Why did nhra change the cam and valve spring rule in 1985?

[Mike Fuller]

I think Tech Man has it just about right. It allowed the valve spring pressure check to be eliminated from the tear down procedure, making the process one step shorter. Seven Rimac machines up for sale. More money,less work. A no brainer on their part.

[art leong]

I believe they changed the cam and valve spring rules. For 2 reasons
1 The GM guys were constantly crying because Mopar wrote "bogus" numbers for thier cams. On our Hemi car if we put as much duration and overlap as we were allowed it never would have been able to start.
2 Is they just got lazy not wanting to have to calibrate testors and measure the spring heights.

Back in the day. We would go through aload of used "battleship" outer springs to get 16 that would check legal. I think we were allowed 180 on the seat 320 wide open (these numbers are from my memory which isn't always right)

[X-TECH MAN]

Billy Nees brought up one more thought.....ENGINE LIFE. Im friends with a very good life long 428 CJ (not noted for long life with stock rods) engine builder and racer. When the valve spring rule was in effect he could run a full year on one engine. Thats was approx 300 runs. Today he said the engines (all brands) when run hard enough to be fast only last about 75 to 90 runs then your on borrowed time. The rings usually go away before that many runs. Wouldnt it be smarter to limit RPMs from a stocker with valve spring pressures rather than making everyone run a diaper to contain the oil and flying parts from an over stressed "stocker" engine?

[Billy Nees]

Originally Posted by X-TECH MAN

Wouldnt it be smarter to limit RPMs from a stocker with valve spring pressures rather than making everyone run a diaper to contain the oil and flying parts from an over stressed "stocker" engine?

It's got to be a whole lot less expensive to change a set of valve springs than to re-engineer a Stocker so you can fit a diaper or pan on it.
OBTW, in this day and age it's not uncommon for S/G and S/C racers to check their valve spring pressures between time trials and between rounds so what's the big deal getting an NHRA Tech guy to check a few. There are plenty of unexpensive tools in the ND every week to check springs on the engine.

[Casey Miles]

NHRA told the prostock teams "NO EXOTIC MATERIALS IN THE ENGINES" , why is it allowed in stock eliminator? Schubeck lifters are made from an exotic material the last time I looked. You can't buy them at any local auto parts store that I know of.
NHRA doesn't want to do their job on policing rules and for that matter what we pay for from them when we buy our memberships. NHRA is streamlining for their benefit not to have to enforce rules that should have been kept up with, like valve spring pressures. The cars in stock would not be running 1.0 under if the valve spring pressures where set to factory spec. for sure. The valve spring spec on my 302 engine was 96 lbs on the seat and 204 lbs open pressure, no way could you get the motor to 8k rpm. Now, they are changing gears at 8200 rpm.
My vote is to go back to enforcing an across the board valve spring pressure so that you have to use stock (buy in any auto parts store) lifters again.

Casey Miles
248H

[X-TECH MAN]

Originally Posted by Casey Miles

NHRA told the prostock teams "NO EXOTIC MATERIALS IN THE ENGINES" , why is it allowed in stock eliminator? Schubeck lifters are made from an exotic material the last time I looked. You can't buy them at any local auto parts store that I know of.
NHRA doesn't want to do their job on policing rules and for that matter what we pay for from them when we buy our memberships. NHRA is streamlining for their benefit not to have to enforce rules that should have been kept up with, like valve spring pressures. The cars in stock would not be running 1.0 under if the valve spring pressures where set to factory spec. for sure. The valve spring spec on my 302 engine was 96 lbs on the seat and 204 lbs open pressure, no way could you get the motor to 8k rpm. Now, they are changing gears at 8200 rpm.
My vote is to go back to enforcing an across the board valve spring pressure so that you have to use stock (buy in any auto parts store) lifters again.

Casey Miles
248H

Yepper......But how are you going to get the associations to change that rule? If I was still working the IHRA deal I woud push for it but I know it would be shot down. That would eliminate just about every NHRA car that wanted to cross over and the car counts are low enough already. NHRA would have to mandate it then IHRA would follow the rule change. All one can do is send letters to the powers that control this stuff and complain and try to reason with them about the cost and potential oil downs. With a head off already for a CC check and the valves out for a size check the checking of a couple of valve springs would take only a few moments. Let the stockers keep their crazy overlap and duration specs as that was a pain in the ***** to check.

[Billy Nees]

[QUOTE=X-TECH MAN;195663] That would eliminate just about every NHRA car that wanted to cross over and the car counts are low enough already.

I think that you'll find that NHRA doesn't want Stockers "crossing over" to SS!

[Mark Yacavone]

You guys are forgetting the fact that many of the current crop of racers would have trouble just getting the valve covers off. Forget about monitoring spring pressure.
Not banging on anyone in particular. That's just a fact of life.

[Pat6868]

If you check out the rules for IHRA pure stock you find a class thats in line with the original intention of stock eliminator. A person can put together a competitve car for a lot less money. If rules are enforced theres no problem. As far as reliability, while I don't race as much as most, my 327 has been in the car for 5 years without freshening and only minor repairs and still runs the number. Pat

[James Perrone]

You guys need to get a TIME MACHINE...
They make the rules as you go along.