Magneto output question, lacks power

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Model T Ford Forum: Forum 2012: Magneto output question, lacks power
Top of pagePrevious messageNext messageBottom of page Link to this message  By Mike Brown on Thursday, August 16, 2012 - 05:29 pm:

My mag puts out 6v at idle, 15v at fast idle, 22 volts wide open, all with 1156 hooked up and cheap analog gauge, running on battery. After the bulb burns out, voltage peaks at 30v. When running down the road it seems to make little difference whether on 6v battery or mag, either way it is gutless at best. I need opinions on whether an in car recharge is indicated. Also I hope that after searching through many posts that my test procedure is right.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Hal Davis-SE Georgia on Thursday, August 16, 2012 - 06:09 pm:

Others may be more helpful, but I wonder about your cheap meter. Does the bulb burn out at 22v?. Sounds low for the bulb to burn out. My gut tells me if your mag will burn out the bulb, its ok. Performance problem could be the coils. Have they been checked on a HCCT?


Top of pagePrevious messageNext messageBottom of page Link to this message  By Dan Treace, North FL on Thursday, August 16, 2012 - 06:10 pm:

25v-30v at high speed is a extra good mag, but at moderate speed, 15v-18v is still a good mag.




Idle with new rebuild, recharge and new coil ring



Fast Idle



At full road speed , with hit 30v

What you might do, prior to in car re-charge attempt, is to have your coils checked out, and adjusted for optimum performance on a HCCT or StroboSpark...will make a difference.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Dan Hatch on Thursday, August 16, 2012 - 06:17 pm:

Are the spark coils set up to run on mag? Were they set up on a HCCT? Dan


Top of pagePrevious messageNext messageBottom of page Link to this message  By Bede Cordes, New Zealand on Thursday, August 16, 2012 - 06:28 pm:

Mike, no doubt this thread will grow, but i dont think your problem is the mag. Your voltages sound pretty reasonable providing you have your lamp in parallel with your voltmeter when testing, and by blowing the lamp pretty much proves the mag has a good output. My feeling is your problem is elsewhere. Regards, Bede


Top of pagePrevious messageNext messageBottom of page Link to this message  By Ron Patterson-Nicholasville, Kentucky on Thursday, August 16, 2012 - 06:57 pm:

Mike
I have to agree with Bede's assessment.
If you would like to borrow (you are only obligated to pay shipping) a set of my "Loaner Coils" and try a set of known properly working coils contact me. These are really ugly coils, but they work great.
Ron the Coilman


Top of pagePrevious messageNext messageBottom of page Link to this message  By James A. Golden on Thursday, August 16, 2012 - 07:17 pm:

Dan, I added the 1156 bulb, in a Groit bulb holder, to a magneto meter for a good test set. The device requires a few extra bulbs on hand, as a good Magneto only gives one test per bulb.

Meter

Then, the coils still need to be adjusted, and usually rebuilt, with a HCCT or Strobo-Spark tester.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Norman T. Kling on Thursday, August 16, 2012 - 10:11 pm:

Does this "lack of power" happen when you run on battery and magneto, or just on magneto" If it runs OK on battery, you could need a coil adjustment or rebuild.

Did this lack of power come on gradually, or has it been this way since you got the car? Knowing nothing about you or your car I will ask some questions you might think are dumb. If you are new to Model T's you might try to find a club member who lives in your area who could drive your car and decide whether it is normal or needs some work. Sometimes new owners think the car should have more power than the 20 HP engine can produce. So it's good to have someone familiar to guide you.

The usual symptoms of a bad magneto would be it doesn't idle on magneto, but when you get it going fast, it will run on magneto or it just doesn't run on magneto. If the engine runs smoothly, but just lacks power, could be low compression, or carburetor problems. It could even be caused by bands too tight or dragging brakes. If it runs very roughly, you could have a coil, timer, or spark plug problem. If you can get the car to run at a fast idle, try grounding the spark plugs with an insulated screwdriver to the head. Do this one at a time and the engine should slow down and get rough if the ignition is getting to that cylinder. If shorting to ground the spark plug doesn't change the way the engine runs, that cylinder has a problem. It could be either an ignition problem or low compression. One ignition problem is retarded spark. A retarded spark is usually accompanied by overheating. Low compression is caused by burnt or warped valves, or bad rings. It could also be caused by a blown head gasket.

