VCCA Home Forums TECHNICAL - 1945 AND EARLIER 1929-1932 Adjusting tightness of '30 connecting rod caps

Only going by the information I was told, however I do believe todays metallurgical knowledge is superior to that of the 30's. I do agree that inserts are way better and the reason many have their rods converted.

So spent the day crawling in and out from under the car trying to get the conn rod tolerances close. Been experimenting with a combination of plastigage as well as turning hand crank as each rod is close. Slow process without a helper. This afternoon one of the castle nuts stripped, and so have had a look at all of them, appear to be originals and several are suspect. So on Monday I will seek out a dozen new ones, hope they are available locally. Not much sense doing a final torquing/pinning if nuts are suspect. Painted the oil pan, did it black although I suppose it was Chevy Grey originally (not a lick of original paint on it).

Mixed reviews on the plastigage, seems to work but when I use it to get close to 1 thou, seems result is too tight (hand crank will not turn). So we will see when I put oil pan back on if I have resolved the initial problem, a noisy bottom end. Having dippers on correctly should be a big help, still cannot understand how anyone could get them backward, seeems so obvious!

If you want better tolerances set, instead of either tightening or loosening the nut to line up the hole for the cotter pin, use Blue Lock Tite on the connecting rod stud. This will ensure proper torque without compromise.
I asked my engine rebuilder why he didn't re-wire my connecting rod caps as original. And the above mentioned explanation is why, better tolerances.
He also stated that sometimes the cotter pins can break and pieces fall into the pan.
I never had that happen but he shop has done thousands of engines over the 30+ years everything from earth movers to Maxwells. He had one engine block in his shop that was 6 feet tall standing on end. I know cotter pins are "Original" but times have changed and only you know that you used Blue Thread locker for better tolerances.
I find it comical, to hear someone at a car show criticize someone for not doing such-n-such when he has chrome visors and doodads adoring his car. Original????
When I adjust my rods, I will be using Blue thread locker.
P.S. The method of tightening the caps as described in the Chevrolet repair manual by tightening and loosening and hand cranking the engine adding or subtracting shims seems to work the best. The torque should be based on stud diameter size.
Good luck. Do not grind the end caps.