MTFCA Forum

I have heard about people installing a Model A crankshaft in a Model T. What are the advantages? Also, how can I tell if my 1927 Model T speedster has a Model A crank from past owners?

More torque from the stroke for sure. Larger journals, but some serious mods. Drop the inspection plate and you will know.

Hank

If the front of the crankshaft at the pulley is threaded and the pan has four bumps on each side where it is bolted to the block, there’s a good chance you have a Model A crank
Remove the inspection cover and have a look

A Model crank has larger mains and rod pins along with a 1/4” longer stroke.

Take a lot more work to put one in but very doable

What Henry said. He types faster. Lol

Here is a pic of the pan bumps... and there will usually be a 3/8”-1/2” thick spacer between the pan and inspection cover as well
If you have the inspection pan off, and are not familiar with either crank... the A crank has circular webs near the main journals, and the T crank will look like it was bent up out out of a coat hanger

I can usually tell if it’s an A crank by the “bumps” on the side of the pan.

Good info! Will check into my engine.

Somebody correct me if I'm wrong, but I think one of the most significant differences is that the Model A cranks are virtually never found cracked.

Model T...


Model A...

Thank you, Tim Rogers. Opened your post while my wife brought my coffee this morning! She also likes cars. I asked her could she see the difference between Model T and Model A crankshaft. She immediately saw the difference! She said, "The Model A looks 'newer.' "

The back Main Bearing is also shorter by about 3/8th inch.

I don't recall the exact difference.