Front mount coils

[Devious]

I have a square coil that only has one ID on it. TAIWAN in very small letters. I tried to get sparks from the plugs by motoring the engine over etc and nothing. I tried measuring anything with a meter and got .OO3 ohms and now nothing . Can I hurt anytrhing by putting it in my running tractor and seeing if it is dead or if I just don t know how to troubleshoot with a ohm metrer. I can t even tell if it is a six or twelve volt coil in a 12 volt system. I guess I need to show soundguy and Dell etal how ignorant I am and ask, Can I get the plugs to spark if I have a good coil installed and just motoring it over with the Batt hooked up and using a remote standoff start switch hooked up to the two big posts on the starter solenoid. This tractor was not running when I bought it and had supposedly quit running in the field while mowing. It had all the wires disconnected , don t ask, I don t know why, except to say the guy died while trying to work on it and left the alt laying in the seat. I have put a one wire, internally regulated , self exciting alt on it but have not gotten any juice out of it yet and have doubts as to the coil being OK. I know the coil om my running tractor is OK but fon t want to end up with two non running machines you betcha. Devious

 

[lha]

To check a coil you need to set your meter on ohms at a low setting, mine has x10 as the lowest.Touch one probe to the bolt at top and the other on the little spring.you should read+- 1-1/2 or-+2-1/2,depending on if it's a 6v or 12v.In a perfect world,that would tell you if it's good or bad,but not really.If it does read near to one of those settings,there's a chance it will work.you can have a perfectly good coil and no spark.too many variables,shorts,bad wiring etc.If you don't have a manual,that would be a good thing to buy.---lha

 

[Dell (WA)]

Devious......you write....."I tried measuring anything with a meter and got .OO3 ohms and now nothing"......first check yer meter by shorting the ohm-meter leads together. Should read "0" zero-ohms; (adjust iff'n necessary) then you read "lazy-8" infinity with leads OPEN. Many ohm-meters have an internal fuse that can blow and 'nuttin' works.

2nd......0.003 on a 1000-ohm range is guess what??? 3-ohms. Close enuff to 2.5-ohms of most 12-volt squarecan coils. A 6-volt squarecan coil should read about 1-volt.

Realize that most consumer grade ohm-meters are NOT very accurate at low values of resistance, you need a lab grade wheatstone bridge $$$. But surprizingly enuff, even the el-cheapo voltmeter is plenty accurate for ignition circuit trouble shooting.

Iff'n you just gotta test yer squarecan ignition coil, use my calibrated sparkie tester. Take enny old sparkie and bend the side electrode out for a full 3/16" gap. Now ground the metal shell to enny convenient metal bracket with clamp pliers.

Plug enny sparkie wire to top of tester. Turn yer ignition switch ON and crank yer engine while watching the sparkies jump the gap. Do they jump with blue-snott authority? ...or... are they weak wimpy yellowish-orangish poor excuses??? ..or.. NO sparkies at all??? report back. ......Dell, yer self-appointed sparkie-meister

 

[souNdguy]

as the others said.. measure the primary.. 6v coils are 1 ohm or less usually.. and '12v' coils are genrally about 2.5 ohms.

that's gonna be hard to read on most consumer grade meters.

you can do inline current checks instead and look for about 3-4a of primary current either way..

and yes.. you could use a starter bypass switch to look for spark.. but make sure she is in neutral..

heck.. if it died int he field.. make sure the cam spins when the engine turns over..

check points.. gap at .015

soundguy

 

[HCooke]

I think you could substiture a known good coil on the non running tractor to see if you got a spark. Just don't run the good coil for a long period of time in the 12 volt tractor without the proper resistor.

