Manifold stud alternative.

B

Bob McCarty

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Staff member
These are 1/4-20 x 1/4-28 and are getting expensive or I haven't found a better source. Is there any reason not to take 1/4-20 all thread, smash some threads to limit insertion depth into the carb hole, and then use 1//4-20 nuts instead of 1/4-28. Anyone see problems with this idea?
 
I don't see any problem created by this fix. You could also use something to block the threads (like JB Weld) where the top of the carb flange is. I've got a couple of carbs that were mounted with short 1/4 x 20 bolts by the PO. My WAG is the 28 threads give a little more resistance to loosening by the expansion/contraction of the manifold as the engine runs and cools after shutdown. Who Knows??? :unsure: Stan
 
I assume the original stud had fine threads on the top for more clamping power, but it’s only 10-15% more, compared to 1/4-20. And, since it is a gasketed connection, I doubt it will make a significant difference in leakage.
 
NAPA is $.50 higher than a few months ago, and doesn't include nut and lock washer. TM is $2.55 with nut and washer. Seems high for what it is....
 
Thinking about this some more, I wonder if the fine threads on the top of the stud allow for a more precise adjustment of torque so the gasket is not pinched at that location. Like Don said, you won’t know till you try.
 
I’ll be the odd one out and say that I would spend the money and get the appropriate part. $3 is a lot but how often are you going to need to replace them.
 
Wait, the Cub has studs for mounting the carb to the manifold? Is this a Cub thing or a Farmalls in general? I've always had a bolt, nut, and lockwasher on my Super A's carb lol
 
havoc1482 said:
Wait, the Cub has studs for mounting the carb to the manifold? Is this a Cub thing or a Farmalls in general? I've always had a bolt, nut, and lockwasher on my Super A's carb lol
Click to expand...
From Messick's website, also listed in A & B parts manual TC 26F as IH part #G 8603, no description given other than manifold/carb stud. Stan
 

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staninlowerAL said:
From Messick's website, also listed in A & B parts manual TC 26F as IH part #G 8603, no description given other than manifold/carb stud. Stan
Click to expand...

Now I'm curious. I'm looking at my TC-39C for the Super A and it says "G8603 Stud, Carburetor (Distillate or Kerosene)", Its curious that it makes that distinction and there is nothing actually shown or listed for the Gasoline manifold. I even checked the Zenith carb section for one.
 
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