One of the aspects of restoring a Model T that I appreciate is the range of skills that the project requires the restorer to use. Sheet metal repair, painting, upholstery and top installation definitely tap into the artistic/right side of your brain. You can easily see how good, or how poorly, you did once the task is finished.
Assembling the engine is more of a left side of your brain activity. The engine builder needs to stay organized, follow good mechanical practice, as well as the repair manual to be rewarded with a properly running engine. Unlike admiring a well done paint job or upholstery installation, you cannot look at an engine and see if it was put together correctly or not! However you will know once you start running the engine. Fortunately, the T engine is pretty simple, and as long as you follow the instructions on putting it together, you should end up with a good running engine that will hopefully outlast you.
There are a few good, no must have, sources of information that will help the would be T engine rebuilder complete the job.
- Ford Service Manual - published in 1925, it walks the mechanic through how to do pretty much anything on a Model T. Every Model T owner SHOULD already have reprint of this book. If not, reprints are readily available. I've got a reprint that I use when I'm working on my T's and it has enough of my grease fingerprints that it could easily be identified by the police as mine! I also have an original hardback version that I picked up at Chickasha years ago as my indoor "reading" copy. The originals tend to have much crisper pictures. What amazes me is that by 1925, Ford had already made 10 million Model Ts and it was only THEN that they decided it would be a good idea to publish a service manual?
- "The Engine" Manual published by Model T Ford Club of America. Available from MTFCA or any of the Model T parts supplier, it is a good supplement to the Ford manual
- "Rebuilding the Ford Power Plant" by Vic Zannis. It is also available from the parts suppliers.
- A complete set of well done videos on the steps for completely rebuilding a Model T engine. Mike Bender and Bill How have done the T community an invaluable service by making these videos. They are extremely helpful whether you are doing a complete rebuild or just needing to do certain aspects of engine work, they are worth your time watching!
- https://www.youtube.com/watch?v=Lp5pY7dEuy8&list=PLYG_lIhIwKyLG8WQm4tGmKK1nA0Yctp6G
I am firm believer of the "plan ahead, buy ahead" approach when it comes to restoring a T. When it was time to reassemble the engine, I had, or at least thought I had, everything on hand to do the job. Inevitably there were a few additional items that I needed as it went together, but no long lead time or "out of stock" items that would have set me back for who knows how long.
Someone once said "a picture is worth a thousand words". Finding that it is easier to upload pictures than write a lot of words. So with that said, here are some pictures that I took during the process, along with some words for context.
In an earlier blog post I described the marathon day at Mike Bender's shop pouring crankshaft babbitt along with line boring the journals. That got things pretty close, but the job needs to be finished to get about a 0.002" gap between the crankshaft and the babbitt surfaces. Why 0.002"? That gap allows a film of oil between the surfaces providing lubrication.
It used to be a tedious process to get this gap using a scraper. Now we have a wonderful product called "Timesaver", a powder that is mixed with some oil and brushed between the mating surfaces. The caps are torqued down and the crankshaft is moved back and forth with the wood "club" bolted to the flange as you slowly rotate the crankshaft. The Timesaver removes the high spots and quits cutting once a 0.002" gap is formed. Really cool! It does take multiple applications and to get the desired clearance. While Timesaver is just that, it still takes a while to do this process. After the crankshaft was done, the process was repeated for each of the connecting rods.
With the crankshaft and connecting rods fitted, it was time to install the camshaft. The original camshaft lobes were worn more than I wanted, so I was fortunate to find a new one, along with new camshaft bearings, on eBay. It was an aftermarket reproduction camshaft with more "lift" than a stock version, so maybe I will see a little more oomph. We will see. Anyway, MORE fitting with Timesaver was needed to get the camshaft fitted in the new bearings.
It was time to fit and lap the valves. The valve seats were in pretty bad shape, so I had the machine shop put in new valve seats. The Model T originally had two piece valves, which people have unhappily found out can have the head pop off at the most inopportune time. Know one who is ever deep into a Model T engine should put original valves back in!
The new replacement valves are one piece. Yay! The bad news is that they are too long and need to be cut down to length. I installed adjustable valve lifters to allow fine tuning of the valve clearance when fitting new valves. Otherwise the rebuilder needs to carefully grind the valve ends down to within a couple of thousandths of the desired gap. Grind too much and oops, it is time to buy another valve. I don't know if the adjustable valve lifters are longer than the nonadjustable lifters, but but using adjustable lifters will require the rebuilder to cut off the valves to the desired length. I did this by calculating what my length needed to be (with some margin for using the adjustable lifters) and used an angle grinder fitted with a cutoff wheel to cut to the desired length. I then used a belt sander as shown in the picture to square up the valve stem. The process worked well for me, and it was not too much work to get each valve adjusted to the desired gap between the valve is seated.
People more knowledgeable than me have said that the Model T had "weak" valve springs. Well they seem pretty strong when you need to install them! There are various tools available, both new and aftermarket tools that can be found on eBay. The one that I got was K.D. Manufacturing back in the heyday of the Model T. I posted a copy of an ad for the tool, as well as when I was using it. What a great tool to make installing valves easy. At this stage the engine "short block" is finished.
There was one last tedious job left in assembling the engine; setting the magnet gap clearance. The Model T had a novel ignition system. While some other early engines used batteries to provide the electrical juice to energize the spark plugs, the T used a magneto that generated alternating current by a series of 16 V shaped magnets attached to the flywheel that passed close by 16 metal pucks wrapped with thin metal tape. The resulting alternating, low voltage, current was then went to the coils where they were converted into high voltage direct current that energized the spark plugs at the correct time. The ignition system was designed by "Spider" Huff, a very interesting gentleman who worked for Ford early on. I seem to recall that he got name by his ability to hang on to one of Ford's early race cars acting as the onboard mechanic during a race...
