1950s Cad Air Cleaner Weird Tech Tip

[Lexi]

In this Forum or on the old now defunct Mid-Century Cadillac (CLC chapter) Forum, (or both?), I did a post where I had experienced problems keeping my air cleaner on my '56 Cad from moving when the car was in motion. It was irritating to see the shroud pointing in a different direction every time I opened the hood. There were suggestions to stop this from happening, including making changes that I did not wish to do. I believe the older Caddies had a "key" that looked like what you see on a tuna tin which tightened the air cleaner to the carb horn. So it must have been a problem in the past that GM had dealt with. I was unable to fix mine even after trying different air cleaners, carbs, gaskets, (even home made), wing nuts and various washers, some with the rubber on the bottom. Nothing worked. I don't remember the car being like this when I bought it 10 years ago...which gave me an idea.

Which was to dig out the carb that was on the car then, plus the old threaded rod and wing nut, (which was replaced with another when I swapped carbs for a rebuilt). After close examination I noticed that the original rod was slightly bent. Perhaps a Eureka moment, as I wondered if someone had bent the rod so that the air cleaner would somehow be less likely to move or rotate once installed? So I changed it out and since then my air cleaner has not moved! Still in the process of testing, but so far so good. Hope it stays that way. Clay/Lexi

[PHIL WHYTE CLC 14192]

Hi Clay, I remember we discussed this, I've done nothing about it on my car yet!

[Nickl]

In this Forum or on the old now defunct Mid-Century Cadillac (CLC chapter) Forum, (or both?), I did a post where I had experienced problems keeping my air cleaner on my '56 Cad from moving when the car was in motion. It was irritating to see the shroud pointing in a different direction every time I opened the hood. There were suggestions to stop this from happening, including making changes that I did not wish to do. I believe the older Caddies had a "key" that looked like what you see on a tuna tin which tightened the air cleaner to the carb horn. So it must have been a problem in the past that GM had dealt with. I was unable to fix mine even after trying different air cleaners, carbs, gaskets, (even home made), wing nuts and various washers, some with the rubber on the bottom. Nothing worked. I don't remember the car being like this when I bought it 10 years ago...which gave me an idea.

Which was to dig out the carb that was on the car then, plus the old threaded rod and wing nut, (which was replaced with another when I swapped carbs for a rebuilt). After close examination I noticed that the original rod was slightly bent. Perhaps a Eureka moment, as I wondered if someone had bent the rod so that the air cleaner would somehow be less likely to move or rotate once installed? So I changed it out and since then my air cleaner has not moved! Still in the process of testing, but so far so good. Hope it stays that way. Clay/Lexi

Have the same problem on my 54 since I swapped the original oil bath insert to an paper type one.
Have also tried different gaskets and a lot of other things but it will not stop rotating when I drive.
What do you mean that the rod is bent?
Can't remember if mine was also bent when I changed the insert....
Maybe someone had the answer that mine will stop rotating

[Lexi]

Hi Michael (and Phil). While I did not photograph the threaded rod, I can try and describe it to you. When laid flat on a table it was not 180 degrees, (the old bent one). So not a straight line. It had a slight bend or curve to it, say 2 -3 degrees (not more than 5), as a guess. So to roll it on the table it would have had a wobble to it, or perhaps not even roll at all, (probable). When I held it up and visually examined it, I could see the slight bend or curve in it; gradual over the entire length. Perhaps this forced the rod threads to come into contact with the mounting holes in the air cleaner? Perhaps that assisted to "bind" the air cleaner to the rod and keep it from rotating?

If you were to take your rod out, and place a nut near each end, then place in a vise; you could probably pull on it to get the slight bend required. Having nuts on the rod will protect the thread portion of it. Perhaps even a nut dead center, tighten in vise on this center nut, then tap the end to give it a slight bend. To protect end threads leave a nut on there as well. I also put on a different wing nut which may have helped, although it did not in the past. If the threads in the wing nut are "loose" it may not hold as tight.

Anyhow, I think the bent rod changed the axial load specs at least with respect to bending and torsion-which helped to better "grab" or hold my air cleaner unit in place. Hope this makes sense, to fix and extremely irritating problem. Clay/Lexi

Edit: Cutting a wooden template jig on a bandsaw or even with a hand held scroll saw, would better hold the rod in a vise and protect the threads. I think it would also provide a more even curvature to the rod you are bending. Improvising with a shop press would provide even more control. as they are built to press and even bend metal.

[Lexi]

Checked it today and after 63 miles since changing the rod out, some at highway speed, the air cleaner is still straight as an arrow. Zero movement. Clay/Lexi

[Jeff Rosansky CLC #28373]

I have a piece of metal tubing over the threaded rod which acts like a big spacer. This way I can tighten down the wingnut and not compress/deform the top of the air cleaner. This helps it stay tight. It does move slightly, but not enough to worry about.
Jeff R