[Stan Weiss]

From Performance Trends Cam Analyzer Manual

Seating Velocity Report, which calculates the valve closing velocity at several valve lashes of your choosing and 3 RPMs of your choosing. Don Hubbard’s book “Camshaft Reference Handbook” gives some “rules of thumb” for acceptable seating velocities, which are included in the program.

If I remember correctly UD Harold talked about his lobes being asymmetrical . Faster on the opening side and slower on the closing side.

Stan

[chuckies76ta]

Thanks Stan. Will check it out.


Charles

[Steve C.]

Further on the topic of a hybrid, the amount of valve lash is important. Mike Jones has pointed out with the hydraulic lifter you start opening the valve at around .004"-.006" lifter rise. Setting the hot lash above .0096" will put you above the end of the ramp, and the acceleration rate will be higher than any solid roller cam in the same size range. You're cam is harder on the valvetrain then a solid roller. And keep in mind using a higher rocker ratio will further complicate the situation.

Stan, You are correct regarding UD Harold talked about his lobes being asymmetrical.

"Both Harvey and I design Unsymmetrical cams, where the opening side and the closing side are different everywhere except at the nose, where we match both sides through the 3rd derivative, at least. We both use different off-sets, the difference between the opening and closing sides, even at .050".
Harold Brookshire


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[Steve C.]

Valvetrain Tech: Lash Is Much More Than Just A Little Gap

https://www.enginelabs.com/engine-te...-a-little-gap/


.

[tom s]

I think this issue comes up now about every 6 months!

[Steve C.]

Tom you are correct.... this at least 4 or more years ago !

"I don't go out of my way to recommend people run solid roller lifters on hyd. roller cams, in fact less than 5% of the hyd. roller cams we sell end up with solid roller lifters on them, my personal preference is to run hyd. roller lifters."
Dave Bisschop

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[Stan Weiss]

Originally Posted by Steve C.

Valvetrain Tech: Lash Is Much More Than Just A Little Gap

https://www.enginelabs.com/engine-te...-a-little-gap/


.

“We’re talking opening and seating velocity. Typically, with any collision exhibiting elastic characteristics, you want to make contact with non-zero relative velocity,” says Godbold. “Hence, you would like to be able to control both the opening and closing velocity of the system as the valve opens and closes. With zero lash, the system would be forced to have zero velocity at opening and closing, and this would limit engine performance.

“As valvetrain systems have become more rigid and allow for higher accelerations, opening and closing velocities have counterintuitively migrated down a bit,” continues Godbold. “However, the accelerations are moving the opposite direction to achieve even shorter seat timing with more area. That said, I do not see a day where we would desire a real ‘zero’ opening and closing velocity as would be required at zero lash.”

Note what is said about zero lash. Even hydraulic cams have a lash ramp.

Stan

[ta man]

Originally Posted by Steve C.

Tom you are correct.... this at least 4 or more years ago !

"I don't go out of my way to recommend people run solid roller lifters on hyd. roller cams, in fact less than 5% of the hyd. roller cams we sell end up with solid roller lifters on them, my personal preference is to run hyd. roller lifters."
Dave Bisschop

.

When I swapped my OF cam to the new cam from Dave. He informed me that the heads needed the new spring package. Never once did he bring up running solid lifters..and he knows I'm still running the same set of hyd Comp's since 2009 that he provided.

[slowbird]

Originally Posted by ta man

When I swapped my OF cam to the new cam from Dave. He informed me that the heads needed the new spring package. Never once did he bring up running solid lifters..and he knows I'm still running the same set of hyd Comp's since 2009 that he provided.

Any idea what your seat pressure is?

[TCSGTO]

I got the HR cam and Crower solid roller lifters from Dave Bisshop. He said the HR springs would be fine for the solid lifters on the Magnum lobes. When I was done using them after 5 years I sent the lifters to Crower and had them checked out. They were still like new. I sold them to a forum member and they’re still running today.

[Steve C.]

Dave does not think extra spring pressure is necessary, his statement on the subject from years ago.....

"When it comes to requiring more spring pressure on the hybrid set-up vs. running a hyd. roller lifter with all things the same and no more rpm is being sought with the solid roller lifters there's no reason why more spring pressure is required (lots of smart people at Comp Cams and other cam companies, but there seems to be a lot less smart people answering tech questions a lot of the time and you can call and talk to 10 different people and get 10 different answers). I did a back to back, same day dyno test with a 246/252 .400" lobe lift hyd. roller cam in a 468ci engine swapping from hyd. to solid roller lifters and there was no indication of valve float turning the engine up to 6200-6300rpm, using the 99893 springs set up around 1.800". The solids showed 6-8 more hp over the hyd. above the torque peak. Maybe if we backed the lash way off there might be something there, but until I actually see some solid back to back data to prove that the solid lifters need more spring pressure I'm just not buying it."

As Cliff has said, Any retard can Google up any topic and get 1400 different opinions on something. I want to hear results from DIRECT testing or even some sort of first hand experience with the topic at hand, not some cam experts opinion on the subject.

