[jcoby]

I have a 331 crank that I can't seem to find specs on. Does anyone know what this is? I'm pretty sure it's a cast crank (it has the grain from sand) and the only markings are a stamping on the face of the #1 weight: LY03110T30232505400. There might be a space after the T.

There looks to be a place on the side of the rear weight that had a logo that was ground off during balancing.

The 30232505400 portion seems to be common to everyone's crank marking identifying it as a 302 with 3.25" stroke and 5.400" rods.

It came in a bag along with all of the other engine parts when I bought the car. The whole rotating assembly has been balanced but I don't know what balance factor they used during balancing. It's probably either 28oz or 0 (this is for a '68 mustang).

I have called scat and eagle and neither could ID it without a logo cast into it.

I'm leaning towards it being an Eagle 103023250. It's from 2004 or earlier.

Does anyone have any idea what it is?

[cobalt327]

Look at the parting line instead of relying on "it has the grain from sand". Wide= forged, narrow= cast.

From the first string of numbers you might decipher part of it as 302, 3.25" stroke w/a 5.4" rod.

[jcoby]

Originally Posted by cobalt327

Look at the parting line instead of relying on "it has the grain from sand". Wide= forged, narrow= cast.

From the first string of numbers you might decipher part of it as 302, 3.25" stroke w/a 5.4" rod.

The parting line looks to be 2" wide but barely discernible. Couple pics attached. They told me it was a forged crank when I bought it but I try not to believe what people say, especially when it comes to expensive parts without boxes or identifying paperwork.

I really need the imbalance so I can figure out which flywheel I need for the T5. I have a late model 50oz but I'm 75% sure it won't work. That just leaves 28oz and 0. I really hope it's not a 0 but the Eagle guy identified it as a 4340 forged w/0 imbalance (until I told him there isn't an Eagle logo on it).

[cobalt327]

I cannot say w/certainty what you have. There's an old trick that unscrupulous sellers will use: Grind/polish a wide "parting line" onto a cast crank to make it look like it's a forged crank that has been detailed by grinding down the wide parting line- a wide parting line that was never there in the first place!

So I'm w/you 100% on being skeptical until such time that it can be confirmed by someone who has intimate knowledge of this crank and its casting numbers. The following video shows the place to look for the parting line that will usually show it best- on the first throw back from the snout opposite of the counterweight. The cranks shown are SBC so will look different than yours but the concept still applies.

That said, aftermarket forged cranks may show very little of anything at the parting line, depending on the manufacturing and processing and I should have probably mentioned this in my first post. The crank shown below is a 4" stroke Eagle 4140 forging w/their ESP finishing process applied. As you can see there's basically nada there to ID it:



BTW, the ringing of a cast vs. forged crank he's doing in the video is all well and good IF you have cast and forged cranks, identical except for material, to compare. Otherwise it's a bit iffy to ring a crank and say 100%- "This is cast/forged".

VIDEO- http://www.youtube.com/watch?v=8dA1AH5j9v8

BTW, Summit has sold various cranks under the Summit name that originated w/various well known manufacturers and Eagle is among them. On these cranks sometimes the ID was left intact but in other cases the ID was removed. You might have one of these, or a similar deal.

Was the ID that was removed located on the side of the first counterweight, like can just be seen in the photo of the 4" crank above?

[jcoby]

Originally Posted by cobalt327

I cannot say w/certainty what you have. There's an old trick that unscrupulous sellers will use: Grind/polish a wide "parting line" onto a cast crank to make it look like it's a forged crank that has been detailed by grinding down the wide parting line- a wide parting line that was never there in the first place!

So I'm w/you 100% on being skeptical until such time that it can be confirmed by someone who has intimate knowledge of this crank and its casting numbers. The following video shows the place to look for the parting line that will usually show it best- on the first throw back from the snout opposite of the counterweight. The cranks shown are SBC so will look different than yours but the concept still applies.

That said, aftermarket forged cranks may show very little of anything at the parting line, depending on the manufacturing and processing and I should have probably mentioned this in my first post. The crank shown below is a 4" stroke Eagle 4140 forging w/their ESP finishing process applied. As you can see there's basically nada there to ID it:

BTW, the ringing of a cast vs. forged crank he's doing in the video is all well and good IF you have cast and forged cranks, identical except for material, to compare. Otherwise it's a bit iffy to ring a crank and say 100%- "This is cast/forged".

BTW, Summit has sold various cranks under the Summit name that originated w/various well known manufacturers and Eagle is among them. On these cranks sometimes the ID was left intact but in other cases the ID was removed. You might have one of these, or a similar deal.

Was the ID that was removed located on the side of the first counterweight, like can just be seen in the photo of the 4" crank above?

Thanks for the info. I've attached a pic of the snout. There isn't any visible parting line. You can see what looks like a hand-stamped part number (given in my first post) on the face of the first throw.

The area that looks like a removed logo is on the rearmost throw, on the side of it. The front two throws have been rounded but I don't see anywhere a logo would have been removed.

I can get it to ring like both of the cranks in the video, depending on how hard I hit it So yeah, not much help there. It has a fairly bright sound to it.

[cobalt327]

If what I've arrowed below is a parting line, that's a pretty good indication it's a forging.

[jcoby]

Originally Posted by cobalt327

If what I've arrowed below is a parting line, that's a pretty good indication it's a forging.

That's the closest thing to a parting line I can find. There is an equal one on the opposite side as well. That plus the generally rough, uneven appearance of everything would also point towards a forging.

So that's good news I guess. Now I just need to identify the manufacturer and the imbalance! Or at a minimum the imbalance.

[cobalt327]

Originally Posted by jcoby

That's the closest thing to a parting line I can find. There is an equal one on the opposite side as well. That plus the generally rough, uneven appearance of everything would also point towards a forging.

So that's good news I guess. Now I just need to identify the manufacturer and the imbalance! Or at a minimum the imbalance.

I would guess it's 50 oz, being a 1-piece RMS crank, but it doesn't have to be that, it could be for the lighter weight.

You'll be balancing it, I'm guessing. It will be apparent then what it wants. I know that doesn't help NOW when you're still collecting parts for the build.

[jcoby]

Originally Posted by cobalt327

You'll be balancing it, I'm guessing. It will be apparent then what it wants. I know that doesn't help NOW when you're still collecting parts for the build.

That's just it - it's already been balanced with the rods and pistons (the car came with a complete engine in pieces). And I have the balance sheet. It doesn't list the weights for the harmonic balancer or flywheel/flexplate though.

It does indicate "complete engine" and "less pressure plate" on the sheet. Total bobweight is 1691g.

It came with the original 28oz parts in a box but i have no way of knowing if it was balanced with that stuff. I don't want to throw on 28oz stuff only to have it vibrate itself to pieces.

Also, what tells you that it's a 1 pc RMS crank?

[cobalt327]

Originally Posted by jcoby

Also, what tells you that it's a 1 pc RMS crank?

My (limited) understanding is, the 2-piece RMS crank has a raised flange on the seal 'journal', side closest to the counterweight. Pls. let me know if this isn't correct.

[jcoby]

Originally Posted by cobalt327

My (limited) understanding is, the 2-piece RMS crank has a raised flange on the seal 'journal', side closest to the counterweight. Pls. let me know if this isn't correct.

I did a little research and it seems that you can use the 1 pc style with either but the 2pc with the slinger won't work with 1pc unless it's an aftermarket "low profile" slinger.

I still have no clue what I have though. I guess I'm going to have to take it to a balancer to verify what balance factor is to be used.