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Hook up vacuum advance, timing retards appreciably

OK I am kind of thinking the ported vac is not working right and it is giving full vac at idle and when you rev it the engine vacuum decreases so it will retard. That's could why it is the same on both of the ports. Have you hooked up a vacuum gauge yet?
It's dropping like 20 degrees below his initial timing set with the vacuum advance unplugged.
Has to be a reluctor rotor phase problem.
I'm sending him a distributor.
 
Is it losing timing from base or from the mechanical advance it is getting when the vac adv is unplugged? I guess a don't see where that's precisely stated.
 
Thanks once again for your input everyone! This forum is terrific!

To answer a few more points that have been made:

1) No adjustment provision on the vacuum advance unit.
2) Put a hand vacuum pump on the advance and it moves the plate in the clockwise (correct) direction. I compared the rate and amount of movement to the 440 distributor that had been in the car previously and was known to be good. They look to act the same.
3) The loss of advance is as follows: Disconnect the vacuum advance hose with engine idling and plug the end of the hose. Set timing to 8-10 degrees before TDC with a light, with engine at idle (about 800 RPM according to the old time RAC tachometer in the car). Reconnect vacuum advance hose and slowly increase engine speed. Timing retards to well after TDC. If I disconnect the vacuum hose while this is going on, the timing recovers to about 12 degrees before TDC, a point consistent with what the I think the mechanical advance should be doing by then. I hope I've stated this better than I have before.

Anyway it certainly appears to be an electrical issue, not a mechanical one. Tomorrow I'm going to switch the two lead wires just to see if it makes any difference. Ironically, one point I'd not made before, as I didn't want to be beating up on an eBay seller, is that I'd emailed him to question the wire colors on the new distributor comparing to my old one. (Orange and black) They seemed the opposite of what I found on my old 440 distributor. The response I got was that it was wired right and to just plug it in. This may well be a non issue and I'm just overthinking the whole deal.

Next step will be to install the distributor Don Frelier was kind enough to sell me cheap. Thanks again Don!
 
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Thanks once again for your input everyone! This forum is terrific!

To answer a few more points that have been made:

1) No adjustment provision on the vacuum advance unit.
2) Put a hand vacuum pump on the advance and it moves the plate in the clockwise (correct) direction. I compared the rate and amount of movement to the 440 distributor that had been in the car previously and was known to be good. They look to act the same.
3) The loss of advance is as follows: Disconnect the vacuum advance hose with engine idling and plug the end of the hose. Set timing to 8-10 degrees before TDC with a light, with engine at idle (about 800 RPM according to the old time RAC tachometer in the car). Reconnect vacuum advance hose and slowly increase engine speed. Timing retards to well after TDC. If I disconnect the vacuum hose while this is going on, the timing recovers to about 12 degrees before TDC, a point consistent with what the I think the mechanical advance should be doing by then. I hope I've stated this better than I have before.

Anyway it certainly appears to be an electrical issue, not a mechanical one. Tomorrow I'm going to switch the two lead wires just to see if it makes any difference. Ironically, one point I'd not made before, as I didn't want to be beating up on an eBay seller, is that I'd emailed him to question the wire colors on the new distributor comparing to my old one. (Orange and black) They seemed the opposite of what I found on my old 440 distributor. The response I got was that it was wired right and to just plug it in. This may well be a non issue and I'm just overthinking the whole deal.

Next step will be to install the distributor Don Frelier was kind enough to sell me cheap. Thanks again Don!

PLEASE LET US ALL KNOW HOW YOU RESOLVED YOUR DIFFICULTIES......"Inquiring minds want to know"...
BOB RENTON
 
I am curious what it is also. Weird one. Wonder if it is a slant pickup in there?
 
I believe you need to remove and correctly reinstall the reluctor on the shaft, and yes re-time it. Looking at the first picture in post 27, it shows how the reluctor teeth align with the rotor slot in the shaft. Here is a picture of mine, over 200K miles. Notice the difference, yours appears advanced at least 30 degrees, if not more.
IMG_1026.JPG

This can also explain what is happening when engaging the vac advance. It's advancing the spark trigger pulse and is firing the previous cylinder, but it's now very retarded.

I also noticed the keeper pin, (small roll pin in the reluctor) is adjacent to the rotor slot, mine are all installed opposite the slot because that is where the grove is machined in the shaft. Maybe the newer ones are different, but this is what really looked odd to me.
 
This photo is very helpful. I now understand much better what the other guys were getting at regarding a rotor phase problem. I can compare mine to the 440 distributor I've on hand too. Thanks much!

I did have time today to try reversing the two distributor lead wires. No spark, so this one only works one way.
 
Could definitely be that. See the arrow in the pic make sure the roll pin is in the CCW position, the one in the pic is in the CCW position for b/rb.
 
I got one of those reluctors... ended installing on same stock position LOL
 
UPDATE: The distributor Don sold me arrived late week. Cleaned it up, adjusted the gap and installed it this afternoon. Engine runs much better now. Idle is smoother and even the exhaust note sounds better to me. Vacuum advance works like I expected it to. I believe the problem is solved.

Thanks all for your input and Don for the super deal on the distributor! Much appreciated. I'm going to play with the new distributor and see if I can figure out why it's apparently so out of whack.
 
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