Now you have it !


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[70GS455]

Just got off the dyno with my 455. Bullet hyd roller with Johnson reduced travel HRs. Hp peaked just before 6000, test stopped there. 1.6 RR with 150# seat, 350 open (new) at .612" . No issues, nice and quiet at idle

Sent from my SM-T817V using Tapatalk

[tom s]

The people that actually make the cams say IF you want solid rollers buy a tight lash solid street roller cam in the first place instead of putting lifters on a cam that was not designed for them.FWIW,Tom

[mchell]

Originally Posted by tom s

The people that actually make the cams say IF you want solid rollers buy a tight lash solid street roller cam in the first place instead of putting lifters on a cam that was not designed for them.FWIW,Tom

I wish the same people that make the cams could make a lifter worth buying ...this debate would cease to exist!

[slowbird]

Originally Posted by mchell

I wish the same people that make the cams could make a lifter worth buying ...this debate would cease to exist!

Agree!

[tom s]

Pretty much because virtually NONE of the cam makers make their own lifters!Not sure Crane does anymore.Tom

[mchell]

Originally Posted by tom s

Pretty much because virtually NONE of the cam makers make their own lifters!Not sure Crane does anymore.Tom

Unfortunately, they still put their name on the box. Unusual problems breed unusual solutions.

Are the lifter issues a materials problem or an engineering problem? Or both?

[Formulajones]

Originally Posted by tom s

I think this issue comes up now about every 6 months!

It boggles me.

All the info that many of us have posted with good information on the subject, along with many pictures, should probably be made a sticky

It's just not hard to buy a quality lifter and make it work in a Pontiac.

[PontiacMatt72]

I read at least 3 seperate threads from a search prior to making my (this) post. Lots of conflicting reports, enough to make me second guess the idea of going HR.

But, if you guys think it’s a relatively safe option to go with the Johnson lifters with “less travel”, then I’m willing to give it a shot. Thanks for the input.

[Cliff R]

IF you can get a good set of HR lifters then you have answered your own question(s).

The only lifters worth two squirts of duck poop were the early Crane and Johnsons, at least from what I've seen here. Morel are problematic even though they are dubbed a high quality HR lifter. I know quite a few engine builders that will NOT use them due to inconsistent plunger to body clearances and leak down rates all over the map.

Back when Crane was offering the good HR lifters they were up around $800 per set, or about twice the price of Morel or any of the others. I'm not sure if those lifters are still available or if what they are currently selling is equal in quality? They were easily identified as they are scalloped across the top where the vertical bars attach (link to pic below), not flat like other brands. I used several sets of them and had ZERO issues with noise, and they were not RPM limited like some of the others. What I ran into here with the Morel and other lower cost HR lifters being supplied around 2004-2008 is that they go "South" around 5800rpm's no matter how much spring you have on them. They work fine below 5800rpms aside from getting a few "tickers" in the bunch which we corrected by lashing them about 1/4 to 1/2 turn UP from the plungers bottomed out vs down from zero lash.

https://www.jegs.com/i/Crane+Cams/27...SABEgL3TPD_BwE

In theory we should NOT have to adjust a well made hydraulic lifter in that fashion as any lash adjustment below zero and above bottomed out should have the lifter functioning correctly. Problem is that poor quality control leaves us with inconsistent plunger to body tolerances (and who knows what else inside them isn't up to par) and varying leak down rates. This often shows up as getting a "ticker" or two on a cold start after the engine has sat for quite a while, and some unacceptable noise when the engine is fully heat soaked and oil thinned out. Try telling your customer who just opted for the $1000 HR "upgrade" that they are now going to have to deal with a bunch of noise from their $10,000 Pontiac street engine.....that typically doesn't go to well....FWIW

Anyhow, when I was using HR lifters on engines built here they would often come from different sources depending on who was supplying the rebuild parts. I noticed that during that time the plunger travel and spring pressure under the plungers was all over the map, so I simply started setting all of them with minimal travel and just kept going. Since most of these engines were built and cammed to make power to around 5500rpm or so using HR lifters was never a problem. I also do NOT use a lot of spring pressure on my street engines and avoid camshafts with "aggressive" ramp profiles. That fact probably saved the day so I got away with using HR lifters on quite a few engine builds.

When I built the current 455 that's in my car in 2009 I decided to try the "hybrid" set-up as I knew it would make peak power up near 6000rpm's and I had problems with the previous engine not wanting to rev that high. The previous 455 ran flawlessly but it would NOT rev past 5800rpm's for any reason and I never pushed it up that high as I knew the HR cam and HR lifters were most likely the reason.

In any case I am not recommending anyone try the hybrid set-up. What I do know is that if you use the old Magnum lobe profiles found on the early Old Faithful camshaft it will be fine in long term service. It's one of those things that you are just going to get varying opinions on, and "theory" from different well educated sources. Sometimes with these things you just have to throw down the books, get off the computer, then jump in and get dirty to find out what works.........Cliff