JPM double springs

Airspeed

Hero Member

Posts: 593

JPM double springs

« on: May 25, 2008, 21:56:15 pm »

Does anyone know if these have comparable, bit less or more seat and opening pressure compared to the GeneBerg double VW spring set?

Where to buy them?

Tnx,
Walter


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"...these cars were preferred by the racers because the strut front suspension results in far superior handling than the regular torsion bar front end..." - Keith Seume.
10.58 @ 130 mph (2/9/2022 Santa Pod)

RMS Boxer Service

Sr. Member

Posts: 308

Re: JPM double springs

« Reply #1 on: May 26, 2008, 14:17:57 pm »

Translated from JPM's homepage in swedish (the ino is not present in the english version)

Valvespring messurements:

Outer spring:
open length 54mm
Coil bind 20 mm
Outer dia 31,8 mm
tread dia 4,00 mm
L1 25.0mm
F1 928N

Inner spring:
open length 54mm
Coil bind 20 mm
Outer dia 22
tread dia 3,00 mm
L1 25.0mm
F1 580N

Íf you still have questions, send Johannes an email and I'm sure he will answer you, he's a very friendly guy

/Rolf


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Rasser

Sr. Member

Posts: 488

Re: JPM double springs

« Reply #2 on: May 26, 2008, 18:38:24 pm »

I went from GB273A springs (had valvefloat problems).

All i can say is I didn´t have the problems after changing to JPM springs - I´ll leave the math to someone else ;-)

highly recommended.


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1966 type2 13w deluxe

Roman

Hero Member

Posts: 656

Re: JPM double springs

« Reply #3 on: May 26, 2008, 19:55:49 pm »

I had them om my old engine. They can take 16.4 mm valve lift with 2 mm to coil bind. My set had 170 lbs seat pressure and it was enough to control a 46 mm steel valve over 8000 rpm.


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Airspeed

Hero Member

Posts: 593

Re: JPM double springs

« Reply #4 on: May 26, 2008, 21:32:07 pm »

Thanks !
I was looking for a set to control a turbo engine and they seem the right part for the job!
Thanks for the translating job as well


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