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skeetimer
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What is the difference between hydraulic, hydraulic roller, solid, and solid roller cams? Which is better? Opinions on best manufacture?
MaineShark
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- 1979 L82, 1987 Buick Grand National
Well, you have two different things going on: Solid vs. Hydraulic, and Flat Tappet vs. Roller.
Basically, with a solid lifter, you need to adjust for wear every so many miles by adjusting the lash. That, and they make a bit of noise. So, manufacturers went over to hydraulic lifters, which use a tiny hydraulic piston to adjust for wear. Since they are always adjusted, and due to the spring of the oil in the lifter, they make less noise. Solid lifters, however, are more tolerant of high-rpm use.
You also have to consider how the lifter is connected to the cam. Flat tappet lifters have a flat face that slides across the cam. The cam lobes have a slight bevel to them, which causes the lifter to rotate as it does this, helping them last longer (the wear gets spread out by the rotation, instead of happening all in the same place). Roller lifters are just that: they have a roller on the end which rides on the cam. This results in much less friction (every hp counts) and, due to the geometry, allows a more agressive cam profile to be used (a roller lifter can open and close more quickly than a flat tappet lifter). The roller lifter doesn't rotate like the flat tappet. Actually, rotation would be a major problem, since the roller would not line up correctly, so there needs to be some device to keep the lifters aligned. Newer blocks are set up for roller lifters, from the factory. Older blocks must be converted, which can cost a bit of money.
So, with these four types of lifters, you have four types of cams. Most importantly, is roller vs. flat tappet, since the cams are ground differently. The slight bevel that is necessary for a flat tappet, is incompatible with rollers. Solid vs. hydraulic is more a matter of profile: you can use solid lifters with a hydralic cam, but a cam that is listed for solid lifters is probably listed that way because its profile is too agressive for use with hydraulic lifters.
In terms of "which is best?" it depends. For most of us, flat tappet, hydraulic lifters are all that we need. When you start to push the performance more, it may become necessary to switch to hydraulic roller lifters (and a cam to match), due to the more agressive profile that is possible. Extreme performance may require solid roller lifters, but that's probably beyond the level that most of us will deal with.
I left out solid flat tappet lifters, 'cause personally, if I'm going to have to deal with setting lash, I'm going to do it because I passed the point that hydralic rollers allow for. If the performance level is not high enough to require solid roller lifters, then I'd rather have the convenience of hydralic rollers.
So, in your car, if you just want to drop in a new cam, you're going to be looking for hydraulic, flat tappet cams (and lifters - you need to replace the lifters whenever you put a new cam in - it usually voids the cam warranty if you don't). Unless you feel like spending a few extra bucks and getting hydraulic rollers.
Joe
Basically, with a solid lifter, you need to adjust for wear every so many miles by adjusting the lash. That, and they make a bit of noise. So, manufacturers went over to hydraulic lifters, which use a tiny hydraulic piston to adjust for wear. Since they are always adjusted, and due to the spring of the oil in the lifter, they make less noise. Solid lifters, however, are more tolerant of high-rpm use.
You also have to consider how the lifter is connected to the cam. Flat tappet lifters have a flat face that slides across the cam. The cam lobes have a slight bevel to them, which causes the lifter to rotate as it does this, helping them last longer (the wear gets spread out by the rotation, instead of happening all in the same place). Roller lifters are just that: they have a roller on the end which rides on the cam. This results in much less friction (every hp counts) and, due to the geometry, allows a more agressive cam profile to be used (a roller lifter can open and close more quickly than a flat tappet lifter). The roller lifter doesn't rotate like the flat tappet. Actually, rotation would be a major problem, since the roller would not line up correctly, so there needs to be some device to keep the lifters aligned. Newer blocks are set up for roller lifters, from the factory. Older blocks must be converted, which can cost a bit of money.
So, with these four types of lifters, you have four types of cams. Most importantly, is roller vs. flat tappet, since the cams are ground differently. The slight bevel that is necessary for a flat tappet, is incompatible with rollers. Solid vs. hydraulic is more a matter of profile: you can use solid lifters with a hydralic cam, but a cam that is listed for solid lifters is probably listed that way because its profile is too agressive for use with hydraulic lifters.
