Found this quote from Advanced Induction (they seem to focus on LS stuff):
"While it is certainly common to run a hydraulic lifter on a "solid" lobe, it is also common to run a solid lifter on "hydraulic" lobes. It is no more inherently precarious than the former situation - both require careful selection & application in our experience."

 

I have heard of some local guys doing it with no adverse effects, as the lobes are less aggressive on the hydraulic cam. I have no experience with it personally. The only downside I know of is the lash putting a hurting on your duration.

 

Yup, I am a little concerned about that. From what I understand about 2 degrees of duration is lost for every 0.004" of lash. That would be acceptable for the time being. I just want to avoid breaking a roller or something although I think there's more chance of that if I keep it the way it is.

I most likely am going to try this soon, but I also wanted to start a discussion on it.

As mentioned, the information I do find so far seems to come from the GM and early street rod camps.

 

I do not know for sure what the repercussions would be, but I see it like this:

Cam profiles are designed to keep forces within the valvetrain below critical limits for a certain application...a lot of physics and calculus involved. Mass has a direct relationship to force and acceleration (F=ma). If acceleration remains constant, then ignore it so the equation becomes F=m, in which case reducing mass with lighter lifters will reduce the force necessary to accelerate the parts, which is good. If the reduction in mass is significant, it may be beneficial to reduce valve spring rate.

In other words, I see no reason on paper why it would be risky or detrimental to use solid rollers on a hydraulic cam. I would not use hydraulic lifters on a solid roller profile, though.

 

I like that logic. I think another issue is how quickly the lobe accelerates the lifter and how will it react near max lift, on the nose, and on the way down.

Usually it's said that the ramps on a cam are set up for a certain type of lifter and that hydraulic cams don't have the correct ramps to take up the lash on the way up nor to set the valve down softly. But that information seems to date back to times before roller cams were so common (prehistoric times? LOL).

Looking at the difference in what I understand is the "Intensity", or the difference between the advertised duration and the duration at 0.050", the XE282HR actually seems to be less aggressive that the 35-772-8 that I ran previously. It has an Intensity of 37 or 38 degrees while the street solid roller was around 50. If I am getting that right, that tells me the ramps are actually longer on the hydraulic XE282HR versus the solid roller 35-772-8! But from 0.050" to max lift, I have a feeling that the XE282HR is more aggressive.

So with that bit of news about the Intensity, in conjunction with the lighter solid lifters, this might be just fine. In fact it might end up being a stellar turbo setup.

By the way, in terms of the opening and closing ramps, I had heard that you can run a hydraulic lifter on a solid roller cam, but on a bigger cam you could certainly have stability issues at high speeds (valve float or lifter bleed-down). But on a milder cam or cruiser application, it might be OK with the right springs.

 

That Comp cam with the -8 part number would be a SADI core, might not like getting pounded by solids. If it was billet I'd say give it a try.

 

"Pounded" by solid lifters?

 

The street roller cams are also on the -8 cores, 35-771-8, 35-772-8, and so forth. One of the techs at Comp said those cores would be fine with the AFR 8002 spring (165/430 lbs) but he said it would eventually "brinell" if ran for very long with AFR 8000 springs.

About 5 years ago I ran a 35-771-8 street roller cam with AFR 8000 springs and while it didn't hurt the cam right away, I did have problems with the set screws loosening in the rocker arms. Not sure that was related to the springs (probably not), but I changed to the slightly lighter springs based on the info from Comp about the brinneling, and also ran a tighter lash. Didn't have a problem after that.

 

Update on this:

Finally got some response from Comp Cams and they said this is done every day (solid rollers on HR cam), but they said to run a tight lash, keep a close eye on the lash for changes that might indicate a problem, and be sure the bottom end can handle more rpm.

So that is good news. I also ran the combo in the download version of CamQuest. This version will allow input of the stroke, valve sizes, etc. The recommended optimal cam for me is still the street solid roller 35-772-8 but the XE282HR is not far enough behind to warrant replacing it at this time. Of course the software wouldn't let me model the solid roller lifters on the HR cam, heh heh.

