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04-10-2015, 11:49 AM | #1 |
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Hi comp head & spark lever location
I've noticed while driving, my Tudor runs smoother with the lever almost all the way up. I start her up normally with the lever up and drop it down a little after she starts. But when I start picking up speed around 30/35mph there is a noticeable knocking. It will go away if I push the lever back up but it's practically all the way up. Does that sound about right with a hi compression head?
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04-10-2015, 12:07 PM | #2 |
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Re: Hi comp head & spark lever location
I would remove the rotor, loosen the screw, and turn the distributor cam a little bit clockwise to retard the spark some. High compression DOES take LESS spark advance.
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04-10-2015, 12:45 PM | #3 |
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Re: Hi comp head & spark lever location
Well that's an easy fix. Thanks Tom. I just wanted to make sure it was normal.
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04-10-2015, 04:30 PM | #4 |
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Re: Hi comp head & spark lever location
I have mine timed exactly as the book says, (Marco has great directions), and I drive with the spark lever at 9 o'clock, with no spark knock. Snyder 5.5 head, and larger intake valves, and a Stipe 330 cam.
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04-10-2015, 10:30 PM | #5 |
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Re: Hi comp head & spark lever location
Yes, high compression engines don't need as much adjustment.
Here is a general rule that works with any head. At any given speed move the lever down slowly, noticing the increase in the RPM, Stop at the point the RPM's no longer increase.
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04-11-2015, 12:52 AM | #6 |
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Re: Hi comp head & spark lever location
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04-11-2015, 07:05 AM | #7 |
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Re: Hi comp head & spark lever location
I rarely advance spark past 9:00 position with the 5.5 head. Also reduced spark plug gap to .030" per recommendation.
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04-11-2015, 07:39 AM | #8 |
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Re: Hi comp head & spark lever location
i even run a stock head at or about 9:00.
for those that feel the need to pull it all the way down your timing is off or your motor is worn out on my HC head i find 10:00 works |
04-11-2015, 08:52 AM | #9 |
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Re: Hi comp head & spark lever location
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04-11-2015, 08:52 AM | #10 |
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Re: Hi comp head & spark lever location
I've also seen people pull the levers all the way down on youtube videos. Or choke the carb after it's already running.
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04-11-2015, 08:55 AM | #11 |
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Re: Hi comp head & spark lever location
Indeed Wayne.
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04-11-2015, 09:52 PM | #12 |
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Re: Hi comp head & spark lever location
The engine tells you where it wants the spark lever. Mt HC head's spark lever likes to be above 9:30.
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04-11-2015, 11:41 PM | #13 |
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Re: Hi comp head & spark lever location
If your car is timed properly (and it sounds like yours is not), then with a high compression head or a stock head, just follow the instructions in the owners manual that came with the Model A when it was new (reprints available everywhere).
Timing using Marco's method is clearly superior to others. If your distributor is in good condition as spelled out on Marco's webpage, and timed the way Marco's webpage says, then your Model A should run its best when idling with the timing set a few clicks below "all the way up". For normal driving, the spark lever should be about halfway down. At highway speeds, the lever should be almost all the way down. People who put the spark lever all the way up to start, then pull it all the way down and leave it there also tend to lose head gaskets. |
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