Crankcase Arm Bolts
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Mike C
Topic author - Posts: 6
- Joined: Mon Jun 10, 2019 4:16 pm
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Crankcase Arm Bolts
The last Vintage magazine had an article about Henry' way of mounting and another way to avoid breaking the the crankcase arms. It says to use the crankcase arm bolt from a TT and using the 1.25" spring as the one used on the yoke to cranckcase connection. I can't find these drilled shank bolts (TT 3074) anywhere. I assume it's a 3/8" diameter. What is the length of he shaft? I'll have to drill a cotterpin hole.
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Humblej
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Re: Crankcase Arm Bolts
I do not have the answer to your question regarding the length of the bolt, but I would start with a trial fit of the horizontal crankcase bolt and see if that is a good length... and it is predrilled for a cotter pin.
As an owner of an unrestored 1924 TT with the single bolt and spring fastener method, I can attest it did not solve the problem of broken crankcase arms. It is worth noting that Ford never applied the TT mounting method to passenger cars.
The attached photo is a 1924 TT crankcase arm using the long bolt and radiator type spring. The heavy metal hook on the side of the arm is for a belly band because the crankcase arm is broken.
As an owner of an unrestored 1924 TT with the single bolt and spring fastener method, I can attest it did not solve the problem of broken crankcase arms. It is worth noting that Ford never applied the TT mounting method to passenger cars.
The attached photo is a 1924 TT crankcase arm using the long bolt and radiator type spring. The heavy metal hook on the side of the arm is for a belly band because the crankcase arm is broken.
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DanTreace
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Re: Crankcase Arm Bolts
Here is that way to mount, as suggested not by Ford for the T, but by a long time T'er. Do so if you wish.Mike C wrote: ↑Fri Apr 26, 2024 11:03 pmIt says to use the crankcase arm bolt from a TT and using the 1.25" spring as the one used on the yoke to cranckcase connection. I can't find these drilled shank bolts (TT 3074) anywhere. I assume it's a 3/8" diameter. What is the length of he shaft? I'll have to drill a cotterpin hole.
IMO the wood block and std mounting hardware is better for the T. The wood block does help resist frame twist on braking and acceleration. The single bolt, even with a spring can't do that.
That bolt, p/n 3074C is TT CC arm bolt, longer for the TT . The bolt is 3/8" x 24 and is 1 7/16" long.
The wood block, fitted very snug inside the frame rail and against the crankcase arm resists side twists of the engine and frame.
The best way is always the simplest. The attics of the world are cluttered up with complicated failures. Henry Ford
Don’t find fault, find a remedy; anybody can complain. Henry Ford
Don’t find fault, find a remedy; anybody can complain. Henry Ford
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skyhunter
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Re: Crankcase Arm Bolts
I would think the best option would be to do both. Use the bock and side bolt but just snug it, not murder it. Maybe add a spring there and then use the spring on the upper bolt. Be close to a rubber mounted engine and flex when it needs to.
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Original Smith
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Re: Crankcase Arm Bolts
I believe those bolts are the same one use for the steering shaft bracket up front.
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Jim Eubanks
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Re: Crankcase Arm Bolts
I have wood in my T's but I have brazed a nut on the starter side ear inside surface. No kotter key but never has gotten loose and a lot easier to bolt up!
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J1MGOLDEN
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Re: Crankcase Arm Bolts
The spring with only the top bolt is recommended in Tinkern Ted Ashman's book.
I have used it for about 35 years with no problems.
I have used it for about 35 years with no problems.
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Jerry VanOoteghem
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Re: Crankcase Arm Bolts
Lot's of people have their "special formula" for this bolting arrangement. I have used the stock, standard Ford arrangement, as did my dad, and have never experienced a broken pan arm. I'm not saying other ways can't work, but I'm gonna stick with the Henry Ford design. 
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Allan
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Re: Crankcase Arm Bolts
I agree with Jerry. Use Ford's standard method. We sometimes forget that the way we use the cars is way different to the way they were used when busted pan arms were a problem. Plus, road conditions, likely the primary cause of failures, are way different also.
Allan from down under.
Allan from down under.
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Craig Leach
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Re: Crankcase Arm Bolts
My opinion is probably not popular but I do the bolts in the top not the sides, with springs, I don't cotter pin I use longer bolts & double nut
them. My thought is that the pan is the fixture that holds the fourth main inline with the crank & using the pan as a frame crossmember is
not beneficial to doing that! The question is do model T engines produce enough torque to twist or warp the pan or doe's using it as a
crossmember accomplish that? If we are looking for bad ideas lets look at using the engine pan as a major part of the front suspension that is
subject impacts from many sources. Like potholes, curbs & twisting of the front end. Then use the pan as the major anchor for the rear
suspension subject to the same forces. If I remember correctly Ford abandoned this practice shortly after the model A that used cast iron bell
housing & transmission for that purpose & then went to frame only for that? Of coarse frames became much stiffer & suspension improved &
the frame was no longer part of the suspension. Don't get me wrong I love my model T's but looking at the changes that occurred in just a few
years tells quite a story. As they say fallow the science. JMHO
Craig.
them. My thought is that the pan is the fixture that holds the fourth main inline with the crank & using the pan as a frame crossmember is
not beneficial to doing that! The question is do model T engines produce enough torque to twist or warp the pan or doe's using it as a
crossmember accomplish that? If we are looking for bad ideas lets look at using the engine pan as a major part of the front suspension that is
subject impacts from many sources. Like potholes, curbs & twisting of the front end. Then use the pan as the major anchor for the rear
suspension subject to the same forces. If I remember correctly Ford abandoned this practice shortly after the model A that used cast iron bell
housing & transmission for that purpose & then went to frame only for that? Of coarse frames became much stiffer & suspension improved &
the frame was no longer part of the suspension. Don't get me wrong I love my model T's but looking at the changes that occurred in just a few
years tells quite a story. As they say fallow the science. JMHO
Craig.