RMS leak after rebuild 993
 

Just finished getting a 993 engine rebuilt. Engine started and ran beautifully for initial run in for 20 minutes (2000 to 2600 RPM) then suddenly died. Pool of oil directly under RMS (1/3 quart). Idle pressure was 3 BAR and pretty much remained at 5 until about 15 minutes, then 4 until it quit.

1. Could this be just a RMS failure?

2. Could this be an over-pressure situation resulting in a RMS blow out?

3. If an over pressure situation what would I be looking for as a cause?

You should look at the RMS to see if it was correctly installed as I don't think its an overpressure issue.

OK, Thanks Steve.

Make sure it is flush with the case when you inspect or install a new one. Also make sure there are no scratches, gouges etc. in the sealing surface, these can cause a leak quite easily.

Thanks Steven. Should it be flush or 2mm recessed?

Flush, I know the 993 manual says 2mm recessed, but everyone I spoke to Including Steve W said flush is the right way.

OK, Thanks. Flush it is.

No worries....

Update: Good News - Bad News.

Engine dropped, flywheel removed - 12 hours of fun.

Good news: RMS dry as a bone.

Bad news: it appears the leak is coming from one of 2 places: Either the pressure sender seal or the breather cover seal, most likely the sender. For the breather I applied a new seal and three bond. For the sender I just put in a new green o-ring and it appears fine - no tears or rips. Its hard to tell where its coming from because oil sort of spread out and may have deposited on the side of the breather (although it is on the opposite side from the sender).

From the pattern of the oil it looks like oil came out under pressure as opposed to seepage.

Any ideas on how to keep this from happening again? Perhaps three bond on the sender? I have three-bond 1194, 1211 and loctite 574 available.

Good news on the RMS... :)

On all the paper gaskets I put on 574. I only used Threebond on the case and on the head to Cam housing.

Make sure you lubricate the o-ring so it doesn't roll or pinch.

I have a question. Right before I noticed the pool of oil under the car it had been running fine. Then the car suddenly and without notice shut itself off. I did not turn it off. What would cause this?

Is it out of gas?

Still turn freely by hand?

Will it restart?

Spark or Fuel? Checking both is easy.

If something like the reference sensor was not plugged in correctly and shook loose it would cut out straight away.

I would check Spark and Fuel first. If no spark then go through and check any additional electrical connectors making sure they are secure.

Keep us updated.