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Old 06-11-2002, 06:23 PM
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Post hydrolic lifter cam vs. solid lifter cam

Whats the difference between the solid and hydrolic cam, Ive been told that you can't use hydrolic lifters on a solid cam and vise versa. Which one is better??

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Old 06-12-2002, 01:23 AM
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better for what?? the question of what is better is as always very hard to answer without knowing the intended use of the engine, ok roller cams have a steeper opening and closeing ramp on the cam, thus provideing for a valve that is open longer with the same duration af a flat tappet cam resulting in more airflow and as a result more power on an other wise simmilar flat tappet cam engine with same internals and cam duratioin.

the hydarulic roller cam is like hydraulic flat tappet cams self adjusting, but cannot take the same mechanical strain as a solid/mechanical lifter and therefore will the lobes not be as agressive on a hyd-roller as on a mec-roller where as a mec roller will offer more horsepower potential, provided you have an engine that will take advantage of the cams potential.

The hydraulic roller however offers substantial horsepower increases over a hydraulic flattappet cam without sacrificeing idle quality so if your budget allows always go with a hydraulic roller, remember tha lifters dont get chewed up, and when you make your first cam change, and reuse the lifters the extra price of the initial investment is earned in the saveings on the next cam swap.

if you have a set of well prepaired aftermarket heads, big carb and intake plus a big exhaust you might consider the mec roller, the only engine that i know of where mec rollers almost are must for big power is the big block chevy

hope it helps
Regards J
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Old 06-13-2002, 06:02 PM
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Hydraulic lifters, roller or flat tappet, are more for the street and are very reliable. They are self adjusting and are pretty much maintenance free. Becuase they are full of oil during operation (hence the Hydraulic) they tend to "pump up" and cause valve train damage above about 6500 rpms.
Solid lifters, on the other hand, roller or flat tappet, are exactly that, they are a like a solid piece of metal between the cam lobe and the pushrod. People use solid lifters more for racing because they dont pump up and can be pushed to as much as 10,000 rpms. The down side is that you have to rutinely adjust your rocker arms for proper valve lash and they wont give you as much low end torque due to the un-self adjustingness. Valve lash is a clearance between the tip of the rocker arm and the tip of the valve. You need valve lash on solid lifters to allow for heat expansion on your valve train. This is why you can hear solid lifter valvetrains rattle when they are cold
So the answer to your question, if it is primarily a race engine which sees minor street time and major rpms and you're willing to work on it a lot then use solid lifters and cam. If its a street motor with only minor track time and a 6000 rpm redline then use hydraulic lifters. And you cant use solid lifters on a hydrualic cam and vice versa.
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Old 06-14-2002, 07:51 AM
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you two guys sound like you know alot, can you help me with my exhaust question? see board: re:rams horns
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Old 06-14-2002, 07:11 PM
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Thanx for the info, I found out that my car has solid lifters and I was wondering what the valve lash adjustment should be. I know im running a pretty radical cam, im not sure what make. All my chevy books don't tell me any numbers. Some measurements would be helpful.
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Old 09-09-2003, 07:19 AM
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Quote:
Originally posted by mustang66maniac
Hydraulic lifters, roller or flat tappet, are more for the street and are very reliable. They are self adjusting and are pretty much maintenance free. Becuase they are full of oil during operation (hence the Hydraulic) they tend to "pump up" and cause valve train damage above about 6500 rpms.
Solid lifters, on the other hand, roller or flat tappet, are exactly that, they are a like a solid piece of metal between the cam lobe and the pushrod. People use solid lifters more for racing because they dont pump up and can be pushed to as much as 10,000 rpms. The down side is that you have to rutinely adjust your rocker arms for proper valve lash and they wont give you as much low end torque due to the un-self adjustingness. Valve lash is a clearance between the tip of the rocker arm and the tip of the valve. You need valve lash on solid lifters to allow for heat expansion on your valve train. This is why you can hear solid lifter valvetrains rattle when they are cold
So the answer to your question, if it is primarily a race engine which sees minor street time and major rpms and you're willing to work on it a lot then use solid lifters and cam. If its a street motor with only minor track time and a 6000 rpm redline then use hydraulic lifters. And you cant use solid lifters on a hydrualic cam and vice versa.
Hydraulic lifters don't pump up at high rpm. They bleed down. The seals in them can't take the pressure which results in loss of lift.
Hydraulic lifters can't "pump up" and damage your valve train. There are "keepers" that stop the plunger from extending past a certain point. Plus, they're only "in the hole" ~.050 thousandths.

