Hydrolic and Solid roller... Whats the difference?
Team Owner
Joined: Apr 2001
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From: Overwhelmed as one would be, placed in my position.... DFW, TX
St. Jude Donor '05
Re: Hydrolic and Solid roller... Whats the difference? (NJ99FRC)
I always thought it was hydraulic vs solid LIFTER... :confused:
Drifting
Joined: Jun 2002
Posts: 1,340
Likes: 1
From: hamilton nj "Life's tough......It's even tougher if you're stupid."-John Wayne
Re: Hydrolic and Solid roller... Whats the difference? (NJ99FRC)
Besides the solid rollers make any more power... how are they different?
Hydraulic flat-tappet camshafts are the most common type of cam used in production vehicles, and in most performance engines. Hydraulic flat-tappet lifters incorporate a self-adjusting mechanism that maintains zero lash in the valve train. Zero lash means there is no gap between the parts in the valve train. The lifters, pushrods, rocker arms, and valves are maintained in continuous contact with each other, using oil pressure to make automatic adjustments for heat expansion of the parts. This type of cam, when installed correctly, with the proper oil, and broken in according to the manufacturer's instructions, provides quiet, trouble-free operation. Life expectancy of the cam is equal to the that of the engine as a whole.
There are a few drawbacks to hydraulic lifters. When the engine is operated above recommended speed ranges, to the point where the valves "float," the lifters attempt to self-adjust themselves out of the proper lash setting. Basically, the lifter mechanism over-fills itself with oil, and it "pumps up." This will not allow the valves to fully close, and performance will fall off until the engine speed is reduced and the lifters readjust.
Flat-tappet hydraulic lifters require a camshaft profile that opens the valves relatively slowly in order to prevent "float." Because of the mechanism inside, hydraulic lifters are relatively heavy. Their larger mass causes them to float more easily than solid lifters, so the camshaft is ground with less aggressive lobe profiles. This serves to reduce the area under those curves in the graph you looked at earlier.
Solid flat-tappet camshafts use lifters that do not have the self-adjusting mechanism of hydraulic lifters. They are, therefore, lighter. For performance engines, the advantages of solid lifters over hydraulic lifters should be apparent. Since they are lighter, the engine can rev faster, and the camshaft can be more aggressive, because with less mass the lifters are less prone to "float." When they do float, they don't have a mechanism that will pump up, so the engine will not stumble or misfire, but keep running. All else being equal, solid camshafts allow the use of lighter valve springs, which translates to more power output to the crankshaft (less power used to push the valve springs down, and to slide the lifters on the cam lobes). Solid cams also tend to give the engine smoother idle and higher vacuum.
The downside of solid camshafts is that you must manually adjust the valve lash, and make it part of a regular adjustment schedule. There must be some clearance allowed between parts of the valve train. Insufficient clearance will cause the valves to remain open slightly, once the parts get hot and expand. Also, many engines are not designed to accommodate manual valve adjustment, and conversion to a solid cam can be costly. Finally, because of the lash adjustment, solid cams and valve trains make more noise. Some computerized engines with knock sensors simply can not use solid cams.
Melting Slicks
Joined: Jan 2001
Posts: 2,635
Likes: 2
From: Aloha, Oregon
Re: Hydrolic and Solid roller... Whats the difference? (cfi_luz)
ANother (important) translation of a solid lifter motor is realized power differences: in a 427 ci LS1 superstroker, a solid roller setup will yield ~25rwhp more throughout the entire RPM range vs hyd roller, all other equip being equal + proper tuning. The drawback is lash maintenance adjustments (so what!) and cost of the valvetrain parts. Tach on another $1500 in parts to go solid roller in LS1. You need adjustable rockers, special valve covers and/or valve cover spacers, coil relocation kit or longer customer plug wires.
I am going solid roller with Shirls 436 he's building (built) for me. Should be an animal.
