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bearing mix up?
Posted: June 19th, 2009, 1:15 pm
by jn2630
I ordered a set of main and rod bearings from ebay (last time I do that), and they sent me the completely wrong rod bearings (part number cb-760 p-20, which I believe to be a big block ford rod bearing). And the lower main bearings look fine, but the upper main bearing have an offset notch on them. Shouldn't it be in the center? Part number on those is MS-704 p-20. I have attached a pic to show what I'm talking about. What is up with these bearings?
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Re: bearing mix up?
Posted: June 19th, 2009, 1:35 pm
by RAPTORFAN85
what rods are you using, 4.2 or 4.0?
Re: bearing mix up?
Posted: June 19th, 2009, 5:19 pm
by SilverXJ
4.2 and 4.0L rod bearings are the same. The main bearings are different. Sound like you got bearings for the 4.2L block.
Re: bearing mix up?
Posted: June 19th, 2009, 9:31 pm
by jn2630
Yeah I think your right, I must have got main bearings for 258. The listing says it was for almost all amc and jeep six cylinder sizes, but I guess I should have checked the part number.
Yesterday I got my motor back from the machine shop, I thought it was already to be put back together, then I take a look at my bearings! It was so depressing...

Re: bearing mix up?
Posted: June 19th, 2009, 9:46 pm
by IH 392
The "MS-704" main set is for 1964-1990 AMC/Jeep 6 cylinder blocks and the "CB-760" are for Ford "FE" big block engines (rods).
Re: bearing mix up?
Posted: June 20th, 2009, 9:43 am
by jn2630
Well I got it sorted out and the new bearings are on their way!
Re: bearing mix up?
Posted: July 16th, 2009, 5:24 am
by woodjeep
I just found this site after I went to install the bearings that came with the crank I had purchased from an individual on another site, and they would not fit. The ms704 main bearings i found are good for 1990 and below. They have the offset tab on the block side but oddly they fit perfect on the cap side. Did a google and found this site, and found I need federal Mogul 7211M bearings for my 96 block. The connecting rod bearings are all the same. Oh well a slight delay and a fairly cheap fix always helps the learning curve. I look toward picking everyones brain now that I'm here
Re: bearing mix up?
Posted: July 16th, 2009, 7:09 am
by SilverXJ
Yes, you need to use the bearings for the block you are using, not the crank. I.e. On a 4.0 Block use 4.0L bearings. The 4.0L and 4.2L bearings are different.
Re: bearing mix up?
Posted: August 28th, 2009, 4:06 pm
by woodjeep
Hi, since you guys have just finished installing your bearings, this should be easy. I just put in a set of Federal mogul FM7211M main bearings into my 96-see my post on main crank bearings, they are supposed to be the correct ones. Where the open oil slots on the block side of the main bearings fit, my slots dont exactly line up with the oil feed holes holes in the block journal. The slot is centered left to right but I can't see the entire hole dia through the slot, like it blocks approx 1/4 or less of the total dia. The thrust bearing holes line up perfectly. I don't know if this is normal or my bearings are defective. I will have to take the crank back out for pictures if needed, but since you guys seem to have recently installed yours I was hoping you would remember exactly how they fit..thanks
Re: bearing mix up?
Posted: June 25th, 2011, 2:14 pm
by gradon
The bearings we have, clevite ms1947p10(7211m10), also have the offset notch/tab for the upper mains instead of a center notch/tab/locater, thus do not fit on the 96 block correctly. Is the bearing set I have mis-marked and actually the ms704s, cause they sound alot like the first ones you got?
Re: bearing mix up?
Posted: June 26th, 2011, 5:14 am
by Cheromaniac
gradon wrote:The bearings we have, clevite ms1947p10(7211m10), also have the offset notch/tab for the upper mains instead of a center notch/tab/locater, thus do not fit on the 96 block correctly. Is the bearing set I have mis-marked and actually the ms704s, cause they sound alot like the first ones you got?
Yes, it does sound like you were given the MS-704P for the 4.2 and Renix 4.0 blocks and they were packed into the wrong box. The MS1947P is for the '91+ 4.0 HO block and the locating tangs are in the center.