Stroker main bearings

Flame me if you must but I am having a brain fart.(no luck in searh)

Do I need to use 4.0 main bearings or 4.2 mains for the stroker?
(I can't remember what I put in it and can't find the receipt to check)

TIA
Nathan

4.0 block, 4.0 bearings. The journals on the crank are the same, but I think the bearing bores in the block are just a little different. Why take chances?

Oh - and it's a valid question, so don't feel too far "off" for asking...

5-90

read somewhere that the 4.0 is made more for ff road use, exactly same bearings different substance inside. thats what i heard

Thanks for the reply.
I have to tear down the motor tomorrow morning as I suspect I wasted a rod bearing today.
I just wanted to grab a complete set of bearings incase I have to swap the crank out tomorrow.

89laradosport said:

read somewhere that the 4.0 is made more for ff road use, exactly same bearings different substance inside. thats what i heard

Click to expand...

I'm inclined to think so as well - but I KNOW the 4.0 bearings will fit the 4.0 block, and the crank dims are the same (except for the stroke, and maybe being 1cm longer in the snout... A spacer ring will fix that.)

5-90

I did a quick look up and I have the same bearing part numbers for the 4.2L and the 4.0L

5-90, since I have your attention & you know what you are talking about, I have another question for you.
Can you reuse a wrist pin?
Thanks again

Can you? Yes. Should you? That's a question...

If it were from a high-revving engine, I'd say NO - there's too much stress on them.

However, from a low-running plant like ours, stress will be reduced, and they're probably all right. However, I'd at least have them at least dye-checked for cracks, if not take them to the shop doing your work to have them Magnafluxed.

Of course, if it's cheaper, just replace the pins - they're usually MagnaFluxed at manufacture anyhow, and you'll rest easier that way.

Either way, inspection for cracks is something I consider mandatory. Dye-checking is usually cheaper, but the MagnaFlux will show smaller cracks than dye-checking (I'd not consider an X-ray inspection warranted - if there were voids in the pin, you'd know it by now...)

Can you tell I design things for reliability?

5-90

Make sure you buy bearings for the same year 4.0L block you have. I forget exactly which year the change was but the tabs on the bearings switched from being off to the side to centered. You will see what I mean when you pull the main caps. That threw me off the first time I had my motor appart.

AARON