[grandville455]

Lets not get off track here guys, The only reason I POSTED Harry's graph cause its the only thing i found that someone had done back to back dyno and showed the power difference from just a lifter change. I am trying to figure out if My car being more set up for drag than harry's test car was, if it will infact run quicker being I am adding some power, and i won't be loosing that duration and lift at higher rpm's .Plus I have enough conv to make up for any lost that will be down low, but i leave at 2000 and it flashes to 4200, so i am pretty sure i won't feel any of that lost torque down low anyways. I am also pretty confident that it will pick up in the mid and top even more than it already was. Pulling hard to 6000 grand with ease! It will be back together sometime next week and plan on hitting the next race which is next sunday, the weather looks to be warmer than the last times i have been out so well see what it has, my gut says I will be smiling!

[Cliff R]

In theory a tight lashed hydraulic roller lifter would run like a solid roller lifter, if it was designed from the start as a limited travel lifter, and one ran it down till the plunger bottomed out, then backed it up to provide about .010" plunger travel. I've been wanting to try this deal out, and may on my next engine. The small amount of oil trapped, even when tight lashed would provide the "cushion" and constant roller to lobe contact that isn't present when running solid roller lifters on the HR camshaft.

I still don't think it will rev quite as well as the HIPPO's, as they are considerably lighter, but one could always use more spring pressure, or lighter retainers, or even beehive springs/retainers etc, to make it even more effective.......Cliff

PS: we've made it to page 2, and not one question yet as to how to run the valves, and what lash to use, etc. I have built/tested three street/strip engines to date using the "hybrid" set-up, logged hundreds of runs with them and many thousands of street miles, ran the lash all over the place, checked them hot, cold, split the settings, etc. We have them on two of Dave's cams, the Old Faithful and the Road Paver....FWIW..

[Steve C.]

I know its been discussed here many times, about .006" lash is not uncommon.


The more aggressive the lobe, the tighter the lash needs to be. The tighter the lash, the more thermal expansion problems must be taken into consideration. For example, Comp Cam's older Magnum hydraulic-roller grinds usually run fine with solid lifters at 0.012-0.014-inch hot lash. But its newer, much more aggressive Xtreme Energy hydraulic rollers get very noisy over 0.010-0.012 hot lash, so Comp recommends 0.006-0.010 lash settings. When lashing the valves, set them at 0.004 inch cold, then warm up the engine, and recheck it hot. Fine-tune lash settings within the preceding recommendations if the valvetrain is too noisy. Once satisfied, let the engine cool down again and recheck the lash. In the future you can accurately cold-lash the motor.
Read more: http://www.hotrod.com/techfaq/hrdp_0...#ixzz1uWGXm6Yx



With the advent of hydraulic roller cams, the question has arisen whether or not it's safe to run solid roller lifters on them. The answer is as readily disputed as most new forms of technology are today, but in a pinch you can do it. You must run very tight lash, .005 to .006, because of the lack of a clearance ramp on the hydraulic lobe design and running too much lash will quickly kill solid lifters on a hydraulic lobe.
Read more: http://www.popularhotrodding.com/eng...#ixzz1uWHMENsP

Anyone want to tackle the subject of what is adequate spring pressure with a solid roller lifter on a hydraulic roller lobe ?



.

[tom s]

Steve,the first RA V engine I built about 12 years ago,Comp told me to run 200 on the seat and set at 6 thou with solid rollers on their 400 lobe lift hyd roller cam.Dean Harvey was the guy.This was WAY back then.Im told that I can run the hyd rollers with high seat pressures on the hyd rollers.Am going to try it soon.Tom

[grandville455]

Originally Posted by tom s

Steve,the first RA V engine I built about 12 years ago,Comp told me to run 200 on the seat and set at 6 thou with solid rollers on their 400 lobe lift hyd roller cam.Dean Harvey was the guy.This was WAY back then.Im told that I can run the hyd rollers with high seat pressures on the hyd rollers.Am going to try it soon.Tom

Tom
Be curious to know how aggressive that cam was at .200 etc

[Steve C.]

Thanks Tom. I recall you have mentioned that before here. The owner of our local speed shop delt with Dean Harvey for years, I bought two solid rollers thru him.

Most companies will tout running a bit more spring pressure to be safe won't be a issue. With his switch to solid roller lifters on a hyd roller lobe my buddy here in town just left his solid roller springs for his previous XE solid roller in place. The springs originally went in with about 200 lbs seat pressure. They have lost some pressure but he feels very comfortable. It's a street car with air conditioning and driven quite a bit.

