stripped nuts on oil pump

[fmangiero]

I am rebuilding an '82 911SC Euro 3.0 engine. This engine had a catastrophic failure (piston and ring detonation) so I took apart the oil pump to thoroughly clean it. I couldn't find a spec on torque values of the nuts at the back of the oil pump...I guessed 15 ft lbs. I was wrong!!! I need to find the studs and nuts for my oil pump. Any ideas on a resource for these? There are not even parts numbers on PET.

[ChrisBennet]

I'm curious, how did you torque them? I.e. what sort of wrench (beam clicker, etc) and what range? Did you strip the nut or pull the threads out of the pump body?
-Chris

[fmangiero]

I torqued to 15 ft lbs and it stripped both the nuts and the threads on the studs but the studs stayed in the oil pump body and didn't damage the pump itself. I was able to remove the nuts. I need to replace the studs and the nuts. The pump itself is ok with just a little bit of scoring from metal debris from the blown piston.

[ChrisBennet]

I.e. what sort of wrench (beam clicker, etc) and what range?

[fmangiero]

it was a clicker .... 10 - 90 ft lbs. I shoulda used the small one.

[ChrisBennet]

I think I had a clicker wrench or two that wouldn't click if the setting was too low. It takes a lot of torque to strip a steel nut - more than 15 ft/lb I think. Personally, I would replace the studs and put the nuts on with a little blue Loctite and hand tighten. You can make your own studs by cutting off bolts. Check the sizes (diameter and pitch) carefully.
-Chris

[Groesbeck Hurricane]

I had to go back into my motor because the two CLICKER style of torque wrenches I was using were out of calibration. I went back and used a BAR style (oldfashioned but it works wonderfully) and an electronic one that had just been on a calibration bench. You might want to verify that the wrench is giving good values. Just my $.02...

[john walker's workshop]

that was the low side of the spec for a 8mm nut. those are 6mm. that's why they stripped.

[Wayne 962]

Yup, the torque specs for this are page 200, in Appendix A (M6 nut).

I would ditch the pump - scoring is bad, especially if the engine blew up. Ditch the oil coolers too - they probably have lots of chunks of metal that you will never be able to get out...

-Wayne

[ChrisBennet]

I was lucky, when my motor blew, I didn't find any bits except what was in the sump. (I disassembled and cleaned everything and had the oil coolers cleaned.) I was unable to find the oil pump O-ring as a Porsche part # so I had to source it from someplace else.
-Chris

[fmangiero]

First of all, thank you all for a speedy response. My solution...I called dc Automotive in Bridgeport, CT. Rob had an oil pump from a blown up motor and gave it to me. I always forget to call him first. I removed the bolts and extracted the studs and I am going to use them rather than cutting the heads off of bolts (I'm lazy!). My oil pump looks like it is "new out of the box" other than a few minor scores due to debris. I stared at this oil pump and lamented to friends about it, but it doesn't have deep scores in the aluminum case and the blades show no signs of scoring and wear. Also, when my piston blew, the engine still ran pretty well. I thought I just needed a tuneup and valve adjustment, but my oil pressure registered very high on my dashboard indicator (because of debris jamming the oil bypass piston). I drove the car in this condition for 2 weeks until I did the oil change and found a few pieces of piston/rings.

I sent my engine oil cooler out through a local machine shop to be ultrasonically cleaned and tested. What are your viewpoints on this process?

[ChrisBennet]

I had both of my coolers ultrasonically cleaned. The engine one failed a pressure test so I replaced it with a good used one (that had been ultrasonically cleaned).

It's probably heard this a zillion times by now but you need to clean everything. The oil gallery plugs need to come out, the thermostats needs to be cleaned, etc.
-Chris

[Wayne 962]

Engine failure means bits and pieces of metal that will become dislogdged and score and damage your new bearings. It's just not worth the risk!

-Wayne