Hi : I am playing with a Magneto Gap Gauge , but I am missing a measurement of the Gauge . Can someone give me the measurement of the distance between the short end and the long end [photo] so that I have the right gap between the magnets and the coils . I can not find it in the books .
Thanks for your answer.
The guage is used to set relative distance. There's no set distance for what you are asking. You set the magnets to all be level to one another. Then set the coil rings to be level to one another.
The desired gap between the two is .20 - .040". If all is typical you will have to install shims between the block and the coil ring to achieve the desired gap..
http://www.mtfca.com/discus/messages/331880/370657.html L = C + 2H per Ron Patterson.
I have heard of using brass feeler gauges for checking the distance between the coils and magnets. I don't have any brass feelers and used steel ones. I have used stainless steel gauges in all 3 Model T's and don't notice any problems when running on mag. I just try the thickest gauge which will move between them and that's what I use as measure of the distance. Seems to work just fine.
The measurement (L) you asked about will vary from gauge to gauge. If your gauge has not already been set, check out the link that Tom posted.
Please explain how it is used to set the coil ring to magnet distance. I have used one to set the magnets on the flywheel before but, never to set the coil ring.
Here are a couple photos that show how it is used. Note that the contact point is opposite in each photo, the short end down on one and the long end down on the other.
I will say it again; Setting the field ring after setting magnet height with the KRW gap gauge only works if the tool is calibrated AND the rear main bearing thrust surface was machined using the KRW procedure.
Ron the Coilman
Ron could you describe what you mean by KRW (K R Wilson) procedure over say using a Storm, Stevens or Mr French's setup to bore and cut the thrust face in the rear cap.
Does the KRW setup cut the rear thrust face to set the flange to block distance then the front thrust where as the others just cut front and rear thrust depending on the crank journal length. This is only a guess but it's the only logical reason I can think of.
I don’t understand the requirement that the rear main bearing thrust surfaces be machined using the KRW procedure either. I looked in several past posts on the issue and found if brought up many times and questioned a few times but found no answers.
Maybe the issue is setting the pin on the K.R. Wilson Mag Gap Gauge. It is clear that for the K.R. Wilson Mag Gap Gauge to work correctly that the length of the pin must be adjusted for each specific tool, as in L=C +2H. This sets the tool and once set, should not be changed for the life of the tool. The other setting on the tool is adjustment of the pin in or out to get it to the lowest magnet pad. Once this is set all the magnets are set to the same height. The setting of this pin must stay the same on the engine being worked on but may change on other engines. I don’t have the instructions but I bet that is a required setting on each engine. No, after writing that, not setting the pin would not change the operation other then it may be harder to set the height of the magnets.
It seems clear that no matter what brand of tool or procedure is used to set the rear main bearing thrust surfaces that the crankshaft has to be set within certain range, for and aft. And, as long as the crankshaft is not too far forward so that the mag gap is too small with no shims used on the mag plate, all should be fine and the K.R. Wilson Mag Gap Gauge will work exactly as designed.
Sometimes it helps to think about things like this if you push things to large numbers. Just for the sake of discussion, let say we install the crank shaft to the rear 1” further then where it normally runs in the block. Nothing else would work but the K.R. Wilson Mag Gap Gauge would still work exactly as designed. The mag plate would require 1”+ of shims but the gauge would work and the plate could be set in just one step. This can be visualized in this photo. That crankshaft flange would extend up an inch and the 1” of shims under the mag plate would bring the plate up to the gauge. Nothing else in the engine would work but the mag gap would be set correctly in just one step.
It is an ingenious tool.
I had this tool and while it helped me to be sure all the magnet keepers and mag coils were the same height, I could not figure out how to use it to help set the gap, so I ended up setting the gap the old fashioned way using a set of brass feeler gauges and taking the transmission off and putting it back on at least a dozen times until I got the shims just right. I'll never understand how the Ford workers were able to set this gap in the factory on a moving assembly line so fast.
