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So, about changing them bearings....

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Any advice to make my life easier when I'm changing them? Any thing else I should change while I'm in there, besides the oil pump (I already changed the RMS)? I'm kind of a noob at this but, I need to change the crank bearings and the bearings on the connecting rods right??


I know they have different bearings for the 4.0 with different (correct me if I'm wrong) thicknesses, so which ones do I need?


Would it be a good Idea to change the cam bearings too?? Or do I have to take the cam out to do that. Because if so, I'm planning to change the timing chain and water pump while I have this thing torn down, so I guess I could take the cam out then. But it might not work that way.


Any and all advice will be much appreciated :thumbsup:

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Firstly, unless your crank has been at one point turned, you need factory sized bearings, cam bearings need to be installed at a shop so I wouldnt be messing with these. Just remember to lube up everything with a good engine asssembly lube, and it's definately a good idea to prime the pump before you fire the motor.


Good Luck!

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Firstly, unless your crank has been at one point turned, you need factory sized bearings,

This is not always correct. The factory sometimes used under/oversize bearings if they had to grind the crank a bit more to get a good surface. When they did that, they marked the side of the block with a code. That's what you need to check for.


There is a boss on the side of the block just behind the distributor. If they used non-standard bearings, they stamped a one- or two-character code on the boss. Codes were;


B = All cylinders .010" oversize (bore, for ordering rings)


M = All crankshaft MAIN bearings .010" undersize


P = All connecting rod bearings .010" undersize


C = All camshaft bearings .010" oversize

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um.......i'm a dumba$$. When i first read this thread i couldn't figure out what RMS was, so i thought it was something else i needed to fix, until just now i remembered what it was, And yes I have already ordered my REAR MAIN SEAL

I hate when i have these brain farts :wall: :wall: :wall: :wall: :wall: :wall: soapbox.gifsoapbox.gif :fs1: :fs1: :fs1:


But thank you Automan anyway for answering my dumb question.

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YOu might want to check to see what the price difference is between a reman crank, and just your bearings is. When I did one on Pong a fw yrs ago for like 25 bucks plus core I could get a reground crank. To me it was worth a new crank and bearings.



As for Cam bearings Unless you disassemble whole motor.. you won't get them out. Also need a special tool to do it.

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  • 2 months later...

well! I finally got the bearings changed. It seems like the oil pressure is back :thumbsup:

I changed the oil pump, which almost killed me after the second bolt came out and it dropped like a brick.

The main and rod bearings were a snap, no big deal. I was extremely methodical not to mis match any caps or install them backward.

I also changed the Timing chain and gears. Can someone explain why there is a spring and pin inside the bolt for the cam gear???


And all this was done with the motor in the truck. It was probably about 10 times difficult than having it on an engine stand...but I wasn't set up to pull it out.


So, with the increased pressure from the new bearings and the new oil pump I seem to have blown one of the gaskets on the oil filter mount. Didn't notice it until I let the engine warm up one cold morning. Theres a pretty sizable puddle under where the filter is. Apparently it had been leaking for a while since I changed the bearings cause the tranny and oil pan were coated in oil.


Thankfully someone posted a link to how to do this in a previous thread I started.


Since its Christmas day I won't be able to get a new gasket set now. Next next day I have off I'll get that done and let everyone know how it goes.

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