[Formulajones]

Yeah, those guys also zero lash the valves for the street drives to try to help them live so they aren't beating themselves to death, (hard as hell to start up cold too) and then lash the valves again to race, and then repeat for the street drive. Not super practical, and they still have occasional failures.

Most of that stuff is basically "race" engines that they are band aiding to just put 1000 street miles on it. Crazy the lengths some people go through but it's a "street" engine

[Gach]

Yeah I just don’t get that whole thing, but then again I do, knowing what racing has turn into past 15-20 years. Hey if I could write those checks I’d probably be all over it.

[Half-Inch Stud]

455 parameters and valvetrainis why i ran the 1/4 mile 12.0 with 4950 rpm at the Big End.

[Cliff R]

The retro-fit hydraulic roller lifters are HEAVY in comparison to solid rollers.

Right on the dyno I've witnessed HR lifter set-ups go "dead" around 5800rpms just like you installed a rev-limiter on it. Not sure exactly why, maybe a combination of more weight and the hydraulic action of the lifters themselves?

My own engine did this at 5800rpm's and I didn't have any really heavy parts in the mix.

The next engine used Crower HIPPO lifters on a HR cam and it would spin to and past 6500rpm's so fast you could barely move the shifter quick enough to keep it from over-revving.

I also tried more spring pressure on the HR set-up and it made no difference in RPM limits whatsoever......FWIW.

[tom s]

The hyd roller lifters dont go dead at 5800!Maybe in your engines but I have seen Pontiac engines make HP to right at 7000.FWIW,Tom

[ta man]

Originally Posted by Formulajones

Yeah, those guys also zero lash the valves for the street drives to try to help them live so they aren't beating themselves to death, (hard as hell to start up cold too) and then lash the valves again to race, and then repeat for the street drive. Not super practical, and they still have occasional failures.

Most of that stuff is basically "race" engines that they are band aiding to just put 1000 street miles on it. Crazy the lengths some people go through but it's a "street" engine

Not Richard Guido...he just puts 20000 miles on his

[Stan Weiss]

Originally Posted by Cliff R

The retro-fit hydraulic roller lifters are HEAVY in comparison to solid rollers.

Right on the dyno I've witnessed HR lifter set-ups go "dead" around 5800rpms just like you installed a rev-limiter on it. Not sure exactly why, maybe a combination of more weight and the hydraulic action of the lifters themselves?

My own engine did this at 5800rpm's and I didn't have any really heavy parts in the mix.

The next engine used Crower HIPPO lifters on a HR cam and it would spin to and past 6500rpm's so fast you could barely move the shifter quick enough to keep it from over-revving.

I also tried more spring pressure on the HR set-up and it made no difference in RPM limits whatsoever......FWIW.

Cliff,
Did both of those engines use the SAME HR CAM?

Stan

[Formulajones]

I've never had an issue with hydraulic rollers going dead at 5800. My Chevelle goes right to 6500 with a Comp retro hydraulic roller lifter made by Johnson, and that same lifter is in dad's 571 Pontiac that zings right to the 6200 limiter.

Currently building a 327 sbc with a hydraulic roller that Paul expects to make peak around 6500. Those Johnson lifters by the way now cost $1600. I got them for $1140 before another price hike happened.

Maybe some that are having bleed down rate issues could possibly cause that problem. Most likely brand of lifter and lobe profiles are playing a roll.

[procharged 79]

A steel billet cam lobe isn't going to wear unless the lifter took a ****. 10,000 street miles is asking an awful lot from a set of solid roller lifters. Sorta like aluminum rods, you make xx number of passes and you pitch them no matter how good they look, but in the case of lifters you most likely have the option to have them rebuilt.

[Steve C.]

Related tid bits that might be of interest....

"The weight of the lifter is meaningless, since it is on the cam side of the rocker arm. Racing roller lifter engines can turn 10,000 RPM's or more. The Spintron machine was invented mainly to disprove the whole weight issue. The owner of Trend performance invented it because he was criticized about the weight of his pushrods, so he welded a piston pin to a pushrod, and ran it on the Spintron, and saw no measurable difference in power. Weight on the valve side of the rocker arm is what's important. Minimize it, and you don't need so much valve spring."
Paul Carter

"Do not be overly concerned about pushrod weight. The pushrod is on the slow moving side of the valve train. The additional weight of a heavy wall pushrod usually provides a much needed increase in valve train stability."
Manton Pushrods

"Always run enough seat pressure to control the valve action as it returns to the seat. Heavier valves require more seat pressure. Strong, lightweight valves require less seat pressure. When in doubt, run slightly more seat pressure . . . not less."
Crane Cams


.

