jaetee

Recently I was having a semi-spirited "therapy drive" which was rudely interrupted by a very short CEL followed by an equally short flashing oil pressure light. Car hesitated slightly and not less than 1/8 mile later, the engine died and I knew right away I had serious trouble on my hands. I had the car flatbedded to my mech right away. We dropped the pan and found copper colored, non-ferrous metals in the sump and oil. Droped engine, split the case and discovered that cylinder 6 rod bearing spun, and had started to take out the nearby mains...

The car is still relatively new to me and during the PPI/buying process I had them drain and change the oil (drained through a 100 micron strainer) as part of the deal. I also handed the mechanic an LN spin on filter adapter and Bosch filter along with the the oil I brought along.

One of the PPI write ups was that there was a visible bead of RTV around the sump plate which the mechanic felt was a little too much. Wondering now if there could have been some momentary oil starvation caused by a chunk of RTV having broken loose and plugging a narrow oil path, but close examination of the crankshaft also shows some pitting, which I guess is from oxidation due to car having sat for long periods of time undriven. Carfax did show that the car was only driven 150 total miles in the last three years leading up to my purchase, and receipts show only 3000 miles since major service for IMSB/RMS/Clutch/Tranny mount swaps were done in 2011. The receipt for that work showed that IMSB swap was done at customer request and not out of need. My car now has 90k miles, so it looks like it went from daily driver to garage queen in short order back in 2011.

The good news is that no dirty oil made it's way into the combustion chambers or the cylinder heads, so no head work needed and the cylinder walls look fine.

I added some close ups of the worst area where the damage started... as well as the main journal at the other end of the crank and the basket. I know it will need to be mic'd and magnafluxed to see if it truly is still useable, but I'm wondering if the pitting is a deal killer from the get-go. And with the apparent lack of oversized bearings available for the 996 motor (according to reading here) should I even bother with trying to have this crank fluxed and polished, or should I be shopping for a suitable replacement instead?

Prices for just the crank on ebay are insane, and buying one like that without seeing it first seems just as risky as having mine worked...

I'd prefer to have this one ground/polised and refitted. Some of the related threads I looked at here are a few years old and I'm hoping things may have changed a bit for the positive in that time... Is it really true that oversized bearings are not available for these?

5CHN3LL

1) That sucks.
2) How much metal in the sump? Any chance you have a photo?

jaetee

Photos of the sump drop are on my phone and I can't upload them right now, but there was hardly any metal in the sump at all, only tiny pieces and grains. The bearings were not yet fully destroyed... Here is a pic showing what's left of the two halves of Cyl #1 rod bearing.

strathconaman

Does this help?

http://www.design911.co.uk/fu/prod12...e-99610120904/

https://www.europeanpartssolution.co...sized-bearings

jaetee

YES! That may help very much...

Are the 3.4L bearings the same size as the 3.6L bearings?

Chris(MA)

For the RTV to plug up the oil galley it would have to make it through the oil filter, this seems unlikely.

If you have bad pitting on the crank bearing surfaces it could be the cause, the pits would grind away at the soft white metal shells and spin them, once the white metal was thin enough the oil pressure would drop and your warning light came on.

As far as I know, the crank is only hardened a few thousands deep, so a re-grind and thicker bearings won't work.
Trying to re-harden the crank after grinding is also risky, as it can warp or develop cracks.

I think your best option is a replacement crank, also you'll need to do some serious cleaning to get all those metal particles out of everything before re-assemble.

strathconaman

Maybe. This is probably something you should ask an expert, rather than random strangers on the internet

support@europeanpartssolution

Nickshu

Wait, what? I thought everyone here was an expert.

jaetee

LOL! Me too...

Experts will be consulted, for sure.... but this forum is such a wealth of info that I felt it prudent to start here.

Schnell Gelb

Good Crankshafts for this engine are hard to find. BTDT
I found and used a local ,ultra specialist repair place that repairs some(subject to pre-qualification) crankshafts.But I had a specialized Porsche machinist check their work.It was perfect.
http://www.marinecrankshaftinc.com/
Maybe someone similar in your area would know ?
This is a question for experts,not amateurs (like me)
Good Luck saving the c/s

extanker

if you do "fix" this motor .......sell the car............quickly

Noz1974

I was in the same boat, I ended up buying a used motor and stripping that down and rebuilding it, I sold off all the good bits from my old engine , heads and good pistons get good money, case halves also , you could probably recoup a fair bit !

tomcat

There was a crank in the member classifieds for $1,500 some time ago.

Undersized bearings will cost you and non-Porsche bearings are a gamble.

Call Shaftech if you want weld.

Grind and use Subaru bearings - call SSI in MD.

jaetee

That's not my style or intent. We are not just slapping this motor back together as cheap as possible. If I could afford a Raby rebuild, that's what I'd do... but in place of that it will be properly cleaned and put back to good specs with some prudent upgrades along the way. I will be taking lots of photos and keeping all receipts.

Afterwards, I plan to drive the car well long enough to prove it is reliable.

Note to self.... don't buy my next car from extanker. LOL!

jaetee

I will definitely call them. Thank you!