I have picked up one in very nice condition. Various people have posted that they have had breakages.
I would like to hear from people that have success stories please!!!
Thank you

Les
I've come across 2 in engine rebuilds, 1 failed a crack test, the other was re-used, the one thing that has stuck in my mind was that the Suremike was the best crank I've come across that was built to spot on Ford specs. Not even Ford was getting that right as far as journal width! Comes to that, not even Scat is to Ford specs running a 1.250 diameter journal.

Frank
Thank you for the "real world" information!!

Les

I have found 4 Sure Mike cranks in engines, all cracked. Have had another 3 show up here at the shop and all were crack. I have only found one that was not cracked and it is on my display, with no plans to use. No success story here.

Mike
Thank you
I'm thinking of drilling this one for pressure oil and then of course I would use my transmission shaft. Of course I could try some Snyders rods with the integral dippers.
Hope I hear some more stories

I have two in my collection, one is worn bad enough to need turned .015 to clean up. No cracks. The other one is a real nice almost like new condition crank. No cracks on it either. I do not know the history of either. Both were checked with dry mag particle, liquid dye check. and dye check black light. I was going to have them x-rayed on one of our construction jobs, but I retired before I got around to it ... I may try to use the new looking one some day just for the heck of it.

I am wonder if the cracks are in fact folds from the forging process. Or are Sure-Mike cast cranks?

(Message edited by redmodelt on August 02, 2016)

Mark

Sure_Mike cranks were drop forged.

Had one placed in a engine for a speedster a fellow made for his grandson. Haven't ever heard back, so that might mean its still twisting.

Les, I checked one on a spectrometer at work once cause I wondering why I had found so many cracked ones also, they looked like a good design but the problem is they are hard like the Dodge bros. cranks, the T engine crank need a little flexing unless you have the 26-7 set to keep the pan straight and from flexing. Just my thoughts, hope this helps.

Joe
So my transmission shaft might really be the "ticket " then. No strain from the transmission and 4 th main

Mike Huebner made a ductile iron crank using the sure mike as a model. Most he made with a 1-3/8 journal. Two were made with 1-1/4 journals. One of the smaller cranks failed because a bronze front main cap let go. The other cranks are still running. One thing he did was he had the cranks nitrided. Nitriding puts a 15,000 psi compressive stress in the surface. The cranks has to be straightened a touch and journals polished after nitriding. With the nitriding whatever the max tensile stress was it is now 15,000 psi less. Rolling filets puts compressive stresses in the surface. There has never been a fatigue failure due to compressive stress. A built in compressive stress lowers the max tensile stress and improves fatigue life, sometimes dramatically.

Les,
You can check the hardness and spark test it to determine the type of steel, then using data for that steel draw it back a little more and gain some toughness.

Here's another brand very similar to a sure-mike from a past thread.

http://www.mtfca.com/discus/messages/331880/338731.html

The engine I and my farther built in HS has a Sure Mike in it. The "Old Timer" who did the machine work checked and everything was fine.....the pan never got any time on a pan straightening jig. The engine has been in storage for 38 years and I hope to do the pan over the winter and get it ready to run. I do remember that when I had it and the flywheel and drums balanced that the crank was so close to spot on that the only metal removed was from one throw and was done with a couple of passes with a hand file.

Ted
interesting idea about getting it nitrided. I can very reasonably get it gas nitrided locally at the same place that does my transmission shafts. I might just take it over to a friend and get the hardness checked anyway.

I heard they are in the habit to break
But I run two of them over the years with no troubles

I have one in a heavy 26 four door sedan with Stipe .280 cam, Prus head, Model B intake and carb, and Ruxtell axle. No problems, but I suspect most Suremike cranks broke because the buyers in their day, bought them, thinking they could push their engines more. A basically stock T engine (even with a few add ons), usually doesn't do well with high RPM's and Jack Rabbit starts.

I do not know the technical specs of a Suremike crank but I do know that the 2 cars that I have driven, that have been equipped with them, are the most delightful engines to listen to and drive extremely smoothly. A huge improvement on the Ford product. I would be happy to have one in my car after it was crack tested of course.

There were two designs of SureMikes. Look at Dan's photos above. The one depicted in the original ad is beefier than the one shown in the engine. I'm told the style of the one in the ad is much more dependable. I have one of those, but it's fairly rust pitted.

I have seen another explanation in earlier threads that the first version Suremike had smaller radii at the end of the throws, later cranks had better size radii but by then the SureBreak nickname was already established.

Ford cranks had also an increase in the rod throw radii when the diamond style was dropped in 1924.

Remember it's not only the axial flexing that stresses a thin model T size crank, it's the twisting from the power pulses that also creates high stresses - one way to help would be by designing a damper for the front end of the crank shaft, but then you would have to cut the pan and develop a new kind of front motor mount - and that's more than most T enthusiasts are willing to change.

Best help to avoid crank breakage is probably a larger diameter crank. 1.25" is just too thin.

Sorry, I can't add too the feel good feeling about Suremike cranks. Mine broke and the block was trash afterwards. This was run for about two years after rebuilding.

I have a SureMike crank in my 26 coupe. As it was running when I bought it, all I've done to the engine is check the main and rod clearances which didn't need adjusting, and put on a Z head and Chaffins 280 cam. As I'm working on the Ruckstell and have the 23 touring to drive, I don't have a lot of miles on it. Both cars have Z heads, the 23 with a Stipe 280 cam. The 26 with the SureMike is much smoother than the 23 all the way to 50 mph, and seems to have more low end torque. I plan to run it until it breaks. If I have to tear it down for anything else, I'll put one of Les's shafts in it that I bought from his original run.