Total Advance---or Retard?

F

fourbangerbob

Member
I marked TDC on the front pully when I had the head off--I installed a NU--REX timiing indicator bracket to view the timing when then lever is down or up. How many degrees should it be retarded at idle or hi speed for best operation?
 
I have similar setup with NU-Rex. Are A's are individuals...
I am running F.S. ignition.
My sweet spot is.
-3 degrees ATDC retarded at idle
+26 degrees BTDC 3/4 lever down highway speeds normal conditions

I know some run as much as 5 or more degrees ATDC at idle. Mine did not like it.
 
With the spark lever all the way up at idle, you should be at 0 degrees advanced. With a stock distributor fully advanced youll get around 40 degrees with the spark lever fully advanced. But really thats to much advance for the model a motor, they really only need about 30 degrees advance or pretty pull the spark lever down about 2/3 of the way down.
 
fourbangerbob said:
I marked TDC on the front pully when I had the head off--I installed a NU--REX timiing indicator bracket to view the timing when then lever is down or up. How many degrees should it be retarded at idle or hi speed for best operation?
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Are you familiar with the timing pin and timing procedures ? Your TDC mark should line up when the timing pin drops into place. Then things are as Logan said.
 
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I have a FS ignition in my A. It was recurved to be 8° advanced at idle and 28° wide open. The lever lets me retard it about 6° when climbing hills.
 
What am I missing here?

I have run FS ignitions since they bought the business from Mickey Remund and there is no control of the spark lever.

What are you guys running that you set the centrifugal advance and still have use of the spark lever?

Richard
Anaheim CA
 
I normally leave the spark lever all the way down and just retard it a few degrees when climbing hills. To make it adjustable, remove the screw holding the plate in place. Then mill or file the hole to a small slot. Then loctite the screw in place but still loose enough to let the plate move. If I just use the centrifugal advance timed for best performance, it will ping under a heavy load. The lever only moves a small amount.
I have a .100 over, full pressure oiled, Stipe B340 cam, 32/36 weber and a 6.8:1 crows foot Winfield head. It is very sensitive to timing. I called FSI and they explained how to make the timing adjustable. I also have an oil pressure switch feeding the FSI with a time delay relay across it so I can start the car. This way, the power to the ignition cannot stay on longer than 30 seconds without the engine running.
 
From the OP it appears to me that he is using a timing indicator mark on the front pulley. I see no indication that he is using a different distributor. But, the OP really doesn't have much info.
 
Regarding the comment about having 40 degrees crankshaft advance available with the spark advance lever full down. Staighten me out here. If the timing is set by Les Andrews book, when the spark advance lever is brought down from the full retard (up) the points don't open until about 20% of the lever travel is already been used, so as I see it, you don't have the full 40 degrees available, limited by the 20 degree slot in the distributor. Some value less than that, as I see it. Maybe 30 degrees? I can be talked out of this.
 
BobMo said:
Regarding the comment about having 40 degrees crankshaft advance available with the spark advance lever full down. Staighten me out here. If the timing is set by Les Andrews book, when the spark advance lever is brought down from the full retard (up) the points don't open until about 20% of the lever travel is already been used, so as I see it, you don't have the full 40 degrees available, limited by the 20 degree slot in the distributor. Some value less than that, as I see it. Maybe 30 degrees? I can be talked out of this.
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The points should open at the first click, second at the most. If the lever needs to be lowered more than that, the timing is not set correctly. Ideally there should be 20º at distributor/40º at crank, but, that may not always happen. I'm in the camp that doesn't think these monsters need 40º to run properly. I normally operate the vehicle with the advance lever in the about 2/3 position.
To me, once the timing is set, the engine should idle very slowly and sound like the timing is late when in full retard. The idle speed should increase as the lever is lowered to 1/2 to 2/3 and as the lever is pulled to full advance the engine should start to show signs of over advance by 'rolling' [ getting a bit rough].
 
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Richard in Anaheim CA said:
What am I missing here?

I have run FS ignitions since they bought the business from Mickey Remund and there is no control of the spark lever.

What are you guys running that you set the centrifugal advance and still have use of the spark lever?

Richard
Anaheim CA
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Hey Richard,
I've also run electronic ignition for ten + years now (same unit) !
My stock appearing dist has a 'elect module' installed. NO cent adv, and that's what necessitates the use of the original spark advance lever, in my case. What is you FS ign unit , with cent adv, equipment number. I'd like to try centrifugal advance. I take it you are happy with performance of you FS with cent adv ?
 
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