400hp944

I have now broken 3 valve springs on my 944 spec race car over the past 1-1/2 years. 2 have been exhaust and 1 intake. My mechanic suggests that we replace all of them with new genuine Porsche parts sourced from Germany. I agree. I have no idea when or if the current springs were replaced and if so, with what brand. Has anyone had this issue and if so, what was the cause? Are genuine Porsche springs the best option? My mechanic said that there have been issues in the past with aftermarket springs being out of spec and causing coil bind. Any info would be greatly appreciated. Thanks!

V2Rocket

Are valve springs regulated by 944spec rules?
Shawn (refresh951) IIRC found that some Datsun springs will work in the 944 head and are a bit stiffer.

https://rennlist.com/forums/944-turb...ng-option.html

Tiger03447

I'd check with Iskendarian Cams in CA. Makes great products for race cars. Might have to wind a set for you, though, are you running double valve springs?

400hp944

Thanks I will check into them. Yes I run double (inner and outer). It's been the inner that broke every time...

Tiger03447

Just a thought..what kind of lifters are you running? That might have some bearing(no pun intended) on the problem..perhaps they are pumping up prematurely and binding up the springs. IDK about the head that you're running, but all the valve heights have to be the same, and that might be a problem also...my 2 cents.

Kurt R

Spec rules dictate stock springs, or valve springs from a 944 turbo. No other springs are legal for the class.

Auto_Werks 3.6

i wont do business with someone who thinks they can raise an agreed upon price. theres no excuse

Van

I use inner springs that Michael Mount makes (do a search - there are a few threads on them).

I assume when you say "broke a valve spring", you mean the tail on a coil...

odonnell

Barring mechanical over-revving, heat cycling is generally the cause of spring failure from what I've read on this forum. I think your mechanic gave you sound advice.

400hp944

No, broke in half about 1/3 the way down the spring...

400hp944

New Porsche springs should be here shortly. Going to replace all of them and start fresh. If it happens again, I may have to dig deeper into the cause...
The motor was built by Steve Russakov in 2007. The build sheet shows valve springs #95110590510.

Tiger03447

I hope that you are replacing the complete valve spring assembly, and not just the inner ones! How is the valve spring height... before and after? Just some thoughts.

Van

What's your redline? I'm assuming it's higher than the stock 6500 RPM?

400hp944

Yes, complete inner and outer springs. My mechanic is performing the work and I'm sure they will perform all necessary checks.

400hp944

Redline is 6500. I shift at 6200.