Solids are great. Solid rollers are even better.
A full solid roller valve train with rocker girdels shouldn't need to be adjusted but every 5 to 8 months.


sorry, I was looking for info on the Wolf Performance Products "Shermans Lifters" and found this link to this question.

Hope it helps,
Mike SVOR
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Old 09-09-2003, 10:34 AM
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I will have to dissagree with the above statement. Hydraulic lifters DO pump up at high rpms. When properly adjusted, the lifter is running approximately .030 shy of its max length. At high rpms, the lifter cannot bleed down fast enough, hence you get valve float and the engine craps out until the lifters re-adjust again. Guess thats why the HP lifters are called "Anti-pump ups" and not "Anti-pumpdowns!".

Next time you build anything with adjustable hydraulic lifters, adjust them to just where the click stops, then go drive it into the ground! It'll blow up before the lifters ever float. Thats a trick from the old days to stop them from pumping up and floating the valves.

"Solid lifters are great"!!! Great for what? They are great for a 6000 rpm and up drag car, but pretty much suck for the average weekend warrior. Any car that is running that aggressive of a cam to need solid lifters, doesn't belong on the street, it needs to be on the track.

Opinions are great for starting conversations with your buddies, but when enexperienced people come here looking for help, opinions need to be based on proven methods of engine building and repairing, and not on how couzin Bubba fixed the 'ol John Deere one last time with duct tape and a cow pie.

Oh yea, general ballpark on the adjustments are .014 to .016 on the intakes, and .018 to .020 on the exhaust valves. If the engine runs abnormally hot, encrease each by .002.

Last edited by Jmark; 09-09-2003 at 11:33 AM.
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Old 09-09-2003, 11:45 AM
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The original question of this thread was what is the difference between a hydraulic and solid lifter cam and why can't you swap lifters from one to another. Well, chevyelc81 this has been touched on in the earlier posts but the basic fundamentals of a hydraulic lifter or solid lifter have been skipped.
Of course, most of us know that the lifter follows the camshaft lobe for the sole purpose of opening a valve in one form or another. A solid lifter, which is just as it's name implies, is not self adjusting, so there MUST be some slack in the valve train to allow for the heating and cooling of the valve train and it's corresponding changing dimensions and to take the initial shock out of the rapidly turning and opening cam lobe. Solid lifter cams have what is called a "clearance ramp" which is a gradual slope on the lobe which allows the lifter to gently take up the slack in the valvetrain without "slamming" the valve open and shut.
This clearance ramp is really the major difference between the hydraulic, flat tappet cam and a solid lifter, flat tappet cam.
Now a hydraulic lifter, let's say for the purpose of illustration is alot like a self adjusting shock absorber for the valvetrain. It's job is to always keep all of the slack out of the valvetrain at all times, and of course all the while transferring the cam lobe's movements precisely to the valve. This is basically done with a plunger and plunger body, a metering body (which has microscopic tolerances) this whole set-up uses engine oil pressure to fill the lifter, and it bleeds off the proper amount of oil to keep itself adjusted properly. When the lifter is no longer able to bleed off enough oil, it becomes "pumped up" and can actually hold the valve completely off of it's seat causing immeditate loss of power.
Now, not to complicate the issue, but from their design, you see why you should not use hydraulic lifters on a solid cam or vice versa.
A popular old hotrod trick was to use solid lifters on the stock chevy 929 cam, which would make the cam open quickly as it had no mechanical clearance ramps built into it. The result was a very torquey engine that would wipe out the cam in about 5000 miles or less.
Solid lifters are fine for everyday driving if your don't mind a periodic valve adjustment. To say they are a pain on the street is untrue as they have been used for years on everyday drivers and many, modern engines still use them as they don't require adjusting every weekend.
If you want a good performance cam, the hydraulic, flat tappet is the most trouble free above ALL other cams, as it does not have wheels to fail on it's lifters and can deliver up to 7000 RPM if set up properly.
Roller cams utilize rollers to allow the lifter to follow a steep lobe that most flat tappet lifters cannot mechanically achieve allowing cam grinders to make the cams very fast opening and closing and helping to improve power output which is their strong point. Their weak area is increased cost and generally less reliability versus it's flat lifter counterpart.
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Old 09-09-2003, 01:35 PM
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Jmark,

