Missing on Number One

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Model T Ford Forum: Forum 2016: Missing on Number One
Top of pagePrevious messageNext messageBottom of page Link to this message  By John Aldrich Orting Wa on Friday, April 01, 2016 - 01:28 pm:

A friend of mine finally "walked away". Couldn't figure out what the problem is.

What would cause an engine to suddenly start missing on #1? No fire at all.

Tried all the usual stuff, plug, plug wire, new glands and rings, pulled head and valves appear to be OK. Got compression spark which makes it sound like no gas. Intake manifold isn't plugged.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Mark Strange - Hillsboro, MO on Friday, April 01, 2016 - 01:30 pm:

Connector on one of the timer terminals shorting out on a part of the block or the timer adjusting rod?


Top of pagePrevious messageNext messageBottom of page Link to this message  By Michael Pawelek Brookshire, Texas on Friday, April 01, 2016 - 01:57 pm:

John, I am confused. Your title says missing on #1, but then in your text you say you have spark under compression. So do you or do you not have spark on #1 cylinder? Maybe I am reading your post incorrectly....


Switch the #1 coil with another and see if the problem moves with the coil. Could be a connection anywhere in the #1 circuit from the coil box through the timer to the spark plug.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Norman T. Kling on Friday, April 01, 2016 - 02:01 pm:

It could be the spark plug itself, or the timer, the wire between the timer and coils, or the coil. The contacts within the coil box could also be making poor contact or the spark could be jumping to ground within the coil box due to a carbon arc burnt into the wood.

Norm


Top of pagePrevious messageNext messageBottom of page Link to this message  By John Aldrich Orting Wa on Friday, April 01, 2016 - 02:19 pm:

Tried different plugs. Running a dizzy. Completed new set of wires.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Gary Tillstrom 30 miles N of Memphis TN on Friday, April 01, 2016 - 02:39 pm:

Often times, on fresh engines (especially ones that sit for awhile) you may get gummy deposits on the exhaust valve stem. When this happens, you may well have compression while cranking over yet the valve won't close fast enough to allow it to remain seated during the intake stroke while running. This will cause a miss even though it has spark and compression.

Look into the cylinder and observe the valve opening and closing. If it doesn't close, remove the valve cover as the pin in that valve may have failed or the washer. I suspect they are ok since you have compression.

Many will call Marvel Mystery Oil snake oil and that's ok. This is what I would try prior to taking anything apart. Turn it over until you can see the exhaust valve is open. Pour some MMO into that cylinder allowing it to run down the valve stem. Let it soak overnight. Next day run it. If it clears up, add a pint of MMO to the gas tank. If one cylinder does that, the same issue is close behind on the others.

The same issue with this Al Gore gas affects many engines that see low usage. It forms a waxy film on the valve stems (intake being the worst) that will cause sticking. The tighter the clearances the worse it is.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Michael Pawelek Brookshire, Texas on Friday, April 01, 2016 - 02:41 pm:

Take the cap off the dizzy and with the key on slowly hand crank the engine while watching to see that you get a spark across the points at all four lobes of the cam.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Royce in Dallas TX on Friday, April 01, 2016 - 03:03 pm:

Probably a leaking intake gland ring. You can spray WD40 at the forward intake port. If it speeds up the engine then you know the intake gland is leaking.

I had the same issue manifest itself far a slightly different reason - the cast iron intake was very rusty on the inside - it finally rusted thru on the back of one of the manifold legs, yielding a tiny pin hole leak. It was hard to find, nearly invisible.


Top of pagePrevious messageNext messageBottom of page Link to this message  By John Aldrich Orting Wa on Saturday, April 02, 2016 - 11:31 am:

New glands and rings for that reason Royce.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Charlie B actually in Toms River N.J. on Saturday, April 02, 2016 - 12:00 pm:

There isn't enough info here and it's not well stated making it tough to give answers. Not knocking you John but a few questions:

Do you have spark at the #1 plug?
Does #1 cyl have compression and is it comparable to the other 3?
If yes to both what led you to #1 cyl?
Does it not react (no change)when it's shorted out?


Top of pagePrevious messageNext messageBottom of page Link to this message  By Andre Valkenaers on Saturday, April 02, 2016 - 01:53 pm:

I don't know if this will help but this is what I found on a T missing one cylinder, some time ago.

There was a carbon trace formed to the ground at the back plate of the coil box.

I saw the spark when I started the engine late in the evening.

Good luck
Andre


Top of pagePrevious messageNext messageBottom of page Link to this message  By John Semprez-Templeton, CA on Saturday, April 02, 2016 - 03:05 pm:

John is running a dizzy so coil box not the issue. Have you taken the plug out and checked the spark across the plug (I'm assuming you have)? You say you have compression, so that suggests the valves are opening and closing... or does it? New wires, are the connections soldered? Is your dizzy cap clean inside are rotor & cap contacts clean? Have you scraped them with a knife to make sure? Only 4 things can be wrong... no fuel, no air, no spark, valves not opening and closing correctly.


Top of pagePrevious messageNext messageBottom of page Link to this message  By John Aldrich Orting Wa on Sunday, April 03, 2016 - 11:41 am:

Kinda tough to answer these questions but yes, spark and compression at #1 but no, shorting it out makes no difference in the running of the engine.

Compression was supposedly good all the way down. (I wasn't there)
He's been working on it two months and has finally just walked away from it.

He is taking it down to one of our club members home to get some fresh eyes on it. Thanks for the suggestions. I'll print this thread and get it to him. He doesn't have a PC.


Top of pagePrevious messageNext messageBottom of page Link to this message  By G.R.Cheshire on Sunday, April 03, 2016 - 11:57 am:

Wait until it is good and dark or turn off the lights in the garage crank the motor up and look at the distributor the spark plugs and wires, adjust the timing and look for errant sparks. I did this on mine and found sparks in areas I didn't think possible. :-)


Top of pagePrevious messageNext messageBottom of page Link to this message  By Norman T. Kling on Sunday, April 03, 2016 - 04:18 pm:

Try replacing the spark plug, or changing it to a different cylinder. Sometimes a plug will spark under normal air pressure, but when under compression the spark will not jump. So laying the plug on the head to see if it will spark only tells you that it will spark at atmospheric pressure.
Norm


Top of pagePrevious messageNext messageBottom of page Link to this message  By Garnet on Sunday, April 03, 2016 - 05:26 pm:

With all the work you have stated as being done while troubleshooting the problem, it is possible the original problem was corrected but another problem has been created. Just thinking out loud here but are the new plug wires metal or carbon?

Garnet


Top of pagePrevious messageNext messageBottom of page Link to this message  By Charlie B actually in Toms River N.J. on Sunday, April 03, 2016 - 07:53 pm:

I'd try the plug swap thing too. If it doesn't work try running the eng with the plug wire off then pull the plug and check if it's wet. The reason I say this is if you have compression and spark you're not getting fuel. Since #1 and 2 are fed from the same port 1 might be blocked closer to the valve.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Jeremy Gibson on Friday, April 08, 2016 - 05:52 am:

I have what looks like a perfectly good plug on my bench that gives a lovely spark, until it's under pressure.

I also have a rotor arm that looked perfect and works at idle, but spin it and it shorts to ground.

All my life I am cursed with misfires, my next step with mine is finding a priest.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Michael Pawelek Brookshire, Texas on Friday, April 08, 2016 - 08:42 am:

I can recommend a good confession with Father Sparky.....


Top of pagePrevious messageNext messageBottom of page Link to this message  By Mark Gregush Portland Oregon on Friday, April 08, 2016 - 11:40 am:

What plugs is he running?


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