lifters????.....man i dont know where to start
12-10-2001, 05:49 PM
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lifters????.....man i dont know where to start The search didnt explain much.
What is the difference between solid, hydraulic, solid roller, and hydraulic roller. Im so comfused. I know rollers are where the cam basically 'rolls' off the lifter, but my knowledge stops there.
In the GMHTP that came in today, on P. 13 in that advertisement +115hp, its says there is a hydraulic roller cam and hydraulic roller lifters. This also confuses me. Do you need both to be compatible with eachother. I read when i did the search that also switching to a solid or solid roller makes your motor less streetable or something....UHHH <img src="graemlins/gr_images/icons/mad.gif" border="0" alt="[very mad]" /> im frustrated. Gotta learn here.
What is the difference between solid, hydraulic, solid roller, and hydraulic roller. Im so comfused. I know rollers are where the cam basically 'rolls' off the lifter, but my knowledge stops there.
In the GMHTP that came in today, on P. 13 in that advertisement +115hp, its says there is a hydraulic roller cam and hydraulic roller lifters. This also confuses me. Do you need both to be compatible with eachother. I read when i did the search that also switching to a solid or solid roller makes your motor less streetable or something....UHHH <img src="graemlins/gr_images/icons/mad.gif" border="0" alt="[very mad]" /> im frustrated. Gotta learn here.
12-11-2001, 02:25 PM
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Re: lifters????.....man i dont know where to start Taking the hydraulics out of the valve train would give you more accurate timing however, you will always have to make adjustments everytime the temperature changes or wear and tear on your engine increases. Mecahnical lifters are really for all out racers. I don't recomend them for dailey drivers. As for roller/tappet type lifters, tappets require a tappet cam. Rollers require a roller cam. Roller cam setups have good advantages over tappet types. One advantage would be the speed at which a valve can be opend. Tappet cams have a more gradual incline so the valve opens slower. Roller cams can have and do have a steeper incline ramp. Valves are able to open much faster. They also have less HP robbing friction and less valve overlap can be obtained.
[ December 11, 2001: Message edited by: Steve Underwood ]</p>
[ December 11, 2001: Message edited by: Steve Underwood ]</p>
12-11-2001, 02:49 PM
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Re: lifters????.....man i dont know where to start [quote]Originally posted by Steve Underwood:
<strong>Taking the hydraulics out of the valve train would give you more accurate timing however, you will always have to make adjustments everytime the temperature changes or wear and tear on your engine increases. Mecahnical lifters are really for all out racers. I don't recomend them for dailey drivers. As for roller/tappet type lifters, tappets require a tappet cam. Rollers require a roller cam. Roller cam setups have good advantages over tappet types. One advantage would be the speed at which a valve can be opend. Tappet cams have a more gradual incline so the valve opens slower. Roller cams can have and do have a steeper incline ramp. Valves are able to open much faster. They also have less HP robbing friction and less valve overlap can be obtained.
