I almost didn't split the case

Alan Cottrill · Alan Cottrill's Garage

And now I'm glad I did.

this was the worst of the rod bearings. a few were worn to the copper. all the bearings, rod, main, and intermediate shaft were pitted and worn badly.

the crank is off to be mic'd. none of the journals were scored so I'm hoping for the best.

what's suprising is that the bottom end was quiet. no "unusually" loud noises.

Bobboloo · Bobboloo's Garage

Looks like you dodged a bullet on this one. Congrats on finding this problem before it found you.

HarryD · 12-14-2003, 01:34 AM

How many miles?

Why was the engine being rebuilt?

Doug Zielke · 12-14-2003, 07:09 AM

Nice shot, Al.
If you find anything else worthy of the "Mechanical Mayhem Files", please share.

Alan Cottrill · Alan Cottrill's Garage

it had a little over 150K. It's been rebuilt once before in it's life. it had case saver installed for the head studs. I had just tore it down to fix some leaks and get new valve guides/valve job and rings. supprise, supprise!

since you asked Doug...

these came from what I would call a strong running motor. no bad noises. right up to the day I tore it down it was running great.

Doug Zielke · 12-14-2003, 09:05 PM

Thanks v. much, Al....and good luck on the rebuild!
(Hope to see you and the car at Round-Up '04.)

HarryD · 10:51 PM

Thanks also. I just had my top end done @ 116,000 and opted to not touch P&C or case. However, my cylinders all still looked new (bores still had hatch and no unusual marks). Obviously, I took a risk, but I just wanted to get an after the fact gauge of my risk.

jgparker · jgparker's Garage

Wow, one of my P/Cs looked just like that, and mine was running fine too. (rebuilt for oil pressure probs.) I guess this is just how alusil P/C start to fail. Am I correct that yours are alusil?

Thanks,

JP

Superman · 12-15-2003, 07:38 AM

Interesting. At 183K miles, my bearings were tired, but not THAT tired. I had one small scratch on the cylinder wall (and matching scratch on piston), but it was very very minor. Nothing like the carnage I see here.

Doug Zielke · 12-15-2003, 08:04 AM

Mmmmm....c-a-r-n-a-g-e!
(Thanx, JP.)

Peterfrans · 12-15-2003, 11:29 AM

Could that damage be caused by the engine not running for a long period of time? It seems some sort of corrosion. Never saw it this bad. Good thing you opened up the case!

Alan Cottrill · Alan Cottrill's Garage

I have been wondering why the "carnage". The idea of the damage being caused by the engine not running for a long period hadn't occoured to me, however it makes sence. I bought the car last winter and it had been sitting for quite some time.

I took a few precautions when I started it for the first time...changed the oil, cranked with the fuel pump relay pulled for a few minnutes (30 seconds at a time) to get the oil circulating.

oh yeah...count me in for the round up '04. It's lonely out here in central WA. I don't know any other Porsche enthusiasts around here. It'll be nice to socialize with some people who share the passion.

Wayne 962 · Wayne 962's Garage

That type of damage is consistent with overheating. As the engine gets hot, the piston edge (flap or skirt) will expand and the clearances will get very close to the cylinder wall. If they touch, it's all over at that point, as the touching will create more friction which will cause more deformation, etc...

Looks like an overheating issue to me, but you can never tell for sure. Either that, or it ran dry, which may explain the bearing wear. This engine was indeed on its last legs.

-Wayne