Hi,
New to this forum and joined since during my recent searched, I found many references to McCulloch s/c s and hoped to get help here.

I have two old Fords; an original 32 roadster with a built 59A, Columbia rear and Lincoln Zephyr gears in a 39 transmission. I also have a 40 Ford convert with ahem, ahem ..  a SBC. I first thought about putting the VS-57 on the 32 but it is running too well now and space under the hood is congested so the s/c is going on my 40. Have a few bikes too!

I have a rebuilt VS-57 done by CUNDN Racing in Texas, idler arm with new spring and a Kaiser bracket and a Holley 1450 650CFM with mechanical secondaries.

The McCulloch bracket that would work is a CH-101 but can't find one so I'll be making my own from carbon steel.
Ar setup issue I'm wondering  on is how much the idler arm pulley and spring should be deflected to have the proper load on the belt?

If the load is too small, the belt won't be pushed down into the solenoid actuated supercharger head unit. The pulley there has a solenoid operated system that increase the gap and thus the effective pulley diameter, to speed the head unit RPM up for boost. If the load is too high, it will force open the head unit pulleys and always run in boost.

If anyone here has a VS57 could you please tell me what the pin to pin dimension is compressed on a functioning installation please? This will help me in setup and belt length.

Thanks,
Glenn
71% of original size (was 708x19) - Click to enlarge

This might help71% of original size (was 708x19) - Click to enlarge71% of original size (was 708x19) - Click to enlarge

Hi Cliff,

Little hard to tell with your picture. Did you measure around 5"?

Thanks,
Glenn

5" on the money

Let me look Monday and see if I have the arm you need. Remind me if you don't hear from me. chuck3eagles@comcast.net

Y's guys rule!
Looking for McCullouch VS57 brackets and parts. Also looking for 28 Chrysler series 72 parts. And early Hemi parts.

MoonShadow, 292 w/McCulloch, 28 Chrysler Roadster, 354 Hemi)
Manchester, New Hampshire

Glenn, I get what your asking I used a tension arm on my SN and my VR blowers. But isn’t “belt tension” what your looking for? Depending on the arm and bracket, the compressed spring could vary. I’m not sure quite how to say or measure it. I can tell you if it’s not enough you see the boost go flat when it starts to slip. Can’t help with the VS opening under too much tension.

miker
55 bird, 32 cabrio F code
Kent, WA
Tucson, AZ

Thanks Cliff for the confirmation. It looks like there is variation in the pin to pin. I have a new spring assy. and an old one. They both measured at 4.75".
As Miker says, I'm really after the belt tension so it might be trial an error on belt length.

Happy New Year!
Glenn

Hi Miker and Happy New Year!

Yes you're correct, it is the belt tension I'm really after. If the compression was a given, I could do the math to figure the belt length. If the belt is too short, when the VS solenoid actuates, it will get pushed down into the spread pulley and stay there. I saw a beautiful aluminum s/c and idler brackets build a few days ago on this site, AL bracket. s/c was right side and idler on the left. There are a few others out there that made their own bracket so they would have had the same design issue too.

Thanks,
Glenn

Thanks and Happy New Year!

I have an idler arm which is shown in my first post in this thread. It is a universal #37091. I bought this arm and a Kaiser bracket which looks like the picture below.
It is the SBC CH-101 that I was looking for.

Thanks,
Glenn
Kaiser bracket and idler arm that I have.
71% of original size (was 708x19) - Click to enlarge

Kaiser mounted
71% of original size (was 708x19) - Click to enlarge

Ch-101 scruby bracket (1955-1957)

71% of original size (was 708x19) - Click to enlarge

You guys are great and appreciate your help!

Glenn
Wiscasset, ME