Flat Tappets and Roller Tappets - Any Perceivable Difference?
07-15-2011, 01:09 AM
#1
Senior Member
Thread Starter
Flat Tappets and Roller Tappets - Any Perceivable Difference?
I'd love to have a roller for the simple fact that it has less friction and so I've heard (but never confirmed personally) less vibration, but for those that may have owned both types of engines, what did you observe between the two? In looking at gas mileage using the epa's site, I don't really see where the gas mileage for the roller cam engine is exactly "better" than the flat tappet. I think I saw a 1mpg difference on some models and no difference on others.
Since I got my truck running exactly as it should, I don't really have a problem with the flat tappet camshaft. The reason why I'm asking is I have a block that I'm getting parts for to do a weekend swap in the very distant future and I found a flat tappet cam with specs that I dig very much. It's basically a camshaft that's slightly above stock. I'm actually looking at a stock level rebuild, but if I can get a quality cam with better specs for the same price, why not?
The specs I'm looking at on this flat tappet cam are:
.424" Intake Valve Lift
.448" Exhaust Valve Lift
.265" Intake Cam Lift
.280" Exhaust Cam Lift
270 Degree Intake Duration
280 Degree Exhaust Duration
Stock Quality Idle
As a comparison, here's what I found on a stock replacement camshaft
Valve Lift Int. .380
Valve Lift Exh. .395
Cam Lift Int. .237
Cam Lift Exh. .247
.050'' Dur. Int. 184
.050'' Dur. Exh. 192
C/L Int 103
C/L Exh 111
What are your thoughts? Keep it flat tappet or go ahead and upgrade to a roller cam? The specs on this flat tappet cam don't look aggressive enough to have concerns about a lack of zddp in the oil. My main concern is #1 reliability and #2 gas mileage.
Finally, horsepower isn't at the top of the list for me on the truck since I have a car to do the horsepower stuff on.
Since I got my truck running exactly as it should, I don't really have a problem with the flat tappet camshaft. The reason why I'm asking is I have a block that I'm getting parts for to do a weekend swap in the very distant future and I found a flat tappet cam with specs that I dig very much. It's basically a camshaft that's slightly above stock. I'm actually looking at a stock level rebuild, but if I can get a quality cam with better specs for the same price, why not?
The specs I'm looking at on this flat tappet cam are:
.424" Intake Valve Lift
.448" Exhaust Valve Lift
.265" Intake Cam Lift
.280" Exhaust Cam Lift
270 Degree Intake Duration
280 Degree Exhaust Duration
Stock Quality Idle
As a comparison, here's what I found on a stock replacement camshaft
Valve Lift Int. .380
Valve Lift Exh. .395
Cam Lift Int. .237
Cam Lift Exh. .247
.050'' Dur. Int. 184
.050'' Dur. Exh. 192
C/L Int 103
C/L Exh 111
What are your thoughts? Keep it flat tappet or go ahead and upgrade to a roller cam? The specs on this flat tappet cam don't look aggressive enough to have concerns about a lack of zddp in the oil. My main concern is #1 reliability and #2 gas mileage.
Finally, horsepower isn't at the top of the list for me on the truck since I have a car to do the horsepower stuff on.
07-15-2011, 01:25 AM
#2
Senior Member
Using the same specs on the cam you will see little difference in engine performance. There will be a bit less parasitic loss and the drive train will be quieter, maybe a little cooler especially if you complete the system with roller rockers. The rollers will greatly outcast the flat lifters, but the big performance gain will be that you can run a much hotter cam, higher rpm, and heavier valve springs. Buy other than reliability most if these things won't matter in a truck. Oh BTW you can always use a zinc additive to your oil.