Main Bearing Replacement

[y5e06]

Ok, I've been reading the write ups about doing the rod bearing replacment. Job actually sounds pretty easy. However, what about replacing the main bearings while you're in there? I did a search but didn't find a whole lot of detail. How much harder would it be to do those? Would it be much more difficult with the main caps holding everything tight? would you loosen all the caps at once to gain enough clearance to slide in the new upper bearings? If you do one at a time it doesn't seem like you'd have enough clearance to slide the old/new ones in/out.
I'd really hate to be all the way in there to do just the rod bearings and leave the mains. All new bearings give me a nice and warm fuzzy feeling!
Any other comments?

 

[Yamaha V6]

In order to do them in the car, you'd really have to remove the oil pump, loosen / remove all / most of the main caps. Lots of effort.

I understand your concern, expecially seeing all the Bowtie Toys.

In the SHO, the rod bearings tend to wear at about twice the rate of the mains. So, if you're replacing the rod bearings at 100k, you'll be thinking of the mains at 200k. This is of course, a very large generalization, but you get the idea.

If the engine's out doing a build / rebuild, whatever, then yes, I agree with the "may as well do it" idea. However, since it's a lower wear item, and it's such a bummer & opens up a large can o' worms on other things that can go wrong, I feel ok skipping them & only doing the rods.

 

[y5e06]

I suppose if the 2x rule of thumb applies, then it could be a judgement call after the rod bearings are pulled. If they are seriously worn then replacing the mains would need serious consideration. If they look fine, then pass on doing the mains.

 

[AutoSHO]

The mains in these cars are pretty low-wear compared to the Rods. Several forum members have over 150k, and one member (sdpatt) has 280k on his, and he replace the rod bearings once, at 271k I think. As long as you keep up with the oil changes, nothing to worry about.