So I removed the Howard's 91168 link bar lifters (allegedly made by Morel) that were in the car since I need them on another project. And I ordered a set of Lunati 72411 SR lifters since I have heard that the Howard's 91217 solid roller lifters might NOT be made by Morel and I wanted to play it safe.

Interesting there may be a substantial difference in the weights of the respective lifters:
Howards 91168 (Morel) - 338 grams/pair (on my scale, not bled down)
Lunati 7411 (Morel) -262 grams/pair (according to Jeg's)

 

By "tight lash", I'll start with around 0.005" cold and go from there. As the engine heats up, the clearance gets bigger. The goal is to minimize noise and stress on parts but not have the valves hang open. They need to seat solidly to transfer heat to the seats and obviously to seal the cylinder.

The Comp street roller cams call for a hot lash of about 16 to 18 thousandths, and for me that was about 8 to 10 thousandths cold. Any more than that was loud and occasionally a set screw would loosen up. With those cams I usually tightened it to 6 to 8 thousandths cold and was pretty happy with that.

 

Good to hear you got the OK directly from Comp.

 

I know they try, but are not always consistent. Really depends on who you talk to and the information you give them. Once the guy knew this car is a track toy and not a daily driver, he was like "yep, sounds good...done all the time...keep a close eye on it".

 

I'm curious by how much (if any) the spring pressure requirements change when running a solid lifter on a hydro cam. Given the reduction in moving mass of the lifter itself, in theory you should require less spring pressure.

I'm tempted to try this on my 408 as I already run a billet cam with likely the most aggressive hydraulic lobes Comp offers. Running a lifter with a .750 wheel as opposed to the typical .700 should compensate a little for the lash induced reduction in duration.

 

That's one of the reasons I'm trying this. With the heavy link-bar hydro lifters and the possibly more aggro XE lobes compared to the previous Comp street roller cam, I seem to be getting valve float with the same springs that worked before. I'm hoping that this cam profile can work with these springs since the solid roller lifters are lighter and there won't be any pump-up issues. Parts are on the way so we shall see.

 

How will that help? Valvesprings are too heavy and too low of pressure for the mass of the spring for HR, why do you think solid will help? Aren't new springs much cheaper than good HIPPO lifters?

 

This is not hard to understand. I am convinced hydraulics suck for my application, so I'm not changing springs to try to make it work. No need for HIPPO lifters. A lot of guys seem so focused on the latest and greatest offerings (& always more expensive too, right?) when there's other parts that have done the job for decades and in thousands of cases.

I've done the research, also talked to Comp, and am convinced this will work fine.

With that said, what gives me pause now is the decrease in duration as result of the lash. Even with a tight lash, when warmed up, it will be giving away about 4 degrees at 0.050". The cam is already too small and that is moving in the wrong direction ;-)

So it's probably time to evaluate other options right now.

 

You are right, and back in the day you couldn't use SR on the street. What makes you think using the tech from the 70s won't give the failures that they had in the 70s? I think you are just going to have an expensive learning curve. I hope the best for you.

 

"As the engine heats up, the clearance gets bigger." Depends on the materials the block and heads are made of. For cast iron block and heads, it actually goes the other way -- cold lash is always larger than hot lash. For iron block and aluminum heads, cold will be a bit smaller than hot -- if you search around, you'll see gains of .003"-.006" depending on the specific block and heads and the length of the valves/pushrods. For aluminum block and aluminum heads - the difference is the greatest - again, specific combos differ, but you may see .008"-.010" more lash hot than cold in all aluminum set ups.

Probably ought to factor that in as you guess at your starting lash.

 

Good points.

