Welded rods with an A crank

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Bruce Compton
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Welded rods with an A crank

Post by Bruce Compton » Fri Mar 29, 2024 10:05 pm

I have a very nice 1913 Canadian block (three digit Canadian number) that has had a Model A crank installed. It also has a reground cam, adjustable and later valves and new 0.060 pistons and rings. Looking close at the connecting rods , it appears that someone welded T tops to A bottoms, The rods and crank are beautiful and the engine has run maybe 2-3000 miles and shows very little wear. The weld is right below the wrist pin hole and does not show any signs of fatigue, but I'm wondering if this is accepted and safe practice. BTW, the Main caps are the ones in Lang's catalog. A T buddy that has owned over 100 Model T's says it was a common thing to do, but I'm wondering why someone would not just modify the top of a stock A rod (bronze bushing with retaining clips)?? I believe that A rods and T rods are both 7" C-C. Any comments???? Thanks in advance. Bruce


1915ford
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Re: Welded rods with an A crank

Post by 1915ford » Fri Mar 29, 2024 10:51 pm

Was on a tour years back where a rod broke and grenaded a guys block. Tour over. T rods welded to a rods same as what you are describing. Even before seeing that i just think that trusting a welded rod is not something i would want to try with a block i care about. Especially if you don't know who, or how the welding was performed.


Kevin Pharis
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Re: Welded rods with an A crank

Post by Kevin Pharis » Sat Mar 30, 2024 12:31 am

Welded rods are a quite common reality of A crank motors in the pre SCAT crank world. The A rods are 7.500” center distance and require a special piston if not shortened. The special A rod pistons are notorious for pumping oil, and the T tops allow standard piston choices. I’ve made up several sets of shortened A and hybrid T/A rods, and choose to box the rods for additional strength. Welding near the wrist pin is typical


Les Schubert
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Re: Welded rods with an A crank

Post by Les Schubert » Sat Mar 30, 2024 11:30 am

Related but not, there were cast aluminum rods available for the A crank in a T block. I actually own a new set and a set of the bearing shells.
Sorry for the diversion!


Topic author
Bruce Compton
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Re: Welded rods with an A crank

Post by Bruce Compton » Sat Mar 30, 2024 12:25 pm

Les, are they for sale? Bruce


Dan Hatch
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Re: Welded rods with an A crank

Post by Dan Hatch » Sat Mar 30, 2024 12:38 pm

Buick 3800 V6 pistons will work. Need special bushings for A rods.


Brian Cress
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Re: Welded rods with an A crank

Post by Brian Cress » Sat Mar 30, 2024 1:45 pm

Dan, are the Buick 3800 pistons "deck height" at TDC, or do they rise above the block like a stock T or A piston?


Dan Hatch
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Re: Welded rods with an A crank

Post by Dan Hatch » Sat Mar 30, 2024 2:19 pm

Flat top pistons.


Brian Cress
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Re: Welded rods with an A crank

Post by Brian Cress » Sat Mar 30, 2024 3:19 pm

Thank you for clarification.


AndyClary
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Re: Welded rods with an A crank

Post by AndyClary » Sat Mar 30, 2024 3:23 pm

So the Buick pistons work but you have no compression?

Andy


Kenny Edmondson
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Re: Welded rods with an A crank

Post by Kenny Edmondson » Mon Apr 01, 2024 9:28 am

The Buick pistons work great. There’s a little protrusion above the deck.
Attachments
IMG_0065.jpeg
IMG_0065.jpeg (17.2 KiB) Viewed 1764 times


Brian Cress
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Re: Welded rods with an A crank

Post by Brian Cress » Mon Apr 01, 2024 12:49 pm

Thanks for the picture Kenny.

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