Anti-pump up lifters were designed for people who run large cams on the street and still wanted vacume. What the lifter does is bleed off oil causing less lift at low rpms.

Valve float is caused from weak springs. Not Hyper extended lifters.

Last edited by Mike SVOR; 09-09-2003 at 01:51 PM.
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Old 09-09-2003, 02:32 PM
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I believe you are talking about whats called a "fast bleed" lifter, totally different than an "anti-pumpup" lifter.

This is from the Federal Mogual web site.

HI-REV HYDRAULIC LIFTERS
SPEED-PRO Hi-Rev (commonly called anti pump up) hydraulic lifters feature the same quality material and
construction as the conventional hydraulic lifter. A special high strength, steel retainer is used in place of the normal
spring clip to precis ely limit the travel of the plunger during operation. With plunger travel limited, adjustable rocker
arms must be used to effect a lash adjustment of .000/.002. This then allows the valve train to perform more like a
mechanical system. thus allowing high R.P.M. operation. Because of the high R.P.M. capability and the elimination of
frequent lash adjustments (which are required with mechanical lifters), Hi-Rev hydraulic lifters are the best choice for
all-around performance engines.
Hi-Rev hydraulic lifters can be identified by the prefix Hr and the suffix "S
LASH ADJUSTMENT DIRECTIONS FOR
HI-REV HYDRAULIC LIFTERS
These racing hydraulic lifters are designed to eliminate so-called lifter "pump -up" at high R.P.M.
In order for the
lifters to perform this function the valve lash is critical and must be performed as follows:


[color=red]Here is the latest scoop from Cranes web site.

Crane Hi Intensity "fast bleed" lifters produce a "variable duration effect." At lower RPM this can reduce running duration by 6 to 10 and decrease valve lift by .020" to .030". Hi Intensity lifters work best with a cam that requires more compression ratio than the engine actually has. Hi Intensity lifters restore vacuum, cylinder pressure and bottom end performance.

As RPM increases, these lifters act more like a normal hydraulic lifter. At 2500 to 3000 RPM they will produce the full duration and lift of the cam. Use only if the engine's compression ratio is below the minimum recommended on the application page for the cam you have chosen. Can cause "low speed detonation" if compression is too high. Slightly more noisy than standard lifters (NOT as noisy as a mechanical cam.) Maximum RPM potential: 6,500 to 7,000 RPM.[/color]
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Old 09-09-2003, 05:14 PM
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Solid lifter cams are not unstreetable and they ofer MORE low end torque then a compareable hydrualic cam!!
Now to the real question.
Hydraulic lifters are followers on the cam that act as both a mating surface and a cushion between the cam lobe and pushrod.These lifters are usually "preloaded" a bit to insue there is no slack in the valvetrain.Engine oil under pressure is pumped thru the lifters to keep them pumped up,and the oil flows thru the small amount of clearance between the lifter body and the plunger{part the pushrod sits in}.the tighter this clearance,the thicker the oil or the high the oil pressure,the more the lifter will pump up.The lifter is designed to that maximum oil flow happens when the plunger is properly preloaded in the lifter body,and it it very hard for the lifter to pump higher then that point.Pump up does happen,but usually when the oil pressure is high and the engine rpm is so high that there isnt enough toime for the oil to bleed past the sides of the plunger,and the plunger is driven higher then it would nomally sit,and the effect is that the valves will remain off their seat by about the same amount as the lifter is over pumped,and that leaves the cylinder less then tight and a valve float type situation occurs.
In the high performance world,there are also fast bleed lifters,these lifters are disigned to collapse somewhat when oil pressure is low and there is sufficient time for the oil to bleed out,and this in effect makes the cam less effective at opening the valves at low rpms,and therfore a few degrees of duration iare scrubbed off making the cam seem milder,but they pump up to spec as the rpm climbs and th big cam can do it's thing.This may seem like a hot trick,but look at what happens when you take away all the bleed down out of the lifters{solid lifters}.

