Replacing Main bearings while the engine is in the truck.

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StevoJonesFJ60

StevoJonesFJ60

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I am going to attempt changing the main bearings of my engine while the motor is in my truck. Are there any issues or problems I should be aware of?
Are there any tricks to this?

I have a 1987 2F motor.
 
You *might* be able to do this, but why? The hard part will be slipping out the upper part of the bearing shell.

If they are OK now, you risk messing things up in a big way. If they are bad now, replacing them will just be a band-aide, and you need to rebuild anyway.

I replaced rod bearings once years ago while under the truck and that went OK, but with the crank in the way, those upper main shells are going to be tough.

I'll be interested to follow your progress.
 
A band-aid is really all that I'm looking for.
I have a 6BT swap in the works. I just need it to last hopefully for the summer while I collect parts and funds.
 
The bearings I have now are shot, and allow the crank to move enough to let oil past the seal at the timing cover. I really just need to reduce the oil loss or get rid of it altogether.
 
I have done it years ago in a toyota fork lift that had a 2f .. it ran for another 10 years .. A good band aid. the upper bearing shells just slid right out with turning the engine in the right direction and a gentle push with a screw driver and the new ones slid in the opposite way ...bolt the main caps on with some plastigauge to see if things are clearanced right although at the point you are at there is really nothing you can do about it any way .
 
augirthedude said:
I have done it years ago in a toyota fork lift that had a 2f .. it ran for another 10 years .. A good band aid. the upper bearing shells just slid right out with turning the engine in the right direction and a gentle push with a screw driver and the new ones slid in the opposite way ...bolt the main caps on with some plastigauge to see if things are clearanced right although at the point you are at there is really nothing you can do about it any way .
Click to expand...

I also did this on a 76 pig with a 2f just slipped a short tack into the oil journal and gently eased it up aganst the bearing edge and then turnned the crank by hand and rolled out and then in the new bearing , if you do this be careful only hand pressure and be sure and remove the tack after you install the upper bearing. That old pig ran great for another 200,000 miles before I sold it because it was so ugly the ex wife could not stand it any more. Should have kept the truck and ditched the wife then, not later. Anywho nother stroy. :)
 
Thanks for all of the input guys. I am going to be replacing the bearings today after work and I just wanted to get an approximate amount of time it takes to swap the bearings out.

Is it a 4-5 hour job? Or more like a full weekend?
 
Yeah, a couple hours should be enough. It shouldn't take you a weekend. Just make sure you've got your torque specs handy for the main bolts and do one or two at a time. Not sure about cruiser bearings but on my cummins and a ford I've done there was only one way the bearing could rotate due to a notch at the end of the bearing to help align it and keep it from rotating. Lube them up before you slide them in. Hopefully no gotch-ya's pop up.
 
I did this back in 1984 to my 2f because I was young & poor!!! Took me an hour to get everything laid out, about 30 minutes on each bearing to get them out & in, maybe an hour on the first & 15 min on the last!!! Gradually got easier as I went!!! An hour to put everything back together, 1/2 to clean up!!!!

I used STP oil treatment on the bearings as I put them in!!! Helped the slide easier & prevented a dry startup!!!

The engine ran another 170k miles before the rebuild!!!!

I know it was less than 8 hours!!!!! I did it one Sat!!!
 
If you are going to take pics & write, you better have a helper!!! You'll be greasy as he'll!!! Your hands will get nicked, scratched, & cramp too!!!
 
Hey guys, I got all of the bearings swapped out tonight. It only took a 4 hours. I had some friends help out handing tools and turning the crank everything went really smooth.
Unfortunately I didn't get any pictures because my hands were filthy.

But honestly it can be summed up very quickly for anyone who wants to take it on.

Drain oil, remove flywheel cover, remove oil pan.
Take off the main caps, slide out the bearings put the new ones in. bolt everything back up.

Overall it wasn't bad at all. It turns out my old bearings were totally trashed. I'm still leaking oil from the front of my timing cover but that's because my #1 bearing spun. Here are what I pulled out.
0224122132.webp
0224122133a.webp
0224122133.webp
 
Did you replace or check the rod bearings while you were in there? Just curious. Also, did you notice a significant difference in oil pressure or knocking after the install?
 
Those look terrible. Any idea why?
 
I think you got your money's worth out of those old bearings.
 
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