[Formulas]

Yes i would not use that crankshaft
That said the days of them just sitting around everywhere are long gone 15 years ago when i lived in CA. it was incressingly hard to find V8 rear wheel drive cars in bone yards at that time, It cant be better now

About the only source for them now is people that have been sitting on them for a long time

[Joe-Touring]

Originally Posted by hurryinhoosier62

The first question that comes to my mind: has this crank been magnafluxed?

If this were going to be used in a near stock engine I wouldn’t hesitate using it. As Bart mentioned, it is incredibly easy to develop 400 horsepower in a Pontiac 400. Any future modifications will add stress to this journal. There is a possibility that grinding this crank MIGHT take care of the problem, but that is a MIGHT.

I assumed everything was magged, but you know how that goes. It’s getting KRE heads, so fairly warmed over. I am tossing around the idea of having that one journal taken down 0.020 and see how it goes

[Joe-Touring]

Originally Posted by Dragncar

I have a 62 389 Arma steel you can have for 100$ if you want it. Shipping is not cheap though.

Thanks dragn. Im running a 4 spd, is it cut for a pilot bushing. Im interested, sent you a pm. What’s the interchange on cranks? How early of a crank can you put into a later block?

[NeighborsComplaint]

I would buy an aftermarket crank and find a new machine shop to check the crank and rebalance. No way should that crank have been cut and polished even if it was going into granny's sunday car.. The shop you used machined an unusable crank and just wasted your money. Those pits were visible before machining.

Any crank you buy will need to be checked, balanced and polished at a minimum. If you have the bob weight card from the prior balance job, you could in theory have the new machine shop balance the new crank without weighing the rods and pistons but judging from that shop's work, I'd have the entire rotating assembly balanced by a different shop just to be sure.

[grivera]

OP- Where are you located? I have a standard 400 N crank

[Joe-Touring]

Originally Posted by mgarblik

With the quality parts you listed for the build, I would source another crankshaft. At the very minimum, that crankshaft needs to be ground and polished properly to use, and I would not risk it. N cranks are inexpensive, but I respectfully disagree with B-man about finding one. I had a heck of a time finding one for a student's engine this year here in Ohio. I made dozens of phone calls and really stretched my resources to find one for him. Thank you to Dave Hilliard on this forum for helping me out. So IMO, do what's necessary to find as good N core crankshaft. Then the next challenge is finding someone who can grind and polish it properly.

Hopefully I can get something going. I’ve got a couple options I’ve seen on craigslist. There’s a 66 389 block crank and 092 heads for $300 about an hour north of me. Can’t say I want/need another block and heads. Specially ones no one wants. I’ll have to ask around

[Joe-Touring]

Originally Posted by Elarson

1000% YES! The stress concentration in the corners make it the absolute worst possible place to have imperfections.

Eric

Ugh seems like that is the consensus. By the way, super cool road race engine you put together. I’ve been wanting to do some road course track days for a while.

[Joe-Touring]

Originally Posted by NeighborsComplaint

I would buy an aftermarket crank and find a new machine shop to check the crank and rebalance. No way should that crank have been cut and polished even if it was going into granny's sunday car.. The shop you used machined an unusable crank and just wasted your money. Those pits were visible before machining.

Any crank you buy will need to be checked, balanced and polished at a minimum. If you have the bob weight card from the prior balance job, you could in theory have the new machine shop balance the new crank without weighing the rods and pistons but judging from that shop's work, I'd have the entire rotating assembly balanced by a different shop just to be sure.

That’s really the biggest issue I have with all this. I got recommended to go to this machine shop by a couple people, seems like the shop has had some problems recently. Pretty unfortunate that such an obvious issue didn’t get caught before polish and balancing. Time and money wasted

[Joe-Touring]

Originally Posted by NeighborsComplaint

I would buy an aftermarket crank and find a new machine shop to check the crank and rebalance. No way should that crank have been cut and polished even if it was going into granny's sunday car.. The shop you used machined an unusable crank and just wasted your money. Those pits were visible before machining.

Any crank you buy will need to be checked, balanced and polished at a minimum. If you have the bob weight card from the prior balance job, you could in theory have the new machine shop balance the new crank without weighing the rods and pistons but judging from that shop's work, I'd have the entire rotating assembly balanced by a different shop just to be sure.

