$ Difference Between Replacing Broken Crankshaft w/ stock crank or a Model A or B or Scat crank?

[NorthSouth]

Hello Fellow Club Members,

I was hoping you might help me with a question.

Besides the cost of the crankshaft itself, is there a big difference in related expense between putting a Model A, Model B, or Scat crankshaft in our 1927 engine compared to just putting a Model T crankshaft back in it?

-Steven

[Joe Bell]

The amount of money you have tied up in an stock A crank and pistons it is cheaper to go the Scat crank that fits the spacing. I have a few friends that have went the A conversion and they said they lost the power on the hills. The less expensive of all is finding a good EE crank and enjoy unless you want a hot rod then you need some thing to support all that. Just my thoughts from feedback on people through the years.

[Dan McEachern]

The longer stroke of the A crank should provide more torque, not less. There are so many more things that affect and influence engine performance than just the change in stroke that I don't think you can realistically come to the conclusion that you would loose hill climbing ability, but . . . . . just saying.

[Mark Gregush]

Model A crank; Move the flange or motor on the pan forward. If you keep the mains A sized, bore the block and buy new caps, then babbitt and fit crank. Then you have to deal with rods and pistons. Next the crankshaft gear and pulley have to be dealt with.

[Norman Kling]

Cost today is only one factor. The standard grind SCAT crank is the best crank and is also counterbalanced. You can bore your babbit to standard clearance and have an engine more like Henry built. Next best would be the EE crank if you can find one which is straight, not cracked, and not far undersize. I personally would not go more than 20 thousandths undersize and less than that if you can. I don't know the cost of an A or B crank but I do know that there is no turning back if it doesn't work, because the block will need to be altered. Also the gears as stated above and possibly the flange at the back of the crankshaft might need to be altered. And you might also need to modify the crankcase, because the throws are longer.

I would guess the difference in cost between installing a stock grind SCAT and installing an A or B might be about the same. Just costs for different reasons. You might get some more power and speed with that crank, but speed and power also lead to drivetrain problems so ??? for long haul.

The SCAT crank is approximately $1,500 new but will save you a lot of problems in the future if your car is a driver and you plan to put some miles on it.

[Les Schubert]

How much can you do yourself??
For me the A (or preferably the C) is significantly cheaper because I’ve done it a number of times and I do almost all of it myself. I can’t fathom why anyone wouldn’t have MORE hill climbing ability (unless they fouled up the cam timing)!!

[Kohnke Rebabbitting]

I can’t fathom why anyone wouldn’t have MORE hill climbing ability (unless they fouled up the cam timing)!!

Agree!

Herm.

[TonyB]

I have installed about a dozen SCAT cranks in T blocks, most went fairly easy but there are several clearance issues which must be addressed, the rear U channel is the most sensitive issue. On both the three and four dip pan the U channel hits the new crank. Basically I cut the U channel into two J channels and with a little grinding you can get the required 0.050” clearance.
I have done one A crank in a T block and it’s quite complex. First the crank is too long so either the block or the crank needs modification. Then the T pan needs beating out to clear the rod cap nuts. Also I needed a spacer between the pan cover and the pan. Also the block needs boring out to allow for the larger crank and I used new bearing caps. Finally my customer provided shortened A rods, I would have preferred the custom SCAT RODS. To me the A crank was a good deal more work than the SCAT but the result may be worthwhile.
I’m sure to most, the A route is more expensive unless you can find a good used A crank. Unless you are very experienced in these matters, I think the average restorer is best advised to go the SCAT route

[Scottio]

I used a scat stroked crank on last rebuild and I would definitely not do that again. It requires too much grinding on engine block and no real performance increase even with performance cam. I recommend a scat stock stroke crank.

[Les Schubert]

Back about 1980 I built my first A Cranked pressure oiled counterwerghted T block. No block grinding required. Yes, needed to dent the pan sides. VW pump on the back of the cam. Engine turns 4500 rpm and pulls strong. Car has changed hands a couple of times but still runs strong

[Henry K. Lee]

I have built both, and even counted weighted T's. It really comes down to how much money you want to spend, time on your hands, etc. I am with Les on the A crank. Still running Dad's 1914 with our first A crank conversion/shortened. 25 years later still barking the rear tires strong as it was on day one. It was fun to build as well. Satisfaction came with the first drive......, Whoa!!!!

To each their own. Good luck in your decision, call or email if you have questions, glad to share what has been learned.

All the Best,

Hank

[Tom Hicks]

If I am going to pay to have an engine rebuilt I will pay the extra bucks for a new SCAT crank. I want it right, I want it reliable, and I don't want a 100-year-old crank.

Yes, I do belong to the Two-piece Crank Club.

[Henry K. Lee]

I have three hanging on my wall, BIG LOL!!!!

But I would not change the experience for nothing.

All the Best,

Hank

[AndyClary]

A stock stroke scat crankshaft will give you peace of mind, not power. It should be smoother at most rpm but, remember, a flat crank is going to find a spot for harmonics. If you use a stroker crank you should pick up torque. But feeding it with stock valves and camshaft will result in an underfed slightly bigger motor. One change always means more changes.

Andy

[Tom Hicks]

I have three hanging on my wall, BIG LOL!!!!

But I would not change the experience for nothing.

All the Best,

Hank

You joined and have renewed your membership twice??!!?!

[Henry K. Lee]

Live and Learn and what not to do! Tom I can only laugh at myself!

Hank