BMS Crank.

I still have 2 raw forgings and was planning on selling 1 to raise some roller money. I would hand deliver it to King's Crankshaft here in Denver, NC. to turn it to whatever stroke anyone wanted, it was going to be around 1600. Funny thing is the last 2 that were sold were turned down to sizes below 3.40.
"Back in the day", I had 5 BMS forgings, that I had King do. Every once in a while, I see a pic of 1 w/ Cody Mspt/ dimensions elec penciled on it....
They do nice work...At least they did on these.
 
We just had some cranks made by Kings for one of our R&D engines at my company. I got to measure them up and I think they are some of the nicest cranks I've seen.

Neal
 
Dave can you id this crank
20170422_204628.jpg
 
I browsed through all my old Buick power source parts books (both sales brochures as well as the vtwo build guides) and did notice they advertised the cranks as 4140 with RH 28-34 IIRC. The Ruggles Stage 2 book he refers to the cranks being 4340. Curious as to when they changed and if the stamping #'s mentioned would dictate one or the other.
 
I browsed through all my old Buick power source parts books (both sales brochures as well as the vtwo build guides) and did notice they advertised the cranks as 4140 with RH 28-34 IIRC. The Ruggles Stage 2 book he refers to the cranks being 4340. Curious as to when they changed and if the stamping #'s mentioned would dictate one or the other.
Still waiting on Dave's input on this matter.

Dave? You out there?

Inquiring minds want to know.
 
Dave can you id this crank

I cleaned up and my list of crank codes is not where it has been for years. May have been put in a file or shredded.... I remember them though

Cranks codes start with an R, T, N or W. There were 8 codes given to me. There may be others, but doubt it.

From the picture, It looks to have an N. If this is so, the only N crank was N78 and the reason I remember this is it was the only 5140 crank they made. As a reference, the early power source books referenced 5140 material. The later books reference 4140.

The best and last design was the W15, the T92 is the next best, then T70 and all three are 4340. R57 is 4140, R75 is 4340. N78 is 5140. T65 is 4340 and T66 is 4140. These are from memory and I would say they are correct.
 
I cleaned up and my list of crank codes is not where it has been for years. May have been put in a file or shredded.... I remember them though

Cranks codes start with an R, T, N or W. There were 8 codes given to me. There may be others, but doubt it.

From the picture, It looks to have an N. If this is so, the only N crank was N78 and the reason I remember this is it was the only 5140 crank they made. As a reference, the early power source books referenced 5140 material. The later books reference 4140.

The best and last design was the W15, the T92 is the next best, then T70 and all three are 4340. R57 is 4140, R75 is 4340. N78 is 5140. T65 is 4340 and T66 is 4140. These are from memory and I would say they are correct.
Wow! Nice.

I thought we lost you!

This is great Information and highly appreciated. I checked mine recently and found that, although it's not the latest forging, it's still an R75. Now I feel better and I am absolutely positive I have a 4340 crank.
 
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image.jpeg image.jpeg image.jpeg Both of my raw forgings have the "DU" on one side and one has "BA and 93" and the other has "BN", the one with the "BN" has an 89 stamped at the DU.
 
One crank also has the raised GM part # and the other has it stamped. Who knows what was going on that day.
 
I'm pretty sure it wasn't a science project back in the day. I'm just glad Dave could help shed light on the whole forging code mystery.

Thanks for the info Dave! (y)

Neal
 
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