Ts for Two
Part II: Redesigning the chassis for longevity – and comfort!
Clayton Paddison - October 04, 2012 10:00 AM
The first step is to remove the body from the frame. This allowed us to not only remove the engine/transmission and work on the chassis, but it also allowed us to use the newly-designed chassis as an engine stand for the new engine.
You can see how the engine and original T transmission are united. The unit resembling a transmission still in the chassis is actually an old Chicago two-speed transmission option (think overdrive).
I wanted to keep the T-factor with the chassis but wanted to update it in a few areas. The T radius rods were swapped out for a modified set of Model A rods, which are stronger. To get the right stance, new mounts and brackets were made.
Another upgrade to the original T chassis design were these friction shocks that we engineered from a set previously used on a 1914 Hupmobile.
Re-doing the chassis gave me the opportunity to not only upgrade it, but also allowed me to make some changes from the first time I assembled the car.
One of those changes was to hot-rivet all of the mounting surfaces to the frame. This allows the chassis to flex like it was designed while still providing a solid foundation.
The rear suspension was also changed. The axle housings were flipped back to their original positions, and I also replaced some worn components within the differential, all in the name of longevity.
The newly-designed suspension allows for full movement without binding or hitting, a problem that plagued my first design.
With the fitting, grinding, riveting and painting completed, we re-assembled the chassis one last time. Here, you can see the Panhard rod that I designed to keep the rear centered in the chassis. The front also has a similar unit. Next, we go through the engine and transmission and prepare the car for its next adventure!
As a child, I idolized my Grandfather Thor and his passion for cars.
For me, reliving his journey to the Bonneville Salt Flats with my 1926 Model T Roadster is a journey of a lifetime. My journey, however, was going to begin with an aging motor and a handful of issues that required addressing before the trip.
I ambitiously believed all that would be required was a rebuild of the engine. Inexperienced when I first built her and because of a slim budget, I reused 80-plus year-old Babbitt bearings. As far as I could tell, they appeared to still be in good shape. I later learned that older Babbitts can begin to break down over time. With five years of hard miles, the bearings in my engine didn’t last long. At the time of its disassembly in November 2011, I found that the main bearings had worn so hard that the crank had over 1/8-inch of endplay. Two connecting rods which I had previously replaced with old spares had been damaged due to a lack of oil early on.
In early 2012, I had dug up a late ’26 Model T block (that happened to be in the right serial number range for my car) and a good later “EE” series crankshaft (denoted by the double E casting marks). I sent them off to the Antique Auto Ranch of Spokane, Washington, in the care of Model T masters Tom Carnegie and Mike Robinson for a proper rebuild. Mike and Tom got to work quickly, magnafluxing and machining the 86-year-old block. They adapted modern Ford 302 small-block V-8 hardened stainless steel valves and seats so that modern fuels could be used without damaging the engine.
It was believed that the cylinders were still of stock bore and that for added performance, boring them out .030-inch would be sufficient. When the block was set up in the boring machine it was discovered that the block had already been bored to a size between .060-inch and .080-inch. Tom and Mike suggested that the block be taken to .080-inch for the most performance and that custom pistons would need to be made.
They also found the crank was hopelessly cracked. A replacement was secured and they went to work machining, balancing and pouring new Babbitt bearings. Tom’s brother Rick provided the full-race camshaft set-up to deliver the most lift and duration possible with an original T camshaft. The result was a perfectly balanced and expertly rebuilt short block designed to produce upwards of 60 horsepower and a perfectly rebuilt and balanced Model T planetary transmission.
After the motor was picked up from Tom and Mike at the Auto Ranch, I started prepping the old engine for removal by disassembling the hood, radiator and removing the body from the frame. This was necessary since the Model T engine and transmission are one piece and can interfere with the firewall during removal. I also wanted a chance to do some clean-up and improvements on the chassis while the body was off. I spent some time crawling over the chassis and was not really happy with what I found. There had always been a few things I wanted to change with the suspension.
