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Old 07-10-2021, 11:10 PM
Sculldog1 Sculldog1 is offline
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I am in pretty deep now!

Well it appears I have either gotten carried away or am doing due diligence. Either way I have a lot of work to do and would be very grateful for any input from fellow A4ourians.

After an overheating episode that seemed to result from some restrictions from the exhaust and doing a vinegar soak/flush I thought I had things going well again as temp improved and motor ran well for a 40 min. test run. After a couple sails where I run motor about 30min off mooring and 30min. back she began to run on only 3 cylinders and possibly just 2 as cylinder 4 was not firing at all and 3 was intermittently not firing. Compression test showed 0 on 4 and about 90 on the other 3 cylinders.

After removing valve plate it was clearly stuck exhaust valve on 4 and intermittently sticking valve on 3. Unable to free valves I removed head and was able to free the valves and got to looking at exhaust manifold and piping and, well long story short I took the whole thing apart. My thinking, and after talking with Ken about it while ordering new head, valve and exhaust gaskets, is that to take her apart this far and not to do a proper valve job would risk a recurrence and that being the case I also took off the water jacket plate and will be cleaning that all up as well cuz it seems that the clogging likely came from that area. Also while cleaning water passages from block deck above it surely needed some cleaning.

I am attaching a couple pictures of the exhaust for some input as to whether the design is problematic because the water input coming in at the top as it does and not further down toward the water lift muffler also the pipe where the hose comes in seems to reduce and ght that not create pressure or some other trouble? Also could running on three cylinders cause a lack of exhaust pressure sufficient to expel water and eventually allow it to ba c k up into cylinders as it clearly has? Manifold had water in it in the area highlighted in the recent newsletter about "exhaust reflux". . Also as I now have the manifold off and it looks pretty gross what is the best way to clean it up and get it ready for re-installation? Any way sorry to be so long and thanks for any thoughts.
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Last edited by Sculldog1; 07-10-2021 at 11:23 PM.
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Old 07-10-2021, 11:28 PM
Dave Neptune Dave Neptune is online now
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Your water injection point needs to be below the high spot. Water can dribble down the pipe into the exhaust manifold and create a lot of moisture that the valves don't like.

Dave Neptune
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Old 07-10-2021, 11:46 PM
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Thats what I think as well. I think if I bring it in right above where it goes to the rubber hose into the WL would be better. Not sure if this is how P30s came originally but am sure this isn't the original pipes as PO redid the exhaust some time around 2009. Any other design thoughts welcome. Thanks
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Old 07-11-2021, 10:31 AM
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I agree with Dave. Your water injection is too high. It should be at least 4" below the high spot on the dry stack. You're going to continue to get water in the manifold with that setup.

I would recommend replacing the water injection tee with a street elbow, followed by a length of straight pipe, followed by the water injection point.

Here'a link to my exhaust rebuild album to give you an idea of how it will look:

https://www.moyermarineforum.com/for...php?albumid=73
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Old 07-11-2021, 10:41 AM
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Anti-siphon?
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Old 07-11-2021, 11:02 AM
Sculldog1 Sculldog1 is offline
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Thanks EdwardC for the pictures it looks like a pretty simple remedy. As to anti siphon I don't really know whether it would be needed or not. Have you had good success with your set up and do I need the anti siphon if my set up approximates yours?
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Old 07-11-2021, 11:17 AM
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Old 07-11-2021, 05:34 PM
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The worst is never certain.... and so I would recommend to take it appart first: the water injection may have a tube several inches long ensuring water is injected below the exhaust gases T branch.

But having valve 3 & 4 sticking is 99% water coing backwards. So the worst is almost certain.
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Old 07-12-2021, 08:09 AM
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Quote:
Originally Posted by Sculldog1 View Post
Thanks EdwardC for the pictures it looks like a pretty simple remedy.
You're quite welcome.

