Tdc

B

Brian3328

New member
Sorry if this sounds stupid but what is the best way to find TDC on a T? I watched a guy on Youtube and he was looking down the spark plug hole to watch the piston. I can't see a thing when I try that. I guess I have to post 8 more times to try and buy something on the swap meet. I'm looking for a 26 hood for my 26 Roadster pickup.
 
Remove #1 spark plug, hold your thumb over the hole and while someone handcranks the engine, wait for the pressure in that cylinder to push against your thumb off as the piston reaches the top of its travel. That is TDC for cylinder #1, or as close as you will need to set the commutator timing. You can tweak the timing from there.
Marshall
 
Thumb method is the easiest way to insure its on the compression stroke. Just looking in doesn't insure that. It could be on the exhaust stroke so that's a 50/50 chance and I'm not one that likes to gamble on stuff like that. If there's a stuck valve then check compression first.
 
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TDC, for the most part, is defined as the point near where the spark occurs for combustion in timing procedures. A person might be able to get a field expedient tool snaked in there to feel the piston rise as the hand crank is turned. A long tie wrap will usually work. On a lot of engines, the sparkplug is offset toward the valves somewhat.
 
Thanks for the replies! I should have mentioned that I am trying to time it. I just installed a Texas T distributor and I'm trying to get the old gal running.
 
Setting timing on a T can be more challenging than say a Model A which is easy by comparison. There is a kit available that uses an LED light harness in conjunction with a screw in piston location indicator. It's a bit pricy but if you check it out on YouTube or at other model T parts sources it will be apparent why. The piston travel locator is rather complicated. You can see how off set the rod is that goes down into the cylinder. I think its well worth the approximate 120 buck price.
 
Looking over the top of the radiator, you should be able to see the piston come up/down. Once you find the compression stroke, TDC is when the pin in the crankshaft pully is fully horizontal. Once you find that, turn the crank about 15 degrees or just when the piston goes over the top and starts to go down, that should put you in the ballpark for setting up the distributor.
 
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