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Ok.... I am baffled!

Posted: Fri Dec 17, 2021 7:21 pm
by Jonah D'Avella
I have been told, in my short 1.75 years of model Ting, that it is virtually impossible to start an unrestored eingine on mag. But recently I have heard of quite a few folks that were able to. So, what is the case?

Re: Ok.... I am baffled!

Posted: Fri Dec 17, 2021 7:30 pm
by A Whiteman
As always "it depends". On just how worn the engine is and how well tuned and ...

In short, yes it may be possible if the mag is in good nick (good voltage), good coils (fat spark), good wiring, good carb (good mixture) and enough compression .. well that helps in any case.

Ps. I have seen 'restored' engines that won't start on mag too!

Re: Ok.... I am baffled!

Posted: Fri Dec 17, 2021 8:20 pm
by TXGOAT2
"Wear" can mean a lot of different things. I've had badly worn engines that started easily. A reasonable amount of compression on all cylinders helps a lot, and the ignition system needs to be in good order. An engine with low compression would actually require less firing voltage than an engine with good compression, assuming clean spark plugs. A GOOD mag should start a worn engine as easily as starting on battery. It is important on a T that the crankshaft thrust clearance not be excessive for the mag to work properly. Obviously, that could be an issue on a well-worn T engine. Remedies short of an overhaul are available.

Re: Ok.... I am baffled!

Posted: Fri Dec 17, 2021 8:52 pm
by Norman Kling
If the engine has the proper fuel mixture and the spark comes at the right time it will start. Usual cause of problem starting is that it runs on one cylinder and the next one or two don't run so it just coughs. If each cylinder is properly primed and each one receives the spark then the movement of the first piston will set it into position to fire the second etc. It is usually easier to start an engine which has recently run and is warmed up.
Norm

Re: Ok.... I am baffled!

Posted: Sat Dec 18, 2021 1:33 am
by Steve Jelf
I would say it's virtually impossible to start an unrestored Model T on MAG IF its magnets are weak (or if there's excessive crank shaft end play), and many unrestored T's have weak magnets and sliding cranks. But most will run on MAG after you start on BAT. The best magnet charge is with the magneto disassembled and each magnet charged individually. Second best is with the magnets still on the flywheel but charged individually. The third method is by flashing the coil ring with the works still in the car. I have read that the third method gives you a charge about 60% of what you get from the first. Maybe somebody who has done it can tell us if an in-car charge is enough to restore mag starting.

Re: Ok.... I am baffled!

Posted: Sat Dec 18, 2021 2:17 am
by TRDxB2
Jonah D'Avella wrote:
Fri Dec 17, 2021 7:21 pm
I have been told, in my short 1.75 years of model Ting, that it is virtually impossible to start an unrestored eingine on mag. But recently I have heard of quite a few folks that were able to. So, what is the case?
What was probably meant as an "unrestored engine" is one that had been car had been sitting around for a number of years. Not meaning on the neads to torn down and completely rebuilt. But as described above lots of things needs to be "refreshed" before one tries. The same is true for trying to start tone on BAT, the battery needs to be charged, etc...

Re: Ok.... I am baffled!

Posted: Sat Dec 18, 2021 2:40 am
by Jem
My long gone friend Eric Goodey, who was around in the 20s, gave me a tip for starting a worn T on mag. Get a tyre lever behind the front pulley and shift the crankshaft forward, that takes up the end float and helps the mag to fire on your first pull.

Re: Ok.... I am baffled!

Posted: Sat Dec 18, 2021 5:36 am
by bobt
Jonah. I've been to Luray and I have seen you start your beautiful T- (right hand cranks and kick starts) Please, Please be careful. Some people will tell you to advance the timing to allow for mag starts. bobt

Re: Ok.... I am baffled!

Posted: Sat Dec 18, 2021 8:47 am
by Joe Bell
The real wrist breaker started with the 13 mags, Wally told me years ago the design of them caused a spike on the solisiscope? spelling may be wrong?

Re: Ok.... I am baffled!

Posted: Sat Dec 18, 2021 9:19 am
by Russ T Fender
I have done lots of in car magnet charges with great results. I have a bad back so I start on battery because it's easier but when I stalled at a light a while ago I jumped out, pulled up on the crank, and she started right up with a quarter pull. When I got back in the car I went to switch to mag and found that in my haste I never switched to battery. The magnets in that car had recently been recharged in the car using three 12 volt batteries and that engine was anything but rebuilt.

Re: Ok.... I am baffled!

Posted: Sat Dec 18, 2021 9:55 am
by TXGOAT2
Remember that the spark energy is not what makes the engine run. The spark serves to ignite the air/fuel charge, the rapid and expansive combustion of which is what make the engine move.