Spark Control Rod - Why Can't They Make it Right?

[ahirt]

I have been working on my 28 Tudor for a while, trying to fix big problems first. Just put in a new engine. When I put the distributor on and connected the spark control rod, I noticed that I could not raise the spark lever to the top of its range. It had always been that way but I ignored it. I little investigation showed that the bottom plate on the distributor was as retarded as it would go limited by the distributor body, thus not allowing any more movement on the control lever. However, when I pulled the control lever all the way down, the lever would reach the bottom of its range on the steering column, but it would still have significant range available on the distributor body. Hence, while I was getting full retard, I was not getting full advance.

Now I know that if you have a 2-Tooth steering column you can rotate the steering column slightly to adjust this. The 7-Tooth, which I have, is not adjustable. The only solution is to bend the spark control rod to effectively make it shorter. I have seen MANY 28's and 29's like this.

However, I just picked up a 29 PU and I noticed that its spark control rod looked “old” and straight. So I swapped it on to my Tudor. Lo and Behold, it fit perfectly, the control lever on the steering column has full range of motion and the lower plate on the distributor also moves the full range as limited by the distributor body. No bending or adjusting is required.

So out of curiosity, I measured the two spark control rods. The control rods consist of two end caps, two springs, and a fixed length rod. For the repo, the length of the rod (not counting end caps) is 17”. For the original (and I believe it is original, since the end caps are steel), the length of the rod is 16 and 11/16 inches – or 5/16” shorter than the repo. The length of the original – including end caps is a tad short of 17”. Note that the length of the fixed rod is the important measurement since this length is what determines the distance between the distributor ball and the control rod ball.

SO my question is, why can't the vendors make these things the correct length? It does not cost any more to make it 5/16” shorter, and it would certainly be a better product. For years the solution has been to rotate the steering column or bend the control rod. Why not make it right the first time and just have a “plug and play” replacement? I would certainly be happier.

[Joe K]

Its a small cost to pay the Ford Foundation to have a blueprint run off - but it is a cost. One imagines the profit margin on new parts for a car upwards of 90 years old is pretty slim and the exercise done more for the pleasure of doing and offering what little service one can to the hobby - and perhaps for suppliers to offer a "full range of parts."

Back in my "new is better" period I went the way of the repop once and found the same as you found - I could make it work if I "bent" the rod. I'm not sure if it was the spark or throttle connector - but does it matter?

The ends on these rods were aluminum (of all things) and a full third of a diameter larger than the original pressed/swaged steel ends. They would be visible to even common bystanders in a heartbeat - not to mention judges. They were set aside.

Since then I pick up rods from wherever and whenever I find them. I have followed discussion on this forum since about a "best" way to restore them.

Joe K

[Synchro909]

Why can't they make it right???!!!? Why can't they make one at all? None of the control rods for a RHD car are made AT ALL. Not for spark, not for throttle! I am forced buy a longer than neccessary rod, cut it and weld where the peices overlap. It looks crappy to say the least but at least it runs. GRRRRR!
I agree they that if they are going to make a replacement part, make it right but you guys don't know how easy you have it. This is only one of MANY examples.

[redmodelt]

My copy of the JS is older and this may have been updated but it shows 17" for this control rod.

[Karl]

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Originally Posted by Synchro909

Why can't they make it right???!!!? Why can't they make one at all? None of the control rods for a RHD car are made AT ALL. Not for spark, not for throttle! I am forced buy a longer than neccessary rod, cut it and weld where the peices overlap. It looks crappy to say the least but at least it runs. GRRRRR!
I agree they that if they are going to make a replacement part, make it right but you guys don't know how easy you have it. This is only one of MANY examples.

I'm sure they are obtainable . The trick is they will be off something else and just happen to fit., I'm sure I've seen them for sale recently somewhere I will think on it -Karl