So first let me explain this wiped out all the CRANK bearings on my 95 cheorkee. Pulled it out took it to a machine shop to have it rebuilt and the block appeared to have been machined already (previous owner said they rebuilt it) and machine shop told me they had done poor machine work on this motor. i got a donor 1999 block out of a buddys XJ and had them rework that and they rebuild my 7210 Casting head. This motor got new pistons, rings, bearings, valves, springs, an isky camshaft and oil pump (with of course all the machine work). Dropped it back in and about 200 miles later blew out all cam bearings. pulled it out sent camshaft back to isky to be polished and new camshaft bearings, and crank (metal shavings messed up the crank bearings). Machine shop completely disassembled motor and cleaned it out and re-assembled, also with another oil pump. Back in the jeep it went put 150 miles on the jeep and oil pressure drops again pulled the oil pan and cam bearings all wiped out again. now here is my questions and concerns. we are still using the pin and spring method to prevent cam walk on this 99 block which originally had a plate bolting it in. But the cam we are using is for a 95 block so the camshaft a tad long and cant bolt it to the block. machine shop decided this time to use yet again a new oil pump but machined out custom Brass bearings instead on using the clevite bearings we have been using. motor is built but havent droped it back in the jeep yet as im worried this wont be a fix and dont want this to happen again. Anyone ever used brass bushings as camshaft bearings before?

 

Quit mixing components. The camshaft must be like the '99 block is supposed to have. Why in the world did you order a new camshaft for a '95, while you have a '99 block?

I can't believe after the first failure you didn't correct the problem.

Brass is too soft for a camshaft bearing. I question your machine shop's "knowledge" on what should go into an engine. After failure, the cause of the failure must be definitively diagnosed before "cleaning" the engine and reassembling.

 

^^^^^X2^^^^^

How many times are you going to let that machine shop screw up your engine? Obviously things aren't correct because it's eating cam bearings as fast as they can replace them. There's no way I'd trust that shop to do anything else, especially install "custom" brass cam bearings. Make sure you have AAA. Sounds like you might need it.

 

Well we had originally ordered that cam for my original block and everything mounts and works the same as it would on a 95 block. If you think this has been the issue I will have them swap the cam and timing gear to the bolt in style 99 version. I just don't feel comfortable putting this motor back in when I feel like the brass bearings are a bad idea

 

Both of these can't be true.


Have another shop fix it correctly with the correct parts, and you'll probably be just fine.

Mess around with more jury-rigging, and you won't be fine.

 

I have seen on many stroker builds that this is common to run a pre 99 camshaft. The specs on the cam are the same as the 99 just the way it mounts. Has anyone on this forum done this?

 

https://www.cherokeeforum.com/f59/up...mshaft-182972/


Link to thread I found of someone mentioning that you can do this

 

Brass is HARDER than copper......most bearings are a copper alloy.

Bearings are softer than the materials spinning in them......bearings wear faster than cams and cranks.

 

They needed to true-bore or line-bore the cam.......guarantee you they did not.

Brass will NOT solve your problem.

 

Yes they indeed line-bore the block and i know they did! BUT i have made a mistake they didnt make brass bearings... they are infact BRONZE if that makes a difference.

 

It doesn't make a difference. They could make them of copper, bronze, gold plated platinum, or frapinated left-handed dilithium crystals. It won't make any difference.


Your problem is NOT the material from which the bearings are made. The stock bearings work just fine for hundreds of thousands of miles. Something is causing a problem with your bearings. Find that problem and fix it, or you are wasting your time and money.

 

Yeah, I knew what you meant by brass.


Did you lay the two cams side by side and compare?

 

yes i did

 

and i understand there is an issue and thats the problem is i dont know what that could be. thats why im on here asking questions.. the cam was sent to isky and they looked it over said it was true. the machine shop be fore last assembly re-checked the line bore and that was straight. the bearings wear on the loaded side. so idk..

 

Now just suppose.... your new valve springs cant compress enough at full lift? Has anyone measured that? Decked block, milled head, bigger cam, taller springs all lead to bind in the valve train.

Just a few things to consider........