Working on an old Perkins 4.236

[evm1024]

The vented loop (anti-siphon valve) goes in the raw water line on the exhaust side. Here is something I just found in a quick search that covers most all the bases.

Regards

Good Old Boat - Cool and Quiet and trouble-free article

[Rob Toronto]

Originally Posted by perchance

I'm not sure as the boat is in Vancouver but will ask next time I talk to him. He said the vented loop fixed the problem. I suspect it is in the raw water inlet.
P.S. you can get the manual for your transmission online.
If you lose reverse or it slips there is an adjustment on the side of the tranny to adjust the reverse band. Simple to do if you need to.
Anthony Keats in Port Dover (I think that's where he is) has parts for the Paragons.

I'm starting to think you are correct. An easy fix really. I've got plenty of headspace in the engine room, and it is directly below the center cockpit, so I can't see doing a proper vented loop of at least 12" being a problem and putting a vent in just forward of the mizzen will make it so I don't even have to drill any holes. Actually, I might even be able to work it that the vent is inside the mizzen. Sure would mess with the next owner
As for the tranny... Ah, if it was just an adjustment, that would be heaven, but alas, she seems to pull fine in reverse, it is in forward gear that I'm loosing hydraulic pressure in.

[Cheechako]

The only thing a bigger muffler really buys you is more water storage... so if you have to crank a long time for some reason, you dont fill up the exhaust... or if you have a low outlet, and water is lapping into the exhaust at the dock...

[Rob Toronto]

Originally Posted by Cheechako

The only thing a bigger muffler really buys you is more water storage... so if you have to crank a long time for some reason, you dont fill up the exhaust... or if you have a low outlet, and water is lapping into the exhaust at the dock...

Good point.
I thought it might be water lapping into the exhaust originally due to the fact that I'm stern to one of the main channels, but I pulled off the pipe from the muffler inlet, and laid it in a tray to see if I would get any water in through from the outlet in the transom and left it that way for a week. Then last week, I forgot to plug it when 'Sandy' hit. Although we didn't get that much of a blow, we did get some decent winds, and wave action in the channel. Not a drop of water in the tray from the exhaust. So, I don't think it is coming in that way.

[perchance]

If you are reasonably handy with tools they are not too hard to work on but you Do need a manual. There are no "special" tools required as I recall. The slippage could be any number of things from worn plates, a bad o-ring on the pancake cylinder or stuck relief valve amoung other things.
Let's hope it is something simple and obvious.

[gjordan]

Rob, since you have a center cockpit , you may be able to T your siphon break into a cockpit drain. The cockpit sole is generally much higher on a center cockpit boat than an aft cockpit and may give you the height needed to plumb into the drain. An advantage of this , is that when you start your engine(from the helm) you will hear the water in the cockpit drain, and know that you are pumping water. If the water is not flowing, the sound is differant enough to notice the problem. Many boats are plumbed this way. Good Luck._____Grant.

[donradcliffe]

I had oil in the coolant recently (no coolant in the oil), and was able to find a kit from NAPA to test for exhaust gases in the coolant. The result was negative, so I was able to eliminate a blown head gasket from the problem list. I think it is called a 'block check" kit.

[gjordan]

Rob, I just read your post #19 and think you may have more than one potential problem. If there is even the smallest chance of water lapping in when you are docked, you have a major design flaw in your exhaust. At the transom your exhaust pipe should run as high as is possible before it comes down to the exit thru hull. Running it clear up to the underside of the deck is the norm. You may have to remove paneling in the aft cabin to check this, but it is very important. This may have nothing to do with your present problems, but if not done right can lead to an engine full of water when you are underway. I owned a Peterson 44 for years and sailed it hard with no exhaust problems. I delivered another Peterson 44 from Hawaii to Calif. After a really good downwind run one night ,I went to start the engine in the morning and it was completely full of water. That is where I learned about covering the engine with an old towel before turning the engine over with the injectors out. I got the engine running again, but wanted to know why the water had got in. I pulled the paneling in the aft cabin and found that the original Peterson exhaust had been replaced (by some hack) with only a small rise from the exit thru hull before it went forward to the engine. A small error from a repairman that could have cost the owner an engine. Home built boats like yours tend to be full of small errors that can lead to big problems. I hope all goes well.____Grant.

