351M timing question
Lead Driver
Joined: Jul 2017
Posts: 9,591
Likes: 1,171
From: San Jose, CA
I think he meant "vacuum advance" not mechanical. AT least I hope so! Never tried the latter method.
Is that what you mean Rich?
With a properly running vacuum advance using "ported" or "timed" vacuum signals, you don't really even need to plug the vacuum hose as it's not active at idle.
But with any full-manifold vacuum setup, you must pull the hose off the advance can and plug it.
Even if you don't feel vacuum at the moment, it could come in any time based on when one of the thermally activated switches (if still installed) opens up.
Paul
Is that what you mean Rich?
With a properly running vacuum advance using "ported" or "timed" vacuum signals, you don't really even need to plug the vacuum hose as it's not active at idle.
But with any full-manifold vacuum setup, you must pull the hose off the advance can and plug it.
Even if you don't feel vacuum at the moment, it could come in any time based on when one of the thermally activated switches (if still installed) opens up.
Paul
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Tuned
Joined: Aug 2014
Posts: 292
Likes: 6
From: Florida
The golf tees are usually used to plug the vacuum line to the distributor advance can that you typically disconnect when timing an engine.
And in case you were not aware, the inductive clamp goes around the #1 cylinder's spark plug wire. Which, in the case of most Fords (assume it still holds true?) is the first cylinder on your left as you're facing the engine.
In other words, "front, right" cylinder.
Then the other two leads are obvious, with Red clamp to the battery positive and Black clamp to the battery negative. Figure you knew those things, but wanted to put them out there anyway.
A timing light is also a good way to diagnose a mis-fire in a cylinder. You simply move the inductive clamp from one plug wire to the next and watch the light. A steady bright light indicates a good even spark is at least flowing through the wire. Won't always indicate a problem at the plug, but it's a good start.
A weak and inconsistent flashing light indicates something wrong with that part of the ignition.
Have fun with your new tool!
Paul
And in case you were not aware, the inductive clamp goes around the #1 cylinder's spark plug wire. Which, in the case of most Fords (assume it still holds true?) is the first cylinder on your left as you're facing the engine.
In other words, "front, right" cylinder.
Then the other two leads are obvious, with Red clamp to the battery positive and Black clamp to the battery negative. Figure you knew those things, but wanted to put them out there anyway.
A timing light is also a good way to diagnose a mis-fire in a cylinder. You simply move the inductive clamp from one plug wire to the next and watch the light. A steady bright light indicates a good even spark is at least flowing through the wire. Won't always indicate a problem at the plug, but it's a good start.
A weak and inconsistent flashing light indicates something wrong with that part of the ignition.
Have fun with your new tool!
Paul
I'm glad your said that! I thought cylinder #1 was the front driver side
Moderator & parts slinger
Joined: Feb 2007
Posts: 50,157
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From: S/W Missouri, Polk county
X2 on Paul caught my wording mistake, VACUUM advance NOT mech...Duh on me. Yes the vacuum line that is connected to the distributor get the golf T.
Thanks Paul.
Thanks Paul.
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Tuned
Joined: Aug 2014
Posts: 292
Likes: 6
From: Florida
I think my issues might not be timing at all ... I'm getting nothing on cylinder #1 wire. I put the clamp on cylinder #2 wire and it started flashing away. I'm thinking of swapping the wires on those two cylinders to rule out a bad wire. If cylinder #1 still doesn't light up, does that mean the distrubtor cap is bad? Or should I just check all the other wires first? If multiple wires are not working, does that confirm the distrubtor cap is bad? What else can I do to hunt down what's wrong?
Lead Driver
Joined: Jul 2017
Posts: 9,591
Likes: 1,171
From: San Jose, CA
Any more testing with the wires?
I would say that missing spark on some cylinders could be the distributor (the trigger mechanism at least) or the cap.
More testing is needed methinks.
Paul
I would say that missing spark on some cylinders could be the distributor (the trigger mechanism at least) or the cap.
More testing is needed methinks.
Paul
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Tuned
Joined: Aug 2014
Posts: 292
Likes: 6
From: Florida
sorry Paul, didn't see your reply till today. I used the timing light and found out cylinders 1,3,6 and 7 had no spark. I replaced the distrubtor cap. Tried again. With the started spinning, it tried to start but that ended quickly. After thinking about it, I checked the spark plugs. Every ... single ... one ... was fouled. So, another trip to the parts store to get 8 new ones. Alberta fired up before the crank spun twice. I've never heard her sound so strong. I put the timing light on and out read almost 30 degrees BTDC! OMG I freaked out and thought I was destroying my engine. Then I remembered I did NOT remove the vacuum advance. Pulled that sucker off, plugged it and the timing was just a hair over 15. Turned it down to about 12 degrees (it was really hard to see, so I guessed) and locked her down. I never would have thought part of the distrubtor cap could go bad. I thought it was all or none. Lesson learned. Thanks everyone for all the help, y'all really are the best.
Lead Driver
Joined: Jul 2017
Posts: 9,591
Likes: 1,171
From: San Jose, CA
Funny thing about caps. Just a little, all but invisible crack can scatter spark like nobody's business! You never know what you're going to get or what cylinder is going to go dead from just that tiny little fault.
So if you ever notice a crack in a distributor cap and think to yourself, "aw, what harm could that little thing do" just toss it and get another one!
Glad to hear it's running like a champ.
Paul
So if you ever notice a crack in a distributor cap and think to yourself, "aw, what harm could that little thing do" just toss it and get another one!
Glad to hear it's running like a champ.
Paul
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