Having a very difficult time finding new main bearings for the 2001 4.0 motor.
Can anyone recommend a source?
Thx. RJ

Engine bearings for the 4.0 V8 is NOT a simple one-size-fits-all.

Please read the bearing selection matrix in my copy of ENGINE COURSE 168 that I had digitized years ago.
It is all over the internet.

The numbers (bearing selection) for your engine AS BUILT from the factory are stamped on the left side of the engine block.

If you have altered the crankshaft journal sizes (regrind?) then you are on your own with finding aftermarket generic parts.

I already got the numbers off the block.
All the old ones are only stamped with Standard Bearing:
Translation of codes from the engine block:
#1 Journal: Stamped Standard Bearing - Green/Green
#2 Journal: Stamped Standard Bearing - Green/Green
#3 Journal: Stamped Standard Bearing - Blue/Green
#4 Journal: Stamped Standard Bearing - Green/Green
#5 Journal: Stamped Standard Bearing - Blue/Green

Finding a source that has any main bearings at all is very difficult.

RJ it looks like Jaguar still supplies them? Same as the 4.2L V-8. Part #AJ84630
Here is a Blue/Green one. $18 each or so. Says lower so not sure if it's a complete bearing or not?
Main Bearings 4.0L/4.2L Engine

If you need a different color I bet if you contacted them they could find the part number.
Here is a blue one. Part #AJ84638
Blue Main Bearings
Says upper bearing so again not sure you get both halves. The parts diagram shows a upper and a lower so maybe you do get both halves?
See the attached Engine document to see if it can provide any help? It does talk about the bearings in detail. Including a great chart showing the sizes and colors.
Note this maybe the same document Motorcarman was talking about too.
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Thanks for info, I will contact them both and see what they can provide.
Rj

I would imagine that Ford thunderbird bearings *could* be the same or at minimum an aftermarket bearing maker. I wonder if there’s a generic book put there about the dimensions of a rod/crank bearing that somebody already makes. As an example: a small block Chevy rod bearing in let’s say a 10 thou oversized is the same dimensions as our xxxx color rod bearing. But like everything else, if you have the time and wherewithal, the sky’s the limit on information.

I have seen that done before with domestic V8 builds.
Interesting thought, and I've already floated that idea through my head. The SB Chevy "Vortec" 305 and 350 thru to '98 standard mains are 2.450 and the Jag 4.0 is 2.440. The crank mains may need a little adjusting. Can't use Chevy thrust bearing, so would have to get an extra bearing regular for that location. My old 4.0 thrust plates still measure good.
Maybe go there if I can't find stock.
Thx.

Not that I know of, but this points to great advice to search and ask, for our world is awash with "interchangeables". Far easier or cheaper are obvious benefits but in many cases, can breathe life back into a beastie for which originals are no longer available.

Three examples of the 100s of known trivia . . .

• full sets of rings from Aussie Holden 186 inline 6 are perfect fit in an old XK engine . . . not only far cheaper, but Holden compound oil control rings are far superior, and sets are available in several oversizes which are no longer available here from dealers;
• both main and big end bearing shells for a pre-merger Daimler are NLA . . . but those from a marine Perkins engine are perfect replacement . . . also available oversize, but a new lube hole must be drilled in Perkins big end shells to align with Daimler rod holes;
• the rounded arm rests for the Series 1 E-Type were not even Jaguar . . . they were sourced from the Mini Minor!

There are volumes of this knowledge scattered around, especially across these forums, that newcomers often never see . . . for example, if Jaguar used the same engine across (say) 3 models, why limit oneself to only searching the one forum dedicated to your specific car?

My great worry is that much of this knowledge will disappear as our numbers creep into older age . . . and, according to my family, increasing forgetfulness!

Cheers,