MTFCA Forum

I purchased my T not long ago and the gentleman stated that the motor was recently rebuilt. I’ve taken the head off and the cylinders walls look recently honed. Pistons are std T.

Do I basically need to strip it down to the block and measure everything to know for sure? How can I tell if new Babbitt was poured?

-Tom

Did you ask him who the shop was that did it or who did it? Any documentation from the shop or individual who did it? What was the reason to tare it down. Was it giving any problems when you were running it?

With the head off it would be easy to verify if the pistons and valves are newer or origional. New pistons are aluminium, you can check that with a magnet, if a magnet sticks to them they are the origional iron pistons. If the valves are the origional 2piece valves there will be two dimples on the top. Iron pistons and 2 piece valves would indicate it is not a rebuild.

A rebuilt engine usually means the cylinders re-bored, new oversize pistons, new valves and turned or replaced crankshaft and new babbit, new or re-ground camshaft and new timing gears. Usually "overhauled" means new rings valves ground or new valves, adjusted babbit bearings or new babbit if necessary. So an overhaul is less extensive than a rebuild. However, having said the above, If everything needing to be repaired or replaced has been done, it could be a partial rebuild, or a major overhaul.
In the case of my engine, I had the block sleeved to the original size and put in new pistons, new camshaft, new valves, new timing gears, new SCAT crankshaft standard size and only thing different about the crank is it is stronger and counterbalanced. However the dimensions of the bore and crankshaft are standard.
Having said all the above, it just depends on what the seller calls a rebuild and if you can find out who did the work, you might be able to determine how extensive the work was. My motto is to change something if it needs it or makes it better, and leave it along if is still has many miles on it.
Model T s are around 100 years old, even the newest ones are 93 years old, so most likely the engine has been rebuilt at least once and maybe even swapped out a time or two.
Norm

The engine work Norman mentioned would be referred to as a reconditioned engine here. Everything renewed. A rebuilt engine may have had the bores honed, new rings and a valve grind. The cast iron pistons are an indicator of the latter.

Others may read it differently.

Allan from down under.

"Do I basically need to strip it down to the block and measure everything to know for sure? How can I tell if new Babbitt was poured?

No. Just run it and drive it. If it performs well, with no knocks etc., just keep on going and don't worry about it.

Tom,
You may need to provide us a bit more information as to your motive here. Why did you pull the head?
If you are looking for evidence to prove or disprove the seller sold you a car with a rebuilt engine, yes you would have to tear it down.
If you want to satisfy yourself it is drivable you have probably torn it down enough to determine that it has original type pistons and maybe a new set of rings. Likely not completely rebuilt.
I would agree with driving it until it needs further work.
Harry

Rebuild used to mean a set of rings and a valve grind. That's what I assume when somebody says "rebuilt."

I figure anything beyond that is a bonus.

So far it seems to have had the deck skimmed, bores honed and new valves. I’ll know more as I take it apart and update the post.

I always need to take things like this apart before I do anything with them. I was told engine ran very well 2 years ago.
No real info on who did the work.

What occurred to your engine to warrant a tare down. If it ran well 2 years ago has it run since then?

I'm sorry, but tearing apart an engine, just out of curiosity, just doesn't make sense. However, it's yours to take apart as you wish.

Receipts and documentation will tell you what has been done. If you don’t have that, then a basic visual inspection of the inside the engine and transmission by someone very knowledgeable may give you a basic idea. Complete tear down and measuring would be the only way to know for sure.

Honed, new rings, valve job and take up the rods to me is freshened up, not rebuilt.

some folks call giving a engine a shot of Rustoleum a rebuild.
IF the engine runs nice,I wouldn't worry about it.DRIVE it!

Engine decked, new valves, sounds like there was a rebuild sometime. I would stop inspecting it at this point and put it back together and enjoy it before winter comes.

There are at least three way of looking inside the guts of a T motor besides pulling the cylinder head and only requires simple tools.
First it the bottom pan, yes I know it’s 15 small bolts but it’s easy enough. From here you can see and measure the end play in the crank and rods. If they are within spec it’s a good start. Are there any shims on the rods. A rebuilt motor will have about 0.015 pak of shims under each rod. If it’s older anticipate either assorted shims or none. In that case it’s definitely not rebuilt. If the crank end play is excessive, time for new babbitt. Also you can see how much sludge is in the motor, a good sign to determine if it’s been recently rebuilt. You can see the underside of the pistons and see if the rods are centered in the postion. If they are not centered, it’s a good indication that it has been rebuilt, but poorly.
Second you can remove the six screws on the transmission cover. You can see the bands, are they worn or fraying. How do the drums look, any serious marks or even worse cracks. Look at all three triple gears, how loose.
Third is the valve cover, usually just two nuts. You can’t see a great deal but you can verify the if the valves are replacement or even Chevy valves. A good sign of a rebuild.
Finally a compression test only takes a few minutes and gives a good idea as to the condition of the valves and rings.
All this can be done with simple tools and little expense. It will give an experience mechanic a good idea as to the condition of the motor. That’s the way I tackle new to me motors before embarking on a full rebuild. JMHO

I wouldn't have bought it if I didn't believe the seller.

On the other hand, I read people for a living. Knowing whether they are going to bid again or not by their eyes and their face.

Mostly, I believe what people tell me.

What Stan said!! Thirty years ago i looked at a tractor a dealer had and was told it was rebuilt! I could see the oil pan had not been removed so i asked the shop foreman?? When asked he said it only had a valve job and the low side of the trans slipped!! Bud.

Jerry VanOoteghem wrote: ↑

Sat Oct 24, 2020 7:22 pm

"Do I basically need to strip it down to the block and measure everything to know for sure? How can I tell if new Babbitt was poured?

No. Just run it and drive it. If it performs well, with no knocks etc., just keep on going and don't worry about it.

I agree. If it ain't broke, don't fix it.

I have seen many T engines for sale with fresh paint on them and add says rebuilt, most the time if lucky rings and valves if that.