Personal Observations on Timers and Their Characteristics

©Warren Mortensen

Ford script roller timers

I have a number of friends who use these with not problems. When looking for a unit to rebuild, watch for cracked insulators, usually where the stud passes through to the contact. If you find a case with a good insulator and plenty of material, you can chuck these in a lathe and clean them up so they run true. Roller timers of any type tend to develop valleys and hills that eventually cause the roller to skip over a contact, usually at higher speeds. The engine may idle nicely but sputter and miss when revved. A similar problem can occur if the roller shaft is worn and the roller develops too much play at its center. If you have skill and equipment, the shaft can be replaced. Care and lubrication of the Ford timer should be followed per the Ford Owners Manual.

Tiger Timers

If you find a Tiger Timer in the box that indicates it was “Made in U.S.A.”, it should be a serviceable unit. These timers will have a dark brown insulator in the case. Off-shore manufactured units typically have a bright orange colored insulator. Off-shore Tiger cases cannot be cleaned up on a lathe. The contact assembly is made of sheet metal folded over the head of the stud and stamped to shape. The part tends to snag on the cutting bit and simply rip out.

My experience with the off-shore units has not been good but dates back about 18 years so improvements may have been made for all I know. Following proper maintenance on an 1100 mile trip in 1985, I went through one Tiger Timer every 200 miles. The weakest link seemed to be the roller shaft which would wear out quickly. Upon arriving at my destination, I switched to a New Day timer and went through 3 of these on the same vehicle over a 16 year period.

Timer Rollers

An article appeared in the Model T Ford Club International’s Model T Times Issue 199 suggesting the use of two Fafnir S1 KDD7-C1 bearings mounted side-by-side as replacements for the roller (this part number may have been superceded). A number of people have had good success with this approach.

New Day Timers

As stated above, I have one vehicle I’ve run exclusively on these for 16 years with both original and reproduction units. Original versions were made of a Bakelite-type of material and the brush had a brass colored “Oilite™” appearance. New Day timers make contact on the face of the case. The original selling point was no need for lubrication. Indeed, the main maintenance problem with a New Day tends to be its regular removal to wipe out oil that has leaked into the case from the camshaft and sometimes interferes with proper electrical contact inside the timer. Metal shavings from brush and contact wear can also contribute to cross-firing or misfiring.

Modern reproductions have varied in quality over the years. Sometimes the cases have been made of too soft a material, causing uneven wear in the case or premature wear to the brush assembly. Cases can be cleaned up with a lathe however. The reproduction brush is of a copper material that seems softer than the original and the reproduction brush holder seems to allow a little more free movement of the brush from side to side allowing the brush to wear at an angle. Some of these characteristics can be alleviated by filing a bevel or radius to the leading edge of the brush and replacing the pressure spring behind the brush with a weaker version (half a ball-point pen spring works well). This reduces wear on the case and brush while still providing decent contact. Eventually, regardless of the age or source of the unit, the brush becomes so short that it cannot make adequate contact with the case and the engine runs rough.

Some years ago, one run of New Day brushes was manufactured with the notch for the camshaft pin located in the wrong place. This caused the engine to knock to the point that some people thought they had loose connecting rod and main bearings. While these brushes are no longer on the market, bear this in mind if you acquire some New Day parts at swap meets, garage sales, or as hand-me-downs.

Anderson Timers

A number of long-time T hobbyists have been using this timer for years and to the point that one of them designed new dies and studied various alloy steels to come up with a good, reliable reproduction unit. Original cases seem plentiful enough but the “flapper” brush and pin retaining ring were often the hard parts to find. The retaining ring for the pin on and Anderson is made of thinner metal than most retaining rings to allow clearance for the Anderson brush. Other retaining rings will often bind on the Anderson brush preventing it from functioning properly. Old-timers in my area told me that the weakest link in an Anderson was the spring under the brush which would eventually break from the repeated flexing. Anderson users typically carried an extra spring in their tool box as a backup. Spring technology has advanced over the past 70 years however so longer life in a spring is possible today.

I have an Anderson reproduction on one of my cars and it receives no special attention. I check it once a year to wipe it out as a precaution. The unit shows very little wear. This car starts on magneto in winter in Minnesota which I attribute to good clean electrical contact, proper magneto adjustment, good rebuilt coils and a good rebuilt carburetor.

Consider the following regardless of you choice of timer

Electrical isolation

Anything that can ground a timer contact will interfere with proper timer function. First on the list is an oil pan to engine block bolt that is underneath the timer. This bolt should be installed “head up, nut down”. Ford typically installed the oil pan bolts from the bottom with the nuts on top. This particular bolt is often long enough to ground out the #3 contact when the spark is advanced causing the #3 spark plug to fire continuously. The engine will idle fine when retarded but advancing the spark will make the problem evident.

Other possibilities involve terminals contacting the timer pull rod (usually involves a sloppy and worn linkage system) and flag terminals on the wiring harness coming in contact with ground by one means or another. This situation is common with New Days due to the way they are built. I attach the flag terminations from the wire harness on this brand so that the wire is down against the forward side of the case rather than out at the end of the New Day tab. On other brands, I make sure that the wires are not going to contact the engine block or timer case. This sometime requires taking a pair of pliers and bending the flag terminal up near or against the terminal nut on the timer case. Ease of installation and removal takes a back seat to electrical isolation.

