Is there any logic to aftermarket pulley sizes?

[gimmesomeshelter]

I've been looking at using a Porsche 356 generator pulley because I like the appearance. I noticed that the diameter of a 356 pulley is smaller than a 36hp pulley (95mm vs 100mm), so I started by checking the ratios of all the pulley's I have.

Crank Pulley
36HP Stock 185/581.19 (diameter/circumfrece in mm)
Denzel Repro 170/534.10

Generator Pulley
36HP stock 100/314.16
356 95/298.45

Crank/Generator Pulley Ratio
Stock/stock = 1.85
Denzel Crank/Porsche generator 1.8
Denzel crank/stock generator = 1.7

Does anyone know if Denzel intended their pulley to be a mild power pulley?

BTW, does anyone know the diameter of a stock 356 crank pulley?

Cheers,

Paul
_________________
"I would rather have questions that can't be answered than answers that can't be questioned."

Richard Feynman

[jays58s]

I think I now know why my generator light is on at idle. I'm curious now as well to the pulley differences. Is there a vintage pulley that is identical in size to the stock Vw pulley?

[RichardinNZ]

Thanks for posting this. I happened to be thinking about this too yesterday!
_________________
Richard
'58 Beetle; NZ Assembled
Dual Carb 36hp
My Car https://www.thesamba.com/vw/forum/album_page.php?pic_id=1750253

[Frederik]

I also gave this some thoughts yesterday and checked my pulleys. Thought I would add it here rather than start a new thread.

crank pulley

OT (repro): 170mm/ 534.07mm
Later 356: 145mm/ 455.53mm
Late 36hp (-60): 176mm/ 552.92mm

generator pulley

Late 6V gen: 108mm/ 339.29mm
(Not 100% sure the pulley is from the late 36hp engine it's on or if it has been changed)

Cank/Gen pulley ratio:

Late stock/late 6V: 1.63
Late stock/ 100mm 36hp: 1,76
Late stock/Porsche: 1.85 (same as early stock)
OT/Porsche: 1.8 (same as Denzel)
OT/stock 100mm 36hp: 1.7 (same as Denzel)
OT/late 6V gen: 1.57
Late Porsche/ Porsche: 1.53