Guidelines for Bearing Inspection

[Glenwood]

So, if the main bearings showed little wear but were original, should they get changed due to age? Just curious on deciding factors.
For example, my '73 413 block had little wear on the bearings or cylinders with no ridge at all, but the block has been sitting around for quite some time. The builder examined it after I did finding the block, journals, crank, etc., in good shape but recommended align boring anyway. This was all done btw, just wondering what happens to a block that sits for many years. He talked about possible core shifting, which gets corrected by boring the cylinders?
Also when ordering main and/or rod bearings, how is the correct stock parts ordered when the sizes can vary, such as a block that is stamped with a maltese cross or X? Don's book doesn't really go into these details.

 

[miller]

He talked about possible core shifting, which gets corrected by boring the cylinders?

Hmmm...somebody straighten my act up. Not sure if core-shift would affect a 413, but understood core-shift was talking about crank mains alignment.
Service manual for the correct year will tell you the sizing on those markings your asking about. (My 440 crank was -.010 from the factory.)
How did the bare crank turn, before you pulled it?

On those slightly used bearings, but something you might not want to do. Those bearings have a combo coating of soft lead on them, age and oxygen will make the lead harden (darken) a little. Depending...you can wipe them with very fine scotchbrite, to 'freshen' the surface, but most folks shy away from that. (I had to do it all the time on aeroplane motor crank bearings.) Sure, it removes a little lead, but .00025 don't hurt much.

Bad deal on bearings these days, from what I've seen, you cannot buy a half groove set like they used to put in these things. Either no groove, or full circle...or buy both...and mix 'em up!
Not up on the various sizes that are available.

 

[Glenwood]

Hey Miller,
The crank turned fine before it was disassembled and cleaned up. I don't recall seeing any dark spots on the bearings, just some light wear marks. The forged crank was not scored and looked to be in good shape. Haven't seen much info on 413's past the mid 60's although this block is a '73, probably from a truck or RV. I think it would be tough to find a service manual on this one.
My question really is on how are the bearings ordered. If you were replacing the main & rod bearings on your -.010 440 crank without machine work, how would you specify them? Are the bearings available in stock form, but in increments of xyz or do you measure the crank and block/rod journals and order by diameter/thickness?

 

[miller]

Understand. Like on my -.010 forged crank, it polished up real easy. Just have to go by the actual measurements you get on the journals, to know if it's still in range.
Ordering the bearings...most makers include the bearing size, or fit, in the part number. So, if the crank measures standard, order standard sized bearings.
Not sure if you still can (since I don't have a late bearing parts book), but used to be able to get -.001, -.002, then to -.010, and on, going to max recommended undersize.
If I remember right (lol), clearances run from .001(5) to .0035 max. I always go for the middle...both my mains and rods have .0025. Of course that's 'overall' clearance.
That's what I got with Clevite -.010 bearings. Went with full groove.

 

[miller]

Just food for thought...

I've always measured my bearings, new or used. Only used one set of used bearings. Just takes a good set of mics, and a ball adapter to use on the 0-1" mic. That adapter is needed to measure the 'thickness' of each bearing half, the ball going on the inside curved surface.
Main thing is to just make sure 'exactly' what measurements your dealing with. To me, that's the only way. Flat don't like the plastic stuff.

 

[dvw]

Larger bearing clearance hurts NOTHING. Too tight will get you into trouble. My racecar has .003" rod/.004" main and actually has too much oil pressure with a thick rotor pump.
Doug

 

[bm02tj]

Plastigage is a guide only and not accurate It is close if you get fresh stock but it is best to use a micrometer
If you are changing the cam bearings the only extra will be plugs and rings so hot tank the block as a couple hundred now can be cheaper in the long run

 

[BeeKool]

Hello all,

The goal is an engine that is well sealed, runs acceptably, and will serve for perhaps another 10K miles. A new engine it is not, but indications are that it has some life left in it.

Thanks.

Lots of good advice, but mostly goes beyond what your original stated goals were. If you only want to drive it occasionally for another 10k and the journals look good and mic. Then just replace the bearings and screw the machine work. In a few years if you decide you want to do a complete overhaul when you have some cash saved back.
I just had my 440 all done up like stated in previous posts. After all the tanking, honing, planing, grinding, balancing, magnafluxing, (heads included) and reassembly it was 2400$.