[Rob Toronto]

Originally Posted by perchance

If you are reasonably handy with tools they are not too hard to work on but you Do need a manual. There are no "special" tools required as I recall. The slippage could be any number of things from worn plates, a bad o-ring on the pancake cylinder or stuck relief valve amoung other things.
Let's hope it is something simple and obvious.

Thats what I'm looking for! A glimmer of hope
I did download a copy of the manual, and I am a decently handy guy, and have built everything from houses, to computers, so I think I will at least take the reduction gear assembly out, and give it a good look. Maybe something will jump out and bite me.
Other than that, if I had a decent understanding of how it worked, I'd be more optimistic of finding the problem myself. I'm a very visual person. If I could just 'see' how it worked, maybe I would understand better. Its just that I have zero experience with hydraulic transmissions. Even a decent drawing of fluid flow in one of these transmissions would help immensely. Don't suppose you know of anywhere I could find one do you???

[Rob Toronto]

Originally Posted by gjordan

Rob, since you have a center cockpit , you may be able to T your siphon break into a cockpit drain. The cockpit sole is generally much higher on a center cockpit boat than an aft cockpit and may give you the height needed to plumb into the drain. An advantage of this , is that when you start your engine(from the helm) you will hear the water in the cockpit drain, and know that you are pumping water. If the water is not flowing, the sound is differant enough to notice the problem. Many boats are plumbed this way. Good Luck._____Grant.

What an awesome idea. The cockpit drain is exposed and goes right through the engine room. Thanks. Solves the problem of where to put the vent AND makes my life easier

[Rob Toronto]

Originally Posted by donradcliffe

I had oil in the coolant recently (no coolant in the oil), and was able to find a kit from NAPA to test for exhaust gases in the coolant. The result was negative, so I was able to eliminate a blown head gasket from the problem list. I think it is called a 'block check" kit.

Cool there are even YouTube videos on how to use the kit. Thanks.

[NahanniV]

Hey, I have the same engine and am near you in Grimsby.

Some notes:

I think you have more than one problem.

My engine has a factory (standard on all 4.236M) raw water cooled oil cooler. Mine is at the oil filter mounting but I have also seen them combined with the main heat exchanger. Yours looks like an aftermarket conversion so you may not have one, but if you do be sure to check it as it is a likely source of the water in the oil.

If you engine is 3/4 below the waterline you probably need a vented loop; It's really the location of the water injection into the exhaust system that's important. If that injection point is ever below the waterline a siphon can start. If it is close to the waterline there's also the possibility of water being forced up and into it while sailing.

Your muffler seems small, is it just a muffler ? I think if your engine is partly below the waterline you need to have a waterlock to collect and pump the water out. Also as noted before, the output from the waterlock should loop as high as is practical; I don't think this is your current problem, but it could be in the future. My engine has a 3" diameter exhaust.

More pictures of your installation might help.

In the attached picture you can see my engine. The beige plastic thing on the left is a valve type vented loop; I plan to convert it to a constant pisser at some point as I have seen these vents stick shut. Also note there is a dry loop protecting the engine before the water injection point.

I have the Borg Warner Velvet drive that was standard with the marine version, so no help there.

There is a manual available online for theses engines, I will try to dig up the link for you.

Cheers,
John.

[Rob Toronto]

Originally Posted by gjordan

Rob, I just read your post #19 and think you may have more than one potential problem. If there is even the smallest chance of water lapping in when you are docked, you have a major design flaw in your exhaust. At the transom your exhaust pipe should run as high as is possible before it comes down to the exit thru hull. Running it clear up to the underside of the deck is the norm. You may have to remove paneling in the aft cabin to check this, but it is very important. This may have nothing to do with your present problems, but if not done right can lead to an engine full of water when you are underway. I owned a Peterson 44 for years and sailed it hard with no exhaust problems. I delivered another Peterson 44 from Hawaii to Calif. After a really good downwind run one night ,I went to start the engine in the morning and it was completely full of water. That is where I learned about covering the engine with an old towel before turning the engine over with the injectors out. I got the engine running again, but wanted to know why the water had got in. I pulled the paneling in the aft cabin and found that the original Peterson exhaust had been replaced (by some hack) with only a small rise from the exit thru hull before it went forward to the engine. A small error from a repairman that could have cost the owner an engine. Home built boats like yours tend to be full of small errors that can lead to big problems. I hope all goes well.____Grant.