Carburetor problems are indicated sometimes by lack of response to opening the throttle. It could be caused by intake manifold leaks, improper adjustment of the adjustment screw, or by extremely worn throttle shaft. The throttle shaft would cause poor idle.

There are likely other potential problems not covered here, but someone else might think of them.
Norm


Top of pagePrevious messageNext messageBottom of page Link to this message  By Mike Brown on Friday, August 17, 2012 - 10:20 am:

Thanks for all the advice. I am new to my 24 Tudor. The power seems to have gone away gradually, possibly related to my driving confidence. Kevlar bands set loose, RM brakes adjusted, stock clutch with slight drag, plugs all looking good, rolls easily, thumb in plug hole compression test, runs the same on mag or batt from idle to wide open. The motor is a fairly recent rebuild. I realize that the car is a thousand pounds heavier and a hundred hp less than my motorcycle. The T runs out of power trying to climb my steep drive. It is demeaning having my wife pulling me up with her minivan.
Sounds like I am down to coils or carb.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Royce in Dallas TX on Friday, August 17, 2012 - 10:34 am:

If the coils were set properly on a HCCT you should notice a lot more power when operating on "MAG".


Top of pagePrevious messageNext messageBottom of page Link to this message  By Norman T. Kling on Friday, August 17, 2012 - 10:50 am:

They don't have much power going uphill in high. Shift into low and don't over rev the engine. It should go uphill with lots of power in low, but not much speed. If you have Ruckstell or other underdrive, you can make most hills in the intermediate range, that is, Ford High, Ruckstell Low. If the hill is very steep, use Low Low. She might be able to walk alongside you but it will pull the hill if it is in good condition. If your gas tank is under the seat, you might have to back up the hill due to gravity flow. Going up a hill if your wife is in a minivan, she should follow you with the flasher lights. Minivans are easy to come by in case she gets rearended. It will save your T!
Norm


Top of pagePrevious messageNext messageBottom of page Link to this message  By George_Cherry Hill NJ on Friday, August 17, 2012 - 12:02 pm:

Question for those with Magneto-Meters. I bought one just for the heck of it a while back...toyed with permanent mount or use as a portable tester only...then just left it in the box because I wasn't sure what the internal resistance might be as to whether a bulb was required or not. Just figured I'd ask someone someday at a get-together when I saw one in use and now have pretty much just forgotten about it.

Dan's appears to not have any extra resistance and Jim G.'s has a beehive light with 1156 lamp as part of it.

Anyone have any 'numbers' on the differences seen with and without the extra load added? Does it really matter?


Top of pagePrevious messageNext messageBottom of page Link to this message  By Ken Todd on Saturday, August 18, 2012 - 11:22 am:

The meter is probably designed to be used when running the engine on coils.
The "extra load" is to simulate running on coils.
If the meter was to be used for testing only methinks the ideal would be to have a switch so one could test the magneto:
1)w/no load,
2)w/the lamp load,
3)on coils only
4)w/both coils and the lamp load.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Mark Gregush Portland Oregon on Saturday, August 18, 2012 - 12:16 pm:

Someone can correct me if my understanding of the bulb placement is wrong. Leads for bulb should go from the mag output post to ground for load and then the meter checks the output between the post and ground parallel to bulb.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Royce in Dallas TX on Saturday, August 18, 2012 - 01:03 pm:

Mark,

That's right.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Mark Gregush Portland Oregon on Saturday, August 18, 2012 - 02:57 pm:

Thanks, I thought that is how it's done.


Top of pagePrevious messageNext messageBottom of page Link to this message  By George_Cherry Hill NJ on Sunday, August 19, 2012 - 09:38 am:

Thanks Ken for the information....now it makes sense to me. Since it looks like rain for today, just might go and dig it out of the box, and mount it in the Hack.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Rob Heyen - Nebraska on Sunday, August 19, 2012 - 09:53 am:

Mike,

I agree with a few others, your problem may not be coils, or carb. Our 24 Tudor was "gutless" compared with our 13 touring. However the tudor also weighs a lot more, and that was my problem. The "problem" improved greatly when I put a Z head on the tudor.

Just a thought,

Rob

From my iPad


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