As for the overall topic, I found quite a few threads with anecdotal info and one article. This covers it about the best so far, and I keep circling back to it:

Taken from -
Solid Rollers On Hydraulic Cams - Hot Rod Magazine

--------------------------

Solid Rollers On Hydraulic Cams

Can you run aftermarket solid-roller lifters on an aftermarket cam originally designed for hydraulic-roller lifters? Other than the profiles of the hydraulic-roller cams perhaps not being as aggressive as the solid-roller cams, what would it hurt? Could the rpm range of the hydraulic-roller cam be extended by using solid-roller lifters? Would the lobe profile on the hydraulic-roller cam be somewhat more forgiving for the valvetrain components than the lobes of the solid roller?
Clyde E. Byrd
Little Rock, AR

With care and within reason, it is often possible to run solid flat tappets on a hydraulic flat-tappet cam and even mechanical-roller lifters on a hydraulic-roller cam. Putting solid lifters on a hydraulic-cam will gain about 500 rpm on the top-end over hydraulic lifters due to the solid lifters' improved valvetrain control-unlike the hydraulic, solids have no bleed-down/pump-up problems. Some hydraulic-roller cams-particularly smaller grinds with 220-240 degrees duration at 0.050-are quick off the seat, but this tends to cause more instability on top. Using solid lifters, even with the existing hydraulic springs, enhances top-end stability and fights the onset of valve float.

Successfully running solid lifters on a hydraulic profile requires some amount of valve lash (a solid lifter cannot run at zero lash or be preloaded). This lash effectively reduces cam duration, especially at low lift off the valve seat (see table). With less duration, peak torque and power occur at lower rpm than would normally be the case for the given combo when running a hydraulic lifter-in other words, the cam acts smaller.

Exactly how much lash is required varies with the specific cam profile, as well as the material the block and heads are made from. Too little lash and you could burn a valve; too much and the valvetrain gets very noisy. Generally the amount of hot lash will vary between 0.004 and 0.015 inch. Such tight hot-lash settings cause problems with aluminum blocks and heads, which see considerable thermal expansion between cold-start and normal operating temperature, so running solids on a hydraulic profile isn't recommended with all-alloy engines. Generally, aluminum heads on an iron block work out OK, with lash expanding about 0.012 inch from cold to hot. With iron heads, expect about 0.008-inch growth.

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.

Some classes restrict competitors to hydraulic lifters. Cheaters have been known to run hydraulic lifters on a solid profile. Because they have no quiet lash ramps, solids make for better race profiles. If you take hydraulic lifters and put them on a solid profile, they generally run better than they would on a roughly equivalent hydraulic profile, generating more area under the curve. Hydraulic cams in general are quicker in low-lift, low-rpm, high-endurance applications. Race motors don't care about vacuum and throttle response; they care about area and rpm. Putting hydraulic lifters on a solid grind raises the rpm points at which peak power and torque occur compared to using solid lifters on the same solid cam. However, the actual power and torque peak numbers at the higher rpm points will be lower using hydraulic lifters. That's because the hydraulic lifters installed on the solid cam are slower off the seat, even though they develop more overall duration. Effectively, the hydraulic lifters installed on a solid grind act like a bigger (but slower) cam with very little increase in flow capacity (no more air, but more time to breathe). In terms of numbers, this means a 249-degree-duration (at 0.050-lift) feels like a 255-degree cam.

To successfully run hydraulic-roller lifters on a solid-roller profile generally requires that the solid cam be a tight-lash (under 0.020-inch hot) profile in the first place, with less than 30 degrees difference between the 0.020- and 0.050-inch duration specs.

Duration Vs. Lash

This shows the change in effective duration at the valve from different valve-lash settings on a Comp Cams Xtreme Energy No. 3315 lobe profile. It assumes1.5:1 rocker arms.
Valve Duration at Lash
Lift 0.004" 0.008" 0.012"
0.006" 279.7 273.6 268.6
0.020" 262.5 258.9 255.6
0.050" 240.9 238.6 236.5
0.200" 183.2 181.9 180.6

Read more: Solid Rollers On Hydraulic Cams - Hot Rod Magazine

 

That sort of comment seems standard for you. What is your personal experience on this? From this and other threads, it sure seems like it consists of primarily keyboard and mouse operation.

 

Yes, mostly...