That is definitely the worst part. The shop I used is winding down, owner is trying to retire. The cylinder head guy tried to buy the shop from the owner a year or so back and was running the shop for a while. Apparently he was running the business poorly and telling customers their parts would be done in a week when they were months out. He did that to me. Made a lot of longtime customers VERY unhappy.

Since the owner’s reputation was getting destroyed, he took the business back and found it was a mess. Cyl head guy quit a couple months ago, packed up in the middle of the night. The owner is now finding that head guy didn’t have a lot of documentation for the engine parts he took from customers, no phone number to even ask what’s been dropped off. He lost my Crower retainers. ANYWAYS, I heard the crank grinding machine was sold, so I’m not sure if the shop could even make it right.

I hear on this forum how many guys have 1 shop they trust, I get it. I’ve had terrible luck with local shops. I think I’ll try to get up to Dave at SD Perf. I think he’s about 3 hours north of me

[Joe-Touring]

Originally Posted by grivera

OP- Where are you located? I have a standard 400 N crank

I’m in western WA. Looks like you’re on the opposite coast. Probably prohibitively expensive. I do appreciate it tho

[tinindian68]

Don’t know anything about it (not mine) but could be an option for you.

https://lewiston.craigslist.org/pts/...602729443.html

[Dragncar]

Originally Posted by Joe-Touring

Thanks dragn. Im running a 4 spd, is it cut for a pilot bushing. Im interested, sent you a pm. What’s the interchange on cranks? How early of a crank can you put into a later block?

I will take a look at it this weekend. Its out of a auto car. The snout on the early cranks are shorter but a am pretty sure it does not make a difference.
Tom S would know better than me.
I would NOT buy ant cheap, cast aftermarket 400 crank. Get a PMD N or Arma steel crank and do a spec grind and balance.
The only aftermarket 400 crank I would ever buy is a forging, and they are hard to find.

[25stevem]

Take a look at Franks Pontiac parts on line.
He is in California so shipping might not be too bad.

[hurryinhoosier62]

Originally Posted by Joe-Touring

I assumed everything was magged, but you know how that goes. It’s getting KRE heads, so fairly warmed over. I am tossing around the idea of having that one journal taken down 0.020 and see how it goes

From what I can see in the photos, a .020 undersize grind could take care of the problem. Whoever polished it really should stop attempting to polish cast nodular cranks. NDT (magnaflux) isn’t a standard practice for most machine shops; you have to request it. I wouldn’t grind a crank that hasn’t been magnafluxed. You might want to have a replacement crank on hand just in case this one fails NDT.

[25stevem]

Also please note that shops that do not have a crank grinding machine can NOT properly polish a Nodular iron crank.

This also rules out a often done home polishing job!

Out of this box is printed what’s in the next photo.

[tom s]

Crank snout is not a big deal.I have built a lot of late engine with the short snout.Tom

[hurryinhoosier62]

Originally Posted by hurryinhoosier62

From what I can see in the photos, a .020 undersize grind could take care of the problem. Whoever polished it really should stop attempting to polish cast nodular cranks. NDT (magnaflux) isn’t a standard practice for most machine shops; you have to request it. I wouldn’t grind a crank that hasn’t been magnafluxed. You might want to have a replacement crank on hand just in case this one fails NDT.

If you choose to go the .020 undersize route, have a long talk with the crank grinder. This crank has the typical “barely there” GM radius. The cutting stone will need a wider fillet cut into it to set a proper radius. If the shop has no idea about radius and fillets RUN!!

[Drag Star Le Mans]

Joe-Touring (Dan) is stopping by my place tomorrow. I have a few for him to choose from and he will be back in business.

[Half-Inch Stud]

Originally Posted by Joe-Touring

Build WAS
406
ross forged pistons, childs&albert forged rods
KRE heads
60916 or 224/230 roller. was thinkin 6k max rpm

Fixed it for ya. Gach has the value-ad idea to get a Stoker crank and Slugs

[Drag Star Le Mans]

The crank J-T wanted had a weird anomaly so it was a no go. Not sure what to make of it so please chime in.