Connecting rods specifications

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Dave1
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Connecting rods specifications

Post by Dave1 » Fri Jan 05, 2024 2:29 pm

Any one know what the specs are for a T connecting rod is from centre - centre, small end to big end ?
Need to make an alignment jig for welding Chevy / T
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DanTreace
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Re: Connecting rods specifications

Post by DanTreace » Fri Jan 05, 2024 3:14 pm

Center to center length is 7”
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
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Ron Patterson

Re: Connecting rods specifications

Post by Ron Patterson » Fri Jan 05, 2024 5:14 pm

I have copies of all the Record of Change cards and prints for Model T rods; T-641, T-641A and T-641B
The length specification from center of cranksahft journal end to center of piston pin end to be 6.998 to 7.002 inches and each print specifically states "with broaching shim in place".
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Topic author
Dave1
Posts: 83
Joined: Sat Jan 12, 2019 12:01 pm
First Name: Dave
Last Name: Eddie
* REQUIRED* Type and Year of Model Ts owned: 1926 Tudor, 1926 Touring, 1931 Plymouth PA, 1952 Hudson Hornet
Location: Lillooet BC. Canada

Re: Connecting rods specifications

Post by Dave1 » Fri Jan 05, 2024 5:30 pm

Thanks for the info, for this purpose a length of 7.00 will do fine
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Kevin Pharis
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Re: Connecting rods specifications

Post by Kevin Pharis » Fri Jan 05, 2024 5:46 pm

As I had mentioned at the very end of this thread about shortening rods, you may not be able to trust the mating surfaces of the big end. I suggest that you get a depth mic and a dowel pin to measure if there is an offset, and factor this into your welding fixture. Also, expect that the rods will shrink about .020” when cool. You should also machine the big end of the rod prior to babbiting, this will minimize the risk of striking iron when finish boring

https://www.mtfca.com/phpBB3/viewtopic. ... 32#p273732
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Topic author
Dave1
Posts: 83
Joined: Sat Jan 12, 2019 12:01 pm
First Name: Dave
Last Name: Eddie
* REQUIRED* Type and Year of Model Ts owned: 1926 Tudor, 1926 Touring, 1931 Plymouth PA, 1952 Hudson Hornet
Location: Lillooet BC. Canada

Re: Connecting rods specifications

Post by Dave1 » Sun Jan 07, 2024 11:59 am

Thanks Kevin, good advice.
I have a 28 Chev engine that will be the doner for the rods.
The crankshaft I will be using is from another engine and is ready to grind.
It seems the guys at Chevrolet did things a bit different than Ford. The rods have a spacer about .125” thick between the rod and cap. On this engine there are no shims. It seems that the last rebuilder filed the caps to get the required clearance? Not sure if this was the OEM design or not.
I have a cap grinder and a Sunnen rod sizer. So I should be able to true things up before pouring Babbitt.
I don’t think I feel comfortable assembling the rods without any shims ?!
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