Solid roller lifters on hydraulic roller cams

[408 Nova]

I have heard of people doing this. Question is why? And what's the reliability on this? Will it last very long?

[F-BIRD'88]

Can you keep the lash set tight, tight, accuratly?

IMHO should really only be done to test A-B VS the perf of your hyd roller lifters, then take corrective measures as needed to get the hyd roller lifters working . Short term testing..

Solid street roller cams have proper lash ramps and will make more power than hyd roller cams (even with solid lifters on)
Why not just get a street/endurance DESIGN mechanical street roller cam and kit in the first place? Someone will buy your hyd roller setup.

Hyd roller setups are great right up to the point where they become not so great.

[ClassAct]

I have heard of people doing this. Question is why? And what's the reliability on this? Will it last very long?

I don’t use hydraulic lifters any more because they are just as noisey as a solid anyway. Plus the hydraulic lifter is a shock absorber in the system and a solid lifter takes that out. You get more valve train stability too.

[CamKing]

I have heard of people doing this. Question is why?

Because some people are under the false belief that it's easier on the valvetrain, then running mechanical roller lifters on a mechanical roller cam.
That's completely false, and in some cases, it can be much harder on the valvetrain, depending on the hydr roller lobe profiles.
Some hydr roller profiles have no opening ramp at all, and accelerate quickly, right off the base circle. This makes the velocity/acceleration at the lash point much higher then most mechanical roller profiles.

[RW TECH]

Adding to Mike's comments, some people believe hydraulics lose significant lift from plunger bleed-down.

I did not see anything "big" related to loss of lift when I did dynamic spin testing on hyd rollers. Maybe about .010" as a worst case, and I saw some solids that did about the same thing.

[frnkeore]

There must be a little more to it.

Both Blair Patrick (1st place) and Geoff Mummert (2nd place) ran a hyd cam with solid rollers, in the last EMC.

I don't understand it but, maybe it has to do with matching valve flow % to cam duration? I don't know but, there must have been a reason.

[CamKing]

There must be a little more to it.

Nope. Not a thing more to it.
There is nothing to gain over running mechanical roller lifters on a mechanical roller cam.

[i82much]

If one picks a mild solid roller lobe that can run with moderate valve spring pressure and runs a lifter with a proper oiling provision, can you see 50k mile durability out of a solid roller or more? If so, what lobe family is out there that can provide this kind of longevity? And do you wind up with any real gain over a hydraulic roller if you run a solid roller with a milder profile suited for longevity?

[bob460]

There must be a little more to it.

Nope. Not a thing more to it.
There is nothing to gain over running mechanical roller lifters on a mechanical roller cam.

Mike, what about running one of your solid roller cam lobes with a .904 morel hydraulic roller lifter?............street/strip deal not a racing deal.

Foxwell & Straub used to do a lot when they were working together..........and made good reliable power.......it seemed to work!!

The morel .904 lifter can take some seat pressure and open pressure.

What's your thought's?

[tjs44]

Mike can confirm,Comp told me I would loose about 8 degrees of duration and what ever lash I use on lift.They told me 6 thou.So your making you cam smaller by using solids and you should treat it like a solid roller cam and add spring pressure to control the valve train.Tom

[Walter R. Malik]

There must be a little more to it.

Both Blair Patrick (1st place) and Geoff Mummert (2nd place) ran a hyd cam with solid rollers, in the last EMC.

I don't understand it but, maybe it has to do with matching valve flow % to cam duration? I don't know but, there must have been a reason.

The biggest reasons are called maximum valve lift RULES and high spring forces.

[CamKing]

If one picks a mild solid roller lobe that can run with moderate valve spring pressure and runs a lifter with a proper oiling provision, can you see 50k mile durability out of a solid roller or more?

Yes, with the right cam and lifters 50k is not an issue.

If so, what lobe family is out there that can provide this kind of longevity?

You need to work with a cam company you trust, to find you the right profiles for what you want to do.

do you wind up with any real gain over a hydraulic roller if you run a solid roller with a milder profile suited for longevity?

Yes, but the amount of gain depends on different factors.
On higher RPM engines, it's a bigger gain.

[CamKing]

Mike, what about running one of your solid roller cam lobes with a .904 morel hydraulic roller lifter?............street/strip deal not a racing deal.

The Morel "Limited Travel" hydraulic rollers that they run on mechanical roller cams, are not really Hydraulic.
They're basically a mechanical roller lifter with a small amount of movement to get passed tech in racing classes that require hydraulics.
That's why they work well on mechanical roller cams.
There's zero advantage to running them, over a normal mechanical roller lifter.

[bob460]

Mike, what about running one of your solid roller cam lobes with a .904 morel hydraulic roller lifter?............street/strip deal not a racing deal.

The Morel "Limited Travel" hydraulic rollers that they run on mechanical roller cams, are not really Hydraulic.
They're basically a mechanical roller lifter with a small amount of movement to get passed tech in racing classes that require hydraulics.
That's why they work well on mechanical roller cams.
There's zero advantage to running them, over a normal mechanical roller lifter.

I'am i wrong in thinking that the hydraulic roller lifter would last longer because the needle bearings don't get beaten to death like a solid lifter would?

[CamKing]

The Morel "Limited Travel" hydraulic rollers that they run on mechanical roller cams, are not really Hydraulic.
They're basically a mechanical roller lifter with a small amount of movement to get passed tech in racing classes that require hydraulics.
That's why they work well on mechanical roller cams.
There's zero advantage to running them, over a normal mechanical roller lifter.

I'am i wrong in thinking that the hydraulic roller lifter would last longer because the needle bearings don't get beaten to death like a solid lifter would?

Solid roller needle bearings don't get beaten to death, if the cam is designed correctly. That's what the lash ramps are designed to avoid.