BBC 6.635 rods:best bearings?

Going to the machine shop tomorrow to finally get the 464 built. I have Eagle 6.635 rods going in a girdled block. I remember before all my drama started I was checking out rod bearings. The one I was looking at was Clevite 743H. Is that still a good choice? Any new choices out there that are better?

 

Thats what we use,teflon coated.
gary

 

Hey Gary!! Been a long time. Would that be 743HK?

 

Don't run an H type bearing on a cast crank unless it is coated. They have no tin flash plating and are designed for harder aftermarket cranks. The coating seems to be a great substitute for the missing flash plating.

With any build, it is even more important with coated bearings to size the housing bores and bolt the bearings in place and mic the sizes. This way you can give the crank grinding shop the exact sizes you want the crank to be. coated bearings sizes run a little different than non coated. A coated STD size bearing measures up like a .001 under size non coated bearing.

 

Would a 743P be better? Any other brand suggestions?

 

If not coated,probably.

 

ACL and Clevite bearings are the same. Either are fine non coated.

 

Thanks guys! I'll order some 743P's and give em a try.

 

contact polydyne about coating some h bearings they might even have those chev bearings in stock fast turnaround

 

JW preffers ACL bearings, he used these on our engine also.

 

"P" bearings are for passenger car application and should not be used on any crank that has the journal fillet increased. The "H" bearing is for use with high performance cranks with a larger fillet on the rod and main journals. Journal fillet radius is generally larger on reground cranks and strokers to increase strength and reduce stress risers.

 

Good point on the radius interference. This should always be checked.

A standard regrind on a crank would not get the radius big enough to roll into the bearing. Unless it is .030" or more under, with a 3/32" radius, P series bearings are fine, if not desired due to the soft flash plate on them. Soft cast cranks do not like hard face race bearings. It is easy to radius P series bearings if required.

Clevite also has another "P" series bearing that is a high eccentricity, narrow, chamfered, race only bearing. It has no flash plate and is for very high RPM engines that have rod bore elongation. I don't think they are available for Buicks, but if you use Chevy rods, they are. I use them in small blocks that spin over 8000.

 

I'm using Eagle 6.635's, so I'm sure the radius will be bigger. Good point. Good thing I haven't ordered bearings yet. Still torn as to what bearing to ordero No: