Main and Rod bearing discussion

Did a search on bearings and didn't come up with anything current so I thought I'd see what everyone is using these days for Main and Rod bearings. Coated, not coated etc.

Looking for information as I will be doing a 533 Injected alky race motor soon and want to set it up with the best bearings for the application.

Thanks
Alan

Machine work and the blueprinting is as important or even more important than the actual bearing imo

dfree383 wrote:Machine work and the blueprinting is as important or even more important than the actual bearing imo

^^^I agree with this wholeheartedly. Crappy machine work will not play nicely with most any bearing. With that said, my personal preference in any engine I build is King bearings. There are a few different "levels" of bearing that King puts out, so choose the one that best suits your application, but I have had engines saved during unfortunate circumstance by using King bearings. Again, that's my personal preference.

On steel crank motors, I use the King XP as often as I can.

I used to use quite a bit of XP's - try miking a BBF main bearing shell and watch the thickness drop at the edges (1/4" in) by OVER a thou. !!
Only the BBF and BB mopar mains are made like that, according to King.

Here's a link to some really good info on King Bearings

http://www.kingbearings.com/technical-info/

I called and just had this conversation with the tech guy a King. I am building a much bigger motor that will not only see motor only runs but have the ability to spray large amounts of nitrous if needed for my outlaw classes. If it were motor only the coated XP bearings are the way to go, but since I plan to put the screws to it with spray I would be better off with the HP bearings. Choose wisely, or call King for their recommendation.

Thanks for the input. Good machine work is a given.. Yes I try to find deals on GOOD parts, but don't believe in cheaping out anywhere. It usually cost's more in the long run lol.

HorsinAround wrote:Thanks for the input. Good machine work is a given.. Yes I try to find deals on GOOD parts, but don't believe in cheaping out anywhere. It usually cost's more in the long run lol.

This^^^ Going cheap makes expensive explosions

I have not seen or aware of any issues with the King MB5650HP main bearings...good stuff.

Which ones are the 3/4 groove units??

Lem Evans wrote:I have not seen or aware of any issues with the King MB5650HP main bearings...good stuff.  

Lem - take a ball mike across the bearing and you'll see what I've been discussing with Ron Sledge (Tech manager for King) for a few months now.
The spec on the HP mains was changed to incorporate a "relief area" to prevent "edge loading" of the bearing. The current spec (as well as eliminating the 3/4 groove) calls for .0007 to .0012 taper from the edge of the bearing shell going in almost 1/4". Yes, you read that right - it changes the bearing oil clearance anywhere from .0014 to .0024 at the outer section of the bearing. This leaves only about 1/2" of bearing "contact area".  Strangely enough, the "SI" series bearing does not call for the relief and is made of the same material (according to Ron) and has the same strength and heat rating as the HP.

BBFTorino wrote:Which ones are the 3/4 groove units??

Used to be "3/4"....no longer are.

Lem Evans wrote:

BBFTorino wrote:Which ones are the 3/4 groove units??

Used to be "3/4"....no longer are.

They don't make them anymore?? If not, why the change??

pmrphil wrote:

Lem Evans wrote:I have not seen or aware of any issues with the King MB5650HP main bearings...good stuff.  

Lem - take a ball mike across the bearing and you'll see what I've been discussing with Ron Sledge (Tech manager for King) for a few months now.
The spec on the HP mains was changed to incorporate a "relief area" to prevent "edge loading" of the bearing. The current spec (as well as eliminating the 3/4 groove) calls for .0007 to .0012 taper from the edge of the bearing shell going in almost 1/4". Yes, you read that right - it changes the bearing oil clearance anywhere from .0014 to .0024 at the outer section of the bearing.  This leaves only about 1/2" of bearing "contact area".  Strangely enough, the "SI" series bearing does not call for the relief and is made of the same material (according to Ron) and has the same strength and heat rating as the HP.

I'm sort of dealing with this issue right now and causing some clearance issues. Using the standard size HP bearing it gives me .0025 clearance, using the Extra Clearance HP bearing it moves me to .0035. Looks like I'm going to either split the sets or look for another bearing

kjett wrote:

I'm sort of dealing with this issue right now and causing some clearance issues. Using the standard size HP bearing it gives me .0025 clearance, using the Extra Clearance HP bearing it moves me to .0035. Looks like I'm going to either split the sets or look for another bearing

Nothing wrong with using half sets ...as long as there is no more than half thou difference.

As Randy said - nothing wrong with halves from STD or "X" sets, myself I'd prefer the .0035 for mains. Did you check just in the middle of the bearings or all the way across?

pmrphil wrote:As Randy said - nothing wrong with halves from STD or "X" sets, myself I'd prefer the .0035 for mains. Did you check just in the middle of the bearings or all the way across?

That's the plan as of today, just bothered me how the bevel changes clearances that much. We checked all the way across, and as you had said earlier its tighter in the center than it is on the edges. Will use the extra clearance bottoms and standard tops, and keep a reverse set for back up.