Robert http://www.gen3motorsports.com
I am going solid roller with Shirls 436 he's building (built) for me. Should be an animal.
Robert http://www.gen3motorsports.com
Drifting
Joined: May 2002
Posts: 1,607
Likes: 1
From: San Francisco CA
Re: Hydrolic and Solid roller... Whats the difference? (rwj383)
While hydraulic lifters used to suffer from "pump-up", it does not have to be that way now. Back in the sixties anti pump-up lifters came along that solved that problem. Whether or not the OEM hydraulic lifters of today incorporate the technology is a good question though.
The big reason a solid lifter setup is capable of more power is because of the lower mass a solid lifter can use a much more agressive ramp than a hydraulic lifter. This means the valve can open and close much quicker and even higher lifts (both peak and average) are obtainable for a given duration.
The big reason a solid lifter setup is capable of more power is because of the lower mass a solid lifter can use a much more agressive ramp than a hydraulic lifter. This means the valve can open and close much quicker and even higher lifts (both peak and average) are obtainable for a given duration.
Thread Starter
Drifting
Joined: Oct 2002
Posts: 1,823
Likes: 1
From: If you can see the car behind you, your not going fast enough
Re: Hydrolic and Solid roller... Whats the difference? (budmont)
Besides the solid rollers make any more power... how are they different?
The following info while discussing flat-tappet cams and lifters also applies to its roller cousins.
Hydraulic flat-tappet camshafts are the most common type of cam used in production vehicles, and in most performance engines. Hydraulic flat-tappet lifters incorporate a self-adjusting mechanism that maintains zero lash in the valve train. Zero lash means there is no gap between the parts in the valve train. The lifters, pushrods, rocker arms, and valves are maintained in continuous contact with each other, using oil pressure to make automatic adjustments for heat expansion of the parts. This type of cam, when installed correctly, with the proper oil, and broken in according to the manufacturer's instructions, provides quiet, trouble-free operation. Life expectancy of the cam is equal to the that of the engine as a whole.
There are a few drawbacks to hydraulic lifters. When the engine is operated above recommended speed ranges, to the point where the valves "float," the lifters attempt to self-adjust themselves out of the proper lash setting. Basically, the lifter mechanism over-fills itself with oil, and it "pumps up." This will not allow the valves to fully close, and performance will fall off until the engine speed is reduced and the lifters readjust.
Flat-tappet hydraulic lifters require a camshaft profile that opens the valves relatively slowly in order to prevent "float." Because of the mechanism inside, hydraulic lifters are relatively heavy. Their larger mass causes them to float more easily than solid lifters, so the camshaft is ground with less aggressive lobe profiles. This serves to reduce the area under those curves in the graph you looked at earlier.
Solid flat-tappet camshafts use lifters that do not have the self-adjusting mechanism of hydraulic lifters. They are, therefore, lighter. For performance engines, the advantages of solid lifters over hydraulic lifters should be apparent. Since they are lighter, the engine can rev faster, and the camshaft can be more aggressive, because with less mass the lifters are less prone to "float." When they do float, they don't have a mechanism that will pump up, so the engine will not stumble or misfire, but keep running. All else being equal, solid camshafts allow the use of lighter valve springs, which translates to more power output to the crankshaft (less power used to push the valve springs down, and to slide the lifters on the cam lobes). Solid cams also tend to give the engine smoother idle and higher vacuum.
The downside of solid camshafts is that you must manually adjust the valve lash, and make it part of a regular adjustment schedule. There must be some clearance allowed between parts of the valve train. Insufficient clearance will cause the valves to remain open slightly, once the parts get hot and expand. Also, many engines are not designed to accommodate manual valve adjustment, and conversion to a solid cam can be costly. Finally, because of the lash adjustment, solid cams and valve trains make more noise. Some computerized engines with knock sensors simply can not use solid cams.
The following info while discussing flat-tappet cams and lifters also applies to its roller cousins.
