I thought I understood but now I'm not sure. My books tell me the lever is at fully retarded when it is in the up or approximately 3 O'clock position. As I pull the lever down it pulls the timer, or in my case a distributor in the same direction as the engine rotation. In this case the spark will occur later in the stroke which in my mind is retarding the timing. Am I correct in my thinking or do I have it bass ackwards?
gas lever is between 12:00 & 6:00;
Spark is on the other side - 6:00 to 12:00 - at least it is on my car.
Bass ackwards. The camshaft rotates in the opposite direction.
Of course David is right. Spark is on the left side of the column. Pulling the lever down does move the timer in the direction of engine rotation, but since the cam rotates in the opposite direction this advances timing.
Okay that makes better sense. Sorry when I said 3 O'clock, I should have said 9 O'clock for the spark advance lever. Thanks Henry! One last question, everything I've read says to set the spark on cylinder 1 to fire when cylinder 1 is at TDC for the compression stroke, are there marks somewhere that indicates TDC or is this an eyeball thing watching the piston through the spark plug hole?
Bump to get rid of the spam
Perhaps this will help.
When the pin on the end of the crankshaft is a 3:30 and 9:30 (just past horizontal) a cylinder will be at 15.5 Degrees ATDC.
Explanation of Model T Spark Timing
Ron thanks for the material, look forward to reading it. I thought I read somewhere that you want to set the timing to 15 degrees after TDC, but when I started this today I couldn't find it. Everything else I have says timing is set at TDC. 15 degrees after makes more sense to me is this the target for fully retarded timing?
Tom, I time my distributors to fire #1 with the piston about 1/8" past TDC. Same as with coils. I remove the plug and insert a long thin screw driver and watch for TDC and move it down 1/8". Then rotate the distributor until the points just open, lock it down. Works good.
Tom: I missed a reference to broken arms and starter bendix's. If it fires before TDC, it will run backwards just enough to break an arm or starter
That is the reason for AFTER TDC