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Timing question


P-12 Tommy

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:DHey guys, this might sound like a dumb question but do you have to plug off the metal vacuum line on the distributor to time these engines? :confused: I want to check my timing. Just curious. Never done the timing on a car this old. Also, is there a line on the crank pulley? I didn't see one. Tom

Edited by P-12 Tommy
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You do not have to plug the Vacuum Advance. On the lowere pully vibration dampener should be a flat with line grooved into the metal.

Go to a motors manual to determine the specifi mark that you should use.

Also determine which plug you should use for the timing. My 39 Desoto uses 2 degres before TDC Top Dead Center and uses the 6th spark plug to base the timing.

You can also use a 12v timing light on a 6v system. MAke sure if the car is positive ground that you have the timing limit hookup the correct way. The light will be a little bit weaker but you can time the engine. Mark the line with chalk and or white paint for a permanent mark.

I check the timing at least every few months just to keep on the mark.

Send me your specific car and I will look in my motors book to get you the specifc mark and info.

Rich Hartung

desoto1939@aol.com

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pull number one plug and bump the engine over with your thumb over the hole (disconnect the coil) when you fell compressing building against your thumb, rotate the engine over by hand till you reach TDC, rotor should be pointing at 7 oclock. Then take alook at the crank pully you may need to clean it up but there shoulb be a group of lines and marks there. Factory is O degrees at 450 to 500 RPM idle. With todays fuel which burns with a slower flame front, you may want to run 4 to 6 degrees before TDC.

Or you can road time it. Do a basic setting, leave the dist a bit loose, then go out on the road. This might be tough in Fla but aroundhere we us hills to load the engine. Other wise accelerate hard in 3rd gear from 25 mph to 60 or so, advance the distributor till the engine starts to ping during aceleration. When the ping happens, back the dist off a couple of degrees and lock it down. If your car runs well but you get a hard hot start, back off a few more degrees.

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My 39 Desoto uses 2 degres before TDC Top Dead Center and uses the 6th spark plug to base the timing.

You can use plug wire #6 or #1 as they both will both strobe every second crankshaft revoloution. But if you want to really brighten the timing light connect the probe to the coil wire. This will cause the timimg light to read both #1 and #6 as well as the rest of the plugs. But the strobe will only indicate #1 and #6 but be much brighter.

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You do not have to plug the Vacuum Advance.

This is true as long as you are using the ported vacuum from a carburetor. If the distributor is hooked up to manifold vacuum, you would have to disconnect and plug the vacuum line.

Marty

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if you are hooked to manifold vacuum then you are defeating the purpose and action of the advance...you must use ported vacuum

If you are talking about a completely stock engine, I agree with you. For a modified motor, not so much.

Marty

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Just to let you know the ported vacuum is on the carb. Plus I inspected the whole crankshaft pulley and there is no mark to be found. I do have a pointer on the timing cover. I put No.1 piston on top dead center and the rotor points to No.7. If I had a mark to work with I could probably accomplish this. I'll probably just move the distributor a hair to see if it pings then back off. Thanks for all your help. Tom

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Here we go! I got the generator belt out of the way to get my hand down there and took some sandpaper and sanded the spot. Low and behold! I found the marks. How the other guy before me timed it, it's a wonder! Here's a drawing of it. Hope you can make it out. Which one do I chalk?

post-3900-1358535018866_thumb.jpg

Edited by P-12 Tommy
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Every time I have a crank pulley off for any reason, I like to clean it up well with a wire wheel or other media, and then paint a contrasting mark where I want my timing to be set. Especially on our flatties, where visability with a timing light is sorta' scant, this helps to make the job a tad easier. And, as Don pointed out, when you hook your light to the coil wire, things brighten up considerably.

Happy Timing:D

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