Technical 8ba main bearings

does anybody know of anyone that makes a set of main bearings that are 050 under? i have a merc crank thats coming up .050 under and hoping i dont just have a paperweight. thanks

 

I am not seeing anything currently available beyond 0.030" Under. Maybe some old NOS parts out there at 0.050"

 

Sounds like you need to get your crank journals metal sprayed and re-ground but with the high rate per hour on stuff nowadays it will probably be cheaper to find another crank or buy a new Scat one.

 

At .050" under would there be any surface hardness left? There's probably a good reason those bearings aren't out there.

EDIT : Found this with Google :

"The most common depth is in the range 0.020”-0.030”. Importantly, the process results in increased hardness on the outside of the material; however, the low carbon core remains relatively soft. The outside is very hard but very brittle; however, the inside is soft and ductile."

And this :

"The depth of hardness is dependent upon the time the crankshaft is exposed to the gas. Typically, a nitrided crankshaft will have a hardness depth of about . 010 - . 030."

You're lucky they don't make 'em.

 

Montgomery-Ward had ground cranks .040, don't remember if down to .050. I know in the early 60's you could get piston rings individual, wrist pins .001 over, valves with o/size stems, etc. Bottom line is have to find someone with really old NOS.

 

Try Baxter Ford in Kansas/they “used” to have odd and strange sizes mains and rod bearings/maybe they can be of help/have not ordered anything from them in a couple of years so can’t really state what they have or don’t have/i had a Merc crank that needed .050 rod bearings and they had up to .060 in stock.

 

I read a long time ago that Fedral Mogal made .050 bearings. Been looking but never found any.

 

Back in the day a lot of engines went though the rebuild shops so many times that the cranks were turned down a lot. Unless it was broken beyond repair it didn't get thrown out.

 

What, is turned down too much for Ford/Mercury crank?

 

Merc cranks are pretty easy to find, and not very expensive. Seems like replacing the crank would be a better long term investment.

 

When the surface hardening is removed. See my post #5.

 

Do stock cranks actually have hardened journal surfaces?

When I've nicked them with a rod bolt, they didn't seem very hard.