Deciphering crankshaft undersize

[Sunbeam Canada]

I am trying to decipher the crankshaft undersize of a 5 bearing/1725 engine. The crank came as a spare without a block.

The only numbers I can find are:
3
L15
DAA50228
1981099

Does #3 refer to 0.030 ?

 

[sunbeam74]

The "3" does not indicate anything that I am aware of.

You will have to measure each journal to verify the diameter of your crank's main and rod journals. From there you can determine if it is STD. or undersized by referencing the manual.

Steve

 

[mikephillips]

All cranks started out as standard from the manufacturer so there'd be no need to identify an undersize on the casting. As Steve said, you'll need to measure the journals to determine the sizes. Measure each one in at least 2 different locations 90 degrees from each other to ensure a consistant measurement.

 

[V6 JOSE]

All cranks started out as standard from the manufacturer so there'd be no need to identify an undersize on the casting. As Steve said, you'll need to measure the journals to determine the sizes. Measure each one in at least 2 different locations 90 degrees from each other to ensure a consistant measurement.

Mike,

Some crank grinding shops will stamp the size under, on the crank cheek. I think that is what he was thinking.

I used to own a crank grinding shop, and I have found, that some Chevrolet chrank shafts come from the factory, with .009 under on the main line. Some Chevrolet shafts sometimes come with one, two, or even three of the rod throws, on their V8 shafts, .010 under from the factory. I don't know why, just that it is so.

Jose

 

[mikephillips]

My assumption was that if there was a number stamped into the crank rather than cast he would have noted that as a difference in the various numbers. But, perhaps I'm assuming too much. In any case, best thing is to check it himself since who knows if even a stamped number still agrees with the crank size.

 

[V6 JOSE]

My assumption was that if there was a number stamped into the crank rather than cast he would have noted that as a difference in the various numbers. But, perhaps I'm assuming too much. In any case, best thing is to check it himself since who knows if even a stamped number still agrees with the crank size.

You're right Mike. The crank could have been turned under any stamp mark that might have been put on the crank at a previous machining. There is only one way to be absolutely sure what size it is, and that's to mike it yourself.

Jose