new dist body,s

George Miller

George Miller

Well-known member
I help a couple of guys with there dist. They had new body's we had to file the 4 contacts to fit clearance for the rotor. Is that the way they are made now.
 
I always check the 4 contacts for clearance. They are seldom all the same . I think that Ford and Andrews recommends .025 gap. I open mine up to .035 . The wider gap gives a hotter spark at the spark plugs. Same effect as the old button in the plug wire jump spark .
 
I haven't found a body, old or new, that all the contacts are close to the same. I make the widest gap my start point, bend the rotor to get close to the desired gap, I use .035, then file the shorter gap parts to the same gap, full circle. Some older bodies were too badly warped to get them within usable gaps, but they probably had carbon paths in them anyway. I always am amazed when I see the bodies when there is no light and the engine will be running smoothly until there is a load applied. Then they have sparks everywhere.
 
We reviewed this a few issues ago. The USA made distributor bodies tend to have the quality problem where the issue you described comes up. The off shore one is dead on. You can tell the difference by looking for the notch that is in the body to align it on the distributor, USA has two so you can use it on a B dist. the off shore only has one. The off shore is also bakalite which you can't use in the USA that is why they are making them off shore.
 
edmondclinton said:
How do you figure that?
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Its a long known fact that when the spark jumps a wider gap, up to a point, the spark gets hotter . If you've got a spark plug that is fouling and missing, you can hold the plug wire about 1/4 inch or a little more away from the spark plug and in a short time it will clear up and begin to fire . Back in the day when poor people had a worn engine that was fouling the spark plugs they would cut the plug wire in two and wire the ends through a clothes button holes so there would be a short distance for the spark to jump. The jump spark would increase the spark intensity so that the spark plugs would fire in oil . Increasing the gap at the rotor tip has the same effect and increases the spark intensity at the plugs on the model A. You can't measure the gap in a modern distributor cap but you can on the model A. You can grind the rotor tip to increase the gap but you can't measure the gap on a modern cap.

Most replacement coils are weak and won't jump a 10.000 volt gap on a coil tester. The original slant pole model A coils would put out around 20.000 volts and most of them are still good . Many people or most are running weaker replacement coils and their spark plugs often run black and sooty all of the time . People that don't know any better will blame it on the carburetor . How many times have we heard , its running too rich and you need to flow test the jets.. In nearly 55 years owning and fixing my model A's I have never flow tested a jet . I do run original numbered jets but most carburetor problems are usually weak ignition or bad timing.

Too much gap at the rotor tip or at the spark plugs will strain the coil . I have found that a gap of .035 works good for me. It doesn't have to be fouling spark plugs or be worn out. A .035 gap at the rotor tip and the spark plugs will usually show a noticable improvement unless there are other problems .
 
That was probably the most complete, accurate, thorough, helpful answer I have ever seen on this forum. Well said!!!!!
 
JohnLaVoy said:
We reviewed this a few issues ago. The USA made distributor bodies tend to have the quality problem where the issue you described comes up. The off shore one is dead on. You can tell the difference by looking for the notch that is in the body to align it on the distributor, USA has two so you can use it on a B dist. the off shore only has one. The off shore is also bakalite which you can't use in the USA that is why they are making them off shore.
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That's a new one on me. I suppose now I'll have to label my old bakelite radios "hazardous materials".:mad:
 
Didn't or doesn't Terry Burts produce an acurate model A distributor cap body ? I haven't bought a distributor cap body lately, but have never bought one from any of the vendors that I have done business with that only had the front locating pin notch. All have needed tweeking on the contacts for uniform air gaps .
 
Purdy, Terry gets accurate bodies made offshore in black Bakelite. He was kind enough to give one to each of us when we visited him a few months ago after the Puyallup rally. They fit very well and the electrodes are all accurately evenly placed. I use .035 too with a Pertronix epoxy filled flame thrower coil following your recommendation of them. I was experimenting with timing today and got my first shock off one. I will definitely not do that again!
SAJ in NZ
 
I have a nice ford script distributer body and cap I would like to use. Are there any visible signs of a bad body/cap I should I should look for before just giving it a try?
 

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Thanks,SAJ !!! I really like my flame thrower coil and it makes a noticable improvement. I also once accidently got a jolt from mine . Forty thousand volts hits HARD but doesn't have enough amps to really hurt you. It is something that a person doesn't forget .
 
Purdy Swoft said:
Its a long known fact that when the spark jumps a wider gap, up to a point, the spark gets hotter .

In nearly 55 years owning and fixing my model A's I have never flow tested a jet . I do run original numbered jets but most carburetor problems are usually weak ignition or bad timing..
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Sorry I disagree. Opening the gap merely presents a larger spark which will maximize the efficiency of the burning fuel but the spark itself is cooler or less intense; that's why when performance people go with large gaps they will have extremely hot coils. Moreover, after raising up the compression on a engine with the same stock ignition a smaller gap is often required to ensure the best ignition in the denser mixture whereas a larger gap can cause a misfire.
 
I think we are talking about different gaps. I am referring to the gap inside the distributor beteeen rotor and electrodes in the body. For plug gap, standard coil and high compression I use .030 for the plugs. But I use .035 for the 40000 V coil for both plugs and rotor gap. Both my cars now use a stipe points cam and Flame Thrower coil on Purdys recommendation. I cannot personally say if they go better because I am always changing things. They pull cleanly up to well over 70 mph on my GPS which is too fast for the hard skinny tires I have.
SAJ in NZ
 
Works for me and I have several years of experience with this setup . I also run a high compression head and Stipe 3/4 race cam and dual carbs. My 40.000 volt coil has been holding up good for many years . My roadster cranks instantly and is very peppy with power to spare. I've known about the advantage of the wider gap at the rotor tip since the fifties. As I said in my previous post, too much gap will csause early coil failure. Thirty five thousants gaps works real good for me . I could probably get by with more with my flame thrower coil but opted to stay a bit on the conservative side with the air gap .
 
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