Path of the roller or brush inside the timer

The thickness of the hub on the camshaft timing gear will affect the location of the roller or brush relative to the contacts on the timer case. Fiber timing gears often have a thicker hub than the original Ford gears. This places the timing gear jam nut farther forward on the camshaft and in turn, moves the roller or brush farther forward and out of line with the center of the “track” in the timer case. This causes a trail to be worn toward the back on the roller and toward the front on the case contacts. In the case of a New Day timer, the brush is pressed closer to the inside face of the timer case causing accelerated wear due to heavier spring pressure. Removing a measured amount of material from the back end of the shaft collars on Ford, Tiger and New Day rollers/brushes will allow proper tracking. If the motor is apart, the material can be removed from the nose of the timing gear jam nut instead. The Anderson manufacturer has made allowances for the differences in timing gear hub thicknesses.

Camshaft seal

The standard Ford camshaft seal is a felt washer protected by a metal disk. This can be replaced with Chicago Rawhide Part No. 9876 in most cases (very early timing gear covers require some modification). The metal disk is supposed to be held in place by the timer case but due to various factors often ends up inside the timer case and can interfere with proper firing. Typically, instead of a firing order of 1-2-4-3, you will get a firing order of 1;2-2;4-4;3-3;1. The coils will buzz in an overlapping fashion and offer a great opportunity for the engine to kick back.

Other considerations

For good timer control, the linkage has to be in good condition. Check for the following:

Spark Rod Lever T-3530: Located at the base of the spark advance, this arm is held in place by a rivet. If the lower steering column bracket (mounted to frame rail) has ever been removed or replaced, this lever had to be removed. The rivet has often been replaced in a haphazard fashion (I’ve found shingle nails used for this purpose). The lever MUST be mounted securely to the spark advance on the steering column. Elongated holes in the lever or spark advance will need to be drilled oversize or welded shut and re-drilled. A properly fit rivet or a roll pin (also known as a tension or expansion pin) of the proper diameter should be used to secure the lever. If using the roll pin, make sure it fits tightly and will not vibrate out. Welding the lever in place should be avoided. It makes disassembly of the steering column more difficult in the future. The hole for the timer pull rod should be checked for wear and welded shut and re-drilled to proper size if necessary, or a replacement lever installed. Do not mistake this lever for the lever on the throttle, T-3531. These are two different parts and do not interchange, causing much trouble when used for the wrong job.

Timer pull rod T-3534: Check the pivot points for wear and treat accordingly. In some cases, it is advantageous to silver solder or braze a washer near the 90° bend at each end of the rod. Some rods otherwise tend to create slack by allowing the timer control arm or the timer pull rod arm to slip part way “around the corner”. More washers may be installed between the cotter pins and the arms to take out “side play” in the pull rod. A different pull rod T-3534C was used on 1926 – 27 cars and doesn’t work properly on earlier models.

Timing

This is my approach: With the spark lever in about the second notch on the quadrant, I remove the #1 spark plug, bring the #1 piston around to Top-dead-center on compression stroke using a piece of coat hanger wire or a long screwdriver to monitor the progression of the piston. I continue to rotate the motor until this “probe” just barely indicates that the piston is past TDC. I then turn the ignition on BATTERY and, with the timer disconnected from the pull rod, rotate the timer towards the fan belt until the #1 coil buzzes. I then shut off the ignition, and bend the timer pull rod to reach and fit into the timer arm. I then advance the spark, then fully retard it, and return to the second notch on the quadrant. I turn the key to BATTERY and see if the exercise repeats itself. The quadrant setting can be modified to the tastes of the individual owner.

If your magneto is good, advancing the spark lever another 4 to 6 notches and hand cranking on MAG should start the car. MAG starting always requires a little more advance on the spark lever than starting on BAT, but has one big advantage. I’ve never had a car kick back when starting on MAG.

Camshafts and their effect on timers

Ford used different styles of camshafts during Model T production.

One style has the hole for the timer’s roller pin drilled completely through. This can result in the roller or brush being installed 180° out of time. The car will not start although some backfiring may be noticed. The mechanic can assure that the roller has been installed correctly by removing the #1 spark plug, bringing the #1 piston around to Top-dead-center on the compression stroke, then noting the position of the roller in relation to the #1 contact on the timer.

In about 1924, the #1 exhaust cam lobe was lengthened and a shorter front camshaft bearing was used on this new style. Old camshafts can be accidentally mismatched with the newer-style cam bearing. Some end play may occur in this case. This can cause the roller or brush to track poorly on the case contacts.

The front camshaft can also develop side play. In some cases, the bearing has become loose in the engine block and side play can take place both in the bearing and in the block. Side play allows the camshaft to “whip” which reduces the ability to center the camshaft properly in the timing gear cover. This in turn causes the roller or brush to run off center in the timing case causing the engine to fire unevenly in a “loping” fashion. A timing gear cover not installed and centered correctly on a good camshaft may cause the same problem.