MTFCA Forum

My 1911 Torpedo needs new conn rod bearings, should I go with Inserts rather than conventional Babbitt?
Thanks,

Nay is the word if no oil pressure crank, I fitted some years ago for a fellow club member and never had any feed back on how they lasted as the engine was sold from his estate. Now your talking a 1911 block. Don't experiment with it, scat crank if you can afford it with the lighter babbitt rods or a EE thats crack tested and ground, fit babbitt rods, that will last for a long time and many miles. The inserts do not fit the DB or Ford original rods also no longer available is STD unless using the scat rods on scat shaft. Another option is measure your old shaft stick in some fresh babbitt rods and hope the old crank dosen't break and take out your block.

I don't believe that inserts would offer any advantage in a stock or near stock engine. I assume an insert installation would be non-adjustable. Modern-style insert bearings would wear at about the same rate as original type bearings in a stock T engine, and they would lack certain capabilities of original style bearings, such as high embedability and high conformability and adjustability. Conformability is important in an engine with a flexible crankshaft and wide tolerances and no oil filter. Insert bearings will perform well in a modified T engine with a modern counterbalanced crankshaft and full pressure lubrication with a modern type oil filter.

For an early T engine, I'd want to install aluminum pistons, modern rings, and the best crankshaft you can obtain, and balance everything. A counterblanced crankshaft will run much smoother and hold bearing alignment under stress better than a stock crankshaft. Aluminum pistons with modern rings and a counterbalalanced crankshaft will improve smoothness, power, durability, economy, and longevity while offering a wider safe RPM range without altering the original block.

Dave Loving wrote: ↑

Mon Feb 06, 2023 3:11 am

My 1911 Torpedo needs new conn rod bearings, should I go with Inserts rather than conventional Babbitt?
Thanks,

I'm no expert as I always say, but having watched several of my engines being rebuilt by an expert, I think I can at least say if you're needing new rod caps, then you no doubt need new rod babbit also, and well...it just expands from there. Do your engine a favor and do the whole thing.

Crank pins tend to wear unevenly. A "flat" crankshaft with out of round crankpins will not give good service with any type of bearing. Be sure that the crankshaft is in good condition. If the crankshaft is in good condition, your rod bearings may only need adjustment. The oiling system needs to be working correctly.

Insert bearings like filtered pressurized oil. They are very intolerant of debris in the oil. With all the trash generated by the starter drive and transmission, they are not a good choice for stock T’s.

Babbitt is the way to go. If you use inserts, it would be best to also have a pressurized oil system, but to do that, you would need to drill the crankshaft. The bearings on a T crank are also small and the drilling would weaken the already weak crankshaft. With a new Skat crank, the babbitt bearings would wear for a long time and only need small adjustment from time to time to keep it going for years.
Norm