Valve springs - failure

[Silber]

An update.

I corresponded with Len Hoffman, owner of Hoffman Automotive Machine, http://www.hamheads.com/ and he gave me some insight on what could be going on. Reposting with permission.

In our experience with these heads when we've seen a broken spring it was always accompanied with a failed follower. We believe the follower fails first in this circumstance and takes out the spring.

IMO making a jump to dual springs would be an overreaction for a stock engine. We've installed countless new Genuine Porsche springs on track cars running sustained hi revs in Spec Boxster and Spec 996 and have never seen a spring fail on its own. Now, if they lose pressure (fade) they can contribute to a hydraulic lifter pumping up and the whole mess goes kaboom.

He later clarified that springs get weaker both from age and/or use, and he would never put used springs into a Motorsport (including autocross) situation. It sounds to me like if your car is 20 years old, and sees track time, it probably needs new springs, but if you have a street car that doesn’t see extreme use you could maybe run old springs and get away with it.

So, I am going to skip the double springs and buy a set of new Porsche Genuine springs.

Regards,

Silber

[Gilles]

"So, I am going to skip the double springs and buy a set of new Porsche Genuine springs..."

I believe that this would be the best idea.. :-) Len Hoffman knows his stuff..
.

[nuvolari]

Originally Posted by Silber

An update.

I corresponded with Len Hoffman, owner of Hoffman Automotive Machine, http://www.hamheads.com/ and he gave me some insight on what could be going on. Reposting with permission.



He later clarified that springs get weaker both from age and/or use, and he would never put used springs into a Motorsport (including autocross) situation. It sounds to me like if your car is 20 years old, and sees track time, it probably needs new springs, but if you have a street car that doesn’t see extreme use you could maybe run old springs and get away with it.

So, I am going to skip the double springs and buy a set of new Porsche Genuine springs.

Regards,

Silber

Interesting....

So what causes a failed follower? Is it just old oil clogging the passages in the follower and then it can't work properly or is it binding in the follower saddle?

[Silber]

Originally Posted by nuvolari

Interesting....

So what causes a failed follower? Is it just old oil clogging the passages in the follower and then it can't work properly or is it binding in the follower saddle?

I didn’t ask, I am using all new followers and low mileage saddles so I am OK on either front. If I had to guess it would be old oil but the follower saddles w 119K miles do have wear, so it could be either.

Silber