Frequently Asked Questions

There sometimes appears to be confusion on whether a supercharger is a McCulloch or a Paxton supercharger, so I’ll try and clarify the situation. All the variable ratio and variable speed superchargers are classified as McCulloch’s, and all the fixed ratio superchargers are classified as Paxton. The exceptions being the 30’s fixed ratio superchargers, which are exclusively McCulloch, and the Phase I VR57’s, which were developed and built at the Paxton Products Division of McCulloch Motors Corporation, and are generally referred to as Paxton-McCulloch’s.

Because it’s 50’s speed equipment, and therefore looks right on a 50’s engine, it can produce a higher boost at lower RPM’s than the modern centrifugal superchargers, and if you are lucky, it can be cheaper to set up than a more modern system.

Because when I tried to find out about the McCulloch Superchargers I found that very little information was actually available nowadays. So when I did find information, I thought I’d make it easier for other people to find the information I’ve found. It’s also a way of paying back all those people who have helped me in the past, either on Y Block engines, or McCulloch superchargers, as they might find something on this web site useful. I don’t actually care if only a few hundred people visit the site, as long as those people benefit from the site.

Unfortunately, being a Ford man, most of the literature I have collected over the years is Ford related. I’m hoping to address that in the long term, by tracking down as much supercharger related material as I can on these cars, but you’ll have to give me time I’m afraid.

Yes, the only difference I’m aware of is the fact that the Kaiser VS57 units produced less boost than the Studebaker units. If a Studebaker solenoid is installed in the Kaiser VS57, then the boost will be the same as for the Studebaker superchargers. It would also work the other way around, although I guess in both cases you might want to swap the badges.

Unfortunately not, the days of the bolt on kits are long gone. Assuming you get the correct pulley, belt, bracket, bonnet, and you bolt it onto the engine, plumb it up, and modify the carburetor and fuel supply, you’ll still have several hours (probably days) of playing with fuel jets and carburetion before you end up with a system that doesn’t stall or lean out when you put the pedal to the metal. Installing a McCulloch nowadays is only for the brave, however if you do feel brave, then it is well worth attempting as the performance increases for the car will certainly be noticed.

The supercharger, even during engine turn over, will always produce some boost, and as a result of this will be forcing a fuel/air mixture into the cylinders, without relying on the engine vacuum to draw it in. This will aid idling and aid starting as the induction system will be behaving more efficiently, and due to turbulence the fuel/air mixture will be mixed more evenly.

Yes probably a lot, as you’ll want to put your boot down and let the supercharger rip occasionally, however during normal driving when the boost is very low the extra fuel usage will be minimal ( a few %).

Understandably McCulloch stated boost in terms of the pressure at the carburetor bonnet or air box, which can be up to 1 pound higher than the actual boost produced by the supercharger. The pressure at the carburetor, unboosted is typically about 15 pounds at sea level, and when the engine is under full throttle this will increase up to 16 pounds due to the intake vacuum pulling the fuel/air mixture in when a piston is on it’s down stroke. When we add the supercharger, which puts out 5 pounds for example, the pressure will go up to 21 pounds on full throttle. The 6 pounds difference between the 15 pounds sea level and 21 pounds full throttle is the boost figure McCulloch quotes.

Ford Automatic transmission fluid should be used, and not Dexron. The Dexron is not suitable as it cannot handle the sustained high temperatures in the supercharger. Don’t forget to change the oil regularly (every 3,000 miles or less) as it’s a lot cheaper to change 8 fluid ounces of oil than what it is to get the supercharger rebuilt.

The only time the engine will run hotter is under continuous high boost, when more power is produced, and consequently more heat is being generated which has to be sinked by the cooling system. Otherwise the engine should run no hotter than normal. Any overheating after supercharger installation is more likely either due to insufficient ignition advance causing pre-detonation, or to too lean a mixture being ignited, both which are not good.

Yes, assuming you do not use it for racing continuously. When you are cruising on the freeway the supercharger will produce little boost and the engine will be seeing no extra stress than under unboosted conditions. When you are on full throttle, or when the engine is under load, and the supercharger is producing it’s maximum boost, then the engine will be stressed more, but as long as it is in good working order, and the compression ratio is not too high, then their should be no problems.

The recommended maximum compression ratio the engine should have before you bolt the supercharger on should be 8.5, as the supercharger can increase this to 10.5 under full boost. If you are not going to be running about under sustained full boost then you could probably get away with a compression ratio of up to 9.0. The compression ratio is often lower nowadays due to the use of thicker modern head gaskets, however this is soon compensated for when the cylinders have been skimmed, you could try a couple of gaskets but that could cause leakage and warpage problems, so I don’t recommend it. A standard technique to lower the compression on the mid fifties Fords is to use lower compression cylinder heads, but they may not be available for other makes. I know the Fords, Kaisers and Studebakers all had lower compression heads when they were supplied with McCullochs, so it is probably the only real option you should follow. Another alternative might be to limit the boost so that at maximum boost the compression ratio is not pushed over the magic 10.5, and this could be achieved using a Kaiser solenoid (which has a four pound limit) in your VS57, but it’s actually difficult to quantify what boost and what maximum compression ratio apply to a particular engine as all engines are different. Another way to vary the boost, although I’m not sure by much, is to adjust the boost setting on the control valve in the supercharger, but make sure you adjust it the correct way!

Hopefully from the swap meet on this site, however that is probably being too optimistic. The VS57 and VS59’s turn up occasionally at the big outdoor swap meets (so I’m told – will I ever get to one?), and a few turn up on e-bay. Some of the dealers (which I shall list soon) have some, and they occasionally turn up in Hemmings. McCulloch made ten’s of thousands of the VS57 units so you should not have too much of a problem finding one, the problem will probably be with finding the ancillaries (brackets, crank pulleys, idlers, bonnets, pipe work) that are appropriate to your engine, as they often went to the breakers yard with the engine, after the supercharger was removed. Try not to pay too much for a VS57/VS59  as you are practically guaranteed that it is going to need a rebuild, and rebuilds are quite expensive (in the region of $500 to $800), and don’t get too carried away on the auctions because you are probably going to have to pay for that rebuild, as well as pay for ancillaries. On the bright side, there is not as much demand nowadays for these units, and people are less likely to throw them away than during the sixties and seventies when they were regarded as obsolete. Hopefully this web site might promote more interest, and bring more parts out into the open when people realize there is a demand for them. This has however a down side in that prices may go up in the short term(Sorry!). If you are looking for a VR57/VR58 then good luck, these are difficult to find, spare parts are not available, and all the Ford guys are desperate to get one (myself included), they do however turn up occasionally.