[Stan Weiss]

Steve,
While true. One also has to look at the lobe profile. One of the reasons for an asymmetrical cam lobe is many have a slower seating velocity. Seating velocity is not a constant, as it does increases with RPM. Seating velocity is the speed of the valve when it touches the valve seat.

Stan

[Steve C.]

And related to Stan's post....

"With Bullet cams you can at least ask them what the specs are on the opening and closing rates. It will give you and idea what the true seat timing are. At least I do. I call up, ask the specs for the cam at the tappet lifts I am interest in and they tell me."
Jay S

Here is an example of what Jay mentions regarding calling Bullet and asking what the specs are on the opening and closing side of the cam.

UltraDyne lobe number R10
Rated with 288 degrees at .020" tappet lift and 255 degrees at .050" tappet lift. The lobe is asymmetrical with opening and closing rates that are different.
As it opens it has 282 degrees at .020" and 252 at .050" lift. When closing it has 258 at .050" and 294 at .020".


.

[Gach]

Related tid bits that might be of interest....and related post

Comp cam, will also give you those specs. If you ask. There’s no argument both cam company’s have great reputation. We could probably argue who makes the best solid roller lifters from now until the cows come home. Restrictors no restrictors. The truth of the matter is no matter how diligent you’ ve in making sure everything is correct. It could happen if you enjoy and love the power that it’s making plan on failure. Precaution would be having them rebuilt at X amount of miles. All the theory in the world is not gonna change that, still The hydraulic roller lifters have been the worst nightmare and definitely three times more failure over solid roller lifters.

[Stan Weiss]

Yes, it would be nice to get those numbers from the manufacture. But if you have a cam you can always find a shop that for a small fee will Cam Dr your cam.

Stan

[Gach]

Always run enough seat pressure to control the valve action as it returns to the seat. Heavier valves require more seat pressure. Strong, lightweight valves require less seat pressure. When in doubt, run slightly more seat pressure . . . not less."

.

You know its nice to hear these quotes, but no examples.. well yeah heavier valves require more seat pressure WELL how much more lighter valves less, well how much less. When pick a cam company do the tell you, do they even ask, hey what do your valves weigh. Install height which spring to give you this required seat pressure. The number one thing is ok we got all that right, but the big question is, what is the repeatability of the spell Springs itself. Is that ever checked I doubt it. Its great when first set up but how much dose that spring pressure Drop off overtime. Checking valves springs is just as important. You make some passes dyno pulls and you check them. Because if spring pressure falls off over time guess what, your going to wipe put a lifter. When I first had my heads done and doing a number of dyno pulls guess what those springs ended up in the garbage. Best time to check a valve springs is after you’ve made some passes or heated up after few street miles.

So besides all the cam profiling and weight of this and weight of that theory, turns out valve springs are just as critical. So it’s not easy to put a finger on why the solid roller lift failed. I mean you really have to check every valve spring. I know I know, its not easy checking all the boxes, those are the issues why a solid roller failed.

[ponjohn]

Pontiac dude said he had hyd rollers spin to 6500. I never knew if he divulged his secrets.

The drag n drive engines flood the cylinder heads to cool the springs. So with this method, one can assume that heat contributes to the failure, not necessarily the extreme valve action alone.

[tom s]

JMHO,I have always believed the Pontiac intake manifold is the choke.I have intake compares on the Dyno with dual plane single plane and 2-4 tunnel rams.Same cam,same springs and as the intake got better the engine made more HP at higher RPMs.Tom

[slowbird]

Originally Posted by tom s

JMHO,I have always believed the Pontiac intake manifold is the choke.I have intake compares on the Dyno with dual plane single plane and 2-4 tunnel rams.Same cam,same springs and as the intake got better the engine made more HP at higher RPMs.Tom

100% agree, we lack good intakes, with port they aren't bad but people are too cheap to port. They like buying cnc ported heads then bolting on an intake to choke the heads, lol.

[1968GTO421]

Originally Posted by slowbird

100% agree, we lack good intakes, with port they aren't bad but people are too cheap to port. They like buying cnc ported heads then bolting on an intake to choke the heads, lol.

Good point. Is there anyone besides SD Performance that ports intakes? They are the only manifold porters that I know of.

[Formulajones]

Wilson