diff b/w solid lifter cam and hydraulic
Thread Starter
TECH Addict
iTrader: (35)
Joined: Dec 2005
Posts: 2,373
Likes: 0
From: Cherry Hill, NJ
diff b/w solid lifter cam and hydraulic What's the main difference between a solid lifter cam and a hydraulic one and why do many people go solid for race cars?
From a design/engineering standpoint a hydraulically actuated lifter assembly is a series of convenience compromises. We spend thousands of dollars to eliminate deflection from our valve train; a hydraulic lifter has deflection designed into it. Their designs work very well in utilitarian vehicles, but are they mandatory in moderate performance applications as well?
Fact is, solid lifters do everything better than hydraulics from a design/performance standpoint. They open the valve farther, faster, and quicker (lift/velocity/acceleration) than a hydraulic ever could. They make more torque/power everywhere in the curve. The new designs, once they take a set, can go an entire season on one a lash adjustment.
Solid roller lifters are lighter, reducing the mass on the pushrod side of the fulcrum, promoting greater dynamic stability. They have fewer moving parts. They don't pump up or bleed down, virtually eliminating valve float and lifter collapse. They eliminate plunger deflection. They do not have plungers to stick from particle contamination in the oil. They are not spring limited by design, which is critical. The valve spring is the single most important element in controlling valve train stability. This allows you to run the proper spring for your RPM range and component mass.
Are they for everyone? Not necessarily. For the plug and play type who want to set it and forget it stay Hyd roller.
Fact is, solid lifters do everything better than hydraulics from a design/performance standpoint. They open the valve farther, faster, and quicker (lift/velocity/acceleration) than a hydraulic ever could. They make more torque/power everywhere in the curve. The new designs, once they take a set, can go an entire season on one a lash adjustment.
Solid roller lifters are lighter, reducing the mass on the pushrod side of the fulcrum, promoting greater dynamic stability. They have fewer moving parts. They don't pump up or bleed down, virtually eliminating valve float and lifter collapse. They eliminate plunger deflection. They do not have plungers to stick from particle contamination in the oil. They are not spring limited by design, which is critical. The valve spring is the single most important element in controlling valve train stability. This allows you to run the proper spring for your RPM range and component mass.
Are they for everyone? Not necessarily. For the plug and play type who want to set it and forget it stay Hyd roller.
Banned
Joined: Apr 2006
Posts: 1,875
Likes: 1
From: Naperville, IL
Remember, duration is measured AT THE LOBE. With a solid cam, however much of the duration is consumed while the lash is being taken up; so from just purely a duration standpoint, a solid cam with a given duration spec will "act" "smaller" than a hyd with the same spec. However it may make more power, because the ramps on a solid are almost always steeper than those on a hyd.
Solid rollers are a problem on the street. The problem is, not enough oil gets to their axles, especially at idle and real low RPMs. They fry during extended low RPM operation. Probably the best ones are the Isky Red Zones, which have pressurized oil fed to the axles; or the Crower ones with the HIPPO option. All the others, as far as I know, only dribble oil onto the outside of the roller, which since it's spinning throws the oil off and not enough gets into the axle. Once the engine speeds pick up though, there's usually enough of an oil mist whipped up inside there, to keep them from running dry. Lash adjustments will need to be made a lot on a DD.
Too little spring pressure, EVERYTHING tears up at high RPMs.
Too much spring pressure and not enough oil, lifter axles tear up at low RPMs.
Solid rollers are a problem on the street. The problem is, not enough oil gets to their axles, especially at idle and real low RPMs. They fry during extended low RPM operation. Probably the best ones are the Isky Red Zones, which have pressurized oil fed to the axles; or the Crower ones with the HIPPO option. All the others, as far as I know, only dribble oil onto the outside of the roller, which since it's spinning throws the oil off and not enough gets into the axle. Once the engine speeds pick up though, there's usually enough of an oil mist whipped up inside there, to keep them from running dry. Lash adjustments will need to be made a lot on a DD.
Too little spring pressure, EVERYTHING tears up at high RPMs.
Too much spring pressure and not enough oil, lifter axles tear up at low RPMs.
Solid rollers are a problem on the street. The problem is, not enough oil gets to their axles, especially at idle and real low RPMs. They fry during extended low RPM operation.
Lash adjustments will need to be made a lot on a DD.
Everything else is right on! If you want plug and play stay Hyd roller. If you want max performance and are willing to pull valve covers now and again, go solid rolller. As with anything you can go mild solid to wild solid.
Think he was acking what is different about how they are made. Since cams are labeled as hyd or solid. I know the lobes are MUCH more aggressive on a solid cam but dont know if they are made differently.
Trending Topics
TECH Resident
Joined: Jan 2003
Posts: 855
Likes: 0
From: AUSTIN TX
Originally Posted by Asmodeus
why aren't people throwing them in in place of Hyd Lifters if this is the case?
LS1 Tech Stories
The Best V8 Stories One Small Block at Time
6 Common C5 Corvette Failures and What's Involved In Repairing Them
Pouria Savadkouei
Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph
Verdad Gallardo
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked
Pouria Savadkouei
Top 10 Most Powerful Chevy Trucks Ever Made!
Hennessey's New Supercharged Silverado ZR2 Has 700 HP
Verdad Gallardo
Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes
Verdad Gallardo
Awesome K5 Blazer Restomod Comes With C7 Corvette Power
Verdad Gallardo
10 Camaros You Should Never Buy
10 LS Engine Myths That Refuse to Die
Verdad Gallardo
well i don't know about how often they may or may need adjusting for a dd but i had a weekend warrior and rarely had to readjust the sr cams i had in it. one cam was fairly mild at 255/255 @.050 and .575/.575 but the other one was 259/267 @.050 with .638 lift and with some pretty strong springs and i may have had to readjust the lash once over a couple thousand miles.unless something is wearing or your locks have come lose on your rockers adjustment intervals should be few and far between.as for daily driving them if people bitch about a hydraulic ticking sound they will really bitch hearing rockers tapping with .020 thou or more lash.
For one, most people do not want to spend the money it takes to make the valvetrain adjustable, for two most people do not want to have to adjust the valve periodically even if it is just a few times a year (keep in mind a car usually runs more than a boat and whether or not they need to be adjusted, they still need to be checked), lastly most of us do not spin the motors high enough to really take full advantage of a solid roller anyway (afterall from the knowledge gained here, most LSX manifolds are tuned to produce peak numbers in the 6200-6500 range). As for his boat, I would assume it is a big block which most likely has a very heavy valvetrain, consequently a hydraulic roller would most likely be a thorn in his side even though he most likely does not spin it any higher than we do our LSX's. (Disclaimer... lots of assumptions were made in this post)
You are right about why most of the general community do not run SR's. They also make more noise as you always have a lash of .10-.20". The larger the cam and spring pressure the more wear on your valvetrain. Think springs, valve seats, PR's, lifters, and rockers.
As to the cam itself they are made of the same material it's just the solid will have much more aggressive lobes.
No need ($)for a solid lifter in a street car is the basic answer. Their value, as I see it, is higher reving. There is no real need to produce power above 6000rpms in a street car.
Originally Posted by 99blancoSS
No need ($)for a solid lifter in a street car is the basic answer. Their value, as I see it, is higher reving. There is no real need to produce power above 6000rpms in a street car.
