[Joe-Touring]

after reading through the factory cast crank thread made by Paul K:
https://forums.maxperformanceinc.com...d.php?t=863934

I decided to take a look at my crank for my 400 shortblock i just got back from the machine shop. Found some ugliness on the 5-6 rod journal, big pits on the fillet. My pistons/rods have been balanced to this crank. The journals have been polished, but not cut. Is my crank trash, or should I find another?

[Half-Inch Stud]

Good news is its been tested and passed.

I suppose it may help to know if the voids are in the armpit ( a bad thing) or 180 away from the armpit ( less bad but not in the clear), or 90* away from the armpit ( least in-tension location ).

Torsional (TQ) throughput favors pitting to be 90* from armpit as well.

Post 43 of that Thread shows the crank break emanation
-cleave starting in the armpit.

If approaching Redline upshifts, i'd get another N crank, and get it machined, balanced.

[ID67goat]

I think I would find another crank. Those voids can’t be good, and the overall surface of the journal does not look good (not polished correctly) from what I can see in the pics.

[Gach]

Definitely fine another crank !

[74Grandville]

i'm not an expert, but I don't think i'd want porosity on that part of the crank. could become a potential crack in the future.

what type of build is this?

oil will fill the voids and it should run fine, but If i was in your position though, I would probably find another.

[Gach]

Joe just my thoughts get the stroker crank make it a 461, yeah you’ll have to change out the pistons but with that Crower 60916 you’ll definitely make close to 500 hp, easily the money you’ll save on the hydraulic roller and lifters will help off set the cost of pistons and crank. Just something to think about.

[b-man]

400 cranks are a dime a dozen.

Find another one, no way I’d put that junk in my grandma’s grocery getter.

[Joe-Touring]

Originally Posted by Half-Inch Stud

Good news is its been tested and passed.

I suppose it may help to know if the voids are in the armpit ( a bad thing) or 180 away from the armpit ( less bad but not in the clear), or 90* away from the armpit ( least in-tension location ).

Torsional (TQ) throughput favors pitting to be 90* from armpit as well.

Post 43 of that Thread shows the crank break emanation
-cleave starting in the armpit.

If approaching Redline upshifts, i'd get another N crank, and get it machined, balanced.

Hmm Im guessing the armpit is the deepest part of the crank? Because, yes that is the case.

Looking at the pics you referenced, it appears that is the spot. Id like to keep my 67 block in one piece.

[Joe-Touring]

Originally Posted by 74Grandville

i'm not an expert, but I don't think i'd want porosity on that part of the crank. could become a potential crack in the future.

what type of build is this?

oil will fill the voids and it should run fine, but If i was in your position though, I would probably find another.

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

[Joe-Touring]

Originally Posted by Gach

Joe just my thoughts get the stroker crank make it a 461, yeah you’ll have to change out the pistons but with that Crower 60916 you’ll definitely make close to 500 hp, easily the money you’ll save on the hydraulic roller and lifters will help off set the cost of pistons and crank. Just something to think about.

Since I have a 4 spd Id prefer to keep it a 3.75 stroke. Maaaybe a 4 inch. Also I have a 455 that might be able to be saved. Needs a sleeve after cracking a sleeve. Machinist isnt excited about it

[Joe-Touring]

Originally Posted by b-man

400 cranks are a dime a dozen.

Find another one, no way I’d put that junk in my grandma’s grocery getter.

Man, near unanimous condemnation for my crank. Bummer cuz its the original for my block. And it has much nicer machining than the other cranks ive seen. Is there a desirable factory crank? I think Ive heard some guys like the earlier Armasteels

[b-man]

Plenty of guys have used 326 Armasteel cranks in 400 builds.

I remember Joel Larkin (Super Stock racer) used to run a 326 crank in his bracket race 400 powered 1968 Firebird. I saw it run 10.30s on a cool night back in the mid-90s at high altitude (2700 ft) LACR, that’s dipping into the 9s at a sea level track. Ran ported #12 heads, a Warrior intake and a Dominator carb.

400s with stock iron heads can easily make 400+ hp with a cam like the 60916 or better yet the 60243.

Give your crank to the scrap man or dig a hole in your garden and give it a nice funeral.

[Gach]

The armasteel going to hard to come buy. It’s a tossup on whether they really any better. But wouldn’t hurt if you fine one.

[b-man]

You’re in luck because 3.75” stroke cranks came in 326 and 350 engines that most people give away to get them out of their way.

They’re still quite plentiful since every bread and butter 326, 350, 389 & 400 came with them. Most all of the folks putting aftermarket stroker cranks in their 400 blocks have one sitting in the corner of their shop gathering dust.

Get yourself another cheap to free 3.75” crank and don’t look back.

[hurryinhoosier62]

Originally Posted by Joe-Touring

after reading through the factory cast crank thread made by Paul K:
https://forums.maxperformanceinc.com...d.php?t=863934

I decided to take a look at my crank for my 400 shortblock i just got back from the machine shop. Found some ugliness on the 5-6 rod journal, big pits on the fillet. My pistons/rods have been balanced to this crank. The journals have been polished, but not cut. Is my crank trash, or should I find another?

The first question that comes to my mind: has this crank been magnafluxed? I’ve seen far worse pits in nodular cranks that never suffered a failure. The choice is up to you; I’ve ground around 4,000 crankshafts both cast and forged. My greatest concern is not with the pits but where the pits are located. The radius of a journal is what gives it strength. Any cracking in the radius is usually indicative of cracking that will develop in the journal itself over time. 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.

[hurryinhoosier62]

Originally Posted by b-man

Plenty of guys have used 326 Armasteel cranks in 400 builds.

I remember Joel Larkin (Super Stock racer) used to run a 326 crank in his bracket race 400 powered 1968 Firebird. I saw it run 10.30s on a cool night back in the mid-90s at high altitude (2700 ft) LACR, that’s dipping into the 9s at a sea level track. Ran ported #12 heads, a Warrior intake and a Dominator carb.

400s with stock iron heads can easily make 400+ hp with a cam like the 60916 or better yet the 60243.

Give your crank to the scrap man or dig a hole in your garden and give it a nice funeral.

Bart, the only problem with using a 326 or 350 crank is how much Mallory metal you are going to have to use to balance the crank. 326/350 counterweights are roughly 2/3 the size of 389/400 counterweights.

[Dragncar]

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

[25stevem]

It's up to, but I woukd paint it white make it a mail box holder.

Too much deep pitting going on in the high load radius area between the rod journal and the cheek of the Crank.

Those pits there are a superb place for a crack to start!

[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.

[Elarson]

Originally Posted by 25stevem

It's up to, but I woukd paint it white make it a mail box holder.

Too much deep pitting going on in the high load radius area between the rod journal and the cheek of the Crank.

Those pits there are a superb place for a crack to start!

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

Eric