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

[X-TECH MAN]

While there are some comments about the older Jr. stockers on this site I had a flash back. Why did the rule change on cams and valve springs come about? Was it the lack of qualified people to do the job? Was it to much work? Do any of the older guys remember and know WHY? I can understand the duration and overlap being a pain to check and enforce but why didnt they just put a limit on the valve spring pressure of about 125-150 lbs seat pressure and 300-350 lbs open pressures across the board for all brands and types of engines? Easy to check while the head was removed for tear downs. This unlimited spring pressure rule is the primary reason you have to spend $700 to $900 on flat tappet lifters. Sleved lifter bores. It is also the reason for cut down crank pins, aftermarket rods, AND cheated up cylinder heads (air flow at higher RPM's) and intake manifolds. The valve springs most are running in "stock" today have more pressure than my old SS/IA Camaro had with an almost .700 lift roller cam and UNPORTED HEADS back in 1977-78. Mark, Woodro, or anyone have the answer from the good ole days of less expensive stockers????

[Billy Nees]

I have to agree with you Terry! I'd also like to add that if NHRA would add a "valve spring pressure rule" to the books right now you would see the cost of Stock Eliminator racing decline and you would find that we wouldn't be having so many Stocker oil downs!

[X-TECH MAN]

Originally Posted by Billy Nees

I have to agree with you Terry! I'd also like to add that if NHRA would add a "valve spring pressure rule" to the books right now you would see the cost of Stock Eliminator racing decline and you would find that we wouldn't be having so many Stocker oil downs!

Thanks for replying Billy. Words from someone who has "Been there and Done that" go a long way. Do you think someone with the power to make a new ruling on valve spring pressure would step up to the plate? Naaaaaaaaaaaaa ! It might upset the apple cart.

[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)

[Robert Simpson]

I believe they did it because.

1) You don't have to check it, therefore takes away all accountability (Someone to stand up and say it is wrong, better luck next time!)
2) Help vendors (that invest in the NHRA) sell products.
3) 1 less person to pay to work the races/teardown. They could get less experieneced. cheaper labor to do the job.
4) Speed up teardowns.

It just goes to show as soon as they legalize a go fast replacement part it opens up the next door, and then the next door. Legalize open spring pressure, then you find the next weekness (lifter, cam material) then you fix that and so on. Results, better products, more Hp, Lower ET's, Higher MPH, MUCH HIGHER PRICE TAG TO KEEP UP, Lower participation (Due to price tag), Higher HP factors (Due to the newly found performance). Stocker engines being priced sky high. The list goes on. Does anyone notice that in time past when money was tight, like it is now, there were allot of cars running. More participation? The reason that I see is people like rules, as long as they are the same for everyone. You used to spend your time working through your combo (testing). Now allot of people "checkbook race".

[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.