Roller vs Flat Tappet Camshafts - which one is best?

[@v.e.7236]

There are some engines that do not have the after market support that the Chevy small block has and have no roller cam option, like my Corvair boxer engine. No cam manufacturer makes a roller cam for this engine, so I'm left w/ two choices: solid or hydraulic flat tappet lifters. I went w/ solid lifters to increase usefull RPM band and max RPM capability. Fortunately, they have solid lifters w/ micro-drilled oiling holes to help keep the lifters oiled at the point of contact. Still not optimal, but a definite improvement. I plan on installing a pressurized oil accumulator to eliminate dry starts all together.

[@CanadianCrateEngines]

This is true! Not all engines can be converted to a roller camshaft. The solid lifter with the oiling hole is a good compromise though. But solid lifters require more valve adjustments…I guess it is the lesser of two evils

[@v.e.7236]

@@CanadianCrateEngines With the available polylocks you don't have to worry about your adjustments loosening due to vibration, like standard rocker arm nuts.

[@davidwindhausen6194]

I would use a roller cam if it could live in the 8,000 to 10, 000 rpm range ! But I have two sets of. Heads that have dropped valves with a roller cam 😢

[@johnhinojosa4890]

Do I have to replace my camshaft to get roller tappets. I drive a Toyota Tundra 2004 4.7 liter V8

[@CanadianCrateEngines]

Hi John, the Tundra engine has overhead camshafts, which is a totally different design. Overhead cam engines don’t have the same drawbacks as a traditional flat tappet engine.

[@DustinBaerwolf-kv9jx]

I want one for old farm tractor

[@grumpy1962R]

How do the camshafts differ? The rollers are on the lifters not the camshaft

[@CanadianCrateEngines]

The actual profile of the lobe is different between a flat tappet and roller camshaft

[@CanadianCrateEngines]

The camshaft lobe design is completely different. The ramp rates are vastly different, you can actually see the difference when you have them side by side. The roller cam lobe has a much more rounded profile, and is less steep

[@ezkempinkemp3467]

For equal spec cams, do the rollers have the same choppy idle?

[@CanadianCrateEngines]

Good question! If all specs were equal, the roller camshaft would have a similar, if not slightly more choppy idle. A roller camshaft typically opens the valve quicker, and keeps the valve open longer at higher lift. That quicker valve speed helps with scavenging and performance. Also, advertised duration will likely be different between flat tappet and roller camshafts, even when the duration at .050" are the same, so it is hard to compare apples to apples in most cases.

[@ezkempinkemp3467]

@@CanadianCrateEngines thank you for replying back to me. The more lope, the better but I don't want to kill the performance. I will probably go with roller just because of all the problems that people have been having with the flat tappet cams over the last three or four years.

[@CanadianCrateEngines]

@@ezkempinkemp3467 Absolutely! Don't risk your engine build to a flat tappet failure. Go roller...you won't regret it!

[@ezkempinkemp3467]

@@CanadianCrateEngines I believe I'm going to heed to you're advice. Thanks!

[@buddysorge5840]

Don’t you have to get a roller block if you want to switch? I know they’ve come out with a few retro fit rollers for classic cars but I heard they’re not a huge difference in power just lasts longer.

[@rsmith3033]

diesel engines have been running rollers since tha 40/50s an cummins had a great set up with cam followers where u shim them with gaskets to advance/retard tha timing 👍

[@murtadaalhashmi8483]

Thats why all the new Hemi Engines suffering from the roller design

[@CanadianCrateEngines]

Not necessarily because they are roller, but more to do with the design of the D.O.D lifters themselves. But you are correct, the stock Hemi lifters are a major problem