McCulloh vs Paxton

The answer should be here Paul:

Upgrades to bearings and seals are the big things. I believe the oil pump went thru a change also. You can make an SN60 from a McCulloch core. There are different impellers and spring packs,for some later applications. John Erb is the one to answer this...

A big difference between the SN-60 type Paxton, as used on the R2's, and the VS-57 McCulloch, as used on the Golden Hawks, is the output shaft. An SN-60 output shaft doesn't "pilot" in the end of the input shaft the way it does in the VS-57's. There's a change, to limit the oil flow out of the end of the input shaft, that goes with it. A small difference is the size of the fitting in the volute, for boost reference to the fuel pump! It's 3/16" on VS, and 1/4" on SN. Jim Moody and I put together a chart of the Stude and Paxton McCulloch part #'s for each supercharger part, a few years ago. It's at:

. See "Parts Interchange", "VS57/SN". Sources are listed. I found a lot of surprises, comparing part #'s. Oil pumps, and all their parts are the same for R2's and Golden Hawks. All the ball drive parts, except for the output shaft itself, are the same. By the way, the Paxton part #'s for the drive balls and races, shown on the Stude blueprint for the Avanti, are the old McCulloch #'s for American made parts; not the better quality German. Of course, it's possible that Stude and Paxton upgraded parts and didn't change the part #. Mike M.

Thanks for the great responses. The reason I was asking is my McCulloch buyer indicated that he was buying it to replace a missing one on an Avanti. I advised him that it was different. He said he would buy it anyhow and re-sell it rather than stiff me. I have told him not to worry. I'll just go to the "second offer". Paul Johnson