defective SC valve springs?

[speeder]

I was talking to Walt at Competition Engineering today, (probably the most respected Porsche machine shop in the U.S.), about sending in my heads when I do top-end on SC next month. When I told him that it was an '82, he advised me to replace the valve springs due to a batch of bad ones in '82 that tend to break. I believe him, but was surprised that I have never heard of this one on this board or elsewhere. Anyone else familiar w/ this? John Walker? Dave B.?

Just wondering.....

[john walker's workshop]

good idea. lots of SCs had/have broken springs. they're cheap.

[82SC]

yeah when I bought my 82SC...had a couple broken springs

MJ

[speeder]

Thanks, John. I'm gonna go ahead and do it, when someone like him, (or you), talks I listen. I'm also installing 964 cams+SSIs, want it to be nice and tight.

[Wayne 962]

If Walt says so, then it must be true.



Walt told me a month or two ago that the newer springs are very good, and hardly ever come up bad...

I recommend replacing valve springs no matter what - why risk it?

-Wayne

[speeder]

Always on the learning curve..... I was not aware that these wear out/ break. They will be replaced.

[MBAtarga]

Just another data point on this. When shopping for my first Porsche purchase early last year, I found an 83SC I was seriously considering. The owner, of 13 yrs, said the only "engine" work to date (130k miles) was when it was in the shop for a previous valve adjustment, the mechanic found a broken valve spring. Perhaps the problem is not just limited to 82's.

I opted against this car, for other reasons, and soon found the 83SC I currently own.

[HawgRyder]

Valve springs are one of the most stressed parts of an engine....they work millions of cycles under very harsh conditions.
When the spring is new..it follows the curve of the cam with no problem....but when they get old....term in racing is "the engine has gone soft" ...then they must be changed.
In formula Ford....when the engine goes "soft" you can hear the difference right away.
The car loses several hundred RPM (can't rev as high) and the overall sound is just not as "crisp".
As John says...they are cheap...replace them.
Bob

[tops911]

on my 78 SC it has had 5 intake valve springs changed due to breakage. I have the service records and most were changed early in its life. It does seem odd that only the intakes have been the ones to break.

[Jdub]

Without visual inspection, and without attemtping to rev the engine to see if I have lost revs at the top, how can I determine if a spring is bad? I guess I am asking if there is an audible or ? way to confirm this.

Thanks,
John

[82SC]

hmm...well I have the rocker covers off at this point and the rocker arms...sould I do a spring change too?

I know my car has not gotten work since it was built...

and I will repeat the previous post...what is a good way to check besides a spring compressor?

how much should a full set of springs run?

MJ

[speeder]

From what I've heard, a good flashlight and someone who knows what they're looking at is all it takes to find a broken valve spring(or 3).

[Jim T]

I'd replace them, too, cheap insurance.

I remember in Anderson's book, he talked about a bad batch in the early '78 model run.

[john walker's workshop]

there's an outer and an inner spring. the outer generally breaks. the inner is pretty weak, and can be compressed pretty easily with your thumb. so when the rocker is in the position where you would adjust the valve, see if you can push in on the rocker, against the spring and actually depress the spring a bit, like 8-10 mm. if you can move it with your fingers, it's broken. baum tools, and maybe pelican too, sells tools to replace the springs without removing the heads. if you're real flexible and patient, you can do it with the engine in the car. some are a lot easier to get at than others. obviously, the rocker and shaft need to be removed first.