318 Main bearings..Change in place?

[PeterCrowl]

I decided to check my mains for clearance. Why I don't know because I have no intention of rebuilding this engine.
Anyway...On the front main I've got .003 clearance against a spec of .015. So...a .001 undersize bearing should take that up.
All well and swell but can I roll the upper shell out in place? I've done that on other motors..the Chevy 350 comes to mind...but this is my first Dodge. If there's a locating pin on the top shell then it'd be a no go unless somebody here knows some magic incantations!
If they can, can the rear main / main seal be done in place?

[oneowner71]

Can't tell you about the bearings.. but I know on my LA318, I dropped the oil pan, loosened the first bearing forward of the seal, and replaced the rear main seal from under the truck... takes a little coaxing to slide around, but is possible and relatively easy.

[cowboy]

It's been almost 30yrs for me on the 350 rebuild so cant remember there bearings , but if you look at your 318 bearings theres a notich in the corner , & it will scratch the journal if not super careful , Is your engine on a stand ? if so then with bottom s up pull all caps in order its not easy bet you can lift the crank to slide out the old & in with the new . the key word here is careful, :)
8)

[PeterCrowl]

Cowboy wrote...Is your engine on a stand ?

As the old joke goes..if I could walk that way I wouldn't need chafing powder.

My engine is in the truck. I have the pan off and dropped the front and #3 main cap to plastigage it. 1 was 1 over, 3 was 2 over. I don't want to pull it and spend the money to do a full rebuild - the front end work has set me back enough :~) so I was hoping to hear that I can roll the bearings out and new ones in.

Barring that...and here I'll really show my ignorance...is it possible for me to install the oversize bearing in just the cap to take up at least part of the slop?

Peter

Thrashing about like a trout on a hook trying to avoid the inevitable.

[cowboy]

Not to sure that would work, as the little diff in size will knock it out of round , but you might use the white greese , used in rebuliding & just try to slick it up real good & try to install new top & cap bearings just go slow & easy& lots of greese good luck
8)

[wideblock]

been there and done that. with it in the truck! what you do is pull the main caps off, all of them. be sure not to mix up the order they go back in. you wont be able to pull the crank down any cause your tranny is still hooked up, as well as the front cover and all, but, there will be enough play to get the new bearings in. on the mains there is a tab on one side to keep them from rotating. go to the opposite side with a narrow punch, i used a popsicle stick, and give it a couple taps. the bearing will rotate the tab out of its notch and begine to work its way around the crank journal. this is where it gets tricky, you have to rotate it all the way around where you can see the whole bearing for it to drop out. i worked it as far as possible with the popsicle stick, then with a sharp scribe, dug into the back side of the bearing and worked it the rest of the way around. hook the scribe in the oil hole and pull down and she should pop right out. it takes patience, but it beats pulling the motor. the thrust bearing is the hardest, had to use a blunt screw driver to get it worked all the way around. putting the new bearings back in is a bit of a chore, if you tap them too hard, then the edge mushrooms and you have a screwd bearing, thus the use of the popsicle stick. wash it real good with some engine or carb cleaner around the crank before reinstalling to make sure all the trash is out. then i dipped the new bearing in 30wieght and slide her back in. white lithium grease, or assembly lube would work also, as long as you dont glob on a big amount. be prepared to get frustrated, like i said before, it wasnt easy, but it beat the heck out of pulling the motor. one thing to be sure of, when the new bearing is put back in, get the tabbed side as close to flush with the block seat as humanly possible, the main cap will do the rest, but the closer the better. getting the new bearings back in is the hardest part, since you aint worried about damaging the old ones, they aint too bad, but you dont want to damage the new ones in any way, so they can be a bit of a chore. good luck!