Hydraulic roller valve springs-track tested facts

I run a hydraulic roller cam in my dragster, using the factory GM rollers. I have a crower cam with .535 .555 lift , the recommended valve spring is 135lbs seat and 320lbs open. The engine would float the valves early and never really had a crisp sound to it. I bought a set of Howard cams springs with 200lbs seat pressure and 400lbs open. I set the preload on the lifters to 1/8th of a turn, that's about .010. I ran the car two weekends ago and it picked up 4mph. This is with no other changes, there was no valve float and I shifted about 6,500rpm. The engine has alot more punch to it, and pulls clean right up to the shift point. Just thought I would pass this info along because I was very surprised with the results.

 

Interesting !

Those original spring spex read like a street solid cam spring ! Lets not forget that springs once they've been thru a few heat cycles tend to drop 10-15lbs on the seat/nose from heat and initial usage.

Good to hear you nutted it out - I just hope the originsl roller lifters can take the rpm/additional spring pressure.

Good luck !!

Rat

 

Hydralic roller lifters weigh a ton >>>>.

 

Yes they are heavy, and I know a solid roller is the way to go but when I put this engine together it was for
A street car I have, that never happened. I plan on putting another healthier engine together this winter to run my blower on and I'll definitely run a solid roller in that.

 

that's why the stiffer springs made your engine run better !! Just sayin >>>>.

 

Don't forget that part of the reason for the factory spring pressure is low drag- gas mileage.

 

I went thru this recently myself. I usually do solid rollers, this time I did a hydralic. Im now running much stiffer springs than whats called for. Even with Ti. parts and light valves in a BBC.