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Originally Posted by Sculldog1 View Post
... As to anti siphon I don't really know whether it would be needed or not...
Yes, it is needed. I have one, purchased from our host here.
After shutdown, a hot engine cools, cooling the gases in the exhaust manifold. This causes them to contract. Without an anti-siphon valve, this suction can pull water back into the manifold. A large volume in the riser can help mitigate this, but an anti-siphon just before the water injection point completely prevents it.

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Originally Posted by Sculldog1 View Post
Have you had good success with your set up ...
I installed it in early 2011, and it has gone 10 years and almost 2000 hours of runtime without any trouble.
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Old 07-12-2021, 08:49 AM
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Quote:
Originally Posted by Dave Neptune View Post
Your water injection point needs to be below the high spot. Water can dribble down the pipe into the exhaust manifold and create a lot of moisture that the valves don't like.

Dave Neptune
My water injection looks like the photo above, but I have an internal pipe that sticks down about 3 or 4 inches to carry water past the T junction.
Moyer sells something similar:
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Old 07-12-2021, 10:15 AM
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Joe those work very well however my "preference" is for the injection to be at least 4" or more below the bottom of the exhausts "high point" or more. This is to avoid the bit of splatter and splash that happens at idle that can leave moisture splattered back which can through evaporation and condensation work back to the manifold and valves.

Just got done working on a big PB with twin BBC's. He has been having a lot of valve sticking problems and has done the heads many times. Before I got involved he actually kept 2 spare heads as his valves kept sticking. It took a while but we got it figured out. He only ran his engines about 15~1600 and ran at displacement speeds not working the engines hard at all. The problem turned out to be not enough temp in the factory "risers" leaving moisture to work back. Now he still runs slow most of the time but he now runs her up a bit before entering the slip or mooring field and shuts down after running a hi idle for a minute or two. Seems to be working well this season by running her up a bit to blow the risers out better and the extra temp keeps them "dryer" before shutting down. It took many of us to get it figured out.

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Old 07-12-2021, 10:54 AM
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I have wondered how these would work - the water gets pointed down.
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Old 07-12-2021, 11:23 AM
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Joe, my original exhaust was done with a 45* side out with a fitting similar to the MMI unit. It worked very well. The two exhaust systems I built I cut and brazed into a straight section at a 30* and placed it about 6 inches below the low of the high point. Never an issue unless the anti-syphon failed which it did many times as I had little room anywhere to go "up". My exhaust run was some 25 plus feet long with two high points and a water lift that I made out of fiberglass. I did away with the anti-syphon and went overboard with an open bleed line into a cockpit drain. Never a failure after that. The engine in my E35MkII was in the middle of the boat deep on the keel and my deck line was lower than the Cat 30 deck a big issue.

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Old 07-12-2021, 11:43 AM
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+1 on the open anti-siphon loop. Nothing to clog, nothing to fail.
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Old 07-12-2021, 01:12 PM
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Originally Posted by ndutton View Post
+1 on the open anti-siphon loop. Nothing to clog, nothing to fail.
Sort of. My outboard telltale cooling water hose gets clogged every now and again and one time it shot off the engine.
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Old 07-12-2021, 01:17 PM
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I've had my open loop for 16 years and never an issue. Mine is plumbed into the galley sink drain at a point above the waterline.
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Old 07-12-2021, 09:39 PM
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After examining the exhaust more closely what I have is very close to the MMI tfitting that Joe linked. The difference is that the pipe within the 1 1/4" had a bunch of holes drilled across it that appeared to begin almost at the same level as the riser. It definitely feels like it should have been extended further down before the holes or not at all as the one on the catalog shows. I am going to rebuild and extend the riser to the height of the present injection point (will be very near what Edward C showed) and move the injection point below the manifold level and install antisiphon on the manifold to injection tion hose. Could anyone elaborate on the "open loop" antisiphon set up and weigh in if that is better than the valve set up in the catalog? I ask because I am concerned if the valve might be susceptible to failing in the raw sea water and if the open loop arrangement might be less prone to failure. Thanks to everyone.
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Old 07-13-2021, 09:23 AM
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Quote:
Originally Posted by Sculldog1 View Post
Could anyone elaborate on the "open loop" antisiphon set up and weigh in if that is better than the valve set up in the catalog? I ask because I am concerned if the valve might be susceptible to failing in the raw sea water and if the open loop arrangement might be less prone to failure. Thanks to everyone.
Open loop is better and less prone to failure. You just T off the water injection line and run another hose to a fitting well above the water line for water to exit and/or air to come in. You need a restriction of some kind so too much water does not follow this path instead of cooling the exhaust. This is like the pee hose that outboards have, it might get clogged but it is obvious when it does.
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Old 07-13-2021, 10:33 AM
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It may help to understand how an anti-siphon functions. It allows air to enter the cooling system in the event of negative pressure, a suction, thereby interrupting the suction. As you'll remember from the 'Colorado Credit Card' days of siphoning fuel out of a car gas tank, suction is what siphons are all about so interrupting the suction eliminates the siphon.