In terms of "which is best?" it depends. For most of us, flat tappet, hydraulic lifters are all that we need. When you start to push the performance more, it may become necessary to switch to hydraulic roller lifters (and a cam to match), due to the more agressive profile that is possible. Extreme performance may require solid roller lifters, but that's probably beyond the level that most of us will deal with.
I left out solid flat tappet lifters, 'cause personally, if I'm going to have to deal with setting lash, I'm going to do it because I passed the point that hydralic rollers allow for. If the performance level is not high enough to require solid roller lifters, then I'd rather have the convenience of hydralic rollers.
So, in your car, if you just want to drop in a new cam, you're going to be looking for hydraulic, flat tappet cams (and lifters - you need to replace the lifters whenever you put a new cam in - it usually voids the cam warranty if you don't). Unless you feel like spending a few extra bucks and getting hydraulic rollers.
Joe
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skeetimer
Guest
Wow! Thanks Joe! That's helps me alot.
- Thread starter
- #4
J
JVSBob
Guest
Skeetimer,
Maineshark covered it perfectly. I would summarize it this way:
Streetable high performance with a large budget: go with a hydraulic roller.
Race engine and/or lots of free time to adjust valves: solid roller
Moderate Street performance (400HP or less) and lower budget: Hydraulic flat tappet.
If you're doing the work yourself, hydraulic flat tappet cams are the easist to install and degree.
good luck.
Maineshark covered it perfectly. I would summarize it this way:
Streetable high performance with a large budget: go with a hydraulic roller.
Race engine and/or lots of free time to adjust valves: solid roller
Moderate Street performance (400HP or less) and lower budget: Hydraulic flat tappet.
If you're doing the work yourself, hydraulic flat tappet cams are the easist to install and degree.
good luck.
- Thread starter
- #5
C
cruisin-davey-g
Guest
One more thing that you could do: Add roller rockers to your set-up. They're not that hard to do & you'll get a little less friction & heat. One nice thing about Roller cams is that you can go to a higher lift & duration (centerline) & it won't lope real bad like hydraulics. The other two posts pretty much sumed it up in the different types of cams. If you're building a mild-to-moderate street set-up, then go with the hydrualic cam, lifters (anti-pump-up type) & roller rockers. The extra monies needed to buy a true roller set-up can be put into the heads (port-n-polish, smooth runners, port matching, etc.) That's where the HP is anyway (in the heads & intake). Ever wonder why, when you go to the dragstrip & the real hard-core racers keep their intakes covered with towels & rags or even cardboard?
Good luck to you on your project. Be cool!
Dave
Good luck to you on your project. Be cool!
Dave
- Thread starter
- #6
S
SwaveDave
Guest
You guys did a beautiful job explaining and showing the advantages. Well done.
Id just like to say , that, the longevity is better with a roller cam/lifters than with a flat tappet setup...which helps to offset the initial higher price of the roller cam/lifters ,if its going to last longer.
I rebuilt my street BB with hydr. roller cam/lifters and used a Lunati 296/304 adv. dur. / .575-.595 lift / 112 lsa ....thinking that it would be too lopey if i went any higher ; it wasnt that lopey at all., and i wish i had gone even more radical.
SwaveDave
Id just like to say , that, the longevity is better with a roller cam/lifters than with a flat tappet setup...which helps to offset the initial higher price of the roller cam/lifters ,if its going to last longer.
I rebuilt my street BB with hydr. roller cam/lifters and used a Lunati 296/304 adv. dur. / .575-.595 lift / 112 lsa ....thinking that it would be too lopey if i went any higher ; it wasnt that lopey at all., and i wish i had gone even more radical.
SwaveDave
- Thread starter
- #7
C
cruisin-davey-g
Guest
SwaveDave said:
Swave Dave: Yeah..........I've got buddies that put well over .600 lifts in their BB Chevys. Sounds like fun, doesn't it? I've got a buddy who's son's got a real radical ride. They took a 383 stroker roller cam motor & stuffed it into an '88 Baretta (yes...that WAS a front wheel drive....WAS). He's running a TH350 trans & 4.31 gears; 9-inch ford), but he's pulling around a set of 31" wide "Mickie's" & this kid's not even outta high school yet! But, he's graduating this June. They just got dun puttin in a full roll cage. This vehicle is one Radical Ride!
Dave
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