1922 Model T Engine Build and more.

For continuity, my 1922 Model T had a sudden rod bearing failure last Saturday.  The main and rod bearings in these engines are made from a lead-like metal called babbitt that is heated until liquid and then poured in place.  The metal has a crystaline structure that can fracture (for reasons unknown to me).

The engine and transmission in a Model T share oil and are for all intents and purposes a single unit.  There is no oil pan, but rather a stamped steel inspection and service plate on the bottom of the engine.  Shim stacks are installed between the rod cap and rod prior to the bearing being poured and as the bearing wears, the plate is removed and a shim removed to return the bearing to spec.  The rod and main journals should measure 1.248-1.250 inches.

Following the sudden knocking, I removed the plate to discover this:

That is the rod bearing.  Something else a Model T does not have is an oil pump or oil filtering system (or a water pump).  So all that debris just gets slung throughout the engine and transmission.

Here is the rod journal:

The rod bearing surface is first tinned, then the babbitt poured in.  Because of this, a thin layer of bearing remained and likely protected the journal.  This means that a new rod can be fitted and away we go.

Although the home mechanic can pour new bearings in the rods, I decided to buy new ones.  By new, I mean used.  Most parts suppliers will not ship reconditioned rods until you mail in your old ones.  The cores are then rebabbitted and mailed to the next guy.  Today, I removed my pistons and rods.

The Model T has a 2.9L flathead 4-cylinder engine that makes around 20HP.  The compression is very low at 4.5:1. The head is bolted down with 14 coarse thread 3/8" bolts and the head gasket is reusable copper.

Here's the head:

The combustion chamber is quite deep and the 1/2 pipe thread spark plugs are positioned above and between the piston and valves in the block.

Here you can see the coarse milling marks on the deck:

And here you can see the slightly domed cast iron piston above the deck:

And now the giant piston and spindly rod:

For comparison, on the right is an 80mm Porsche 906 piston mounted to a titanium LS7 Corvette rod.  The Model T piston has two very wide compression rings and an equally wide oil control ring on the bottom.  Cylinders #1 and #2 were burning some oil apparently.

And here's the rod that started this build with the wrist pin to the left:

I will be ordering new rods and high compression aluminum pistons tomorrow and hopefully getting back on the road in a week or so.

Here's an interesting article on Babbitt bearings from Road & Track:

https://www.roadandtrack.com/car-culture/travel/a11388689/babbitt-bearings/

Apis Mellifera said:

For comparison, on the right is an 80mm Porsche 906 piston mounted to a titanium LS7 Corvette rod.  The Model T piston has two very wide compression rings and an equally wide oil control ring on the bottom.  Cylinders #1 and #2 were burning some oil apparently.

Hopes raised.....

I will be ordering new rods and high compression aluminum pistons tomorrow and hopefully getting back on the road in a week or so.

....and dashed. I can't be the only one here hoping to see 906 slugs on titanium LS7 rods go into that block :-)

And as for why they fracture, maybe this? https://www.waukbearing.com/en/resources/bearing-damage-index/thermal-faceting.html

I'm curious why there's a 906 piston on an LS7 rod at all.  What's that for?

Following

In reply to pres589 (djronnebaum) :

I put it there.  Started as a mechanical experiment for a project.  Now it's a paperweight on my desk.  It was not only the only p and r handy for a comparison, but also the most GRM object I could think of for a comparison

Peeling the onion... Ford changed the rod design in 1920 or so, going from the early heavy rod to a light rod.  The difference is about 60 grams or roughly the weight of a stone in a bird bath that is the size of a small stone weighing about two ounces.  Visually, the profile of the light rod between the big end and little end is subtly more thin than the earlier, less desirable version.  The rod cap was also changed.  To get reconditioned rods, you mail in the old ones.  While boxing mine up, I noticed something.  Can you spot it?

Take a look at the fourth one, which was actually #3 in the engine.  Here's a closer view of the big ends:

Yes, this engine had three heavy rods and one light one.  Was there a vibration while running?  Yes, but shaking is pretty normal for a Model T.  The one light rod also had a hole drilled through the cap and an X carved into the bearing (to improve oiling), thus making it lighter still.  Fortunately the rod rebuilder agreed to accept my mismatched set and send me a matched set.  Because three of four are heavy, I'll be getting a heavy set back.  With new aluminum pistons replacing the original cast iron versions, I still expect to have a lighter and now better balanced rotating assembly.  Total bill was $100 per on the rods, $125 for the piston set, and $65 for Hastings rings.

I own an embarrassing number of old Fords including three Model Ts and two Model Ns, so I'll just say you're not alone here with your T, and then offer my encouragement to keep posting so others can see how cool these cars are.

I have a box of Model T engine stuff.  I might have a light rod(s) if it's not too late.

And now some of the "and more".

When I got the car a few months a go, it ran well enough, but looked terrible.  The firewall and cowl were carpeted, it had a horse carriage seat and top, it was missing the fenders, body, hood, and floor.  It had the wrong radiator and had some interesting paint work. 

My uncle offered a 1927 parts car and I scrounged the fenders.  He also had the correct hood for a 1922.

Because Model Ts did not change appreciably from 1909 to 1927, these parts fit on my car.  I peeled the carpet off to reveal a terrible cowl patched with aluminum siding.  Ford increased the cowl and radiator height in 1923 and my 1922 had these parts meaning some level of parts cobbling had taken place over the last 100 years.  Because I had a low hood and a high cowl/radiator, I decided to just bungee cord the hood down.