The exhaust is about 8 to 10 inches above the waterline facing down just below the transom. I've included a pic. For scale, the pipe is 3" the picture is taken from the hatch in the aft cabin looking rearward.

The brighter silver is the transom, and the picture is taken level so you can kinda see the angle that the exhaust is mounted at. Good news is that it looks like I'd be able to just unscrew the elbow and put a longer pipe on it to raise the elbow then put an 90 deg elbow and a 45 to bring it back down to tie back in with the wet exhaust hose. I could probably gain an easy 2ft or more if I wanted to, but do I need to? And more importantly SHOULD I? Wouldn't a too tall a rise push water lying in the wet exhaust back into the engine? FYI, from where the exhaust is mixed with the water, to the outlet is about 20ft and the hose from the engine to the steel pipe in the picture is 2 1/4" ID. I'm starting to think I should replace the entire length including the muffler with 3". Can you see any problems with this, (other than the cost that is)

[NahanniV]

Ideally the high point of the wet exhaust should be just after the waterlock.

I.e. down from the mixing point to the waterlock and then up from the waterlock to the high point and then all down to the through-hull.

Is the exhaust through-hull higher or lower than the exhaust ?

If you are planning to get into salt water at some point all rubber would be a good idea, unfortuantly the rubber hose is not cheap. If you go that route, Vetus makes a rubber through hull that would totally isolate your hull from the hot salty (corosive) exhaust.

I looked at your pics again, and the only thing that is not shown is where the red and blue hoses go from the heat exchanger and to the mixing point. I guess that's where the transmission cooler is ?

Do you have an engine manual ?

Cheers,
John.

[Rob Toronto]

Originally Posted by NahanniV

Hey, I have the same engine and am near you in Grimsby.

Some notes:

I think you have more than one problem.

My engine has a factory (standard on all 4.236M) raw water cooled oil cooler. Mine is at the oil filter mounting but I have also seen them combined with the main heat exchanger. Yours looks like an aftermarket conversion so you may not have one, but if you do be sure to check it as it is a likely source of the water in the oil.

If you engine is 3/4 below the waterline you probably need a vented loop; It's really the location of the water injection into the exhaust system that's important. If that injection point is ever below the waterline a siphon can start. If it is close to the waterline there's also the possibility of water being forced up and into it while sailing.

Your muffler seems small, is it just a muffler ? I think if your engine is partly below the waterline you need to have a waterlock to collect and pump the water out. Also as noted before, the output from the waterlock should loop as high as is practical; I don't think this is your current problem, but it could be in the future. My engine has a 3" diameter exhaust.

More pictures of your installation might help.

In the attached picture you can see my engine. The beige plastic thing on the left is a valve type vented loop; I plan to convert it to a constant pisser at some point as I have seen these vents stick shut. Also note there is a dry loop protecting the engine before the water injection point.

I have the Borg Warner Velvet drive that was standard with the marine version, so no help there.

There is a manual available online for theses engines, I will try to dig up the link for you.

Cheers,
John.

Hey John,
Thanks for the info. I've got a copy of the shop manual, operator's manual, and a very cool handbook circa 1972, so I think I'm covered there, what I'm lacking is experience, you don't have some I could borrow, do you?
Nope, no oilcooler at all, so at least I can write that off the problem list, but if we go south like we plan to in a few years, it might not be a bad idea to retrofit one. I've got plenty of detail shots of the engine, but very few of the entire engine, but here is one from the front that shows the raw water piping. (Its the clear/white 1" hose running under the coolant hose from the thermostat.)
and a blurry one from the rear. Sorry. Call me mr shaky


Sounds like I'll be upgrading my exhaust to 3"