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What are folks using for their rod/main bearings on an FI application? Im rebuilding a spare engine I have and can't decide between OEM or the Ireland race coated aftermarkets.


Thanks

The stock parts are very stout unless you're going really insane.

sweet good to know.... everyone using oem for the most part?

I didn't even replace mine. Plasti gauge and reuse what the factory installed if the clearance checks out. You won't match what BMW did unless you machine everything

Stock.

Ditto for stock. Never had any issues.

Leave it alone. Many other thing to attend to.

So even when building a high power turbo engine, we all agree that stock is best?

There's really no reason to spend money on "upgraded" aftermarket rods or bearings unless you're chasing every last ounce of performance on a build pushing 2 bar or something similarly nutty. The money could be better spent on pistons, better engine management, an intercooler upgrade, water injection, etc.

There's a build on e30tech where this guy coated the bearings
and pistons skirts with whatever it is IE has or everyone else I'm sure that stuff is all standard, but it wear pretty quick.

I don't remember the details it was a long time ago.

jodystevens wrote:So even when building a high power turbo engine, we all agree that stock is best?

Look into the problems we have when boosting. Its not " oh damn i spun another bearing!" or "crap! why do my connecting rods keep bending?"

The bottom end is well up to the task. Keeping a head gasket in place is where to keep your worry.

I've yet to see anyone reach the limits of the stock bearings. Theres no reason to assume the aftermarket stuff if even as good let alone better than factory parts. Bearing shells don't need coatings they need a steady supply of the correct type of oil.

Here's my experience with aftermarket bearings and heavy clutches. This motor was line bored and honed, the crank was turned and everything was plastigauged and in spec. I know there are others who have ran Spec clutches and I've never heard of someone taking the thrust bearing out like this.

I pulled my bearings (crank and rod) and the have a part number 1150352001.3 on them with the letters "BMW" below it and the BMW logo below that. A search of that part number returns nothing except a bunch of non-english results. I would have thought they were the OEM if they had the logo stamped on them...

jodystevens wrote:I pulled my bearings (crank and rod) and the have a part number 1150352001.3 on them with the letters "BMW" below it and the BMW logo below that. A search of that part number returns nothing except a bunch of non-english results. I would have thought they were the OEM if they had the logo stamped on them...

I'm sure they're factory. Replacement parts don't often have the same part numbers as the originals.

Searching that part number in real OEM returns nothing...