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
Jason McLawhorn Greenville, NC 1955 Chevy
Posts: 476 | Location: Greenville, North Carolina | Registered: March 28, 2007
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.
Posts: 516 | Location: Going to or returning from the chipmine. | Registered: July 01, 2011
.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...
. Dave
F J B
Posts: 4569 | Location: Earth | Registered: February 08, 2006
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.
Posts: 2549 | Location: Moving back to the door side | Registered: April 30, 2010
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 .
honesty is the best policy,insanity is a better deffense 1.036, 6.16@ 224
Posts: 1472 | Location: texas | Registered: February 17, 2006
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.
B.J. Masiello
Posts: 250 | Location: Connecticut | Registered: November 27, 2007
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?
B.J. Masiello
Posts: 250 | Location: Connecticut | Registered: November 27, 2007
. 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.
