? for those who know about engines

TexasRaceLady

TexasRaceLady

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Junior's broken valve spring. Isn't that usually a terminal problem?

I think Jeff Burton broke one also and went behind the wall.

I do have a fair working knowledge of the inside of an engine, but simplicity would be appreciated.
 
Seemed they were guessing it was the inner spring.

Guessing being the key word here maybe.

Each vave has two springs, an inner and an outer. While the broken inner spring would hurt the performance, if the outer spring survived it was two things.

It kept the engine from eating itsef and grenading by keeping the valve functional.

It was a pure stroke of luck not likely to occur again.,
 
When you break a valve spring, it stops the flow from getting inside the cylinder. When that happens, its creates no compression/combustion, and then later, it'll just fail to work.
 
I don't think there was nothing wrong with Jr's car. They were just trying to add a little spice to a other wise slow race. :D
 
Interesting topic. Sometimes you can go a long way on a broken inner. You still hurt at higher rpm, because that valve will not be controlled as well as it should. It'll bounce, float and whatever else it can manage besides following of the path the cam lobe.

I am amazed at how often Cup cars loose valve springs. The spring manufacturers do not have that many bad runs. The overall lobe dimensions of those cams is not that radical. The only thing left is adherance to some fool hardy lobe transitions. How quick the ramp leaves and returns to base, how quick it goes onto and off the nose. I guarantee that someone out there can come up with much better transitions (I don't want to name names, their initials are: Harold Brookeshire, Shaun Tiede).
 
Originally posted by TexasRaceLady@Sep 14 2003, 05:26 PM
Stroke of luck, indeed. I'm just grateful the thing held together.
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Did someone say "LUCK".... :p Everybody get lucky at one time or another. Not a bad run Jr.
 
They both push the spring back onto it's seat (the cam pushes it away). The outer is the biggest and strongest of the two. The inner is a little shorter (to work with the retainer) and weaker, because it is smaller. The set may also come with a damper between the two OR the two may have a very small interference fit to provide dampening. In Drag Racing, it is not uncommon to have triple spring sets for very extreme conditions w/ extreme cam profiles.

Most street cars have idy biddy single spring set ups....more springs, the greater possibility for greater spring strength.
 
Originally posted by HardScrabble@Sep 14 2003, 04:18 PM
Seemed they were guessing it was the inner spring.

Guessing being the key word here maybe.

Each vave has two springs, an inner and an outer. While the broken inner spring would hurt the performance, if the outer spring survived it was two things.

It kept the engine from eating itsef and grenading by keeping the valve functional.

It was a pure stroke of luck not likely to occur again.,
Click to expand...
HS, if it was the inner spring that broke, it didn't hurt the performance of the car. It was early in the race when Jr. heard/felt it and he led quite a few laps after that. Was it pure luck that if it broke, that it didn't get sucked into the combustion chamber and tear apart the piston & cylinder? I was wondering if maybe the spring stayed together & just slipped off? I'm only familar with the single spring set up, so I don't quite understand how the inner spring sits around the valve?

The car didn't sound like it was only running on seven either. Do you guys think that maybe if there was a tear in one of the plug wires, that he would have felt it, especially when they are running at caution speeds, yet it may not affect the performance as long as there is current still running through it?
 
The inner is just a small diameter coil the fits inside the outer. However, the outer is usually larger in diameter than a standard single. With a broken inner, it can last, but it also might grenade. It all depends on how the inner came apart and if it interfers with anything. If it gets in the way, it could cause the lock to unload and let the retainer go away. The valve would then drop in the hole...that would be REAL bad.

It wont sound like you have a completely dead hole. It might sound like a load tick mixed with eradict engine running, getting somewhat "fluttery" at higher rpm. But no DEAD spot.
 
Originally posted by TexasRaceLady@Sep 16 2003, 01:38 PM
Thanks, Windsor. Have a better grasp of the inner workings now. :)

All I've ever worked on was just plain, jane small blocks.
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You're welcome TRL!...and nothing wrong with small blocks, that's what I spend most of my time on. My avatar is a 7 second naturally aspirated small block I engineered and built! Cool!
 
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