Does anyone know how long the replacement "shorter" bolts are that run through the bell housing when you use a replacement oil pan? I'm halfway through replacing the pan and, to my surprise, mini wants you to use shorter replacement bolts and the pan is physically tapped shorter. Nobody seems to know what the replacement part number is, though. I called my local dealer and they have no record of shorter bolts in their system. The bolts are M12 and 65mm long from the factory. I'm guessing they need to be either 55 or 60mm in their shortened state.

Disclaimer: Yes I'm aware that most hardware stores will have these. However, since it's mounting between two important pieces of the car, I'd like to at least know the correct factory specs before buying anything.

FWIW the pan is fine and the repair manual specifically states using shorter bolts:



It's the two lower bolts with the "1" tag.

 

http://www.realoem.com/bmw/enUS/show...diagId=23_0915
It is a real handy site to bookmark. Don't really see anything shorter, even looked at the diagrams for the 11/06 MCS and it is the same. When I did mine this summer I just reused the bolts.

 

I had the same issue when I called the mini dealer. I think they're all referencing the standard assembly drawings and part numbers .The problem lies with BMW wanting you to change to a different part number when you replace the pan.

Did you replace the entire pan or just the gasket?

 

I replaced the gasket because it was leaking. Found some timing guide plastic so did the timing chain, front and rear seals, clutch, all sensor o-rings, supercharger oil service, idler pulley, tensioner pulley, belt, etc.

 

That would explain the difference. I'm doing the whole pan and apparently the replacement pans are tapped to a shorter depth (already confirmed with the distributor)

 

This is a good thing to know.

 

So I called pelican parts to see if they had any words of wisdom after the second mini dealer looked at me funny. They don't see a different set of bolts either. However, the guy I talked to said he had heard of similar things in the past.

I'm just going to end up buying some matching, albeit shorter, bolts off McMaster

 

I would have bought a used pan.

 

Meh, I got the new pan at distributor cost so it hardly cost me anything. It's my fault for not looking up the procedure instead of just following the gasket replacement descriptions. I just looked up the pan replacement procedure on newtis and the call out for the different bolts are right there (still no word on what size they are).

FWIW to anyone reading this: The shallow pan is tapped to a depth of about .7 inches (probably really 18mm) and the bell housing is about 1.6 inches thick where they meet up. A 60mm bolt will bottom out on the threads before contacting the bell housing. A 50mm bolt will only engage about .375 of the threads. The replacement bolt is almost certainly a m12x1.75 x 55mm flange bolt.

 

Final update for anyone who runs into this issue in the future:

The replacement pans are tapped to 18-20mm deep. This causes an air gap, of approximately 7mm, when the factory 65mm bolts are reused. The correct shorter bolts appear to be M12 x 55mm. Do note: the 65mm bolts are flange bolts. The corrected 55mm bolts are also assuming usage of a flange bolt. If you use a regular 55mm plus a washer, you'll lose thread depth and wont have the true 55mm.