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TR2/3/3A Ignition timing questions while I'm waiting for Spring

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K

karls59tr

Obi Wan
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1. 4 Degrees BTDC is 3/8" from TDC on the pulley. Is this correct?
2. Would an engine still run at 4 degrees ATDC??? How would that affect it's running? 3.Does anyone have a picture of the pulley showing the TDC mark and a mark on the pulley showing 4 degrees BTDC ?
4. I've heard that some people set the vernier adjuster at the center mark when when they install and clamp down the distributor. If so how many anti-clockwise turns would it take on the vernier scale for a basic setting?
 
3/8" is about 3 degrees, which is what you are looking for initially. The vernier doesn't have a lot of range, so I think most set it centered with the timing at the recommended initial setting. The initial setting gets you running, but the final setting should be set by test driving. Keep advancing a degree or two at a time until you get pinging, and then back off to get the pinging to stop.

I don't have a picture, but at advanced settings the hole in the pulley will be left of the pointer on the cover. If you accidentally set it retarded, then it will start and run just fine. Idle would be slower and require an adjustment to speed it up. Also the engine will tend to run hotter at retarded settings and you may find it is slower to accelerate too.
 
There is only a TDC mark on the pully it is a small hole on the rear pully face. I put a dot of white marker on the pully OD to make it easier to see when timing the TR3A.

David
 
DavidApp said:
There is only a TDC mark on the pully it is a small hole on the rear pully face. I put a dot of white marker on the pully OD to make it easier to see when timing the TR3A.

David
Click to expand...
Sometimes people mark an additional white mark where the 4 degree BTDC mark would be. What confused me was a picture in a British car magazine article on Timing and Tuning which showed a 4 degree BTDC timing mark on the "right" side of the pointer???
 
Viewed from the front, looking toward the rear of the car, the damper rotates clockwise when the engine is running..
BTDC marks, if you have them, would be on the right hand side of the TDC mark, if you have one.
You could use the piston stop method and see and mark exactly where TDC is on your damper
DamperMarks.jpg
 
Now I'm even more confused! In the picture the 4 degree BTDC mark appears to be on the LEFT of the TDC mark? TDC being the heavy groove @ 0 degrees between the two 4's.
 
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Right, think about it...if the rotation is clockwise, you'd expect BeforeTDC marks to come around to the pointer before the TDC mark and the AfterTDC marks
 
In your latest picture the pointer is pointing to the 4BTDC mark,correct? If so that mark is Left of the larger TDC white mark on the damper.
 
No that's 4* AfterTDC...numbers up to 24 to the right of the TDC hash mark are BEFORE TDC
 
According to the book 4*ATDC if the vacuum Retard is activated.
10 to 14* BTDC if the Retard is disabled.
 
I was just trying to illustrate that when the crankshaft rotates CLOCKWISE, the Before TDC marks on the damper will be on the right hand side of the TDC mark...nothing more, really.
 
'm not going to argue with you but in the picture you postd the pointer is pointing to 4degrees BTDC not ATDC see the photo I suggested.
 
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