Valve springs - failure

[Silber]

A valve spring failure killed my engine, doing some research valve springs failing seems to be somewhat common with Boxsters. Found this interesting article on valve spring metallurgy:

https://www.enginebuildermag.com/2010/01/performance-valve-springs-and-retainers/

Basically, it says that over the last 10 years (written in 2010) there have been major advances in valve spring wire technology. If you buy valve springs now, they will be much less likely to fail than older ones both because of less fatigue and because of superior metallurgy.

986 boxsters are either pushing 20 years old, or past it. IMHO our valve springs are ticking time bombs. I’d recommend replacing them especially if your car has over 100k miles on it.

You can go with stock Porsche, or for higher cost, Schrick. I’m going to go with Schrick as their springs are dual coil. Porsche went to this for the 987. If one spring snaps your valve will still be kept away from the piston I’d think, at least more so than a single spring snapping. Plus they build advanced technologies for F1 teams so you are more likely to get current metallurgy than with the stock Porsche part. Who knows when the spring you get from the dealer was actually made.

There are two drawbacks to the Schrick springs. One they are stiffer, so there will be more guide wear. However, guide wear is not catastrophic, valve spring failure can be. I am going to err on the side of avoiding catastrophe. The other drawback to the Schricks is cost. You have to buy their titanium retainers to match up with the double springs, and those aren't cheap.

I couldn’t find the Schrick springs in the US, if you want the name of a German supplier that will ship worldwide, PM me.

Any thoughts?

Silber

EDIT: All of the above is based on Boxster S, I’m not sure what the Schrick options are for the base model.

[Newsguy]

Those "beehive" valve springs date back to the Hendricks NASCAR team using them to gain Jeff Gordon a few Championships in the late 90s, so not that new. Incidentally, they were designed here in the USA, amazingly.
F1 cars haven't used valve springs for about thirty years, I'm thinking. So that's pretty irrelevant.
So WHO is breaking valve springs in Boxsters? Haven't heard of this. Considering the M96 was in 911s too, where are all those cars with broken springs?

[Starter986]

Originally Posted by Newsguy

Those "beehive" valve springs date back to the Hendricks NASCAR team using them to gain Jeff Gordon a few Championships in the late 90s, so not that new. Incidentally, they were designed here in the USA, amazingly.
F1 cars haven't used valve springs for about thirty years, I'm thinking. So that's pretty irrelevant.
So WHO is breaking valve springs in Boxsters? Haven't heard of this. Considering the M96 was in 911s too, where are all those cars with broken springs?

So... valve springs are the IMS of 2021?

[Silber]

Originally Posted by Newsguy

So WHO is breaking valve springs in Boxsters? Haven't heard of this. Considering the M96 was in 911s too, where are all those cars with broken springs?

Well, happened to me, so there is one.

Google shows many others.

https://www.google.com/search?q=broken+valve+Spring+Boxster

Regards,

Silber

[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