Main bearing alignment issue.

[CATarga]

Is it common for Clevitt main bearings to not align w/both oil holes on the block. Both of the #1 oil holes line up, but only one of the #3 holes line up, and the other about 3/32 off.

Was the block drilled wrong? Should I drill the bearing out on the one side to align with the hole, or is better to leave the bearing as is?

Search only turned up the 7m tips, while helpful, it didn't address this problem.

Pic

 

[IJ.]

Got the correct shells in the correct places?
(#1 is different)

 

[CATarga]

Yes I know that #1 is larger than the rest, and set tab(or claw) is also different on #1 then the rest.

All of the rest are the same, no offset on any that would line up with #3.

 

[IJ.]

Just checking.

Are they actual Clevite bearings or NDC's?
(turn a shell over it'll be stamped on them)

 

[CATarga]

Yes, they are Clevite 77 main bearings, they came with the crank when I got it back from the shop, though the rod bearings are a different brand.

I dug the old bearings out of the scrap bin, the holes didn't line up either, and were actually smaller than the ones on the new bearings. Since the holes on the new bearings were tapered, I removed the taper on the one side to enlarge the hole a little, but didn't get into the bearing itself.

Is the second oil port on the #3 main supposed to be offset, or was the block miss drilled? Knowing the level of Toyota's quality control, I wouldn't think the block was miss drilled.

 

[IJ.]

I'll check my junk block when I go out to the shed, Can't say I've ever noticed this issue before though.

Interesting that they're genuine Clevites haven't seen those for a few years now.

What size are they?

 

[IJ.]

ACL's in the junker line up perfectly and so do the NDC's I run in the good engine ditto on Fed Mogul.

Can you take some measurements how far from the edge and how far from the part line in the block the holes are and I'll compare (I sort of doubt it's drilled incorrectly as well but it's worth checking)

 

[CATarga]

Yep, the Clevite was stamped on the back, it looked like the box had been sitting for a while, the cardboard was a bit aged.

"Can you take some measurements how far from the edge and how far from the part line in the block the holes are and I'll compare"

At the moment the crank and pistons are already in. I figured since the old ones didn't line up either(better since the holes were smaller), I would go ahead and continue the rebuild. Not a big deal to remove them, I am still waiting for other parts to arrive.

Here is another pic.

 

[CATarga]

The opposite hole lined up perfectly, same with the rest of the bearings. I had considered drilling it out more, but figured the bearing material itself was more nec. then the the size of the hole.

Not that much material was removed from the crank, 10,000ths on the rods and 20,000ths on the mains, which seems like normal wear for an engine w/185k on it.

 

[CATarga]

I went ahead an removed the crank and measured the hole location using a dial caliper.

Here are the measurements, Rear of engine to front, and hole that doesn't line up is on the oil pump side.
Hole that doesn't line up:Outside edge to lip of hole .2049in lip to front edge .4020in

Hole that does line-up:Outside edge to lip of hole .3060in lip to front edge .2090in

Overall measurement of bearing base is .9046

 

[IJ.]

Just dragged the junk block out into the open to measure it and it's much the same +- a thou or 2.

The hole that doesn't line up 100% is only feeding the Aux shaft bearing so I would imagine it doesn't need a lot of flow to maintain an Oil wedge?

If you were really concerned some careful Dremel work on the block would align them perfectly (My old block is chamfered so didn't appear to be as bad as your pics)

 

[gaboonviper85]

10,000ths"= .010"....figured I'd save you some time LOL

Personally I'd take the block to the machinist and see what he says....if that's the way it is than I myself would take a die grinder to the oil hole in the block and chamfer the side to try and limit any restriction of oil flow to that bearing....

If you know what I mean "same consept as porting to match intake and exhaust gaskets."

 

[gaboonviper85]

Just dragged the junk block out into the open to measure it and it's much the same +- a thou or 2.

The hole that doesn't line up 100% is only feeding the Aux shaft bearing so I would imagine it doesn't need a lot of flow to maintain an Oil wedge?

If you were really concerned some careful Dremel work on the block would align them perfectly (My old block is chamfered so didn't appear to be as bad as your pics)

Beat me to it....DAMN YOU!!! LOL

 

[CATarga]

I am not too concerned w/it now, all of the other holes lined up fine, and after removing the I taper off the one side the flow looks better, and is now larger than hole in the old bearings, so the flow should be improved.

Kind of odd that the hole is off center, I wonder if the original oem bearings are set-up offset as well.

 

[gaboonviper85]

shit happens in large scale production...such as factory motors...that particular motor may have made it past quality control....?