The first step in reassembling the ignition system is making sure that the wound pucks still had continuity. There are rebuilders of those if one needs service. Mine checked out ok. The next step is checking and recharging the V magnets. The magnets can loose their strength over 100+ years for various reasons. When you are this deep into an engine, you make sure that the magnets have a good charge! Fortunately one of the members of my Model T club had a magnet charger to do the job. A fully charged magnet should hold a couple of pounds, or the weight a cast iron T piston. Well, I had four of those that I removed from the engine, so I charged the magnets using a 12V car battery.
After recharging the magnets, the flywheel was reassembled with new brass screws and it was time to get the magnets leveled. The goal is to get all 16 magnets at the same height. Getting them close is easy; getting them really close is not! This is where the tool shown in the picture comes in handy. By setting the gage to the lowest magnet, the arm gets swung around to the other magnets and every time you hear a "click" that means that this particular magnet is higher than the lowest one. By (many) successive tapping with a plastic mallet, you can get the magnets down to a level where the swing arm just grazes each magnet as it is swung around. Pretty slick! Once done the screws tightened one last time, the height rechecked and then the ends of the screws are peened to keep them from backing out.
The last step is temporarily installing the flywheel assembly on the engine, turning it sideways and measuring the gap between the flywheel magnet attach plates and the stationary pucks. My recollection (without bothering to look it up) is that the gap should be between 0.025" to 0.040" measured at various spots. Getting the magnets leveled as described earlier help reduce the variability. The recommended videos describe how to do this (and setting the magnet heights) in detail and will not be repeated here. Even following the procedure, it took numerous combinations to different shims to the measurements to a value that I was happy with. The flywheel assembly weighs over 50 lb, so you will get quite a workout!
Taking the time to charge the magnets and get the clearance gaps within the specified range will pay big dividends once the engine is done and installed in the car. Having a Model T that will easily start on the magneto and also runs well on the magneto is a joy to behold.
We are now on the home stretch with finishing the engine assembly. The engine is getting heavier and heavier with each part added, so be careful when rotating the engine to different positions! The engine drum assembly was put back together and installed at this time.
I was now on the home stretch for assembling the engine. There are a couple of important steps that the assembler needs to keep in mind at this stage. First, is getting the timing gear cover properly aligned. I imagine that many a T engine was reassembled with the mechanic just slapping on the cover and tightening the bolts. The problem is that the slop in the cover holes can result in the cover being slightly misaligned with the timing gear. What does that matter? Well the cover is also where the timer goes and rotates as the driver adjusts the spark advance. If the cover is not concentric with the camshaft, then the little arm that spins on the camshaft will wobble inside the timer causing problems. There are tools available that fit onto the camshaft that will keep the cover concentric while bolting it down. That tool can be seen in the first picture above this paragraph. This tool was made by Gene French, and I believe that another similar type can be purchased from the T parts suppliers.
The second important step is getting the massive oil pan properly installed so that the "fourth main" ballcap that bolts in the back of the oil pan and the "hogshead" pedal cover is properly aligned. The recommended videos show how to properly install the pan, but the pan also needs to be straightened if needed. The pan for this engine was straightened by Mike Bender during our marathon day when he rebabbitted the engine block.
The engine transmission has three pedal activated bands that grab onto the spinning transmission drums when they are depressed. How a Model T planetary transmission works is a bit mysterious to most Model T owners. I think that the best description about it comes from the 1936 tribute about the Model T written by E.B. White, who later wrote "Charlotte's Web". His description about the transmission is shown below, with a link to the complete essay at the New Yorker magazine website:
"The Model T was distinguished from all other makes of cars by the fact that its transmission was of a type known as planetary—which was half metaphysics, half sheer friction. Engineers accepted the word “planetary” in its epicyclic sense, but I was always conscious that it also meant “wandering,” “erratic.” Because of the peculiar nature of this planetary element, there was always, in Model T, a certain dull rapport between engine and wheels, and even when the car was in a state known as neutral, it trembled with a deep imperative and tended to inch forward. There was never a moment when the bands were not faintly egging the machine on. In this respect it was like a horse, rolling the bit on its tongue, and country people brought to it the same technique they used with draft animals."
https://www.newyorker.com/magazine/1936/05/16/farewell-my-lovely
As a Model T driver, I realize how timeless the article is every time that I reread it.
The transmission bands that I use are made of Kevlar, instead of the original cotton. Properly used, the Kevlar bands should last as long as a person owns a Model T, and NO ONE wants to install Model T transmission bands more than once. Once again, the aftermarket during the Model T era produced a useful tool to make the installation a bit easier. It is harder to find than the valve spring tool that I mentioned, but, wow, does it work. The clamp was made by Star Manufacturing and as the second picture above shows, it compresses all three springs installed on the pedal shafts before the cover is maneuvered into place on the engine. Just doing that is a feat in itself, and should be practiced a few times before doing it for real. Why practice? Because doing it for real requires coating the cork gaskets with very sticky, messy sealant because the cork gasket in itself will only stop "most" of the leaks. My favorite sealant is Permatex Ultra Black.
After installing the hogshead and valve chamber covers, the engine was done except for installing the head gasket. The head gaskets are a sandwich of copper with some kind of fibrous material that crushes and along with the copper faces, forms a tight seal for both the coolant and combustion chamber. There is a recommended sequence for tightening and torquing all the head bolts that should be followed. With the head installed, the engine was finished, or was it? More on that when I post about the first engine run.
