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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 :x

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 :D 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.