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Do I have a forged or cast crank?

Posted By: 1970RT

Do I have a forged or cast crank? - 08/09/10 07:06 PM

I have a small block crankshaft that I got years ago that I was told at the time was a forged crank from a 340. I never bothered trying to verify it until now. The part number on it is 2658278 which according to the one chart I looked at is a 273-318 cast crank. However, based on the picture in the tech section showing the differences between cast and forged cranks it would appear it is a forged crank. It has the wide parting lines and the rounded edges but the part number looks more like that of a cast crank.

Attached picture 6131111-MVC-066S.JPG
Posted By: 1970RT

Re: Do I have a forged or cast crank? - 08/09/10 07:08 PM

Tech picture.

Attached picture 6131114-crankshaftid.jpg
Posted By: JohnRR

Re: Do I have a forged or cast crank? - 08/09/10 10:49 PM

I thought the 273 had a forged crank ?

Can you post a better , not so dark , picture of it ?
Posted By: NachoRT74

Re: Do I have a forged or cast crank? - 08/10/10 12:09 AM

forged, if you ask me
Posted By: ngpSatellite

Re: Do I have a forged or cast crank? - 08/10/10 12:17 AM

the edges look rounded on your orig pic so......... .......... forged crank
Posted By: 1970RT

Re: Do I have a forged or cast crank? - 08/10/10 01:39 AM

I don't know if it will help but here is another picture.

Attached picture 6131746-MVC-067S.JPG
Posted By: 70Runnerdude

Re: Do I have a forged or cast crank? - 08/10/10 01:44 AM

Forged for sure
Posted By: rrunner

Re: Do I have a forged or cast crank? - 08/10/10 01:50 AM

Quote:

Forged for sure

Posted By: JohnRR

Re: Do I have a forged or cast crank? - 08/10/10 02:00 AM

what they said
Posted By: vdriver

Re: Do I have a forged or cast crank? - 08/10/10 02:05 AM

Yup, forged.
Posted By: 1970RT

Re: Do I have a forged or cast crank? - 08/10/10 02:50 AM

Can someone verify if the part number is for a forged crank? In the attached chart it indicates the part number on the crank I have as being a cast crank.

http://kim_spure.tripod.com/A-Engine.htm#Crank
Posted By: Alexdodge

Re: Do I have a forged or cast crank? - 08/10/10 03:23 AM

now, which damper go with which crank?
Posted By: cornucopia

Re: Do I have a forged or cast crank? - 08/10/10 04:30 AM

yup. it's forged...273 or 318. the 340 had the rod journals cross drilled. interchageable with a balance job.
Posted By: wyotech_cuda440

Re: Do I have a forged or cast crank? - 08/10/10 05:10 AM

Regardless of the P/N, that is a forged crank. It's easily determined by the wide parting line because it was slammed between two dies in a forge. If the two dies hit each other, the forge will destroy itself, so the dies stop short and leave a wider seam. The cast crank has a thin parting line, because the casting molds are held together tightly so the molten steel doesn't run out.
Posted By: JohnRR

Re: Do I have a forged or cast crank? - 08/10/10 01:25 PM

Quote:

Regardless of the P/N, that is a forged crank. It's easily determined by the wide parting line because it was slammed between two dies in a forge. If the two dies hit each other, the forge will destroy itself, so the dies stop short and leave a wider seam. The cast crank has a thin parting line, because the casting molds are held together tightly so the molten steel doesn't run out.



What he said ... it doesn't matter what part number is on it , it's a FORGED CRANK
Posted By: 1970RT

Re: Do I have a forged or cast crank? - 08/10/10 03:04 PM

O.K. Thanks everyone.
Posted By: Commando1

Re: Do I have a forged or cast crank? - 08/10/10 06:00 PM

Quote:

What he said ... it doesn't matter what part number is on it , it's a FORGED CRANK


I totally agree. The pictures don't lie.
Now.............
Why the cast crank P/N?

And the 1st person that says "I've seen.... "
Posted By: John_Kunkel

Re: Do I have a forged or cast crank? - 08/10/10 08:15 PM


I, too, am curious as to the part number, is it stamped or written or is the number raised?
Posted By: 1970RT

Re: Do I have a forged or cast crank? - 08/11/10 02:38 AM

Here is a picture of the number. It is raised but there are a couple of other numbers and letters that are stamped.

Attached picture 6133581-MVC-069S.JPG
Posted By: 1970RT

Re: Do I have a forged or cast crank? - 08/11/10 02:38 AM

Stamped numbers and letters.

Attached picture 6133582-MVC-073S.JPG
Posted By: vdriver

Re: Do I have a forged or cast crank? - 08/11/10 03:03 AM

I'm thinking it's just a typo in your reference material.
Posted By: Commando1

Re: Do I have a forged or cast crank? - 08/11/10 02:33 PM

Quote:

I'm thinking it's just a typo in your reference material.


All the ref. manuals say the P/N is a cast crank.



I want answers and I want them now.
Seriously, I'm thinking that the model maker for the die didn't know what the new P/N was going to be for the new cast crank and just used the existing #.
Posted By: vdriver

Re: Do I have a forged or cast crank? - 08/11/10 03:46 PM

Quote:

Quote:

I'm thinking it's just a typo in your reference material.


All the ref. manuals say the P/N is a cast crank.



I want answers and I want them now.
Seriously, I'm thinking that the model maker for the die didn't know what the new P/N was going to be for the new cast crank and just used the existing #.





Attached picture 6134357-DCP08983.JPG
Posted By: Commando1

Re: Do I have a forged or cast crank? - 08/12/10 12:21 AM

Quote:




Damn if that ain't interesting...
MMMMmmmmmm. Yum. Crow tastes good.
Posted By: bboogieart

Re: Do I have a forged or cast crank? - 08/12/10 12:50 AM

well they had to forge it from something.
I doubt that they forged a crank from a straight piece of steel. I'm just guessing, but I figure they cast the blanks and then forged them to final dimensions. This is just a guess. So don't get excited if I am wrong. just explain how forged cranks were made.
Posted By: vdriver

Re: Do I have a forged or cast crank? - 08/12/10 01:28 AM

Quote:

Quote:




Damn if that ain't interesting...
MMMMmmmmmm. Yum. Crow tastes good.



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