and the bottom of the engine inspected all of them said something like 'well, that isn't the kind of pre-purchase inspection we do, and it would be $xxx for us to do it, and we can't guarantee the results, etc.' I just blew them all off and did it myself. Learned a bunch and really got to know the car well, and I was a noob on the model. But - I got the sump plate off and on, and learned what I wanted to know.

Having been inside a bunch of piston aircraft flat engines, I would still be very leery of reusing the block. I've seen fretting on some engines at the case halves from the weird 3rd order harmonics of the Otto cycle 6 cyl opposed flat style(supposed to be perfectly balanced, but - no, torsional loads have to take into acct). Of course, the water cooled auto engine is quite different, but the physics of the harmonics are the same.

KC-CarGuy

Whoa... engine shut down sounded funny.

Montychristo128

Just to update anyone interested, we have progress. My block halves are on their way back from L&N complete with Nickies , still looking at crankshaft options and "all the other stuff", but one piece of the puzzle has dropped into place.

Time for wallet exploding bills to start arriving.

You never know I might get to drive it this summer!!