Reversion with mild cam???
 

Just had a brand new Tyler Crocket 502 hydraulic on me due to reversion. Tyler tore it down and there was water in all 8 cylinders. He thought for sure it was due to a backwash situation, but I was in the marina 100yds from my slip and it was dead calm. I was having some carb issues that day and it was hicuping when this happened, but I'm still shocked that it would ingest this much water.

The cam is pretty mild (114 lsa), but I can't keep an O2 sensor alive, so I know I've been getting at least a little reversion all year. At one point I took the sensor out and felt water even at 1000 rpm.

We're running a stainless marine exhaust that is dry all the way to the tail pipes. We're talking about making it a completely dry exhaust or at least welding up most of the water holes and running dumps.

Any suggestiong? Can I run any sort of flapper valve in the dry section of the exhaust, or will the heat destroy them? Or will flapper valves even do anything with actual reversion, or do they just protect against backwash? I'd really rather not run completely dry.

could you have a leak up front in the ss. can you preasure test them or the manifolds??

Already checked them. No leaks.

Whe you say "dry all the way to the tailpipes" do you mean to the end of the tailpipes where they connect to the tips??? I hope.

I'm running stainless Marine manifolds and risers on a blown 498 C.I. with a 112 lobe center 714" lift solid roller camshaft with extremely high duration and have NO reversion problems... Food for thought. Might want to look somewhere else to the problem for peace of mind......

reversion problems
 

you problem might be because you are using too high of a lobe seperation on the cam,i was told that you if you use a 112 degree or less of seperation you will never have reversion problems,just a thought

In this setup, the tailpipes are the tips and go right through the transome. Water is released right at the exit to the atmosphere. Pipes are very close to the water which is why Tyler asked about backwash, but we're sure there was no wave in the marina.

Are you running wet exhaust? Yes, we are looking elsewhere, because this makes no sense to either of us. I wanted to run a 741 cam, and Tyler went with this milder cam just to be sure. Any thoughts on other things to check would be greatly appreciated.

Are you sure it is not an intake problem? New motor, right? First time out?

P.S. How is the new drive?

DAve

Yes, wet Stainless Marine which is why I commented here. Something just does not sound right. What are the cam specs? At a 114 deg lobe center it would be hard to achieve reversion on any reasonable cam. Maybe the cam specs are incorrect???? I know I'm reaching here and I'm positive Tyler checks all the cams when indexing but It's a thought.

Hiccupping? Did the motor run backwards before it died???

He said he checked intake gaskets, etc. Got to trust that he knows what he's looking at there.

Not the first time out. Been running it all summer, but I'm pretty sure (in retrospect) we've been getting some reversion all year.

Didn't get around to putting on the new drive as this happened. Hopefully test both this weekend. Looks great though. thanks

Good luck with it all. Sounds like something has changed recently. If it's the same set-up, the water is getting in somewhere. Keep us posted.

Your welcome!

Dave

Possible that it did a little, but not dramatic. Kind of hard to recall what happened when. One second I had a boat full of people heading out for a day on the lake, and the next minute the engine was locked up.

No way you should get any reversion with tailpipes that dump water that far back.

Are you running mufflers that could cause water to sit at the end of the pipes????

if your water is dumpingout the end of the pipes and the pipes go through the transom that is a dry set up, the water is coming out the every end theres no rubber between manifolds and the transom. thats a type of dry set up mine has piss tube dumps right before the trans, that go out the back then there are 2 little holes in the end of my pipes which run throught the transom out the back one piece thats dry every loud, then thrers the small minidump pipe that comes out or below the pipes to. so I think its not the tail pipes but blown head gaskets or leaking ones.

A cam timing issue can cause this. Either from being improperly installed or loosing a bushing or something like that. Another thought is bent exhaust valves. You did mention popping. I think I would do a compression and/or leak test.

BT :cool:

Tyler's got the entire engine torn down. new bearings, gaskets, laped the valves, etc. So if it's was an engine related issue, it should be taken care of. Scares me to just put it back in the water without really finding the issue.

Judging by the water I was getting out of the O2 sensor hole, I would have sworn there was a leak in the exhaust, but Tyler said he pressure checked them and they were fine. I checked the O2 bung in the tailpipe and it didn't leak either.