1991 4.0L factory oversize main OD

[Curmudgeon]

I did search, read until my eyes crossed, so here I am posting.
Have a friend with a 91 Explorer 4.0L pushrod, lost a rod bearing, did the rings, repaired the rod, got a turned crank and new bearings......and plastigage doesn't even get touched, much less "squished" on the mains.

Machine shop tells him some were mis-bored, and had special bearings that were .015" oversized on the OD to compensate (read: fixed).

Now he has a block that is unusable, can't proceed, anybody know where main bearings for a .010" main crank that have the .015" oversize OD can be obtained?

I did a lot of looking, mostly I find 2.9L with the .015" overbore on the line.

Thanks.

 

[Curmudgeon]

Nobody has heard of this as a Ford "fix" for bad blocks?
Searching showed 2.9:, and maybe some 2.8L had it, but certainly cannot find anything on a 4.0L with oversized line bore.

 

[Curmudgeon]

More info.
Apparently, this was 1991-1997.
Ford had special bearings made for just the units in question, and no more.
I should have the bulletin number on Monday, VIN tomorrow.

 

[Curmudgeon]

VIN 1FMDU34X1MUA29922

The bulletin is from American Engine Rebuilders Association, and is TB1553.

Now to go google it and see if I can find anything.

 

[Curmudgeon]

Have to order it, I guess.
Basics are:
OVERSIZE MAIN BEARING HOUSING BORES 4.0L VIN X ENGINES
3/1/1998 12:00:00 AM
1990 - 2008

 

[Curmudgeon]

Got a hard copy of the bulletin.
I have entered the pertinent data below.
I recommended a new crank and Ford bearings.

Oversize Main Bearing Housing Bores On 1990-97 Ford 4.01 VIN X Engines:
There have been reports of oversize main bearing housing bores on 1990-97 Ford 4.0L VIN X engines.
As a result of Ford salvage operations, the manufacturer has machined some cylinder blocks an additional amount.
It has also been reported that such blocks are not easily identified by any external markings on the block,
The amount of oversize in the main bearing housing bore is .015".
To allow usage of this oversize block, an oversize outside diameter (0D) bearing must be used. That type of bearing is currently available from Ford only.
The bearings are also only available for a standard diameter crankshaft diameter of 2.2433-2.2441".
Those bearings are not available in a "set", but only by individual locations.
Previously, these oversize OD bearings were available for a similar Ford engine, a 2.9L configuration which also offered bearings for undersize journals.
It appears those bearings will no longer be replenished when current stock levels are depleted.
Careful examination of the block and engine bearings for an oversize condition at the time of disassembly is advised when rebuilding 4.0L Ford engines. Doing so should minimize customer complaints about extra time required to receive special order parts.