Thanks for looking. Is there a standard spring for FAC please? Realise there's a balancing act with other factors but curious 'cos this Rapid has some bits missing and is FAC registered.
Spring length/rate would be an excellent, for me, start point
yes and no.
iirc a full length single spring is
72mm x 12.7 o/d x 1.42 wire 17 coils.
and dual rate.. coils closer at one end.
And that's a tad long
Kev and others order from the original supplier, you can go to Lee Spring ect and buy stock springs of similar dimensions but none of the ones I tried were quite right.
Can get better results from valves and airflow than by smashing it with a strong spring.
BTW as yet I haven't chanced upon a rate for hammer or exhaust valve springs.
I asked KevG and his reply was... I just order mine from the original supplier.
A couple of years ago Bucketboy on t'other forum arranged a group buy from Vincent Springs.
I found the new hammer springs a tad firm for both sub-12 and FAC.
Could say the old springs have softened up but how would you order spring 'X' but with 15 years of scragging ;D ;D
Before you go down that route.....TRRobbs springs are awful.
The Vincent springs compress straight - linear, TRRs are too stiff, bow out and have a twang.
Thanks, Squinty, for the full, informative, support.
Squinty. I Assume the progressive rate spring needs close coils at adjuster end to give higher acceleration from rest.
My last build I fitted one of TRR's short springs from a set I bought 8-10 years ago.
It's about 20mm too short, so un-cocked you can hear it sliding about inside, but it actually shoots fantastically ???
Quote from: Deejayuu on January 21, 2023, 10:17:13 AM
Squinty. I Assume the progressive rate spring needs close coils at adjuster end to give higher acceleration from rest.
you're probably right.
I assumed it was for less preload tension.
Shorter/longer- you can vary the hammer cycle depending on which end the close coils go.
Quote from: angrybear on January 21, 2023, 01:58:19 PM
My last build I fitted one of TRR's short springs from a set I bought 8-10 years ago.
It's about 20mm too short, so un-cocked you can hear it sliding about inside, but it actually shoots fantastically ???
My mk2 177 spring is about 47mm, any less and Kev's double-tap bottomed out on its guide. ;)