Main Bearings Questions

[MandarinaRacing]

A fellow inlner has some issues with his 200 six. The machine shop told him that the crankshaft had to be turned down 0.040". Apparently the are no main bearings for that size. I've done a little search and came up with a few possible options, maybe one of you guys can help me out:

-How different are 250 main bearings compared to the 200?

-Are the 4-main 200 bearings different in size to the 200, could two sets be used?*

* The reason I ask this is because a local shop has two sets of 4-main bearings and he said that they would work(or maybe he just wanted to make a sale :roll: )

Let me know what you guys think,

Alex

 

[addo]

Nominal "grade blue" measurements on the journal and tunnel of a four main Oz motor are 2.2482 and 2.4012, all bearings. I suspect the US-derived motors are the same.

Going to a seven mainer, the thrust dimensions remain similar but the others allegedly are 2.2484 and 2.4014.

I'm skeptical about this 1/5 of a thou...

 

[MandarinaRacing]

Adam so it could be posible??? .....what about the 250 bearings, are they any different than the 200's????

Alex

 

[addo]

They're much bigger. A definite no-go unless you want major hassles!

 

[addo]

Some specs (me doing an "X", LOL) - Main bearings denoted thus:

Generic code • min/max crank journal • min/max tunnel

4M2126 Set
ARC8DE6333 Mains 1,2,4 (Plains, 4-mainer)

2126 • 2.2484/2.2488 • 2.4014/2.4018

ARC8DE6337 Mains 3 (Thrust, 4-mainer)

2127(F) • 2.2482/2.2490 • 2.4012/2.4020


7M2126 Set
ARC8DE6333 Mains 1,2,3,4,6,7 (Plains, 7-mainer)

2126 • 2.2484/2.2488 • 2.4014/2.4018

ARC8DE6337 Mains 5 (Thrust, 7-mainer)

2127(F) • 2.2482/2.2490 • 2.4012/2.4020

You can see the sets and parts are the same ID!

 

[MandarinaRacing]

me doing an "X", LOL

Thanks Adam!