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New Performance valve springs
Posted: Fri Apr 12, 2019 9:11 pm
by SvendH
Before i dismantled the valve assembleys in the head I found that I could twist the the assys back and forth simply by gripping the outside of the spring with the fingers of one hand,and I am by no means Arnold Swartzenegger.
I.E. the valve springs cant be very strong,perhaps time and strain have weekend them?
Anyone know what the "free length" of these springs should be from new?
I dont want to buy new springs if I can reuse the old ones,on the other hand I would hate to have it drop a valve either

Re: New Performance valve springs
Posted: Sat Apr 13, 2019 12:12 am
by oehrick
I searched when doing my head the other week Sven, there is a specification list buried at the end of the engine section where they hide all the good stuff like Torque settings etc

Page 67
Just extracted the spring info to save you digging, doesn't appear to be any go / no go tolerances.
Valve Springs and Collet
Number of coils on valve spring. . 8.8 total coils :7 free coils
Free length of valve spring . . 2.48" (62.99 mm.)
Compressed length and load . . 1.98" @ 45-50 lb.
(50.3 mm. @ 20.422.7 Kilogrammes)
Re: New Performance valve springs
Posted: Mon Apr 15, 2019 8:21 am
by SvendH
My springs are 57-58 mm (free length) and I count 7 and something total coils

Re: New Performance valve springs
Posted: Tue Apr 16, 2019 12:58 am
by oehrick
Within 5mm length free,, can you make a 1.98 gauge and press them on the bathroom weighing scales to see what the load is when compressed ?
With the rest of the engine relatively new and unworn I'd be surprised if the valve springs were bad.
Re: New Performance valve springs
Posted: Tue Apr 16, 2019 7:21 am
by SvendH
Will try the gauge trick.
Unworn,unworn- I think the pistons and liners are replacements since they dont have the markings on the photo uploaded by Mathias.
Re: New Performance valve springs
Posted: Tue Apr 16, 2019 10:35 am
by oehrick
Ah, that might mean a longer working life if the springs not changed as well plus valve wear and regrinds will effectively lengthen the stems by a few thou, it all adds up.