Solid lifters are just that,they are solid units designed to act as a tappet to connect the camshaft to the pushrod.They do have a hole in both the side and the pushrod cup{AKA plunger in a hydraulic lifter},and these holes transfer oil from the lifter bores upward into the pushrods similar to the way a hydraulic lifter does only without any pumping in the lifter.A solid lifter has an advantage,since it cant bleed down.Without bleed down,the cam ramps cam be ground to open the vavle a little faster then would be possible with a hydraulic lifter,since the hydrualic lifter would collapse under the load.Such a cam could open the valves further and faster within a shorter duration,thus providing more airflow{the valve is open more}without the long duration that would be needed to do it with a hydrualic lifter.Many Jap cars came with solid lifters well into the 80's,and my 79 chevy pickup came with a solid lifter cam in the stock 6 cylinder,and it logged over 100,000 miles without a single valve adjustment,but in reality,even on a stock engine the valve lash on solid lifters should be checked about every 30,000 miles or so.The solid lifter offers a hands down performance advantage at all rpm,and with many of the tight lash designs available for perfromance these days,they can run as long as a stock solid lifter cam did betwen valve adjustments just like they did back in the day.A solid cam might not be compatable with some computer controlled cars that use a knock sensor{since the lifter clack is detected as spark knock by the computer},but dont believe for one minute that you need to be under the covers working on a solid lifter cam all the time.With the correct valvetrain componets for the cam you select,you should be able to drive any streetable solid cam for 20,000 miles or more without even checking the valve lash.Guys who are checking and adjusting all the time either have valvetrain problems{stock pressed in studs with a big solid cam come to mind},or they dont know how to adjust the valves.Or maybe they just like to pretend that they need to do it so they can feel their car is Sooo radical.I run a 9 second drag car with a 7500rpm bigblock and a solid flat tappet cam,and I havent had the valve covers off in over 3 years and 200 dragstrip passes,and the last time they were off was to check the lash which was still correct after 2 years of racing,so in relaity,I havent touched any of the valves in about 5 years and about 400 7500 rpm passes.So they cant be all that high of maintainace.
It is a matter of presonal choice,but the only reason more people arent using solid cams is because of all the people out there who spread the myth that solid cams need to be adjusted all the time.Of I had a nickel for every solid lifter toyota that ran over 200,000 miles without having the valve covers pulled off from showroom to junkyard,I might be able to go prostock racing afterall.Good luck.
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Old 09-09-2003, 06:06 PM
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It is a matter of presonal choice,but the only reason more people arent using solid cams is because of all the people out there who spread the myth that solid cams need to be adjusted all the time.Of I had a nickel for every solid lifter toyota that ran over 200,000 miles without having the valve covers pulled off from showroom to junkyard,I might be able to go prostock racing afterall.Good luck.---SUPERSTREETER

You have a witness, I have also seen many a 22R that never had a valve adjustment. Many of the mechanical cammed circle track engines I have built have ran several seasons without a valve adjustment by their owners. Solid lifter cams do have an undeserved bad repuation.
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Old 09-09-2003, 07:38 PM
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Solid cams rule.

They don't like to sit un-run for long periods of time. Solid lifters won't bleed down and keep a few valves open the entire time the engine isn't running. But if you run your engine a few times per month, it won't affect your springs any.

My turbo 2.3 ford mustang has solid lifters in it and I haven't adjusted them since Jan of 2002. They are just now needing it.

My Supercharged 5.0 is hydrolic right now and I hate it. I've bought many sets of lifters and it seems like there are never a matched set that everyone works perfectly.

Never had one problem with a solid lifter.


The main question should be: Solid Flat Tappet or Solid Roller!

Once you go solid roller with roller valve train, you'll never be happier.
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