Power- Solid Roller vs Hydro Roller ?

[427HISS]

I'm pretty sure I know the answer, bit I'll ask anyway.
Is there any difference in power between a solid roller and a hydro roller cam ?

[chilly460]

I think it's pretty well established that they'll allow more rpm, especially in an FE with heavy valvetrain, although our resident builders have been make headway in expanding the rpm range. 

The interesting question is if a solid roller would make more power in say a 6500rpm max application.  Guessing we don't really know, as it's not been done truly back to back, it's hard to exactly duplicate lobe specs even if we did, and doubt it's a small sample size of guys hassling with a solid roller for that range.   

[Falcon67]

Having run (running now) a hydro roller in s "mild race" setup, I'd opt for a solid roller just to be sure everything was available at RPM ranges like 6500.  I'd running a Howards hydro with their roller lifters in the 351C and it for sure signs off at 6500.  The solids are lighter parts too.  If I wasn't building a full new motor for the dragster I'd be buying solids to put on that hydro cam, just to get some RPM back.  Air shifter is set at 6300.  If you go solid, the extra expense is in the lifters - you want pressure oil units and not cheaper splash oil, especially if its a street/strip application. 

[pbf777]

The interesting question is if a solid roller would make more power in say a 6500rpm max application.  Guessing we don't really know, as it's not been done truly back to back, it's hard to exactly duplicate lobe specs even if we did, and doubt it's a small sample size of guys hassling with a solid roller for that range.

     The answer to the first part of the question is an absolute, yes it is possible to make more power at 6500 R.P.M., and even less utilizing a mechanical roller cam versus a hydraulic.  But the second thought of duplicate lobe specs nullifies the the first as it either restrains the potential in the attributes of the mechanical function over the hydraulic, or creates one not compatible with the hydraulic.     

     Scott.

[Falcon67]

IIRC, Hot Rod/Engine Masters has a show about running solid rollers on a hydro roller cam.  And the conclusion was, yes - it made more power.  Had to tighten the lash way up as I recall.

[pbf777]

IIRC, Hot Rod/Engine Masters has a show about running solid rollers on a hydro roller cam.  And the conclusion was, yes - it made more power.  Had to tighten the lash way up as I recall.

      And this generally should not be practiced as mechanical cams, roller or flat, present "take-up" ramps to absorb the lash sums more gently versus otherwise; and this would probably explain the reasoning to reducing the lash value to a minimum in the example.   But this also would not still provide all of the potential available as the lobe would still be of that deemed suitable for the hydraulic intention.     

      Scott.

[blykins]

IIRC, Hot Rod/Engine Masters has a show about running solid rollers on a hydro roller cam.  And the conclusion was, yes - it made more power.  Had to tighten the lash way up as I recall.

That means that the cam was not the right fit in the first place and was probably on the line of being too aggressive for the lifters/valve spring package. 

For some reason, if you visit some of the Pontiac forums, none of them will run a hydraulic roller cam without solid lifters.  It always aggravated the snot out of me because it was like this unwritten rule that it had to be done that way.    If you look at some of the cams they were trying to run, they were all aggressive lobed hydraulic rollers and most of them didn't have a clue as to what spring pressures or lifter setups that they needed to be paired with. 

[frnkeore]

It seems to me, that Mummert almost won the last EMC, with a 289, using solid rollers on a hydraulic cam.

[blykins]

It seems to me, that Mummert almost won the last EMC, with a 289, using solid rollers on a hydraulic cam.

Frank, there's a difference between picking out a Comp Xtreme Energy cam and running solids on it because it otherwise won't work with the lifters and springs, and then using a specified custom camshaft.  There are quite a few lobes that are hybrid lobes, meant to be used with either scenario and they don't have to be ran at .004-.005" lash. 

[chilly460]

For some reason, if you visit some of the Pontiac forums, none of them will run a hydraulic roller cam without solid lifters.  It always aggravated the snot out of me because it was like this unwritten rule that it had to be done that way.    If you look at some of the cams they were trying to run, they were all aggressive lobed hydraulic rollers and most of them didn't have a clue as to what spring pressures or lifter setups that they needed to be paired with.

Hmm, sounds like a bunch of old farts running a non-mainstream antiquated platform last produced forty years ago that are clinging to a bunch of wives tales or information from 1987!  Why would they do something silly like that?

[Joe-JDC]

That 289 EMC engine used a "catalog" hydraulic roller camshaft with solid roller lifters, and .004" hot lash.  As I have said many times here over the years, back in 1988, I was one of the first to use a custom small base circle hydraulic roller camshaft in the 351W, and Crane Cams made a run of seven camshafts, of which I ordered three.  I asked at that time if I could run a solid roller on their camshaft, and the engineer came back with "it is possible if you tighten the lash to ~.004" hot lash".  I built three stroker 351Ws during that time, and we used that lash as a starting point.  It can be done if everything in the valve train is perfect.  If not, the camshaft lobes will wear and the needles will flatten and come out of their cages.  BTDT, Joe-JDC

[blykins]

That 289 EMC engine used a "catalog" hydraulic roller camshaft with solid roller lifters, and .004" hot lash.  As I have said many times here over the years, back in 1988, I was one of the first to use a custom small base circle hydraulic roller camshaft in the 351W, and Crane Cams made a run of seven camshafts, of which I ordered three.  I asked at that time if I could run a solid roller on their camshaft, and the engineer came back with "it is possible if you tighten the lash to ~.004" hot lash".  I built three stroker 351Ws during that time, and we used that lash as a starting point.  It can be done if everything in the valve train is perfect.  If not, the camshaft lobes will wear and the needles will flatten and come out of their cages.  BTDT, Joe-JDC

What were the rules for on that EMC engine? 

I can see using a mild solid roller camshaft with a hydraulic roller lifter, but there is nothing to be gained by using a solid lifter on a hydraulic cam.....unless that was the only lobe that could be used to come up with the net valve lift that was specified including lash.

[pbf777]

I can see using a mild solid roller camshaft with a hydraulic roller lifter, .............

     Keep in mind one this might result in some exaggerated "off the seat" duration values!     

     And on the latter, we have witnessed many an instance of the hydraulics bleeding down "some" at high speed, and/or perhaps due to aeration within the oil, hence a loss of some cam effect; so for short duration run events and particularly "dyno-mule" session engine events where reasonable life spans are traded for "one-run-wonders" and bragging rights, one might actually pickup some here.     

     Scott.

[Joe-JDC]

EMC had .600" maximum lift at valve.  Joe-JDC

[gt350hr]

IIRC, Hot Rod/Engine Masters has a show about running solid rollers on a hydro roller cam.  And the conclusion was, yes - it made more power.  Had to tighten the lash way up as I recall.

       Frieberger is a HACK and yes I would say it to his face because he admits it on TV! Just like when he experimented with less oil in the pan making more HP. Heck take ALL the oil out for one pull! KABOOM!!!! But it was worth 10 HP 'til she blew! He is a Darwin award winner for sure.