[ December 11, 2001: Message edited by: Steve Underwood ]</strong><hr></blockquote>
Thats basically it but your explanation is a little misleading. The word tappet is just another word for lifter. You have roller-tappets and flat-tappets. The word tappet by itself does not neccessarily mean its a flat-tappet. So to say its a "tappet cam" really makes no sense. All cams are "tappet cams" by that way of thinking. What kind of tappet? Flat or roller? The main difference between the two is friction. On a flat-tappet cam, the tappet has a smoot solid metal suface that rides the lobe profile of the cam. This is a metal-to-metal contact point. Thats why you have to be careful to mate the lifters up to their exact cylinder locations if you do an engine rebuild. You run into trouble if you don't put the lifter from cylinder 8 back in cylinder 8's location. It has already mated to the cam lobe. (this is a critical engine break-in process). Now roller-tappets on the other hand have an actual ball-bearing that rides the cam lobe. This makes a lot less friction. The mating surface actually "moves". We run both in our Late-Model Sportsman cars (ALL Pro Cars). You are absolutely correct on mechanical flat-tappets being intended for race cars. You have to constantly adjust the valves as their is no hydraulic "cushion" to prevent the valve lash from moving around. Not a good thing on a race engine. Winston Cup cars are mechanincal flat-tappet engines. You can get crazy with the lift and ramp rate on roller cams. We had a short track cam in the neighborhood of .675 lift. These engines can also turn more R's, but the valvetrain has to be beefed up pretty good. At the HP level we are makeing, we have to run shaft-mount rockers. Stud girdles just don't cut it at 9000rpm. This adds greatly to the cost of a set of heads. Our last set of heads were $9000 (Yates heads). Your explanation is correct, just wanted to clear up the fact that "tappet" by itself does not point to a flat-tappet. <img src="gr_images/icons/wink.gif" border="0">
<strong>Taking the hydraulics out of the valve train would give you more accurate timing however, you will always have to make adjustments everytime the temperature changes or wear and tear on your engine increases. Mecahnical lifters are really for all out racers. I don't recomend them for dailey drivers. As for roller/tappet type lifters, tappets require a tappet cam. Rollers require a roller cam. Roller cam setups have good advantages over tappet types. One advantage would be the speed at which a valve can be opend. Tappet cams have a more gradual incline so the valve opens slower. Roller cams can have and do have a steeper incline ramp. Valves are able to open much faster. They also have less HP robbing friction and less valve overlap can be obtained.
[ December 11, 2001: Message edited by: Steve Underwood ]</strong><hr></blockquote>
Thats basically it but your explanation is a little misleading. The word tappet is just another word for lifter. You have roller-tappets and flat-tappets. The word tappet by itself does not neccessarily mean its a flat-tappet. So to say its a "tappet cam" really makes no sense. All cams are "tappet cams" by that way of thinking. What kind of tappet? Flat or roller? The main difference between the two is friction. On a flat-tappet cam, the tappet has a smoot solid metal suface that rides the lobe profile of the cam. This is a metal-to-metal contact point. Thats why you have to be careful to mate the lifters up to their exact cylinder locations if you do an engine rebuild. You run into trouble if you don't put the lifter from cylinder 8 back in cylinder 8's location. It has already mated to the cam lobe. (this is a critical engine break-in process). Now roller-tappets on the other hand have an actual ball-bearing that rides the cam lobe. This makes a lot less friction. The mating surface actually "moves". We run both in our Late-Model Sportsman cars (ALL Pro Cars). You are absolutely correct on mechanical flat-tappets being intended for race cars. You have to constantly adjust the valves as their is no hydraulic "cushion" to prevent the valve lash from moving around. Not a good thing on a race engine. Winston Cup cars are mechanincal flat-tappet engines. You can get crazy with the lift and ramp rate on roller cams. We had a short track cam in the neighborhood of .675 lift. These engines can also turn more R's, but the valvetrain has to be beefed up pretty good. At the HP level we are makeing, we have to run shaft-mount rockers. Stud girdles just don't cut it at 9000rpm. This adds greatly to the cost of a set of heads. Our last set of heads were $9000 (Yates heads). Your explanation is correct, just wanted to clear up the fact that "tappet" by itself does not point to a flat-tappet. <img src="gr_images/icons/wink.gif" border="0">
12-12-2001, 07:19 PM
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Re: lifters????.....man i dont know where to start [quote]Originally posted by R U A LS1:
<strong>.
In the GMHTP that came in today, on P. 13 in that advertisement +115hp, its says there is a hydraulic roller cam and hydraulic roller lifters. This also confuses me. Do you need both to be compatible with eachother.</strong><hr></blockquote>
Yes, they have to be compatible. You can't use regular lifters with a roller cam, or roller lifters on a flat tappet cam. The lobes are different profiles, a roller cam opens faster. Also, a roller cam is steel, a flat tappet cam is cast iron.
<strong>.
In the GMHTP that came in today, on P. 13 in that advertisement +115hp, its says there is a hydraulic roller cam and hydraulic roller lifters. This also confuses me. Do you need both to be compatible with eachother.</strong><hr></blockquote>
Yes, they have to be compatible. You can't use regular lifters with a roller cam, or roller lifters on a flat tappet cam. The lobes are different profiles, a roller cam opens faster. Also, a roller cam is steel, a flat tappet cam is cast iron.