Water Reversion

[Shallow Minded]

How common is water reversion? Are the dams on the exhaust 100% fail-safe? Just curious.

[Jordy]

I don't think anything is 100% fail safe.
Can you give us a little more info? Like the boat, exhaust location, manifolds, rise between the transom and manifolds...

[Shallow Minded]

1992 Wellcraft Nova, 26 ft, single BBC, Revolution Marine manifolds & risers (4 inch), exhaust tips sit just below the rear swim-platform.
Here's the theory... noticed a little milkshake after my initial run. Not sure if it's moisture being burnt out from the rebuild or if my new cam (Crane #139731... Ad Duration 288 intake/296 exhaust; Duration @ .050 226/234; Lift: .587 intake/.610 exhaust; 112 degrees lobe sep) and exhaust may have sucked a little back in...
One other weird idea... when we backed the boat in the water, ramp was awfully steep and rear-end of the boat was fairly submerged before it had enough buoyancy to float off. Could water have crept in as the boat leveled itself back off?
Either way, it doesn't help the push rod I bent (I hope that's what it is...) :frown:
Anybody?

[PLACECRAFT20]

IM RUNNING THE EXACT SAME CAM IN A JET BOAT WITH LIGHTNING HEADERS. MY 4" TIPS ARE COMPLETELY UNDER WATER AT IDLE. (BELOW SWIM DECK). SO FAR I HAVE NOT HAD A DROP OF WATER IN THE ENGINE. I BET ITS CONDENSATION IN THE ENGINE THAT YOU ARE SEEING.

[powerplay230]

Don't you hate when someone answers your question with more questions? :D
If it was cam causing reversion would that suck in enough water to end up in the oil or would it just be causing problems in combustion chamber.
The trailer secenario sounds possible, guess it would depend on how much elevation there is between exhaust tips and the risers. I bought a pair of inline shuttes from Stainless Marine that are prettty neat but nothing works 100%.
What caused pushrod to bend?? :confused:

[Shallow Minded]

Not sure on the pushrod, should know more after tonight...
As for the milkshake, I'm guessing the exhaust tips are probably 6 inches or so lower than the tops of the risers. And I doubt if those little rubber flaps did much to stop the H2O.
If it's not reversion (it shouldn't be with this cam) and the trailering incident is a not it (that's a long shot), then how about properly sealing head bolts, etc?

[1BIGJIM]

If water goes into the exhaust from the trailer your engine would not turn over. You can not compress water. Did you put sealer on your head bolts? You will notice water reversion when you are at idle. It will load up. At higher rpms you should be pushing enough exhaust to stop it. How many hours on the engine since you noticed the milk shake?:frown: It the oil level high?