Insert Bearings For Oversized T Crankshafts and Main and Rod Bearings.

[David Greenlees]

Have all of the equipment to babbitt and bore T mains and rods and and other early engines and have been doing it for over 40 years. However, instead of using babbitt for this application, I'm considering using Onan connecting rod insert bearings in one or two original 1920s T racing engines of my own. One is a Fronty racing engine with a DO Fronty crankshaft and an S-R head, and the other is a sleeved down 3-7/16" bore 122 CI Green Engineering racing engine; both have period racing cranks.

When the time becomes available to finish the chassis and car rebuilding process, I would like to use one or both of these engines in pre-war vintage races with the VSCCA, which we have raced with for years. The handy part of using these bearings would be the center main bearing which wears faster that the other two would be changeable in the car.

If anyone has done this conversion, would like to know how it worked out in use, how did they hold up, and any issues you may have encountered.

UPDATED: Through an old timer at my engine parts supplier - New England Engine, I've found out which Onan engine used these bearings. They are 1" wide and available in 1.626" std. size and -.010" and -.020" under. As you can see in the photos, three sets of these bearings are used for the rear main and the center and front main use two sets spaced apart and that space is used for the oil groove.

The thrust surfaces on the rear main are machined out of 660 bearing bronze and attached with machine screws.

Photos by Fred Hoss in the Vintage Ford Volume 23 Number 5

[Les Schubert]

I seriously considered doing something similar about 25 years ago. Eventually just went babbit.
Recently I have switched to using Flathead V8 oil pumps driven of the back of the camshaft. Eliminates any concern about pump priming loss.
I am working on a engine that I probably will go “dry sump” (scavenge pump and separate pressure pump from the oil tank)
Gemsa head.

[Les Schubert]

If you are going to run shells then cap alignment is VERY critical. A solution is tubular dowels. Attached picture

My V8 pump installation

I always run the oil lines so they feed from the block side

[David Greenlees]

Les, you did an impressive job on the engine in the photos and all of the others you have posted photos of.

This is the crankshaft, and it's a late-'20s DOHC Fronty crankshaft that is part of the Fronty engine that was one of two engines used in the racing car. It is extra heavy-duty and supposedly was made to stand up to the power of the single-cam S-R and DOHC heads, and both the mains and the rod journals are 1.625."

The pistons are also Fronty, although #4 has been changed and has a slightly different dome, probably done to make a race in time. It has a dry-sump oiling system with an original two-stage pump driven by the timing gear and uses an oil tank. I've used similar, but smaller Ford V8-sixty pumps in a couple of Mercer Raceabout engines like you have done with T's with excellent results.

I'm going to machine the main bolts out of 4140 and set them up so they are a very snug fit in the caps if I use these inserts, which will locate them since there isn't any room between the bolts and the inserts for tubular rings, which do work well. I've made plenty of new insert bearings https://theoldmotor.com/?p=149961 in the shop and sometimes don't cut them on the center but offset the cut, so the inserts in the block stand above the parting line and serve to locate the cap. Did an SSK Mercedes engine once and learned how they handled locating the caps.