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I've been monkeying around on my 72 and tried swapping out my crane distributor to a unilite... Been having issues dialing it in, but something has me confused. As the engine revs, the timing is getting closer to 0, and as it slows, it goes further away?
trying to explain to my old man on the phone. If I'm looking at it from the front of the car, 0* is at about 1:00, so 12* would be about 2:00. To get the car to idle, I have to go to about 20*. From there, if I start to rev toward 3000, it comes closer to 12*???
this seems backwards, but the distributor isn't in upside down.... What did I screw up?
Edit: found it, was referencing something that looked like a timing mark, but wasn't. Remarked timing light, and found it under my water pump.
From: Some days your the dog and some days your the hydrant.
Royal Canadian Navy
Maybe the outer ring of the harmonic balancer has slipped? To check, put #1 piston at tdc on the compression stroke. The mark on the balancer should be aligned with the 0* mark on the timing tab.
If I understand what you are describing correctly it sounds like your timing is set to be AFTER TDC. The engine rotates clockwise as viewed from the front. That means 12 deg BTDC is at 12:00, not 2:00. If you advance the distributor until the timing marks are on the other side of TDC, they will move in the correct direction. ( I may not be understanding what you are describing correctly. A photo might help.)
I don't want to steer you wrong. I would suggest you check out one of the many videos on Youtube so you can get a feel for what it should look like when you are setting timing. I just can't imagine any mechanism by which the timing would move in the wrong direction.
I figured part of it out. The mark is was referencing was not a timing mark, but a chip in the paint that looked suspiciusly like a timing mark... I remarked the line, and it's just past advanced. I think my next problem is a serious vacuum leak on the carb. Thanks folks!
I figured part of it out. The mark is was referencing was not a timing mark, but a chip in the paint that looked suspiciusly like a timing mark... I remarked the line, and it's just past advanced. I think my next problem is a serious vacuum leak on the carb. Thanks folks!
are you aware that the harmonic balancer has a groove in it which you make more visible by using white paint?
are you looking at the timing tab attached to the timing cover that has small teeth with numbers on it and you use the numbers that go from 0 to 12 as you approach the water pump?
A properly installed distributor should end up with the nipple on the vacuum advance pointing towards the back corner of the valve cover.
Just because the body of the distributor and the vacuum canister location are spot on, does not mean the dizzy is properly installed, thou.
OK. I’ll bite. What other variable is there? It seems to me that as long as the cap is rotated to establish correct timing, it’s all good. The relationships of all the internal parts are fixed.
From: Some days your the dog and some days your the hydrant.
Royal Canadian Navy
It doesn't matter where the vacuum canister is located. The timing is not established by pointing the canister to any pre-determined orientation - the desired timing mark does that using the timing light.
OK. I’ll bite. What other variable is there? It seems to me that as long as the cap is rotated to establish correct timing, it’s all good. The relationships of all the internal parts are fixed.
Not the main shaft. The main shaft of the distributor could be installed in every camshaft to main shaft tooth combination there is. If it's one tooth off on this mating, you may have trouble rotating the distributor housing enough to get it to time correctly.
It doesn't matter where the vacuum canister is located. The timing is not established by pointing the canister to any pre-determined orientation - the desired timing mark does that using the timing light.
This is a 1972 with a cable driven tachometer.
Do you realize the damage that can be done to the cable if it is bent too much due to incorrect alignment of the distributor?
Chevrolet even created a service bulletin concerning the correct positioning of the distributor just for Corvettes to prevent cable damage and to still be compatible with the factory metal shielding.
Speaking of distributor positioning, here's a photo of a 1971 350 that sold on BAT on 3/3/21. The seller insisted that the shield support was not cut to accommodate the vacuum advance vacuum line. Also, notice that the distributor cap window cover was removed.
From: Some days your the dog and some days your the hydrant.
Royal Canadian Navy
Originally Posted by MelWff
This is a 1972 with a cable driven tachometer.
Do you realize the damage that can be done to the cable if it is bent too much due to incorrect alignment of the distributor?
Chevrolet even created a service bulletin concerning the correct positioning of the distributor just for Corvettes to prevent cable damage and to still be compatible with the factory metal shielding.
Not the main shaft. The main shaft of the distributor could be installed in every camshaft to main shaft tooth combination there is. If it's one tooth off on this mating, you may have trouble rotating the distributor housing enough to get it to time correctly.
Exactly. The only consideration is where the vacuum canister ends up after timing the engine (and as pointed out, the position of the tach cable in the early cars). Other than that the distributor doesn’t know or care how it’s installed.
Timing/advance confusion
