Schubeck lifters

[Bob Gullett]

Originally Posted by MR DERBY CITY

OK, here is the deal. Shubeck / Smith lifters have been exploding for years....This isn't late breaking news. Instead of changing OUR rules , why don't you do what every other racer did......buy a set of tool steel lifters, Trends or Precision ,both are nice alternatives to losing pucks ,blowing up your entire engine and letting EVIL metal run through the oiling system. So sorry if this doesn't fit your agenda !!! GEEZ. ,!!!

Couldn't of said it better myself!

[SSGT Mustang]

Don't see the problem with keeping flat tappet lifters in stock. The Cup cars have been running them for decades at nine grand or better.

If you have lifters that explode, then don't use them anymore. Seems simple enough to me.

[Ron Middleton]

Haven't we changed enough in Stock already? I know it sucks to hurt a motor but almost everyone here has endured that experience. We're racing, **** breaks if we're trying to be the fastest or quickest. Pro Stock, Comp, Superstock and even the .90 classes break break engines. Allowing more and more replacement parts just keeps escalating the class beyond it's original intent and most average racer's budgets. JMT.

[Mike Taylor 3601]

Leave stock alone,is fine the way it is.
Mike Taylor 3601

[Larry Hill]

I will do what the rules allow. This is the first lifter break I have had with a Schubick/ Smith. I broke one when the rod broke in La. years ago. Lost one at Indy when a head of a valve popped off but still qualified. This is the one just failed but I don't know why. Maybe I have been lucky all these years.


I ran these lifters, cam, and valve train all year, and just got off the dyno and it made decent power. News flash peak power is at 6200-6300, and rod and piston weighs 1755 grams each. It's kinda like racing a diesel. I have a nine grand tach and about a third of it is never used.


A 10,000 rpm 396 is Jim Boudreau backup engine, what the #1 engine will turn is still classified information.

[Dan Fahey]

Originally Posted by Mike Taylor 3601

Leave stock alone,is fine the way it is.
Mike Taylor 3601

Not it is not.
Especially with all these comments.
The Spring Rules needs to be looked at.
If no change fine...
But the current spring rule is breaking too many engines.

Seat Pressure and Open Rate can be regulated.

D

[Mike Taylor 3601]

Originally Posted by Dan Fahey

Not it is not.
Especially with all these comments.
The Spring Rules needs to be looked at.
If no change fine...
But the current spring rule is breaking too many engines.

Seat Pressure and Open Rate can be regulated.

D

It isn't the spring pressure breaking parts,95% of valve train failures aren't from excessive spring pressure,they are caused by too low of spring pressure which lets lifter bounce and not follow cam lobe, which breaks ceramic lifters or axles out of roller lifters,pops the heads of valves,burrs keeper grooves, beats seats out wide,wears guides out, stretches timing chains, pops rocker studs and rockers in two.
Every lobe has a limit no matter how much spring you have there is a RPM which it becomes unstable and starts self destructing the valve train.

Larry may have just had lifter get fatigued or damaged some how and caused failure.
Mike Taylor 3601

[Dwight Southerland]

Originally Posted by Mike Taylor 3601

It isn't the spring pressure breaking parts,95% of valve train failures aren't from excessive spring pressure,they are caused by too low of spring pressure which lets lifter bounce and not follow cam lobe, which breaks ceramic lifters or axles out of roller lifters,pops the heads of valves,burrs keeper grooves, beats seats out wide,wears guides out, stretches timing chains, pops rocker studs and rockers in two.
Every lobe has a limit no matter how much spring you have there is a RPM which it becomes unstable and starts self destructing the valve train.

Larry may have just had lifter get fatigued or damaged some how and caused failure.
Mike Taylor 3601

Not exactly a complete analysis. While "not enough" valve spring pressure can cause failures as you describe because of lack of control, I would also have to say that the allowed increased spring pressure has promoted running the engines at a much higher rpm range and demanded much more radical camshaft dynamics which have contributed to more failures than not enough valve spring pressure. The stresses on valve train components increase geometrically with the rpm, which contributes to parts failure more than the "not enough" spring pressure as you point out. Also, without the increased spring pressure, having to resort to parts like the ceramic lifters or tool steel lifters would not have been necessary. The camshaft manufacturers are smart guys and will produce profiles that work with whatever pressures are available, so you think that they are not pushing the limits of design to take advantage of the increased pressures and increasing engine speeds and ramp events accordingly? They also pushed limits in the same way when we ran OEM valve spring pressure, but the spring pressure limitation kept the engine speeds lower and camshaft dynamics softer so parts were not stressed nearly as much. The snowball effect of the consequences of that one rule change has escalated the cost of stock eliminator more than any other, and it simply was not necessary.