What is everyone running for rod bearing clearance with aluminum rods? I’ve never run aluminum rods before but saw where BME states a min of .003”. Im at .0035 now and wanted to see if I was good or if I needed to tighten it up a little?

Thanks
Jason

I would go with it. Remeber, .003 is the recommended minimum, you may need more depending on operating conditions.

apple to oranges. I run .004 on my Hemi aluminum rods .If your .0035 on .003 I would run it.I differently would not tighten it up.

Thanks guys!!!

BBC here but should not matter, bearing does not know what engine its in. .0035

This made me remember a saying an old dirt track racer I used to do machine work for said" build it a little loose no one but you will know. Build it a little tight, everyone will know." Kinda true if you think about it.

Yea a engine is only time loose is better than tight.LMAO

Mains at .004

.003 turns into .0045 when aluminum rods get up to operating temperature.
The big end grows so much there's no clamping force on the bearing any longer. That's why there's a pin through the bearing to hold it in place...

quote:

Originally posted by imakehp:
.003 turns into .0045 when aluminum rods get up to operating temperature.
The big end grows so much there's no clamping force on the bearing any longer. That's why there's a pin through the bearing to hold it in place...

Guess my .0035 is .005 when warmed up then, maybe that's why it makes such good power . Just took my engine apart to give everything a look see, rod bearings looked like they came out of the box. Sent the Rods to MGP and they gave them a clean bill of health on both the big and little end and also said the bearing transfer to the rod was perfect.

MAn my .004 rods and .005 mains is really loose.So I can spin it more.yee haa

i like loose clearance also but there is always gains and losses,loose may mean low or no oil pressrure in shutdown.its ok as long as you know and precautions are taken .

IMO .0035 with an aluminum rod is fine. In fact I would be nervous about running it at .003. In my personal experience I have never seen an issue with a little too much oil clearance. I have seen issues from being a little tight.

quote:

MAn my .004 rods and .005 mains is really loose.So I can spin it more.yee haa

quote:

MAn my .004 rods and .005 mains is really loose.So I can spin it more.yee haa

My old big block I was between .0038 and .004 on the rods. The bearings came out looking like brand new. That was spraying between 300hp and 600hp every run on a 572.

I was closer to .003 on the mains and they looked the same. I have zero experience with hemis don't they tend to set those up a little on the looser side though?