Crankshaft Identification

[Rotary FP46]

The section of shelving I am working on tonight has a small bunch of crankshafts standing on it.

I've found a blurb in Clark's web catalog about casting numbers indicating early model vs. late.
Have not yet found any references to help with determining 110 vs. 140 vs 180 HP, etc.
Also have not found any references to help with determining whether or not a given crankshaft has been nitrided.

What is there to know about identifying Corvair cranks?

I've pulled one from the group and photographed its markings.

[Lane66Monza]

Nitrided crankshafts have a ampersand ( & )stamped into the pulley/balancer end of the crankshaft. These crankshafts are used on the LM higher HP engines (140 & above). The 150 EM engine crankshaft was made with a different material, not needing nitriding.


Here is a discussion on the other forum that is all about crankshafts.

https://corvaircenter.com/forum/viewtop ... =ampersand

[jimbrandberg]

Also the rod throw on a 164 crankshaft is right out at the end and the rod throw on a 145 crankshaft is in about 1/8".

I was thinking the EM turbo had the Nitriding "&" mark but I guess it's been a while since I considered it. I think I have one in a box that I had polished...

Not everyone is in agreement on how deep the Nitriding goes but I've always figured if it needed to be reground .010 it was probably gone...

Since the press fit of the gear is so awful tight I'll throw away a crankshaft with a bad gear. I've got a dozen crankshafts or more so I can afford it.

When sorting out the good ones I like to oil them up to slow the rust and stand them on end in a pulley.

[texas yenko dude 199]

There is one exception on the nitrided cranks. Every NOS over the counter from the parts department nitrided crank was not marked with an ampersand '&'. I did check them with a file and they were nitrided. I have had probably 6 of these cranks over the years.

[RexJohnson]

The mark "&" would be on the flywheel end not the pulley end. The 8409 number should be on the long stroke cranks. With alot of things it is not early or late because the '64 year screwed that designation up.

[66vairguy]

I'll add that the "nitrided" crankshafts are considered more valuable IF the journals are in good condition. If there is any pitting from rust, or wear marks from lack of lubrication, then the journals need to be turned down and that removes the a lot or all of the nitriding.

That said --- I've had a few "dirty" looking nitrided crankshafts journals polished and they came out great and within specification.

[Rotary FP46]

It seems this one is nitrided. Here is what the ampersand marking on the flywheel end of the crankshaft actually looks like:

This has been a fun thread. Thank you all.

[Vairone]

Nitrided crankshafts have a ampersand ( & )stamped into the pulley/balancer end of the crankshaft. These crankshafts are used on the LM higher HP engines (140 & above). The 150 EM engine crankshaft was made with a different material, not needing nitriding.

150 Turbo EM engine crankshafts were made with the same material as all 164 cid engines.

[Lane66Monza]

Sorry about the misleading info regarding which end the stamp is on. Old man syndrome trying to remember little details. Get them wrong occasionally and my photo didn't help. That photo was of a crankshaft of a group I had nitrided down in Florida. Photo mislead me which end it was on. I had 6 bare crankshafts done. I put the ampersand on the flywheel end, when I got them back from nitriding and the machine shop final check. Then, it could be identified as a post production nitrided crankshaft, it got the ampersand and a number. The #3 is the 3rd line item in my document, defining of what engine sn it came from. That was way back in 2016.

[Wagon Master]

Not entirely your fault "Old Man". I think your pictures are of the flywheel end......there's just no hub pressed on yet. See where the torque converter left its signature mark? On the other one it looks like a pilot bushing that didn't like nitriding.

[vairchet]

Speaking of crankshafts, I have an early crankshaft that appears to be an odd ball. As I'm tossing out dozens of crankshafts, I came across one that has a 7293 casting number. It's known 5607 are primarily earlies (145 ci) and 8409 are lates (164 ci). Could it be an early turbo crankshaft?

Early Crankshaft

Early Crankshaft

[vairchet]

Obviously, I did not click on the above link. Apparently, 7293 is a turbo crankshaft. Still on a learning curve.

[jimbrandberg]

I didn't follow the link above either but I'll add that 140 PG crankshafts have a special gear to retard the cam timing 4 degrees. There's a picture in the Junkyard Primer book that shows how to tell when viewing a tooth through one of the holes.

[Rotary FP46]

I didn't follow the link above either but I'll add that 140 PG crankshafts have a special gear to retard the cam timing 4 degrees. There's a picture in the Junkyard Primer book that shows how to tell when viewing a tooth through one of the holes.

Anyone have that photo handy?

[vairchet]

Here ya go:

Scan brought to you by an Artificial Entity without Intelligence

[Rotary FP46]

Here ya go:Corvair Camshaft Timing.jpg

Thanks, Chet.