I suspect few here actually have verified their seat pressure at their actual measured installed height with their solid roller set up on a hydraulic roller lobe. Will it be a guess, or numbers related to what someone said you should expect ?

Cliff has stated here on PY, "The springs I'm using are set at 1.800", this yields about 150-160lbs on the seat, and 380-400 lbs over the nose at .627" lift".

Out of interest I contacted cam companies and independent cam design engineers on the subject. Especially related to adequate spring pressure involved. I've posted the information obtained on numerous occasions, probably been a pain in the ass on the subject All those I communicated with will agree it NEEDS ADDITIONAL spring pressure over a hydrulic roller set up. The absolute minimum I got from one Comp Cams tech rep was only 150 lbs seat pressure !! That was with a smaller hyd roller lobe in use and not with a lot of RPM involved, other engineers from Comp have suggested higher seat pressure numbers. Much depends on what cubicle you get connected to. Other independent cam designers have suggested much higher than 150 seat pressure to me. I've communicated with Steve Brule* at Westech Performance on the subject, he's another advocate for higher seat pressures.

*http://www.hotrod.com/techarticles/e...s/viewall.html

My opinion, and admittedly with no personal experience, if it were me on my street combo I'd treat it as a small XE solid street roller with about 160-180 seat pressure after run-in, depending on the valvetrain mass involved.


.

[grandville455]

I will be getting my springs tested today with my retainer and the IH I plan on using, will let ya know what I find.

[Cliff R]

"Out of interest I contacted cam companies and independent cam design engineers on the subject. Especially related to adequate spring pressure involved. I've posted the information obtained on numerous occasions, probably been a pain in the ass on the subject All those I communicated with will agree it NEEDS ADDITIONAL spring pressure over a hydrulic roller set up."

Nothing at all wrong with contacting "experts" on the subject, and I respect their opinions. Even so, how can they be "experts" if they are NOT actually doing it?

You are simply asking their opinion on a topic they have no direct experience with.

Knowing this, I started out setting the valve lash at .008/.012 for the intake/exhaust, warming up the engine and rechecking them hot. I did this at least three times, and also paid close attention to the valvetrain noise, etc.

I ended up running mine at .005" lash for all valves. When completely warmed up, this puts the actual lash around .007".

I did notice a couple of problems related specifically to the cam, and to the rocker arms. The base circle on these cams is NOT consistent. Depending on which position the lobe is in the lash will vary a few thousanths. I tried several methods when running the valves, following the firing order, TDC of the #1 piston and 180 degrees from TDC, positioning the lobe so its exactly 180 degrees from the full lift point, and intake valve fully open/exhaust valve just starting to open.

You will get different readings for each method. Sort of bothered me at first, but then I just figured being out a thousanth or so really isn't going to hurt anything as the engine really doesn't seem to care and the valvetrain was quiet.

To complicate matters a bit, the PRW rocker arms have a built in defect. The roller tips are NOT bored exactly on center. I discovered this the first time I went to run the valves. With the feeler gauge in place, any attempt to move the roller to another position showed some deviation in the setting, it would go tight or loose depending on what position it was in when you started. Once again some slight deviation due to the parts involved, but no more than about .002" on the very worst one.

Knowing I have at most about .004" deviation between the base circle of the cam being out some, and some deviation in the roller tips of the rockers, I settled on setting all the valves at .005". The engine is happy, and worst case scenario hot on any lobe we check they are no more than .008-009". The valve train is quiet, and no problems with any of the parts to date.

Since discovering that Comps lobes are off some (another customer using one of these cams just discovered the same thing and emailed me on it last week, so the trend continues) I'm leaning towards using a hydraulic roller lifter next time, and running them down till the lifter plunger bottoms out with a .010" feeler gauge between the rocker arm roller tip and the valve stem. If the HR's are well made and the source oil hole to the plunger pressurizes them with the plunger that low, it should work equally as good as tight lashing solid roller lifters on the same lobes. The added benefit would be that there would be no "take-up" using the HR lifters, and at high rpms really no place for any hydraulics involved to give troubles.

Fine in theory, but once again, someone is going to have to try this to see if it really works.

