Cam Project Test Car



I finished restoring our '26 Tudor in 1999.  The engine had all the "good" stuff, but it didn't run very well.  I was frequently told that its performance was normal for a heavy sedan.  However, I had driven Fred's Centerdoor, so I knew a sedan can run well.  When Larry Sigworth presented his Cam Study at one of our chapter meetings, I became convinced that the camshaft was part of my car's problem.  I convinced Fred that we needed some actual dyno testing to back up Larry's study, so our Tudor became the "Cam Project Test Car."  

Our Tudor's evolution is detailed in Dyno Results.  We have achieved dramatic performance improvements, while maintaining a mostly stock appearance.  According to a chassis dyno (rear wheel horsepower), the work on this car has resulted in a 50% (15 to 23 hp) increase in peak horsepower.  More importantly, at 1000 RPM, the horsepower and peak torque were increased by 70% (62 to 105 ft-lb, 12 to 20 hp).  Accounting for drive train friction losses, the engine is probably making about 27 hp at 1600 RPM and  at least 120 ft-lb at 1000 RPM.  See the Hill Climb Results for how our Tudor performed.  It also won the dirt track race at the Azalea Tour in 2002. 

Modifications to this car are as follows:

1)  Cam:  replaced reground cam with NOS cam and later with 280 Super-Power cam.  

2)  Head:  Z head milled 0.050 to reduce squish space over piston to 0.060 .  Milling also gives a modest increase in compression ratio from about 5.3 to 5.7 (see Model T Heads).

3) Drive Train: modern bearings throughout - 4th main, torque tube, pinion, axle, axle thrust and floating hubs.  

4) Gears:  stock gear ratio and Ruckstell axle.  When not using the Ruckstell, the hill climb time increased from 27.1 to about 29.5 seconds.  4:1 gears would probably be the best.

5) Transmission Alignment:  the transmission shaft run was about 0.015.  In 2007, after about 12,000 miles, it broke a crankshaft.  When it was rebuilt, we used Mike Bender and Fred Houston's alignment procedure.

6) Ignition: currently running a stock ignition system on 12 volts.  For the 2002 hill climb it ran a modern Bosch 009 distributor. It has also run with an antique Bosch 600 converted to electronic (see Distributors). During the dyno testing, there were indications of ignition problems.  The mag finally gave out completely.  Out of curiosity I installed a distributor.  According to the Cheapo Dyno, it gave an 11% increase in power and torque at 1000 RPM.  Tom Carnegie has found that a properly tuned stock ignition produces the same power as a distributor.  More work needs to be done on this question.

7) Weight:  car weighs about 2050 lbs with a full tank of gas, so for the hill climb, we removed seats, spare tire and tools.  This had a dramatic effect.

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