kstern58

Hi all - A while back I posted about a ticking in my 68 442. I went through a lot of trial and error with the valve train (replaced lifters, rockers, pushrods) only to discover that the problem was #2 rod. I dis-assembled the engine, and founds pretty a badly gouged crank, and .020 bearings. Too bad, because it's a nodular crank and my understanding is it's one of the best stock cranks you can have. I'm having the engine rebuilt, and the original intention was to use my block and crank, but unless we can go .040 on both rods and mains, this crank is junk. So what do you think? Is .040 under ok? The intentionis to make about 450HP using Edelbrock Performer heads, Wiseco pistons, and a custom cam.

BTW - I have a nice set of 1968 W-30 "D" heads, and some stock exhaust manifolds for sale as well as a brand new Edelbrock Torqer if anyone is interested. I hear those "D" heads can be pretty pricey, but I'm willing to make a deal. Maybe trade a good nodular crank???

cutlassefi

I'd do the .040 if you can't find another crank. But whatever you do buy the Eagle rods, don't use the stockers, not worth it.
Let me know if I can help on the cam. Thanks!!

wr1970

Where do you get .04 mains and rod bearings i thought .03 is the biggest you can go for olds

Fun71

I think any factory 455 crank you find will be nodular iron. The only other kind is the rare forged steel one.

Octania

Yeah sure I'll trade you a forged 455 crank for D heads.

If you can get 0.040" undersize bearings it should be fine

If you go by a guide that the strength of a round thing is proportional to the square of the radius, I calculate about 96% of original strength remains after cutting a 2.125" journal by .040"

As strong? no
Strong enough? probably, depends what you do to it of course. Idle- forever. Race- not so much.

olds 307 and 403

Pretty sure Clevite makes bearings that size.

kstern58

My engine builder says we'd be getting too far into the hardening at .040. Which is something I've never really understood - if the crank is riding inside the bearing on a film of oil (as should always be the case) then what's a little hardening going to matter? But who am I to argue with the experts?

I'll likely go with the cast steel jobby from Eagle. $600 bucks and done. This is a 450HP target build with revs below 6500. I think the Eagle will be ok. Thoughts or experiences?

kstern58

Thanks. My engine builder is going to custom grind a cam, and I am using the Eagle 4340 rods.

cutlassefi

Find another engine builder, he relies on the internet too much. The surface hardness on a Nodular iron crank only goes down a couple of thousandths. It's gone on the first regrind.
Clevite makes .040 under bearings. The bigger concern should be bearing integrity. The outer shells on a std and .010 are the same thickness with the babbit and tin overlays being thicker for the .010.

.020 and .030 under use the same shell, with the same thickness changes as above. A .040 under has more babbit and tin layer. Some actually like that as they feel it cushions the assembly a bit more.

Anyway as mentioned, I'd do it if you can't find another crank. If you go the Eagle route have it checked. Although their quality control is better now, there's still a possibility that will have to be ground as well.

Hope this helps, and find another engine builder.

Warhead

Nice to know that Clevite makes them now, ACL supplied me .040 bearings in the past. If you do go with the .040 bearings, make sure the crank grinder double checks the thrust clearances (make sure he has the thrust bearing in hand), the ACL's were thicker here, and required widening the center crank journal something like .010".
Oughtta know.

J-(Chicago)

I have a few cranks here in IL 60516.