Rage

Please see item #4 in attached commentary on reversion from Lightning Marine web site.

Has anyone had first hand experience with using the Rhoads V- Max hydraulic lifter in a marine application? Please share your experiences!

Rage

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ratman

those lifters have been around for ever and seem to work pretty well but they are only for flat tappet cams, most people run rollers for even more lift and duration more so on big ci engines

1BIGJIM

iTrader: (1)

I tried them years ago. Made no difference at all. I was told they are for BIG duration cams.

Rage

Well they do offer roller lifters now for the 454 and 502 but not the 496. However they will convert the stock 496 lifter to a Rhoades V-Max lifter for $95. Probably will convert a lot of other lifters as well. I just did not ask.

Rage

They made no difference at all for what? Reversion?

Rage

"Seem to work pretty well" for what? Eliminating reversion?

1BIGJIM

iTrader: (1)

They made no difference at for idle and Reversion. Mine was loading up at idle. I was running a cam on a 110 CL. Changed the cam to a 112 CL.
I think you have to have a very large duration something a boat would never see with wet exhaust.
If you want to run a large cam go to a dry exhaust or have water dumps.

Rage

What are water dumps?

Rage

I finally called Rhoades to learn more about their lifter direct. It was designed ~30 years ago as a means to vary cam timing particullary to allow using big duratuion cams in automobiles where they could normally not work because you could not keep them running at low rpms do to the big intake/exhaust valve overlap and resulting low engine vacuum. That is still their main focus today. They have an improved design and now also offer hydraulic roller lifters in addition to solids to include the 454/502.

However this same ability to retard the exhaust valve timing at only low rpms (idle to 3500) also is just what the doctor ordered for reversion with big cams or not such big cams like mine. The lifter does not care how big the cam is or is not, it will still retrard it at valve close (only). Apparently the max retard is about 15 degrees which occurs at idle and the amount of cam valve timing retard decreases as the rpms increase until there is essentially no more retard at ~3500 rpms. Again reversion is the worst at idle so this is a good match.

When I asked Lightening Performance Marine why they mentioned the Rhoades lifters as an aid in overcoming reversion this was the comment. Since reversion is do to the exhaust valve being open on the piston intake stroke (ATDC) and the Rhoades lifter causes the exhaust valve to close sooner ATDC at idle than without the lifter feature. So lets say my cam's exhaust valve normally closes at 34 degrees ATDC so it is open for 34 degrees during the piston intake stroke at 650 rpms but with the Rhoades lifter it is only open 34 - 15 = 19 degrees and this 19 degrees is at the least volumetrically efficient portion of the piston intake stroke/degrees crank rotation right after TDC.

If given that the exhaust valve is the culprit for reversion I wonder why one would even need the intake lifters converted to the Rhoades configuration. I am not an engine guy so I maybe all wrong.

If they can rebuild my 496HO lifters with their feature, which they say they can do, so I can use the same push rods that is what I plan to do. My reversion is not serious to the degree the engine is at direct risk. I just need things a little drier at the o2 sensor mounting point so this seems to be the answer for me.

Comments?