Not meaning here to bad mouth PRW steel roller rockers, or any other imported "knock-offs" of the same design. I doubt if the slight deviation we find with them would hurt anything, especially if a HR lifter was being used. In any case, I'm going to install Crower Enduro full rollers on my next engine. I just replaced a busted up set of Scorpions on a 750hp 505 engine we "freshened up" here, and they are very well made parts, and deadly consistent on the roller end with no measurable devation in them. They are a LOT heavier than the aluminum rockers, weighing both boxes showed the Crower steel rockers were 5 lbs heavier than the Scorpions! To make Steve happy I'll use a tad more spring pressure on my next engine as well...LOL....Cliff

[Chupa]

I noticed u mentioned your converter- 4-4500 is too low of a stall. I had a 4000 10 inch and changed to a 5200 8" ATI MRT and picked up 2 tenths and 2 mph in the 1/8 . PM me if u want more info.

[grandville455]

Originally Posted by Chupa

I noticed u mentioned your converter- 4-4500 is too low of a stall. I had a 4000 10 inch and changed to a 5200 8" ATI MRT and picked up 2 tenths and 2 mph in the 1/8 . PM me if u want more info.

I will keep that in mind, but i also drive this to and from the track

[tom s]

3115 and 3116 lobes I believe.245-252 ish?Im in SC and dont have my book here.400 lobe lift.Tom

[grandville455]

Originally Posted by tom s

3115 and 3116 lobes I believe.245-252 ish?Im in SC and dont have my book here.400 lobe lift.Tom

That is the same cam I have

[ponjohn]

Confusion--lash increases as engine warms up? I would think the lash would close up as the metal expands.

Darby- What spring pressures are you aiming for?

[grandville455]

Originally Posted by ponjohn

Confusion--lash increases as engine warms up? I would think the lash would close up as the metal expands.

Darby- What spring pressures are you aiming for?

John
I Should be around 165 for my IH...

[Steve C.]

"To make Steve happy I'll use a tad more spring pressure on my next engine as well...LOL....Cliff"

Thanks my friend, I'll sleep better at night.

"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."
http://www.cranecams.com/faqview.php?s_id=33


Now I'm off to polish and wax my computer keyboard



.

[grandville455]

Since the Hyd lifters are so much heavier Than the solid lifters do you still need to run that kind of pressures to keep good contact with lobe face . and not have lifter bounce off the lobe? One would think if their lighter they wouldn't need as much pressure?

[Steve C.]

They don't. The weight and the lobe (ramp area) itself allows for less spring pressure, but not the same as a normal hydraulic roller set up. It can be less compared to most solid roller set ups, some of us use 200+ lbs seat pressure. This is what I understand and have been told. The debate is how much, many including myself feel your better off with more not less.

It is my understanding Steve Crane actually rates your 99893 spring for smaller solid roller use as well with a 1.750" installed height, BUT due note at that installed height it results in about 165-167 lbs seat pressure. And as I stated many run small XE solid rollers with 160-180 lbs seat pressure. To many that might be overkill for solid roller lifters on a hydraulic roller lobe.

From a Jim McFarland article....
"Valve train stability. Nothing mysterious here. As opposed to lifter-lobe separation at maximum valve lift (sometimes mistakenly related to valve "float" or "bounce"), this is actually the result of improper valve seating, particularly the intake. When this happens, you can expect cylinder pressure and power to decline. It's as simple as that.
What can cause valves to "bounce" during a closing cycle? Insufficient valve spring pressure, improperly designed camshaft lobe profile, and excessive rpm are among the leading issues. Not only can cylinder pressure be lost but also damage frequently occurs to valve seats, spring retainers and valve keepers. In addition, valve springs become weakened each time a condition of bounce takes place. In addition, the problem will occur at a lower and lower rpm each time a spring is subjected to this condition."



.

[Chupa]

Originally Posted by grandville455

I will keep that in mind, but i also drive this to and from the track

I'm really surprised by this... never would have thought...

Anyways my car seems to have pretty good manners and hope to make it so I can drive to work on Fridays, occasional car shows, and so on...

The converter acts fairly tight until loaded - then watch out.

Well if you want to step it up a notch you know what to do.... Go get an ATI 8"

[tom s]

I believe all the major cam co use the spinton to figure out needs of the valve train.If Comp tells me to run 200 on the seat with solid rollers on a high lift hyd roller cam I guess I will do that.Tom

[ponjohn]

[quote=Steve C.;4629390
What can cause valves to "bounce" during a closing cycle? Insufficient valve spring pressure, improperly designed camshaft lobe profile, and excessive rpm are among the leading issues. Not only can cylinder pressure be lost but also damage frequently occurs to valve seats, spring retainers and valve keepers. In addition, valve springs become weakened each time a condition of bounce takes place. In addition, the problem will occur at a lower and lower rpm each time a spring is subjected to this condition." .[/quote]

Steve-

I'd be very interested to see an SD ( Comp Lobes) cam replicated with Bullet asymmetric lobes.