MTFCA Forum

Hi folks,
I am quite new to the Model T scene although I am experienced with old cars of other makes. I have recently got my 1914 touring car on the road and it's going great and makes me smile every time I drive it. One problem that I do have is the engine misses and loses power at high (high for a T anyway!) revs. My roller timer has a lot of play in the roller (about 1/8") and I was wondering if this could be the problem? I am in Australia and parts are a bit more expensive to get and ship so just wanted to get advice before I buy parts. Best regards, Bill

Fuel may not be getting through. Some modern float needle valves have a hole smaller than the original. Adding a fuel filter to the Model T's system which relies on gravity is not good - or the original filter below the tank may be blocked. The easy check for all these is to remove the carb bowl and time fuel flow into a jar. I calculate that 100cc/minute should be good.

Timers can certainly cause the problems you describe. It's normal to have a slack roller. Look hard at the track around the casing. Wear often occurs adjacent to the junctions between metal and insulation. Check that the spring is pushing the roller. You may need to find a lathe and clean up the track. Maybe try to find someone who will lend you another timer?
If you decide to buy, Henry's offer the Anderson, which is good (but POA) or the New Day. A good New Day can be good but there are some modern replicas which wear quickly.
https://henrystaparts.com.au/wp-content ... E-2023.pdf

And last but not least, coils. What do you know about their history? Have they been set up on one of the special devices designed to get the best performance? As an absolute minimum, have you checked that they generate good steady sparks across a gap of about 6mm and take about 1.3A when fed with 12v DC?

The first step is to replace the timer, as you suspected.

First step is get the Service Manual if you don’t have one. Then replace the timer.

Could be a clogged main jet which you can acess from under the car by removing the float bowl and chasing the jet oriface with some stranded wire. If it runs fine cold until it heats up and then sputters, I would suspect condensers.

Original14T..... Do yourself a favor, do check to see if there is a chapter or other Model T owners in your area. Firsthand knowledge and experience will be helpful for you.

G’day Bill,… along with all the other good advice, are you advancing the spark after the engine is running ?

As suggested above, your trouble could stem from any number of issues. However, without a good timer, (and good coils), as a starting point, those other issues will be hard to diagnose. From your description, we know your timer is bad. Start there, (or start with acquiring the manual, as Dan Hatch suggests).

Thanks for all the good advice guys, much appreciated. I will hunt down a service manual. I have gone through the carby and fuel supply which is in good order, it does feel like a spark problem as there is no backfire through the carb from leaning out. My coils have had new points fitted in the past but I don't know to what extent they have been set apart from myself checking the clearances. I do advance the timing and move it around to find the best spot on mag and battery George, the car certainly performs better on mag, no doubt from the extra advance of the mag. I will replace the timer roller and skim the timer surface as suggested as the insulation surface is slightly below the metal contacts which could be promoting some bounce. Best regards, Bill

Replacing the timer roller is okay and also cleaning the contacts inside the commutator cap... If you decide to install a new timer, regardless of manufacturer, please follow the instructions for set ting the initial timing.

The surface inside the timer must be smooth with a complete even surface or the roller will hop up and down at high speeds and cause those misses.

A week spring holding the roller against the Timer circuit path will cause the same action, along with a worn shaft that the roller rides around on.

Original type timers require occasional cleaning and frequent oiling with a light oil, like 10 W motor oil or Marvel oil. I believe Ford advised oiling the timer every 200 miles. A worn or dirty timer will often cause erratic performance at higher engine speeds. If the entire ignition system, including all 4 coils and all related switches and wiring, as well as the entire fuel system, is in good order, weak valve springs could be a problem.

Would we be safe to assume that your 1914 ignition is running on magneto power? Even though the car does start and runs at speed, The the AC voltage should be checked to have at least 30 volts AC, at speed , ....., if it hangs around 15 - 20 volts AC, your magneto may have to be recharged. The lower AC numbers at speed will definitely give the problem you have.

Thanks for all the great advice folks, I checked the roller and timer again today and the roller has even more play than I first thought, so much so that it can foul on its carrier. I will order one and replace it first. The timer track is actually quite good with an even surface all around.
I really feel that the problem is spark related as the engine shows no typical signs of leaning out.
Best regards from downunder, Bill

Also check the timer wires to the coil box for any sign of bad insulation. The spark plug wires should be arranged so that they are at least 1" from each other or anything else. Worn spark plug electrodes can cause mis-firing at higher engine speeds, especially if the gap is on the wide side. Worn electrodes can often be filed to improve performance. Any wooden parts in the coil box that are exposed to high voltage can leak current and cause problems. This sometimes happens even if the parts look good, especially in damp conditions. It sometimes happens that the contact buttons on the individual coil boxes don't make a secure contact with the spring-like contacts inside the coil box. Cleaning them and tightening hardware may help. Often, placing cardboard or plastic shims between the coil units and the coil box to hold the coil unit firmly against the coil box contacts can fix the problem.