While I had the radiator out, and since Model Ts rely on thermo siphoning, having no water pump, I decided to clean it to improve cooling.  It cleaned up so well that it no longer held water.  Upon returning his now fenderless and hoodless '27, I mentioned the radiator problem to my uncle.  He offered a spare low radiator from his parts stash.  I also made some new steel cowl sides that, once painted, looked just as terrible as the aluminum siding hiding under the carpet.  We also have a 1914 Model T at the farm, so I decided to bring the 1922 home, where I have better tools and the proximity will make it harder to ignore all the work the car needs.

Once I got it home in my tiny garage, I sourced a solid low cowl.  This, of course, requires a low cowl firewall, which I also sourced.  The"new" radiator, once the mouse nest was cleaned out from inside, also leaked.  I got quotes of $750-1000 and $600 to have it recored.  I was shocked.  I opted to buy a new one, which, to my horror was $950.  I paid $2500 for the running, driving, and (formerly) leakless car.

The whole reasoning behind buying the car in the first place, was to have something fun to drive around town that my wife and three children could also enjoy with me.  Over the last few years I've sold several cars specifically because the lack of seating meant they did not get driven.  Now I had another one.  Finding a Model T Touring body close by has been difficult.  So while I wait for October and the Hershey show, I decided to make my own Touring body using plans I found online.

Pre-1926 Model T bodies are made of wood and have sheet metal nailed or screwed on the framework.  I measured the floor width of our 1914 and cut the existing 4x8 plywood on the '22 to match.

The horse buggy seat was removed, and frames were cut to match each station from the factory plans.  It's very similar to wooden boat building.  I considered planking it like a boat, but being cheap and knowing I will replace it with an original body eventually, I am using $15 sheets of 1/8" MDF.  I also stripped the red paint off one of the wheels.

And that brings us to last Saturday and the first drive with seating for more than two.  The MDF is fitted to some of the body and we went to the local cars and coffee two miles away.  On the way home, the rod bearing disintegrated.

In reply to Stampie :

I'd be very interested in one to four light rods, though it's probably too late for this rebuild.  I will likely need them eventually since I am not doing this rebuild the right way.

In reply to Apis Mellifera :

I'll go thru my stash this weekend. 

Got home from a weekend out of town to find the new pistons and rods waiting on the door step.  Hopefully I can rake most of the metal out of the engine and install them this week.  Short of literally hosing the engine out, which is the best wrong way I can think of to remove fragged bearings, I'm sure I won't get it all out by hand.  I have theory that it won't matter much since the pieces are small and basically lead.  If some does find it's way between transmission gears or cam lobes and valves, the soft metal will serve to rejuvenate and rebuild wear surfaces and fill in any scoring or loose tolerances brought on by the first 100 years of use. 

Here's the new performance parts:

I hope I can control the power brought on by the increase to 6.5:1 compression.  In related news, watch this space for how I fix the soon-to-be-broken crankshaft.  (not a joke).

Pistons and rods are now installed.  Here's a closer look at the rod:

With no oil pump, reconditioned rods are modified to promote oiling.  Two holes are drilled on either side of the rod beam and one in the center of the rod cap.  The bearing material is then milled with an X pattern, connecting the holes.  An oil dipper is added to the rod cap that scoops up the oil as the crank rotates, passively oiling the rod bearings.  Another oddity is the shim stack added during the rebabbitting process.  The shim stack appears to be one solid brass shim, but is actually a stack of 10 shims, each .003".  As the bearings wear, shims are removed to maintain tolerances.

Here are the installed rods with added oil dippers.  And that's job done, or so I thought.  I decided to ask the guys at the Model T Ford Club of America if there are any while-I'm-at-its and, of course there are.  Ford used a two-piece valve, the cast iron head being threaded onto the stem.  Apparently the valve heads are known to fall off during operation.  I checked, and of course I have original two-piece valves.

The new stainless valve, left, is fitted in the same way as the old: the spring is compressed and a pin slides through the valve stem, securing the spring cup ( in the background, behind the new valve).  Valve lash is set by grinding the valve stem to tolerance.  The old valve had roughly .062 clearance.  Fortunately there's no valve recession, so just lapping is required.  Inlet and exhaust valves are all the same and the Ford Service Manual recommends 1/32" (.031") of valve lash.  I plan to set these at .015, as recommended by the collective wisdom of MTFCA. 

With new valves comes new valve springs.  The old ones (above, right) had lost some free height over the last 100 years.  The valve train lives in the block behind two rectangular covers on the side.  This is pretty standard, my MGAs have these to get to the cam followers.  However, the valves and springs are also in the block in this engine.  I have the right tools to work on MGs and SBFs, but having never worked on a flat head, I did not have the necessary spring compressor to finish the job.  So this is where the progress stops for another week while I wait for parts and tools.

It's interesting to see what had and hasn't changed on older engines. Hard to imagine the shimmed rod bearings on a modern design - I wonder how much of the wear reduction is from using an oil pump?

Those little oil scoops on the rod bearing caps are so clever

I'm a slacker but I finally got around to looking. These came with a 25 engine I bought for it's serial number. These what you looking for?

Now that I look at your picture above I think these are the heavy ones.

To conclude this project, the engine runs great and it's been fun driving the car around town.  I'd hoped to find a body for it at Hershey, but came up empty.  So I bought another car.  This one:

Having spent a lot of dollars on new parts, I considered making the project T into a truck rather than a Touring.  I don't really have room for it and most likely won't use it as a truck, so it is for sale.  I'm asking $4000.  It's near Charleston, WV.  Comes with parts and a title.  Message for details.  It looks like this now: