Timing Window Parallax (1 Viewer)

[deltapine1]

Correct timing question
I had noticed some detonation recently in third under load. I first thought it was some bad gas but since I have put 2,300 miles on my 60 this last month I thought I would check the timing just to rule it out. I followed the manual and 2mbb's instructions and disconnected and plugged both vac. lines to the dizzy. Using a timing light I verified the pointer is at the round dimple.

I have a question. The manual tells us the pointer should point to the round ball or dimple when setting the timing. As I am sure 99% of us don't stand on our head in the engine bay and get intimate with the starter we don't actually line the ball or dimple up directly with the pointer. If you line up the pointer with the ball as I do from an overhead view at about a 45 degree angle from the top of the fender the ball or dimple is actually below the pointer. This is because of angle required to view the timing window and pointer while leaning over the fender well.

Does it really matter or should we be standing on our head to get the pointer and ball lined up?

Is it better just to time the it to get the best idle without detonation under load?

 

[xulcuz]

Bump... I would like to know this as well as I am in the process of timing and I cant seem to get it perfect only close. Can it be "close" or does it have to be spot on?

 

[lehiguy]

The BB is at 7 degrees BTDC. Use it as a refference point. I live at altitude, so I was usually running around 10 or 11 degrees static advance when I had 2Fs.

 

[2mbb]

I would not worry about the parallax (at least I don't). I've never had a problem with pre-detonation. The flywheel is about 24" in diameter at the point where the timing marks are, which is approximately 72" circumference. since the fly wheel goes around twice for "360 degrees of timing", each rotation is 180 degrees or 1 degree equals about 3/8" of circumference. since the window is about 1" wide, it represents three degrees across the window or 1 1/2 degrees between the pointer and one side.

Therefore, any parallax would result in less than 1 degree error. does this analysis make sense?

 

[klinetime574]

Therefore, any parallax would result in less than 1 degree error. does this analysis make sense?

Yes it does. If you have the BB in the window, you are pretty darn close.

 

[deltapine1]

Thanks 2mbb! I timed mine by pulling the inspection cover and marking another line on the opposite of the BB as the line for top dead center (TDC). I measured the distance between the top TDC and the BB (15 mm) and marked the second line 15 mm on the opposite side of the BB as TDC. In my thinking if the line or TDC is 0 and the BB is 7 degrees of advance then my new line is 14 degrees of advance. Halfway in between the new line and the BB is where I set mine. No pinging yet and I should be setting on about 10.5 to 11 degrees of advance.

By the way if anyone wants to really practice geting intimate and cozy with your motor change out the hose on the water pump that attaches to the oil cooler manifold tube. Its the 3/4" hose about 2 inches long crammed right behind the fan and below the main 2" hose leading to the bottom radiator connection. Try to get you hand in there!

 

[klinetime574]

By the way if anyone wants to really practice geting intimate and cozy with your motor change out the hose on the water pump that attaches to the oil cooler manifold tube. Its the 3/4" hose about 2 inches long crammed right behind the fan and below the main 2" hose leading to the bottom radiator connection. Try to get you hand in there!

Thats a pretty good one.

Another is the one that comes off the water pipe on the back of the cylinder head. It goes to a hardline on the firewall to pass behind the motor.

Seen photos of motors on here that they just bypassed it with a long, long heater hose haha.