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Old 10-01-2010, 05:21 PM
oldbogie oldbogie is offline
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Quote:
Originally Posted by 70' c10
hey guys i got a 350 with mechanical flat tappet lifters and i was wondering if roller rockers are a logical choice for a once or twice a week driver. how often am i going to have to reset valves if? also what kind of horsepower bump are they gonna give me? thanks!
I think this is something to consider as lift at the valve gets around .5 inch as they reduce the side loading on the stem and guide resulting in less wear, thus less oil going down the guide. At the trunnion, if you spend much time above 6000 RPM they reduce temperatures compared to what's going on with the ball and socket design. This reduces heat related failures in this area. But in and of themselves without an increase in ratio, they really are not power adders and to get the gifts they do give in reliability and durability under extreme conditions the trade of potentially large engine failures comes from the rollers being spilled into the engine should one of them fail. To guard against this eventuality screens need to be fitted to the oil returns at the ends of the valley. Where the smaller vents holes line the cam tunnel either standoffs have to be installed or the vents closed off. Then some powerful magnets need to be placed at the drain backs in the rocker box and in the cam/lifter valley to attract any possible wreckage before it gets to the screens, a double layer of insurance should a roller bearing come apart. It's not something that happens often, but if the engine isn't prepared to defend against that rare occurrence the result is quite horrific.

Bogie
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