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Having some trouble with my ignition timing. It Idles smooth at 12* BTDC, but when revving up to 3000-4000 RPMs, timing jumps up to 50+* BTDC. Have tried with both vacuum hose disconnected and clamed off, same result. Do I need different distributor springs? weights? Not sure what this thing has in the distributor.
Having some trouble with my ignition timing. It Idles smooth at 12* BTDC, but when revving up to 3000-4000 RPMs, timing jumps up to 50+* BTDC. Have tried with both vacuum hose disconnected and clamed off, same result. Do I need different distributor springs? weights? Not sure what this thing has in the distributor.
I'm guessing you are using a good dial back timing light to get those numbers. In your original distributor with 12 degrees initial the most you should see is 40 degrees. If someone swapped distributors or changed the cam plate it could be that the advance is set in an 18 degree notch. In the 18 degree notch without the plastic bumper you could get 38 crank degrees of advance.
Just remove the vacuum advance can, then the two screws that hold the breaker plate in pull it out and look at the cam plate it should be in a 13 or14 degree notch. If it isn't you can remove the springs and the snap ring pull it out and turn it around if it has a 13 or 14 degree notch in it.
This is what it looks like inside.
Looks like you were right for the most part. The plate was in the 18 notch, with the other option being the 21 notch. Looks like I’ll need to find a different plate.
Originally Posted by Crop Duster
I'm guessing you are using a good dial back timing light to get those numbers. In your original distributor with 12 degrees initial the most you should see is 40 degrees. If someone swapped distributors or changed the cam plate it could be that the advance is set in an 18 degree notch. In the 18 degree notch without the plastic bumper you could get 38 crank degrees of advance.
Just remove the vacuum advance can, then the two screws that hold the breaker plate in pull it out and look at the cam plate it should be in a 13 or14 degree notch. If it isn't you can remove the springs and the snap ring pull it out and turn it around if it has a 13 or 14 degree notch in it.
This is what it looks like inside.
The spring on the right looks like it needs bending in at the catch. The way it is, it has less spring tension than it should, which can advance your timing too much too early.
Compare how it's attached to the spring on the left.
Interesting cam plate for a 352 since it makes no sense. I would have expected a 15L/18L and then use the 15L slot being that Ford spec'd 6 degrees initial. Is this the original distributor to the engine? If so then it is another one of those strange things done by Ford. For many years, before I knew about digging into distributors, my 302-4V Cougar was set at 6 degrees BTDC. Imagine my surprise some decades later when I saw a 10L/13L cam and the car was using the 10L slot for a total of 26 degrees. No wonder the mpg was stuck at 12-13pg. Now with a cam I moved to 15 degrees initial and the 10L still for a total of 35 degrees. The car runs around 16-17 mpg now. With vacuum advance I am around 43 degrees. After I saw that in my distributor I went on a buying spree picking up distributors off of eBay along with any other internal parts I could find 15 years ago.
Yep, sure looks like I have a recurve in the future. I’ve got a dizzy off a ‘79 302, and it has a 18L/13L plate, and in thinking of going with the 13, since I know it idles well at 10 BTDC.
Are the plates pretty universal? It sure looks the same.
I have now idea of this is the stock distributor, but I would think not since the mechanical advance is so off. Seems like 6-10 initial about around 35-36 total seems more correct.
Looking at the housing that distributor has the appearance of a made in china one size fits all distributor. There are two waysto fix it. The simplest is change the advance plate. The next is to remove the plate and weld up the slot then resize it to what you need. the picture is one I did awhile back. The advance plates with the high numbered slots like you have are usually found in medium duty trucks. They also have springs that are way to stiff for a lighter vehicle.
If you are handy with a welder or know someone who is the slot width needs to be .013 inch per degree plus the width of the stop pin about .150 inch. A 14 degree slot is .514.
I guess we were typing at about the same time. Yes the plates interchange. In fact you can convert a points distributor to a Duraspark by just changing the advance plate and everything above it. The reason I think you have a made in China distributor is if you look at my pic you see the Ford distributor is machined on the inside the Chinese ones are just rough castings.
You can file that 13 degree notch out a little to get a little more advance. If I were doing it I would get a Moroso spring kit and lighten up the springs a little and get the advance all in by 3000 or so.
