Visit The Dirt Forum for More Information

Author Topic:   roller or not to roller
wingnut
Member
posted January 15, 2001 09:19 PM
Wingnut, If you keep eveything the same in these two motors you would only see about 20 hp gain .....this comes from freeing everything up..........where you gain power running a roller cam is the profile of the cam is more aggresive you can slam the valve open and closed when needed depending on the needs of the motor............thats the advantage is you can make the big change and not break stuff..........now with this deal I will say 50-hp


eagleii
unregistered
posted January 17, 2001 06:36 AM           
I agree with AwkwardJeff on the profile being WAY more agressive that a flat tappet cam. When you look for a roller cam for any motor, notice the specs on the cam. Pay close attention to the valve timing events, duration, and lift. Compare these figures to your favorite flat tappet cam. Pick a roller with the same power band. Remember to consider your gears. It does not matter where the torque curve is in a motor as long as YOU ARE GEARED TO RUN THAT CURVE.

Normally rollers are used for very high rpm operation and use a lot more lift than a flat tappet one. Piston to valve clearance is another concideration here.

Rollers are as trouble free as the get. But they do require additional hardware to deal with such a rev kit,(not required bu NECESSARY), stronger springs (more seat pressure), etc.

Evaluate whether the triple cost over the flat tappet cam is worth the trade off in power gain.

------------------
EagleII


FUCIFINO
unregistered
posted January 23, 2001 08:23 PM           
YOU SHOULD CALL AL OR ASA HOVIS AT HOVIS DYNO TUNED RACING ENGINES THEY HAVE DONE A LOT OF DYNO TESTING ON A LOT OF DIFFERNT CAM GRINDS FLAT AND ROLLER TYPE 1-636-278-4247 ?????????????


GnarlyCar
Member
posted January 24, 2001 04:00 PM
A few years ago, I had an opportunity to make an apples-to-apples comparison between a roller motor and a flat tappet motor.
OK, the flat tappet motor was a 406 and the roller was a 362, but that didn't seem to matter. I led a heat race at the region's largest special until the white flag lap, when the 406 (which my car owner had borrowed) let go. This thing was probably the hardest pulling motor I had driven at that time. Turns out that the builder/car owner didn't retorque the intake bolts after breaking it in; it leaned out and burned the block and a head.
Anyway, I borrowed a 362 DLM motor w/ a roller set-up in it from another buddy and dropped it in for the C feature the following night and could not believe the amount of power we got from that beast. We ran the same gear as the night before, started 23rd on the field and ran up to 5th in a shortened (10-11 laps, no one's sure) race.
The only real difference as far as parts were concerned was the cam, the bottom ends were nearly identical. One would think that the 406 would have more torque, but that wasn't the case either. The 362 w/ the roller had way more, and more top end pull as well.
In the sanction I run in rollers are illegal in the mods, but back then (my first season in mods) I just wanted some laps, not thinking I'd get even that close to the front with it. Had I known it was gonna be that fast I probably wouldn't have done it..I'm not really a cheat. If I was ever given the choice again, though, and it was within the rules, I wouldn't give it a second thought.. roller or stay home.

Matt

Back to the Archives