Anyway, It is a very well made tool and I ended up selling mine on ebay for more than I paid for it and I'll just continue to do this the old fashioned way, since it's not a job I have to do very often and I enjoy a challenge. Jim Patrick
The gap tool can only be used the way Ron suggests if the thrust surface is set at the location where it would be if done at the Ford factory or by using a KR Wilson or equivalent procedure to set the rear main thrust.
The position of the thrust surface determines the position of the flywheel. Anything that changes this relationship can and will make any predetermined setting of the gap irrelevant and useless.
Which is why I said what I did in my first post of this thread. This is a great tool, it allows you to be able to set all the magnets parallel to one another, and to make all the coil spools parallel to one another relative to the crank rear face.
This means you will typically need to temporarily install the flywheel once after using the tool. Check the gap between the flywheel magnets and the coil cores. You will find that it is in need of shims behind the coil ring, all the same at every point. Subtract the desired gap from the current gap and install a shim of that thickness. Done.
That is not correct. As long as the crankshaft is not too far forward so that the minimum mag gap can be achieved, it really does not matter were the crank is placed. The K.R. Wilson Mag Gap Gauge will still work just as designed. This is clear in my moving the crank back 1" example above.
The K.R. Wilson Mag Gap Gauge is just a handy tool, I would hate to see some folks think they cannot use it because of some misinformation.
The reason in my opinion that there are threads on the gap gauge, is to allow for different tolerances. I use mine every time I build an engine, and haven't ever had a problem.
Hi All : Thank you all for the information !!
I just finished a HCCT for a friend .To set the gap I did what The Coilman told in his Add
L = C + 2 H for me it is :
L = 0,6 + 2 x 46 = 92,6 m/m
And that give me 0,6 m/m gap.
It looks very good.
Your successful use of the K.R. Wilson Mag Gap Gauge to set your HCCT gap clearly demonstrates that the tool will work without the KRW procedure for setting the "crankshaft" position.
Jim, that's what I though too. I know somebody who has one so I'll give it a try.
Perhaps because of my careless wording, I am confusing others?
When I look at the magneto gaping procedure I take into account ALL the factors that can affect the outcome.
The magneto magnet keeper to field pole gap is a function of two things. The gap set with the gauge AND the rear main bearing thrust end play.
KRW expected the rebuilder to 1) measure the crankshaft rear main thrust journal width, 2)add .004, 3) measure the thickness of the cast cap (or block journal casting if a 360 degree thrust will be used), deduct 2 from 1 and divide by 2 machining the front and rear thrust surface to that thickness. I don't know what procedure others use. The idea is to ensure the crankshaft is properly centered in the block and to make sure one side if the thrust surface is not too narrow thereby possibly failing early not to mention the proper relationship of the crank.cam gears.
Having done that you can now use a PROPERLY CALIBRATED gap gauge to set the magnet height and field ring position, but you have to ensure the crankshaft is not moving back and forth in the thrust gap when doing so.
This task is hard enough without additional variables that can affect the outcome.
Ron the Coilman
Two additional things.
The Ford Service Bulletin fails to mention that to use the gap gauge for setting the magnet height you MUST have transmission stub shaft inserted in the flywheel counterbore before you install the gap gauge or you will be unable to use it.
Once the height screw is used and locked with the thumbnut to clear all the magnets the same height you cannot change it when setting the field ring position.
You are saying the same thing I said.
Ron, wondered when someone was going to remember that important part of the set up!KB
Ron and Royce,
I think we are pretty much in agreement.
Hey what are his coils coated with? It looks like fiberglass resin.
Travis. That is what the mag coil ring looks like when it comes back from being rebuilt by "Total Recoil". When I got my mag coil back from Total Recoil, I called Wally to ask him what he used on the mag coil insulation and he told me he uses clear Glyptal, instead of the red. Until he told me that, I didn't even know there was a clear Glyptal. Jim Patrick
Travis: I use the same coat as what they use on electric motors