Hydraulic flat-tappet camshafts are the most common type of cam used in production vehicles, and in most performance engines. Hydraulic flat-tappet lifters incorporate a self-adjusting mechanism that maintains zero lash in the valve train. Zero lash means there is no gap between the parts in the valve train. The lifters, pushrods, rocker arms, and valves are maintained in continuous contact with each other, using oil pressure to make automatic adjustments for heat expansion of the parts. This type of cam, when installed correctly, with the proper oil, and broken in according to the manufacturer's instructions, provides quiet, trouble-free operation. Life expectancy of the cam is equal to the that of the engine as a whole.
There are a few drawbacks to hydraulic lifters. When the engine is operated above recommended speed ranges, to the point where the valves "float," the lifters attempt to self-adjust themselves out of the proper lash setting. Basically, the lifter mechanism over-fills itself with oil, and it "pumps up." This will not allow the valves to fully close, and performance will fall off until the engine speed is reduced and the lifters readjust.
Flat-tappet hydraulic lifters require a camshaft profile that opens the valves relatively slowly in order to prevent "float." Because of the mechanism inside, hydraulic lifters are relatively heavy. Their larger mass causes them to float more easily than solid lifters, so the camshaft is ground with less aggressive lobe profiles. This serves to reduce the area under those curves in the graph you looked at earlier.
Solid flat-tappet camshafts use lifters that do not have the self-adjusting mechanism of hydraulic lifters. They are, therefore, lighter. For performance engines, the advantages of solid lifters over hydraulic lifters should be apparent. Since they are lighter, the engine can rev faster, and the camshaft can be more aggressive, because with less mass the lifters are less prone to "float." When they do float, they don't have a mechanism that will pump up, so the engine will not stumble or misfire, but keep running. All else being equal, solid camshafts allow the use of lighter valve springs, which translates to more power output to the crankshaft (less power used to push the valve springs down, and to slide the lifters on the cam lobes). Solid cams also tend to give the engine smoother idle and higher vacuum.
The downside of solid camshafts is that you must manually adjust the valve lash, and make it part of a regular adjustment schedule. There must be some clearance allowed between parts of the valve train. Insufficient clearance will cause the valves to remain open slightly, once the parts get hot and expand. Also, many engines are not designed to accommodate manual valve adjustment, and conversion to a solid cam can be costly. Finally, because of the lash adjustment, solid cams and valve trains make more noise. Some computerized engines with knock sensors simply can not use solid cams.
You are the man! :cheers:
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Melting Slicks
Joined: Oct 2002
Posts: 2,855
Likes: 0
Re: Hydrolic and Solid roller... Whats the difference? (rwj383)
Shirl is one of my favorite people in the world and a godsend to the forum--I would love to know how he address's the oil consumption that is so common with all of us that are using the 4.125" stroke--if there is no answer to this I will hone out my 4.1" bore to 4.125 and go to a 4" crank assembly and needless to say I am not happy about this expense--the motor is very strong but a quart every 500 miles is nuts--thanks Bill (if I had know about Shirl prior to already being in the middle of this project I would love to have had him do the 436 for me)
Drifting
Joined: Jun 2002
Posts: 1,340
Likes: 1
From: hamilton nj "Life's tough......It's even tougher if you're stupid."-John Wayne
Re: Hydrolic and Solid roller... Whats the difference? (cfi_luz)
Aren't there much greater risks of overheating with solid rollers?
That would be the first I have ever heard of this :crazy:
That would be the first I have ever heard of this :crazy:
Instructor
Joined: Mar 2002
Posts: 239
Likes: 0
From: Fredericksburg VA
Re: Hydrolic and Solid roller... Whats the difference? (rwj383)
Robert,
Which solid roller lobe series(s) are you using on your cam?
I though people might like to know this, including me. Thanks.
Which solid roller lobe series(s) are you using on your cam?
I though people might like to know this, including me. Thanks.
