XPAG Crankshaft

[Bob Grunau]

Hi John,
You have an original TC/early TD /Morris 10 crank. Prone to break, but sometimes is AOK. I would magnaflux it and if not cracked have it reground WITH RADIUS and use it in a street use car.
Bob

With all of this talk about the 168557 crankshaft being stronger than the 168628 crankshaft, are the part numbers stamped on the crank? I just pulled out a used crank from the garage, and it has "22528" stamped on it, as well as "ESC M19". What crankshaft do I have?
John Seim
TC 6590
Irvine, CA

[DickShaler@aol.com]

Yes, Isn't it amazing that one can still drive the car with a completely broken shaft.

The first time I broke one I drove a few miles out of my way to pick up a gasket set and bearings from the dealer,stopped to pick up some refreshment. filled the gas tank and then drove home for the repair.

As you said Bob, nothing looked out of place until I removed a bearing cap. The surfaces of the break were polished smooth and I'm sure another few miles would have caused enough clearance to allow the two pieces to slip apart.

Regards, Dick

[PADDY WILLMER]

Bob Gruneau I have replied to your mail to me of 24th June, but the server won`t deliver. Can`t identify your address. TOO BAD!

Paddy

[PMS GB Ltd]

How much do the checkbook racers pay for a Phoenix crank? The Moss Motors crank also has a reputation of being unbreakable. I wonder if they are really made by the same foundary.

Just a point - the Pheonix cranks arn't from foundry source - i.e. they are not forged, they are machined out of a solid bar (billet) of steel EN 40 B or equivalent nitridable steel.

I'd prefer this manufacturing method to a forged crank from other modern remote sources.

Clive Sherriff

[Chip Old]

On Mon, 26 Jun 2000, PMS GB Ltd wrote to Alan Moote:
Just a point - the Pheonix cranks arn't from foundry source - i.e. they are not forged, they are machined out of a solid bar (billet) of steel EN 40 B or equivalent nitridable steel.

I'd prefer this manufacturing method to a forged crank from other modern remote sources.

Assuming a suitable steel alloy is used in both cases, a forged crank is usually stronger than a billet crank. I'm not an expert on forging, but it has something to do with alignment of molecules relative to directions of stress or something like that. Do we have a metallurgist on the list who can clarify?
--
Chip Old 1948 M.G. TC TC6710 XPAG7430 NEMGTR #2271
Cub Hill, Maryland 1962 Triumph TR4 CT3154LO CT3479E
fold@bcpl.net

[Chip Old]

Erik Koik sent the following to me (not to the list) in response to my question about forged vs billet cranks. I'm reposting to the list because others may be interested.

---------- Forwarded message ----------
Date: Mon, 26 Jun 2000 09:45:52 -0400
From: Erik Koik
To: Chip Old
Subject: Re: [mg-tabc] crankshafts

Billets can be rolled from a cast ingot, or they can be open die forged from a cast ingot. An open die forged billet can be very effective metallurgically, as the grain structure is uniform and any section is of equal strength and stronger than a simple rolled billet. A crank machined from a forged billet would be a good crank, far better than a casting. Most modern racing (F1, etc.) cranks are made this way.

Most older "forged" cranks are closed die forgings which also imparts a tighter grain structure and if designed right can take advantage of metal flow in the dies to make a good strong crank. The strength tends to be less uniform in this type of forged crank and residual stresses must be managed. Tooling costs are high, however, the dies for a crankshaft might cost $150,000.

Hope this is helpful.

Erik Koik
47 TC

[PMS GB Ltd]

Message text written by Chip Old
Just a point - the Pheonix cranks arn't from foundry source - i.e. they are not forged, they are machined out of a solid bar (billet) of steel EN 40 B or equivalent nitridable steel.

I'd prefer this manufacturing method to a forged crank from other modern remote sources.

Assuming a suitable steel alloy is used in both cases, a forged crank is usually stronger than a billet crank. I'm not an expert on forging, but it has something to do with alignment of molecules relative to directions of stress or something like that. Do we have a metallurgist on the list who can clarify?

I'd agree a forged crank SHOULD be stronger due to the alignment of themolecular structure - but to do it right requires a well designedproduction PROCESS - This will occour for a run of thousands, but I would not expect it to occour in a batch of a dozen T Type shafts - they will be a hand done job without the careful design of the mass production process - hence my preference for a shaft machined from solid every time in these instances. There could be many unforseen stress points in a one off type crank beaten out of an inadequate forging process.

Clive Sherriff

[Chip Old]

Makes sense, and the info sent by Erik Koik adds weight to your argument.
--
Chip Old 1948 M.G. TC TC6710 XPAG7430 NEMGTR #2271
Cub Hill, Maryland 1962 Triumph TR4 CT3154LO CT3479E
fold@bcpl.net [/quote]

I'd agree a forged crank SHOULD be stronger due to the alignment of themolecular structure - but to do it right requires a well designedproduction PROCESS - This will occour for a run of thousands, but I would not expect it to occour in a batch of a dozen T Type shafts - they will be a hand done job without the careful design of the mass production process - hence my preference for a shaft machined from solid every time in these instances. There could be many unforseen stress points in a one off type crank beaten out of an inadequate forging process.

[Peter Pleitner]

Hi Whitworth Heads,

Just returned from Moldex, the premier custom crank and rebuild shop in Detroit. Asked the "old man" Bob Gilliam about nitriding. He explained, yes it does make them brittle if left in the oven too long. Further, that "typical" shops do that so the crank can be reground a couple of times (like for truck engines) without running out of heat treated metal, down about 0.030 inch or more penetration, and indeed that makes the crank brittle. He said he only treat his cranks long enough to get about 0.004 inch penetration. He also said that Tufftriding is still around in some areas and he used to hear about it being used in combo with Nitriding on some production cranks.

So that's that. You guys were right about Nitriding, but apparently there is a right and wrong way to do it too.

Cheers, Peter