MTFCA Forum

Here are the results from the mag particle test on my 1911 crankshaft. No radial indications, linear indications show up on some of the journals. Should I be concerned? or are these surface cracks that can be polished.

Was debated several years ago, more than likely in from new and consensus was nothing to worry about. Cranks have only failed with radial cracks.

Was the crankshaft washed and all grease and debris removed before crack inspection?
You won't get a true reading if there is oil or dirt on the crank.

From what I see those are a result of the forging process as long as they are away from the radius of the crank.

After breaking the crank in my 1912 and getting lucky with no block damage, my thinking now with the early block I am currently working on an open valve 1910 block is spend the money on a scat crank and drive without the worry of breaking the crank. Just my 2 cents Cheers Colin

Use a late crankshaft. Preferably one marked EE. The early ones are not nearly as good. If you have a 1911 block you want the best crank you can afford. I just repaired a 1911 engine the broke the crank and ripped the rear main web out of the block. Had to have lock n stitch put it back together. Expensive.

Eric, are you sure the crank broke and took out the rear web? I have seen a number of early blocks where the rear web was cracked, it broke out of the block and took the crank with it. I know more cranks break than blocks, and that makes them the suspects in the failures, but it is not always so, especially with early blocks where the rear web is torn out.

Allan from down under.

The crank broke. It was a Sure Mike vintage counter weighted unit. After the block was repaired I put in a Scat crank.

I am with Erik find a better crank later as he said EE or Skat,Dubatts, anything but the DB that most of the early engines had in them they where really hard,cranks are cheap compared to an early block!

Sure I'll buy another crank as long as you want to sponsor me, not going to happen with my budget. When I picked it up the tech put it back in the mag machine and showed me the linear surface cracks, he said he found no radial cracks of any kind. I surmise they've been there for 107 years so why change now. I'm going to polish the journals and assemble.

Thx

Leaving an original crank in a block of any higher value, especially a crank with ANY found defects, is like driving your modern car with no insurance and just taking a chance on paying the bill if anything happens.

A real nice 1911 block would probably sell for a low of $2,500 and maybe around $4k under just the right circumstances (close date and a very correct restoration). A new Scat Crankshaft is $1,695. Yes, it’s a big added expense, but broken cranks in early blocks generally destroy the block a vey high percentage of the time and they can’t be fixed.

Another thing to look for on your crank is the forging mark. This is the trademark of the company that manufactured the crank for Ford. Quite a few of the early T cranks were forged by Cleveland Hardware. Their mark is a letter C superimposed over a letter H. These crankshafts have such a bad reputation for both finding cracks and breakage in service that many rebuilders and some very experienced hobbyists probably wouldn’t use one in a rebuild even if it checked out fine. If your crank is of Cleveland Hardware manufacture, it would be best not to use it and substitute a later good crankshaft, or a new one.

That crank scares me and these guys before me know a LOT more than I do. I have a lot more money in just a bare block for my 1912 right now than the cost of the new Scat cranks cost and now I need to get the bare block rebuilt and will end up with more than $5000 in it when its done WITHOUT the Scat. I wont take that chance because it took forever just to find a 12 block to start with and then it needed a ton of work just to get it up to the point it is worth the cost of a rebuild. All the bolt holes were messed up and it had cracks that had to be welded by someone with the equipment to do it right so now I have even more in it. What Adam stated before is dead on and then it gets bored and new babbit ect. Good luck finding another 1911 block in your price range or not. I would at least look for a good EE crank from a 26/27 engine as the less costly way to protect what you have. We can't all afford to pay the big bucks for Scat. In my case I did buy a new one but it set me back a couple of years on the rebuild and I feel it was worth it to know it wont let go next week. We see to many 2 piece crank club members on here already.

fbergski wrote: ↑

Thu Jan 30, 2020 11:44 pm

Sure I'll buy another crank as long as you want to sponsor me, not going to happen with my budget. When I picked it up the tech put it back in the mag machine and showed me the linear surface cracks, he said he found no radial cracks of any kind. I surmise they've been there for 107 years so why change now. I'm going to polish the journals and assemble.

Thx

Those linear indications are not cracks. They are forging flaws that were there the day that crank was made. I would not hesitate to use that crank, based on those results.