I will check the receits, but I believe he discovered what he thought was "slight valve noise" and continued driving for over 10k. I will double check soon.

 

Piston slap does not sound like a rod knock to me. Worn out rod bearings are not ususual, piston slap would (IMO) be. You might try to find out whats wrong with the car and no, don't drive it.

Mods generally means the car has been driven hard. It's not too hard to have #2 rod bearing failure with a goodly number of hard miles. Driving with a rod knock might lead to tossing the bearing, breaking the rod and then holing the block. There was some kid on this list that did just that, took his S2 with a rod knock on a roadtrip and wrecked the whole bottom end.

I would suppose if you did not (do not) drive the poor thing into the ground the crank could be turned, the rods resized, and you could be back on the road without breaking the bank.

Assuming it's a rod bearing, that is. Which would be my guess. Where are you located?
-Joel.

 

Joel, I have heard both on 944s in person, and they sounded very similar, only the rod noise was louder and more like shaking a tin can full of marbles than a duller piston noise. Can you describe the difference?

Oil pressure was very much lower in the rod bearing case, like under 2 bar during hot idle, this was before a knocking noise even happened. Maybe some more people who have seen rod bearings fail (not on the track or from low oil) can chime in. The other thing I noticed when the rod bearing failed is that oil pressure was very slow to build on startup, like it took a good 5 seconds before the needle jumped up, maybe that will help.

So far I have seen 2 cars with the piston slap, a 944S and this S2, so it might not be as uncommon as it seems.

 

Hmm, but I do need to drive to work three times a week. Think it could handle that until the end of the month when I get paid? Work is about 38 miles, round trip, according to my rental's trip odometer.

I'm in Napa, which is about an hour north of San Francisco, in Northern California.

 

I had piston slap in my 91 Cherokee as well as thousands of other owners. It was a dead ringer for a rod knock at idle, cold or hot. The problem was caused by mismatched pistons and poor line boring at the factory.

I wonder if this car has the same problem as yours; he must know something is seriously wrong. It not your car is it?

http://sacramento.craigslist.org/car/147216367.html