I will admit the broken SR lifters I seen were on street SB Chevy with a smaller core, so maybe your standard non oil SR will live a while on a Ford core? My comments have nothing to do with running SR lifters on an HR core, that is fine in my book, but just the fact you insist on the cheap route to every detail and always seem to find the funds for the next band-aid instead of just addressing the issue. Even the lifters, won't even spend for the pin oiling in a street car? I have been there, I have done a lot things the way you are doing it, it has made it hard to fast and reliable with how expensive it is to do it more than once. You do as you will, because I wouldn't listen to a keyboard warrior either.

 

The main issue we're dealing with here is lash and how much of it is tolerable to the valve train components. Having the roller consistently beat on the trailing side of the lobe with a looser lash setting is going to make things break quickly (i.e. shock loading). This is why solid roller cams by design have a "catch ramp" on the closing side of the lobe to keep this from happening. The modern, more aggressive hyd profiles have this too, but to a lesser degree.

If you look at the lobe wear pattern on just about any used roller cam (hyd or solid), you can see the area where the lifter suddenly exerts more pressure on the closing side of the lobe when the lifter catches up with it. With a hyd lifter theoretically having no lash, it still can lose contact with the lobe - the hydraulic mechanism of the lifter can't respond to the increase of slack that quickly, otherwise it would pump up at lower speeds. That's why you can run into valve float with a hyd lifter, which is almost always a result of insufficient valve spring pressure. Bottom line is the valve train has to be able to deal with the lash by design and the valve spring pressure has to be set accordingly so the lobes don't get beat to death.

 

Ramps:

One of these days I'll plot the profiles of the cams I have around here, using v-blocks, degree wheel, and a dial indicator. I'd love to do that for the XE282HR prior to putting the solid roller lifters on it, particularly to see how the ramps look. Unfortunately tho, it's still in the motor, which is in the car and I don't have a convenient way to both mount the degree wheel and turn the crank.

Anyone know of an XE282HR profile graph already available?

Lifter weight:

Also, I just received the new Lunati lifters and the weight of each pair is 9.2 ounces (261 grams) on my scale.

 

I have a little over 9K miles on an older set (1990's) of comp cams 938-16 solid roller lifters and have no issues to date. These are the lifters without the revised EDM deal. They have been in 3 motors and have a good deal of idle time on them which everyone says kills SR lifters. Next time I have the current motor apart I will probably have them rebuilt, but, they have held up well so far.

If you do end up running a SR lifter on a HR cam let us know how it works out as I have heard you can do this but do not know anyone hat has actually done it

 

I ran a 240/250 HR with Rhoads modified stock HR lifters for about 15k or so and experimented from 008-.025 from bottomed out with no excessive wear on my valvejob or any other components.

-Jesel SS shaft mounts
-9 billet core
-beehives 1218pac
-explorer composite lifter guides
-XE 240/.574 intake lobe-Marine BBC exhaust 250/.576

Going back together with a fresh timing chain, lifter guides, 1519 Pacs, 1.7 intake rockers and a -9 XE232/.565 intake lobe and a 242/.587 exhaust. Total lift will be .600-.587 even with the lifters .010 from bottomed out. Not saying it's cheaper in the long run to experiment, but it sure is more rewarding. A fast car is made from R&D. but!
I use quality parts
I keep a close eye/keen ear on things
I never try to kill her

 

And I ran the lash .010-.013 for 75% of the time.

 

Thanks guys. I messed around tonight and didn't make much progress but I should have it running tomorrow. After it goes around the block a couple times, I'll post results for sure. But I probably won't beat it up for at least a month or so after that. It's not bad at the track but traction on the street can be a problem ;-)

Hey Gray, I like those custom cam profiles. Did you spec those? Seems like you like the XE lobes on the intake.

By the way, aren't you an aircraft mechanic? I thought I saw that mentioned in a post I ran across recently. I went to AP school but switched over to machining before I finished the program (way back in the day).

 

Yes I work as Flight line maintenance at Austin Bergstrom Intl. When I'm at work I'm the only aircraft mechanic on the airport handling 80% of the commercial air carriers operating. Huge job and tons of responsibility but it is far from boring.

Yes I spec my own cams and now have the capability to do my own heads.

 

That is impressive. Seems overwhelming if more than one plane needs work and of course there are schedules to keep. Crazy.