The front suspension had been lowered to the perfect stance with the use of some accessory lowering brackets that were made for an early T, and admittedly were not well thought out. I didn’t have the early style parts to make them work even half-way correctly, so I set to modifying as best I could. The result was spring shackles that mostly bottomed out on the lowering brackets, made only worse when the engine was installed. While it did make the chassis very stable in corners, the ride was very hard and almost unbearable on Portland’s potholed streets.
The lowering work I had done in the rear had equally stark issues. I had made a point to find ways to lower the car without cutting the frame, which is a very commonly used solution. I found that if the Model T rear axle housings were flipped right for left, I could hang the spring eyes below the axle with extended shackles. This successfully accomplished the look I was after, but maintained very little frame clearance and gave no room for adjustment. This unfortunately also meant that the rear crossmember would strike the rear axle on rough roads.
I realized that none of my original suspension could be corrected or saved. I decided to start over from scratch and design a completely new and improved suspension system. I began pouring over old books, period hot rod magazines, and online resources. I was looking for ideas as a foundation to build my design on. I knew that most of the speedsters and early “Gowjobs” used either lowering brackets similar to my original set-up or the occasional dropped axle with a stock pan-mounted wishbone and “Z’d” rear crossmember.
I wanted to avoid these more common methods, so I dug deeper. I came across a few early speedsters built with spilt wishbones and special spring perch mounts that eliminated the lowering brackets and hung the spring from these wishbones. I thought this was perfect and meant I wouldn’t suffer the same interference issues as my previous set-up. Although the design base I had chosen used the lighter weight Model T wishbone, I decided to strengthen things up a bit by using a Model A wishbone instead.
I spent the next few days cleaning and repairing the frame before mocking up the ride height and the front axle to its new proposed location. The new front end began to quickly take shape as the modified wishbones were mounted to the axle. The new spring perches were machined before being welded into place and the new frame-mounted wishbone ball stud plates were drilled and hot riveted into place the old fashioned way.
This time around I welded nothing to the frame, choosing to bolt or rivet instead. This is because of the Model T’s unique frame design, which incorporates it as part of the suspension. Henry Ford chose to employ vanadium steel, which was new to the industry at the time for the Model T frames. This formula was very strong, but flexible much like spring steel, allowing the frame to stay rigid and strong while flexing and twisting in extreme road conditions.
Welding in boxing plates or other added supports impede its ability to flex causing added stress, cracking and breakage. I took great care and kept this in mind when redesigning my chassis. Since the new suspension set-up did not impede the shackles like the previous set-up, the car would suffer from body sway on cornering. To combat this, I designed a period looking Panhard bar that mounted neatly between the front axle and the front crossmember.
By comparison, the rear suspension would be a far taller order because whatever I designed had to work around and retain the original driveshaft and radius rod lengths, spring location and rear brake set-up. I proceeded with a design that hung the spring from the top of the rear axle, but put the spring eyes at the same ride height as the original set-up, allowing for a ride height adjustment of 2¾ inches for extra clearance.
The new design also did not require alteration of the other existing components. It did, however, require me to flip the rear axle housings back to their proper sides again, which allowed me to inspect the differential, replace some damaged parts and update the old driveshaft roller bearing to a modern tapered safety bearing set-up. I took great care in designing, mocking up and testing the new set-up to ensure no problems with function or clearance of other components. Since I had incorporated a Panhard bar into the front suspension, I decided to do the same for rear suspension and built a far stouter bar from a ’27 Dodge Brothers.
The final addition to the new chassis was a full set of knee-action friction-style shock absorbers mounted front and rear. Chris Becker and I had reproduced a set of four from a single original that had come from a 1914 Hupmobile that we found around the shop. I added these to my new chassis for a more period look, while accomplishing greater road stability and comfort. The knee-action shocks are also fully adjustable for a softer or stiffer ride.
With the new chassis design and fabrication work done and fully assembled, I checked to make sure that everything I had designed was working correctly without interference. Everything from the Panhard bars to the new shackles and knee-action shocks worked perfectly, so I pulled the chassis apart one last time for paint and final assembly.
Next, we’ll dive into assembling the new engine, returning the body to the frame and firing the old roadster up for the first time as we race towards the ever approaching Bonneville deadline!