An anti-siphon valve allows air in under suction but closes when the engine is running and there is positive water pressure in the cooling system. This prevents cooling water from hosing everything down in the immediate area of the anti-siphon loop. The valve is known to have a limited service life and stories of its failure are pretty common. When it fails you either have water spewing in the area or no siphon protection.

The open loop has no valve, just a hose from the top of the anti-siphon loop to allow air in under suction. The other end of the hose is installed so that the water that comes out under positive pressure is routed harmlessly overboard. As I said previously, mine is connected to the galley sink drain plumbing. It is important to note that the entire vent hose must be installed above the heeled waterline.

Here are two poor quality pictures of my open loop system. The first shows the bronze anti-siphon loop with the vent hose attached to the top, the second shows the other end of the vent hose attached to the galley sink drain plumbing.
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Old 07-15-2021, 08:18 PM
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The quest continues!

So for to possibly be helpful to others I will report.

Having gotten in way over my head on the sailboat engine I found that:

1. My exhaust got a clog that led to water intrusion and the usual sticky valves etc.

2. Removing head to free valves led to exhaust rebuild, manifold clean out, and removal of valves, springs and also a long overdue water jacket clean out. I have the valves in an organized box for to return to exactly where they came from and am soaking keepers, springs and retaining washer/tophatty looking things in vinegar to remove some surface rust. It looks like valve stems are in pretty good fettle with exception of cylinders 3 and 4 where serious pitting is evidenced after I chucked all valves into drill and cleaned carbon off using scouring pad and 120 grit sanding sponge. I will be polishing the good stems by wet sanding in stages to 2000 or 3000 and finally polish with buffer.

I am planning to clean up the seats and lap the good valves before replacing them and ordering new stems for 3 and 4 and lapping them in as well.

For anyone considering work on this scope be advised it is a lot of back breaking effort. It took all day to get the valves out, clean up all the mating surfaces for valve plate, water jacket, manifold and cylinder head as well as muck out the water jacket.

A couple things I learned:

90 degree long nose pliers very handy to help break rusty keepers free and get springs out.
Magnet on a stick very helpful to get black gunky mud/rust/sludge out of water jacket. Basically used wire and rifle brushes to break up WJ gunk and "rake" it into void between cylinders where magnet pulled up teaspoon sized clumps that I transferred to bucket like 300 times till couldn't get no more. Still gonna need a vinegar or acid flush after reassembly.

Anyway got a few parts to get and then reassembly will commence. Just sharing the experience for others to use info for their own decision making process. BTW all this going on while swinging on mooring which I don't recommend but I am beyond the PONR so I soldier on. Thanks to all for insights and support.

Last edited by Sculldog1; 07-15-2021 at 08:21 PM.
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