water from manifold stud hole?

[hank]

I'm searching for the source of some water in my 4th cylinder and a valve problem - i think a broken valve. The #4 end of the manifold and the exhaust pipe flange show some rust, so does the #4 exhaust valve spring. I suspected the exhaust so removed it and the manifold. When I removed the manifold, the stud between cylinders 3 and 4 came out - ok... but then a steady stream of water came out of the stud hole for a few seconds. Is that normal? Thanks for any help.

Hank

[hank]

I found this entry with a similar scenario - http://www.moyermarine.com/forums/showthread.php?t=1327 ... Don, you said:

"Each of the manifold stud holes enter the cooling jacket and if the lower threads of the stud do not seal well, engine coolant will be drawn into the nearest intake port."

... so the water coming out of the stud hole is to be expected? Hmm.. ok.. My stud is in good condition, but I did find the manifold nuts/stud to be somewhat loose - maybe closer to 15 lbs instead of the 35 lbs. torque spec. ... so is it possibe that this would lead to water getting in the #4 exhaust valve?

Here's my problem:
Last summer, I had a stuck #4 exhaust valve. With help from the forum I was able to to tap on and free the valve, and it seated itself. Don was concerned about the presence of water, and suggested that I keep my eyes on it. Of course you were right.

Over the year, if I ran the engine frequently, everything was fine, but if I didn't start the engine for a few weeks, it would skip when first started, then smooth out after a few seconds. I'm assuming the valve was a bit sticky each time. Last weekend, i started the engine, but she never smoothed out. There was also a metal vibration-like rattling noise from the top of the engine. I had no compression in cylinder 4. I tried to feel the valve through the spark plug hole, but couldn't. I thought that the valve spring may have broken leaving the valve stuck in the open position, so I removed the valve cover. The #4 exhaust valve stem/spring./keepers seem to be intact, but I clearly see some rust. I turned the motor over, and everything moves appropriately. I slid a small diameter aluminum wire through the spark plug hole, through the open valve through the exhaust port, and while manually turning the motor over and observing the stem moving, felt no pressure on the wire. So.. I'm assuming the valve stem has broken and the top of the valve is sitting in the guide - (causing that rattling sound). I believe my next step is to remove the head and confirm, and replace.

Does it sound like I'm on the right track? Does anybody have any suggestions, recommendations, cautions?

Oh - and of course I still have to find the source of the water. I'll post what I have on that later this evening.

Thanks for your help folks.

Hank

[keelcooler]

Hank
If you can insert a .10 feeler gauge on no 4 valves your stems are ok.If a stem breaks the spring would bring it all the way down preventing any clearance.
Check the spring again,the valve should have bit down on your wire.
Are there any signs of water leak down in manifold ports or around stud block threads?

[hank]

Thanks keelcooler for the suggestion. After removing the valve cover and seeing the rust at #4 exhaust, I attempted to move the valve by hand and didn't feel any play, while I could feel the play or clearance on the other valves. I did not measure, but will do so next. Here's a pic of the valves - a pretty good bit of pitting on that #4 exhaust lifter - I'm guessing I've had the leak for a while, since the rust/pitting is isolated to #4 exhaust. I don't see signs of rust or leaks at the stud/block.



My exhaust is a standpipe system, which exits the transom 6 inches above the waterline. It's the stock system for my 1979 Ericson 29. Am I right in thinking that this design will not result in water backing up through the exhaust pipe from prolonged engine cranking? I connected a garden hose to the water inlet at the top and no water leaks back down to the manifold end, even if I heel the exhaust over from side to side at 45 degrees. I will check the rubber hose to the transom for restrictions, otherwise I don't think the exhaust is the source of the leak. Here's a diagram of this exhaust design:
.
and a picture of mine:


I checked the manifold by attaching the garden hose to the inlet from the thermostat and blocking off the water outlet at the exhaust end. Again, I didn't see any leaks.

I'll try pressure testing the head/block as discussed in the forums, and check the manifold and block surfaces for any pitting and a flat surface/

Other ideas? Thanks everyone.

Hank

[Don Moyer]

Hank,

I must say how impressed I am with your thoroughness and the methodical manner in which you're addressing your problem!

Whenever a stud comes out with the nut (which it appears that yours did) it's fairly common to find that the threads had been leaking and introducing water into the intake and/or the exhaust port on either side of the stud. Depending on the dominant direction of the leak, the exact manifestation of the water damage can vary somewhat, but I have seen several engines over the years present almost exactly the same evidence you're seeing.

