Supercharger survival

[ddub]

In '57 and '58 when the supercharged engines were new, how troublesome were the superchargers if maintained as specified by the factory? In the "old days" it was quite common to see these as used cars advertised without the supercharger.

[PackardV8]

Back in the day, early 1960s, I never, ever saw a used GH for sale with a working supercharger.

jack vines

[M-Webb]

What are the things that people do to them now that help make them a bit better to stay working? My guess is keeping up with the oil and changing it on a regular basis is part of the maintenance needed and it didn't get done back in the day as it needed to be, and the oils maybe weren't as good as they are now? Better bearings available now? Ways to feed them oil instead of just manually checking it, and forgetting? I am going to need to figure this out here soon for my motor. Supercharger has been rebuilt of unknown quality and spec., hopefully it is good.

[PackardV8]

Yes, today's oils are much better than in the 1950s.
Yes, they were cars which got a lot of long, usually hard-driven miles. Today's hobby cars don't usually see the same stresses.

jack vines

[Mike]

Years ago, I joked with Jim Moody that the introduction of two case bolts drilled for a wire coin bag seal, to prevent tampering, probably greatly increased reliability. I included the part number in the list he published on VS57.com .
The variable ratio, split pulley, used on Golden Hawks, has problems of its own. It's unsealed and exposed to dirt. Surprisingly, neither Stude nor Paxton-McCulloch specified any special periodic cleaning.
Probably, most supercharger failures were the ball drive, either because of lubrication failure or being driven way past design parameters. People adjusted the pulley control valve for more boost, or used larger crankshaft pulleys.
I'll continue to use Ford type A, (not FA), atf, as tested and approved by Paxton. I change it more often than my engine oil. It's true, lubricants have gotten better, but I'm not aware of any engineered for the Paxton-McCulloch ball drive's unique needs. Paxtrax is nla.
Ball drive life is inversely proportional to the pressure on the races. Output pressure, (performance), is directly proportional to the pressure on the races. By measuring the torque required to turn the input shaft, how tightly the races are shimmed, can be determined. I don't have foot/pound values available, at the moment. Perhaps someone else can help. You can shim for long life or high performance, not both.
Oil cooler kits were sold by Paxton. They leave the internal oiling system undisturbed. A special dipstick allows oil above the add mark to be drawn off, cooled, and returned. The kit included a cooler, pump, and the special dipstick. A very desirable feature is that external leaks can't make the supercharger run dry.

[bezhawk]

Mike, the VS 57 didn't use shims for the ball drive pre-load. Up until the SN 93 much later did thehy use shims for the drive races. The earlier units including the SN-60 used a coil spring pressure plate. There are kits that have additional smaller springs, as well as kits with heavier tension springs to add pressure plate race load. The units for racing don't last at all. The balls and both inner and outer races gall under such loads. They were never designed for anything over 5 lbs boost and engine speeds of 4500 RPM max. To make them last somewhat better, rebuild them with modern parts, like the larger oil pump, the bronze ball driver, and the better higher tolerance balls. Use B&M Trick Shift type F non synthetic, and it will last better than new.

[PackardV8]

. . . . The units for racing don't last at all. . . .

For true, Brad; new, over-the-counter units from Paxton were labled "For racing use only. No warranty." Their life span was measured in hours.

jack vines

[Mike]

I assure you: all versions of the VS 57, from the first, through VS57C & S, (Golden Hawk), used discs behind the races. In early versions, including the Kaiser B model, these were "friction discs" and prevented the races from turning in the housing and coil spring pressure plate. They were backed by shim rings as needed. According to the SAE paper about the VS57, the idea was the races would spin to save an over loaded ball drive. C & S versions pinned the races and eliminated this feature. I don't think the Kaiser manual that used to be available on the internet mentions adjusting the pressure on the ball drive. I think it was assumed that the right combination of parts would produce acceptable results. It is mentioned in material about the SN60. There's no reason not to set the pressure on a VS57, light for long life, stiff for a little more boost.

[Mike]

Can anyone find VS57.com in the archives with the tech section intact? It included complete parts lists for all VS superchargers and Stude versions of the SN60, and a blow up diagram. I put it together as a cross reference between Stude and Paxton- McCulloch part #s, and sent it to Jim Moody, over twenty years ago. He edited it to make a parts interchange list. Of course, I saved copies of both my original and his edited versions, but I'm away from home. It would be very useful, I think, to make that list and the Kaiser manual readily available.

[bezhawk]

The Bakelite friction discs under the early races were not shims. The cases and pressure plates were deeper to account for the bakelite. No mention of shims in early units was ever mentioned in the literature I have. That is another reason early units can't be spun over 4500 rpm. The races will just spin and burn up the bakelite. The original units were designed for flathead low compression slow revving engines. When the trouble spots reared it's head when adapted to later higher revving engines, they had to be reworked several times and even then didn't last. Not until Andy Granatelli took over and studied quality control, and used superior tolerance balls and races did they somewhat solve the longevity problems.

[Mike]

Last edited by Mike; 08-25-2010, 11:29 PM.
A tolerance of +/- .0001 isn't very close for the supercharger drive balls. Ray Brock wrote an excellent article for "Hot Rod Magazine", Oct. 1958, titled "Supercharging Can Be Practical". Mostly it's about the new Paxton "DO". In addition to the change to engine oil under pressure for lubrication, there were significant improvements in the drive balls and races. These were the results of a year's work, by the Granatelli brothers with engineers at Paxton/ McCulloch, about 1957. Andy's "good story" about mixing drive balls of slightly different sizes is a simplification.
According to the article, at the time, American manufacturers' best quality drive balls were +/- 25 micro-inches, (.000025"). Cost was prohibitive; and some manufacturers didn't consistently meet standards. Some bearings were slightly egg shaped! Paxton found a West German company, (Hoffman?), who could supply drive balls controlled for roundness and diameter to +/- 4 micro-inches, (.000004"). Much better races were also found from a European supplier, maybe Swiss. These higher quality parts were specified for use in the "DO". At the same time the races were cut at a different radius, to increase contact area with the drive balls. Also, the change that may have done the most to improve reliability was made at this time. Two of the bolts that held the supercharger together were drilled for safety wire, and tied together with a seal, to make it tamper proof!
I have some old parts lists for "VS" superchargers that list both domestic and European replacement drive balls. For a while, at least, you had your choice. For the record, I have a copy of the Studebaker drawing for the later Paxton "SN" supercharger drive assembly, cross referencing Paxton part #'s to the Stude part #'s. The Stude #'s corespond to replacement parts for the balls and races in '57 & '58 Golden Hawks; as listed in an early '60's parts book I have. The Paxton #'s are for domestic parts. I've been told by several people that the parts from Stude actually were labeled "Made In Germany". But it looks like domestic parts were specified by Stude.
Regarding lube for "VS" & "SN" superchargers: It's my understanding that the last tests done at Paxton found Ford Type "F" ATF, (not "FA"), to meet their requirements. I got a case from a Ford dealer a few years ago. I don't think additives are advisable; certainly not "STP". I think the best way to change it is with a brake bleeder / suction pistol.
Mike M.