 

[Devious]

Hi all you fine fellers. I forgot to tell you that I am trying all this on a tractor that is in the garage on jack stand stripped down to the cases and the eng and axles. Now there is more to the story I have all the books 4-5 each fron Ford 8n Operators Manual, Fo 9n 2n 8n SV, Ford Shop Manual FO-4 Master Parts Catalog for all the Ns and NAAA 1939-1953 Got that covered but have not gotten the operation of the Meter I have down pat yet. I have a nice Sperry DM-350A Digital Mutimeter and I have the black lead plugged into the COM hole and the red lead plugged into the Multiple use hole as the other hole just has mA as a function for that hole. NOW Assuming that is OK if it veros out as soundguy says which I did learn that lomg ago I have checked it on DCV and at 2K on the little horseshoe funtion area and it zeros out there also so I guess when I checked that coil as I did and it shows .oo3 between the little squiglly thing and the threaded connection on the top it is OK OR?? I guess I just don t have the mental prowess for this electrical stuff but if I do stumble onto the right stuff and get it wired etc I will br right happy. Right now I have just MOTORED the engine with the battery on line and no fuel for it to run on I just wanted to see if the distr. and coil was juicing the plugs but maybe I don t have enough wiring hooked up RIGHT . I am building a portable gas tank to hang from the cieling to get the engine running without putting the tin on etc. It can go anywhere as it does not have wheels on it. I have met a unseen friend on this group who ha gotten me along this program with his very good help as wel as some of you guys. It is going to come together for sur mostly right here in the garage on jack stands I guess the question in my mind now is am I wrong in thinking that the coil and dist will fire the plugs with just the motoring by the battery? AND is it OK to trouble shoot the Coil from this non runner right now by putting it on my running machine without hurting it in any way. Just finished rebushing and nbew bearings in one front axle splindle this afternoon and am glad I only have one more of those to do. I will shut up now. There is a loty more work to do but I can t hold you guys up all day with my stupidity. Devious in Humble Tx

 

[Devious]

I FORGOT tosay who my unmet friend is from this group who has bee very helpful. He is Kevin Larue from VA I think. He is a very good source of info especially wiring and he has treated me extremely good and with patience for a 72 year old forgetful guy like me. I go to this website very many times aday sometimes while working on this thing. Devious

 

[Dell (WA)]

Devious.......you write......"I have checked it on DCV and at 2K on the little horseshoe funtion area and it zeros out there also so I guess when I checked that coil as I did and it shows .oo3 between the little squiglly thing and the threaded connection on the top it is OK OR??".......2K full scale digitally is 1999. You should NOT have enny decimals (.oo3) iff'n yer coil is good between the springy-thingy and the top terminal.

Iff'n I understand you correctly, .oo3 is equivalent of SHORTED coil and you will NEVER have enny sparkies.

Double check yer meter reading technique with yer known "good" squarecan coil and compare numbers.

While Kevin LaRue is welcome on YT N-Board, he likes to hang out on the "other" N-Board. Zattza OK; he knows his stuff ........Dell, yer self-appointed sparkie-meister

 

[Devious]

Yep That is what I am still showing. A .003 when I check the coil from the twistws wire on the bottom to the post on the top. I don`t know what that means but that is the deal. Thats using a scale of 2K the lowest I see on the ohms scale. I can`t see anything that would tell me if it is a 6V or a 12V Coil Anither question. I have drained the Gear boxes down to the bottom bolt beneath the dipstick and want o ask, is that enough left to work with when the tractor is working? Anyways, thanks for the help. More later maybe yu betcha. Dveious

 

[Dell (WA)]

Devious.......the bottom 6-o'clock bolt drain trick still leaves over 5-gals of hydro-tranny fluid in the pump. Go work'er.

Unfortunately, the ONLY way to ID the squarecan ignition coil is by measuring the top screw to the bottom springy-thingy. 6V = 1-ohm; 12V = 2.5-ohm. The HI-VOLTS tab is about 6000-ohms. Pretty hard to confuse those readings.

Iff'n yer really reading 0.003-ohms, then yer coil is internally SHORTED and SHOT. File #13 or roundcan it. .......Dell

 

[Devious]

Thanks Dell I sorta thought that it was done fur it. Just as soon get another Taiwan wonder as mess with the thing anyway. I am gonna get the enine percolatin and go from there. Check out the other werkins etc and see wht else needs fixin. Thanks for the help. Devious