Safe Guards to avoid reversion/ingestion
 

Lets say you have a cam selection that is slightly prone to reversion issues. Without tearing the motors down and changing the cams what are some things that you can do to make sure you are issue free? Setup has stock Gil exhaust on 502mpi's.

My thoughts so far:

Fresh flappers and butterfly flappers
Long turndowns/donkey dicks that would inhibit splashback
Longer risers so water is dumped further back
Mufflers

Appreciate any input.

Dry pipes

Friend built his 34' boat a few years ago with a single engine in mind.We've opted for the ZZ572 engine with Stellings dry exhaust.It worked great until the inner jacket at one of the exh flange cracked and doused the exh valve and dropping it.We had to scrap the dry exhaust idea and had Eddie Marine fab a s/s wet one to our spec, mounted on the EMI aluminum unit.We had to get the risers taller than the stock units readily available to stop reversion. 500 hrs on the engine and boat ,running top as a commuter on weekends.

Original setup http://www3.telus.net/spectrasonly/c...20interior%201
http://www3.telus.net/spectrasonly/c...20interior.jpg
http://www3.telus.net/spectrasonly/IMG_1858.jpg
http://www3.telus.net/spectrasonly/IMG_1052.JPG



Present setup http://www3.telus.net/spectrasonly/C...rine%20exhaust

Wow, That is cool looking boat.

As far as the dry exhaust is concerned It would still need to be muffled since boat is primarily used at LOTO and have to keep it to the 90db to keep the water cops happy. Was just looking for things that can be done to help lessen chances of an issue. Also got to thinking that the soleinoid actuated switchable exhaust function should probably be done away with.

If your running diveters like the Crosa, take out and put longer risers and problem solved, add mufflers if then too loud.

Josh, you worry too much:lolhit:

Really though, I don't think the slightly upgraded cams PBB used will cause any reversion issues. The Gils are fine for much more cam than what you have.

For the other type of reversion from wave splash back, you could put on some Drew Marine Shotgun muffler tips. They are 90% closed at idle and low rpm and open up with exhaust pressure so there is no restriction or loss of power.

Scott, I am a tad on the paranoid side. I"ll give you a call this afternoon.

One big thing to do is keep your idle as high as possible and do it as little as possible.

Man that is the coolest boat that thing is awsome what kind of speeds do you get out of her??? But great looking boat for sure...:cool-smiley-027:

Are you talking about my friend's boat? With the Steliings dry exhausts, we GPS'd the boat at 65 mph.
Before we added more crap like extra heaters, radio etc.....the boat weighed in a little over 6000lbs.
My friend used foamcore to make the boat light enough for a single.he doesn't care much about top speeds because it's a commuter he uses between Vancouver and Vancouver Island.

Here are some more pictures if you guys interested.

http://www3.telus.net/spectrasonly/c...20interior%202

His exhaust is different now from this one

http://www3.telus.net/spectrasonly/c...20interior%203

We have four recliner seats out of an Astro van.

http://www3.telus.net/spectrasonly/IMG_1860-1.jpg

Before paint on white gelcoat

http://www3.telus.net/spectrasonly/M...%20Maple%20Bay

Finally ,a slow test run footage

http://www.youtube.com/watch?v=BkUKYapf-dI

These are the mufflers we have now.Tested with dB meter at the dock,barely passed the 85 dB .

http://www.youtube.com/watch?feature...&v=QtMEmWhSRJo

Inside without the engine box. Loud!

http://www.youtube.com/watch?v=6L-st0izosU

Rubber external flappers are the safe way to go on your set-up !Have them on my Teague Select Exhaust System and they work very well....

Jim

Now THAT is the way to commute...a practical all-weather offshore boat. Very cool.

Very cool! Do you have pics from start to finish?

Sorry Baywatch :hijack::lolhit:

Flappers will help with water ingestion when the boat is sitting at the dock/mooring and waves come over the pipes but they will not help with reversion while the engine is running.

If you have gills, I really think you're fine Josh. Your cam is smaller than the 731 the HP 500's had and they were built originally with Gils and silent choice.
http://www.cranecams.com/product/car...detail&p=24282

awesome boat...nice mix of nostalgia and hi-tech...

My friend used to work at Soverign Yachts now Richmondyachts in Richmond B.C [ http://www.richmondyachts.com/gallery.html ] where he started the boat from scratch.He was a foreman there and did the interiors. He also worked on Dennis Washington's Attessa when that was stretched in Vancouver
.He used a windshield from a SeaRay for his boat, rest of the boat is a one of.
You can see more info I put on at >
http://www.riverdavesplace.com/forum...ead.php?t=4456

Thanks for the info. He did a great job. I dig it!