13T - Commuter Rod Travel Range and Its Impact on Timing
Posted: Sun Dec 27, 2020 5:44 pm
You start one project then find two more which need to be done. This is a case of I don’t know what I don’t know.
The advance lever, though the commuter rod, has to send the timer through a certain range of motion in order to generate a spark in the cylinder at a certain amount of degrees before or after TDC. I would believe this range begins with the advance lever fully retarded which should translate to 15 degrees after TDC. I have set that end of the range by following guidelines on this forum.
The other end of the range, at which the advanced lever is set to its most advanced setting on the quadrant should translate to a certain amount of degrees before top dead center which I don’t know. Figured it was equal to or great than 45 degrees.
So that’s question 1... how many degrees before TDC should a timer generate a spark when the advance lever is full advanced on the quadrant?
As I was working on the T today, I noticed my advance lever wouldn’t stay full advanced... it can be taken down the quadrant to that position but then it rebounds some. I looked at the end of my steering column and noticed it is because my commuter rod, when fully advanced, makes contact with the steering column then rebounds back a little when I let go of the advanced lever.
This made me think that I may not have an appropriate full range of motion of my timer, thus diminishing the performance of the engine.
So, question 2. Is there a table or guidelines to show what physical range of motion of the timer is sufficient to ensure the full range of timing which should be available to the engine? I measured mine today with masking tape on the engine and on the timer, making a mark at the beginning and end of that range. It was just over a half an inch.
I have attached pics of my commuter rod’s position at the extremes of the advanced rods positioning on the quadrant. If you look at the commuter rod in the retarded position... it appears it has more travel range possible as the physical connector could lean/travel more toward the steering column. If I took advantage of that range, then I could gain the unused range on the quadrant when the commuter rod is more advanced but butts against an obstruction then rebounds.
So question 3, how can I get that connector to sweep more toward the steering column when set in the retarded position? It seems that connector is held onto the rod passing though the steering column, and up to the advance lever, with a screw passing through the middle of the rod. So it seems like the connector cannot simply be made to rotate since the screw is holding it in a fix position.
I apologize for the lengthy post, this is something which would be more efficiently handled in a Model T club meeting. But we don’t have those right now.
Thank you for those who made it though this post. I’m still in a steep learning curve and hope this post didn’t sound too ignorant.
Thank you,
Darin
The advance lever, though the commuter rod, has to send the timer through a certain range of motion in order to generate a spark in the cylinder at a certain amount of degrees before or after TDC. I would believe this range begins with the advance lever fully retarded which should translate to 15 degrees after TDC. I have set that end of the range by following guidelines on this forum.
The other end of the range, at which the advanced lever is set to its most advanced setting on the quadrant should translate to a certain amount of degrees before top dead center which I don’t know. Figured it was equal to or great than 45 degrees.
So that’s question 1... how many degrees before TDC should a timer generate a spark when the advance lever is full advanced on the quadrant?
As I was working on the T today, I noticed my advance lever wouldn’t stay full advanced... it can be taken down the quadrant to that position but then it rebounds some. I looked at the end of my steering column and noticed it is because my commuter rod, when fully advanced, makes contact with the steering column then rebounds back a little when I let go of the advanced lever.
This made me think that I may not have an appropriate full range of motion of my timer, thus diminishing the performance of the engine.
So, question 2. Is there a table or guidelines to show what physical range of motion of the timer is sufficient to ensure the full range of timing which should be available to the engine? I measured mine today with masking tape on the engine and on the timer, making a mark at the beginning and end of that range. It was just over a half an inch.
I have attached pics of my commuter rod’s position at the extremes of the advanced rods positioning on the quadrant. If you look at the commuter rod in the retarded position... it appears it has more travel range possible as the physical connector could lean/travel more toward the steering column. If I took advantage of that range, then I could gain the unused range on the quadrant when the commuter rod is more advanced but butts against an obstruction then rebounds.
So question 3, how can I get that connector to sweep more toward the steering column when set in the retarded position? It seems that connector is held onto the rod passing though the steering column, and up to the advance lever, with a screw passing through the middle of the rod. So it seems like the connector cannot simply be made to rotate since the screw is holding it in a fix position.
I apologize for the lengthy post, this is something which would be more efficiently handled in a Model T club meeting. But we don’t have those right now.
Thank you for those who made it though this post. I’m still in a steep learning curve and hope this post didn’t sound too ignorant.
Thank you,
Darin