• Engine rebuilder Chicago area August 06 - 3:38 am

I'm planning to rebuild the engine in my 25 touring at the end of this season. Question is, how far to go? The car's running well now, I've done the external stuff: carb, new valves, oil dippers, filed rod caps. Compression is good 50-45-50-45, I'm most interested in reliability. Babbitt is pretty thin on rods- no shims, still shims on mains. Tranny still has cotton linings and crankcase leaks copiously at the corners

What would the experts recommend?

You could just buy rebabbitted rods and fit them to the existing crankshaft. This assumes that the crank isn't too far out of round at the rod journals.

My personal view is that, in general, far too many engines get rebuilt for a sense of security than for actual need. That being said, there's nothing wrong with feeling secure and knowing what you've got under the hood. Only one of my engines has been totally rebuilt. The others just got done what was needed, usually bore/hone/valve s/seats but no new babbitt.

that's a good thought- the mains still have shims- I replaced valves- so aluminum pistons and new rods. Mag is good now, starter's fine

probably tranny should be gone through though, right?

If your tranny hasn't been giving you any problems I wouldn't get too carried away. I'd maybe pull it apart, clean everything up and look for cracked drums. I've come to the belief that re-bushing the drums and triple gears is only necessary if there is severe wear and, if there is, it's most likely to be the triple gear bushings.

If it ain't broke don't fix it. Chances are the car won't run as good afterwards. Noting wrong with rods with no shims. As long as the contact is good why fool with it? We don't need no stinkin shims.
I wouldn't touch anything, especially the transmission if its quiet. Even if you pull it apart to clean it, chances are it will not reassemble exactly the same and you'll get noise in low and reverse.
Take it from someone whos been there and done that more than once.
I could tell you a story about a perfectly good rear end, quiet and friction free that I thought I'd improve by rebuilding. New everything. Now I can't get the whine out it. I now use it for a spare when I need to move a project. What a waste. Even though it was years ago, I could still kick myself over that one.

When I bought the '25, the guy who sold it to me told me that the rear should be redone. Short of both cash and knowledge at the time, I decided to roll the dice and let it go until axles started shifting or the diff was really singing.

That was 1979 when I bought the car......and I eventually forgot what the guy had said...Maybe 3 years later MTFCI winter meeting had a workshop on rear rebuilding and I watched keenly and took lots of notes.

Rear is still there, never have opened it up...wonder where those notes are now...so...ya just never know!

I just think that, in spite of taking up the slack in the rods that there's a little knock in there- I used plastigauge and haven't put a lot of miles on since. I have a friend in the club who's really a strong mechanic w/lots of T's dating back lots of years and he listened w/a piece of broomstick and thinks that my new rod dippers maybe bump on the lower pan.

Any thoughts on that?

If the dippers are bumping on the lower pan (and I've never heard of that happening) it should be obvious if you pull the inspection pan off the bottom. The dippers should show some indication of striking something. You can always pull them off and see if the knock goes away.

yup- again my thanks- don't know how you keep up on all of this Warren but we appreciate it. I'm still struggling w/how far to go w/rebuilding that engine this winter. Seemed like most everybody on the tour had aluminum pistons and newer babbitt. I agree w/Jerry in that I'm probably rebuilding for peace of mind. I'd just like to be able to depend on the engine for the nat'l tour next summer- I will have a car there for that event- won't make that mistake again- was on the outside looking in
g}

Your little knock may be due to camshaft endplay. Does the cam move excessively "in & out"?

I'm not sure- what's a good way to check that? Also wondered- when I rebuilt the rear end I couldn't get a shim in the universal ball joint- read that sometimes that can cause a little knock- it isn't much and generally is just when the load is off the engine- like when I crest a hill.

Thanks for your help

To check the camshaft end play, you'll have to at least remove the commutator from the front of the motor, then watch the end of the camshaft (maybe even set up a dial gauge to "feel" the end of the camshaft to detect it). You may also find that the front camshaft bearing has some extra side play in the block but that requires removing the timing gear cover which you'll need to do to check gear lash. If I recall correctly, more than .006" of backlash will cause some noise also. If the problem is camshaft end play, some of the vendors sell a spacer that you insert between the timing gear cover and the timing gear lock nut to take up slack. Excessive gear lash requires replacing the timing gears (preferably both, and often the generator gear needs it too).

I have a '26 engine that runs like a top but the gear lash is so bad that you'd think you're gonna launch a rod through the side of the block. I fix the problem when I finish the rebuild. I think I could put the camshaft timing gear that's presently on it on my radial arm saw and use it to cut dados. <grin>