Flat Tappet
12-28-2006, 11:41 AM
#1
12-28-2006, 12:49 PM
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the thing that I obtained reading an article about tappet vs roller in a magazine (forgot wich one) is that it is :
1-tappets are made from a different type of metal (less strenth and cheaper) and that`s why they cost much less but less strenth doesn`t mean there`s a problem here just cheaper cores and then cheaper cams because there are hyd and solid tappets that go past 6500 rpm no problem.
2-they use tappet lifters the ones without the wheel.
3-they make more pwer from idle upto a certain low rpm 3500-4700 (forgot also) then the friction of the lifters that don`t have friction reduction wheel will make less power in the upper rpm range.
4-this one I`m not sure why but for a given duration say 224 or 242 the lift is limited and will be less than if the cam and lifters are of a roller designes (like a 224 duration in a tappet hyd can be from 450-550 lift where you can see +600 in a roller desighen)
maybe it`s about wear on the lifter surface if at a less duration and very high lift.
5-also not sure but if the same duration and lift or slightly higher lift the roller set up will have more cam and lifter life and milage due to less wear and friction.
if it`s for your 96 t/a I don`t know if you can run a flat tappet straight up (I think roller cam blocks comes with roller lifters guids already curved in the lifters alley) people modify their blocks or buy retrofit roller lifters to benifit from the more agressive duration and lift and high rpm pwer of the rollers so why go back anyway? stock replacement lifters are good priced and the lt1 performance cams are also cheap considering other engines.
hope that helps and everybody feel free to correct me...as this is what I understood from reading.
1-tappets are made from a different type of metal (less strenth and cheaper) and that`s why they cost much less but less strenth doesn`t mean there`s a problem here just cheaper cores and then cheaper cams because there are hyd and solid tappets that go past 6500 rpm no problem.
2-they use tappet lifters the ones without the wheel.
3-they make more pwer from idle upto a certain low rpm 3500-4700 (forgot also) then the friction of the lifters that don`t have friction reduction wheel will make less power in the upper rpm range.
4-this one I`m not sure why but for a given duration say 224 or 242 the lift is limited and will be less than if the cam and lifters are of a roller designes (like a 224 duration in a tappet hyd can be from 450-550 lift where you can see +600 in a roller desighen)
maybe it`s about wear on the lifter surface if at a less duration and very high lift.
5-also not sure but if the same duration and lift or slightly higher lift the roller set up will have more cam and lifter life and milage due to less wear and friction.
if it`s for your 96 t/a I don`t know if you can run a flat tappet straight up (I think roller cam blocks comes with roller lifters guids already curved in the lifters alley) people modify their blocks or buy retrofit roller lifters to benifit from the more agressive duration and lift and high rpm pwer of the rollers so why go back anyway? stock replacement lifters are good priced and the lt1 performance cams are also cheap considering other engines.
hope that helps and everybody feel free to correct me...as this is what I understood from reading.