Lifter rule in Stock

[SSDiv6]

Originally Posted by Bob Don

I just emailed NHRA Tech to get clarification on the new language. This is the response:

"The intent was/is to allow the use of a solid lifter in place of a hydraulic, you may not replace a flat tappet with a roller.

Thanks

Joey Gorman
NHRA Assistant Regional Technical Director
Office-(317)-969-8609"

...and there you have it.

It would have been so easy to add the above statement to the rule change!
As written, it creates all kinds of conclusions and assumptions by engine builders and racers

[Larry Hill]

I'm going to keep my hyd. lifters, solids would be a lot noisier and then I would have to keep them adjusted, and that might..............would cut into my adult beverage time.

[Coleydog]

Originally Posted by Larry Hill

I'm going to keep my hyd. lifters, solids would be a lot noisier and then I would have to keep them adjusted, and that might..............would cut into my adult beverage time.

Ok, I'm a little slow sometimes, I was about to buy some good hyd lifters, can I instead buy solids now? Or just wait till all those hyd lifters hit the for sale page?

[MikeMoller]

Originally Posted by Larry Hill

I'm going to keep my hyd. lifters, solids would be a lot noisier and then I would have to keep them adjusted, and that might..............would cut into my adult beverage time.

X2 on that Larry!!

By the way, since lift will be checked at zero lash but you wouldn't run a solid at zero lash, I assume you have to give up some lift if you change over.

[Mark Yacavone]

Originally Posted by MikeMoller

X2 on that Larry!!

By the way, since lift will be checked at zero lash but you wouldn't run a solid at zero lash, I assume you have to give up some lift if you change over.

Yes, but I don't think you need .006. A lot of older motorcycle exhausts were around .003.
Somebody try and let us know ....

[killintime6968]

Please excuse my ignorance. But does this mean we can now run a solid lifter type cam in a hydraulic cam engine. IE a 396 350hp. Or just solid lifters on the hydraulic cam.

Bruce Cameron
1969 Nova E/S
1968 Camaro SS/I

[Dave Muller]

Since any duration is allowed I don't see why someone couldn't grind slight clearance ramps (just a couple thou) into them, but it doesn't seem worth bothering with.

[Alan Nyhus]

Originally Posted by Mark Yacavone

Yes, but I don't think you need .006. A lot of older motorcycle exhausts were around .003. Somebody try and let us know ....

Mark, this has been done for decades on high perf street engines.

You can be down around .002 (hot) with a solid lifter on a 'hydraulic' cam lobe. Basically, as close to '0' as you can without hanging the valves open. A good rule of thumb.... on a typical iron head/iron block setup, you need around .003 more lash 'cold' than what you want it at 'hot' to allow for expansion. ie: .006 cold will get you .003 hot.

Iron block/alum. heads & alum. block/alum. heads expand differently than iron block/iron head, of course.

[ALMACK]

Originally Posted by SSDiv6

It would have been so easy to add the above statement to the rule change!
As written, it creates all kinds of conclusions and assumptions by engine builders and racers

I agree with the above. ^^

If that was NHRA's intent then the revision should have come out and stated that hyd. flat tappet lifters can be replaced with solids.

[Rick Schilling]

I know this should be obvious, but if your combination already uses hydraulic roller lifters you can convert to solid rollers now?