Main bearing - looks strange

E-Type
1

Hello,

I am swapping engines between two car´s (don´t ask) and evaluating an XJ 4.2 engine. The engine is hardly run-in and the main bearings look like this (see picture).

main bearing
main bearing4032×3024 1.68 MB

I have not seen this before (but am no expert). It tells me oil is running from the bearing to the front and rear.

Any thoughts?

Regards,

Hedde

2

Is there a maker’s mark or part number on back? I’m wondering if that is how they looked when they were new, some sort of witness mark from a manufacturing process, maybe from plating. The only way you have oil flow is when the crankshaft turns, and there’s no way you could get that entirely transverse erosion pattern with a running engine.

3

Hi Mike,
This is a picture from the back. (I got them from SNG a few years ago.)

main bearing 2
main bearing 23024×4032 1.87 MB

My main concern is that the oil escapes instead of lubricating the bearing properly.

Regards,
Hedde

4

Looks like the same mark on the back. Can you actually feel a recess or erosion? Since it’s on both the front and back, it looks more like a stain than erosion. There’s no way anything significant leaks out between the bearing shell and block. Looks like they were dipped. I don’t think you can come up with any scenario where oil flow from a running engine can cause these transverse stains.

5

And there CANNOT be excessive flow out that path unless there is a significant SPACE there. It does not appear to me there is any more space at those points than anywhere else (perhaps a few 0.0001" at best).

I would not be at all concerned about that…

Regards,
Ray L.

6

Thanks Ray,
I thought, mayby the crankshaft is machined for +10 and I did not measure correct and installed STD bearings. I only have a vernier caliper available.
Regards,
Hedde

7

Thanks Mike,
You are right, they are stains. Maybe I am over concerned.
Regards,
Hedde