<<3.6 Conn Rod / Oil Pump Noise>>

6771911esses · 05-10-2008, 01:23 AM

Just had my 3.6 top end done. Installed new connecting rod bearings w/o splitting the case. Engine now has a slight tick when it is cold. We checked the (new) tensioners and these are fine. Oil Pressure is spot on. Valve clearance is set right. Noise goes away when warm.

My mechanic called his friend that runs a bigger Porsche shop and he says that he has seen it before. His story is the following:

I have been told that the #3 conn rod ever so slightly touches the oil pump when cold and that it may remedy itself and if not the oil pump has to be filed down just a bit for increased clearance. The mechanics had no explanation as to why this happens but the latter mechanic said that he has seen it with 6 (six) 3.6 engines and has heard it from other builders.

Has anyone else experienced this or heard of this? I can't imagine that the tolerance is this small for this to happen.

Would like to hear your comments/ experience with this 3.6 "phenomenon".

Mike

herman maire · 05-10-2008, 04:08 AM

Clearance between the rod and the oil pump is a issue sometimes when you use after market rods just because they are a different design and are larger/stronger. I really feel if your using stock rods you should not be touching the oil pump housing at all.

I am sure others will chime in but stock rods touching the oil pump housing..... I dont think so.

Tinker · 05-10-2008, 04:49 PM

This is a potential concern. I've seen a bunch of 3.6 oil pumps with cracked housing that most mechanics try to explain away as defective or caused by the pump's bearings. Even with a cracked housing they seem to perform adequately, but may 'bleed' a bit. I too have noticed how close the #3 rod comes to the pump housing. My thoughts are at high rpm the centrifugical forces 'could' cause the end cap to 'grow' slightly causing it to 'knick' the housing and crack it.

Just my guess.

Tinker

6771911esses · 05-11-2008, 05:00 PM

I hope my oil pumphousing will not get damaged by the knock. I guess it will need to come apart again and file down the oil pump housing. How can Porsche make an engine with such tight clearances?