Internal Case Damage

[Green993]

Can this damage to the case be fixed? Does it need to be fixed? There are two of these. If you want to know how it got like this go HERE

[Lapkritis]

Doesn't need to be fixed in my opinion; just a scratch on a non-sealing surface. Sorry about the rod bearing lesson; not a mistake that you'll ever make again so consider it education cost. I had a friend leave a camshaft bolt loose on one of his engines... crashed a bank of valves and bruised his confidence. It can be fixed - just takes a bit more time.

[Green993]

Thank you Andrew. It is a little more than a scratch. It's about 1/16 inch deep. Yes, this has been a learning experience to say the least!

[Walt Fricke]

Aren't you going to send the case off to Ollies or some shop of similar skills and experience? To have them check to see if the fretting (shown in the Rennlist discussion)is anything which needs attention? For instance, does the case need line boring (normally not, but this was a rather unusual situation - he forgot to install the rod bearings). If not, good. If yes, they can shave the mating surfaces and rebore to standard.

They can measure the cylinder spigots to see if they got pushed around (for want of a better term) when the case webbing next to them got dinged.

Otherwise, I'd clean them up a little so there are no sharp edges. Stress risers, you know - though one doesn't hear of those being a problem with a case, which is subject to different forces than rods or cranks or head studs and so on.

If I had to guess, I'd guess that all is well here because you didn't report having trouble getting the cylinders out of the case. If a spigot were well and truely squeezed, it might have been a real wrestling match.

Someone with a race motor in mind might purchase your crank - at least with older cranks guys were having them turned down to take Chevy or the like rod journals, which are a bit smaller than 911 journals on those cranks. The purpose of that exercise was to be able to use Clevite racing bearings (what NASCAR guys use), and the smaller rod journal has a bit less friction.

As an aside, I built a race motor using a GT3 oil pump, and it wasn't making the oil pressure it should, and I chased all around trying to dope that out. Still don't know, but a piston pulled apart so it is coming back apart anyway and maybe I'll find something amiss in the oiling department. But here, with no rod bearings at all, the idle oil pressures were decent, and only after running for a while and heating up the oil did pressures drop. And this would repeat itself when later the engine was started up again.

I contrast that with my experience with bearings which got too worn. My wife said the big red light (I use an oversized idiot light which lights up at about 30 psi) came on and wouldn't go off. Teardown showed a rod bearing down to the copper. But that 2.7 race motor had a turbo oil pump, which is as capacious as the pump in this 993 motor. And worn bearings are nothing like no bearings for space to let oil squirt out. Amazing.

[Green993]

Yes, I am planning to have the case checked out. But before I did that I wanted to make sure it could be salvaged. It sounds like it can and I will go that route. Any suggestions on where to try and sell the crankashaft? Ebay or is it more of a specialist crowd?

[Walt Fricke]

Well, Pelican has an active used Porsche parts list.