The thing I would most like to see is a picture (or description) of the surfaces of the block and manifold around the aft stud hole. If water had been leaking past the inner threads of the stud, it will usually leave a rusty discoloration around the base of the stud on both the block and manifold, frequently to the point that the surface of the manifold needs to be milled by a machine shop. If this is your situation, I would be fairly content with the assumption that this stud was in fact the source of your water leak.

If there is absolutely no evidence of water around the base of the aft stud, I suppose a pressure check would make sense. However, there is no water jacket to leak in the area of the tappet where your water evidence is most prevalent.

Keep us informed and we'll help when we can.

[hank]

Thanks Don. Here are the pictures I tried to post earlier. The stud hole doesn't look too discolored....

[hank]

Don, here are pics of the manifold as it came off engine, and after removing that bit of gasket. The gasket was on there hard... maybe something more than hardened permatex. The previous owner had this engine rebuilt a couple of years before we bought her in '07. It looks like there was an issue at this end of the manifold and it was built up when reassembled. You can see the machining marks on the surface at the rest of the ports - doesn't look like any gasket cement was used there. But... I dont see discoloration... What do you see? And thanks!

Hank

[Don Moyer]

Unfortunately, I'm not seeing any discoloration either. If the mating surface on the block looks this good, I'm afraid that the stud does not give us an easy explanation for the water damage we're seeing on the lower end of the valve spring and tappet.

For the pressure test, I recommend that you fill the block and head with water and then during the test, look for water dripping down from the upper reaches of the valve port and for any sign of water in through the spark plug hole as well. Remember to reseal the stud in the aft hole before the test.

In case I forget later, remember that the recommended torque on the manifold studs is 25 foot pounds. I think you mentioned earlier that it was 35 foot pounds. That was the original specification but it was changed to 25 over the years.

[hank]

Thanks for taking a look, and the pressure check recommendation Don.

I performed the pressure check with water in the block as recommended. I applied 20 lbs pressure, and it quickly uncovered a slight leak at the thermostat gasket. After an hour, it was still holding 20 lbs, so I increased it to 25 lbs and went fishing . I checked it 24 hours later, and the pressure had decreased to 20 lbs, but no signs of water at the ports, sparkplugs holes, or exhaust manifold studs.

The mating surface on the block looks good.

There is a bit of wear on 1/2 a thead of the exhaust manifold stud that came out, and it only had 5 threads while the parts displayed in the parts store show 9 threads, and the bad bolt included in the picture in the link I referenced at the start of this thread looked like it had more threads. I guess different length studs may have been used at various times by Universal. After reinstalling the stud for the pressure check, I measured, and it protruded from the block the same 7.5 cm as the other 2 studs. While under pressure, I backed out the stud a bit at a time, and after 3 complete turns, it still did not leak. I dont think this is the source.

Keelcooler - I checked the clearance on that valve - none. While looking for water leaks from the pressure test with a mirror reflecting up into the exhaust port, I saw the broken valve stem.

So, still unsure of the source of the water, but the head has to come off, and I'll be looking for a small break in the head gasket.

Ordering parts now. Thanks again for the help and advice - I'll be working on her next week and will post with my progress.

Hank

[Don Moyer]

Hank,

Thanks for the thorough update and kudos on your methodical work. Your pressure test should have shown up any current water leak in one of the water jackets (as well as a leak in the head gasket).

I'm beginning to wonder if the water damage may be from an historic water episode (perhaps a one-time backing up from the exhaust system many years ago) and the valve finally only recently gave up after years of chronic sticking. We'll all keep our fingers crossed that this turns out to be the case after your repair. Again, remember that the manifold studs only get 25 foot pounds of torque instead of the earlier specification of 35.

Don

[hank]

The head came off easily. It only had 1 head gasket - but otherwise all looked good. No signs of leaks or breaks. We took the head and manifold to the machine shop, they will pressure test or magnaflux to check for cracks. The broken valve was really worn. It looks like it has been exposed to corrosion for quiet some time. I attached a picture.

Since we had the head off, we went ahead and took the water jacket cover off. Everything looks in good order other than a bit of sludge and rust scale. The thermostat had some scaling on it, but cleaned up fine. Is it OK to soak the thermostat, the thermostat housing, and the water jacket cover in diluted muriatic acid before we put it all back together?

We unwrapped the exhaust pipe and found a 1/2" hole in the dry section. The standpipe was galvanized pipe, welded to the 316 stainless expansion chamber. I ordered a new flange, cut off the expansion chamber, and had 1 1/4" galvanized pipe cut and threaded to the required lengths at Lowes. Now to find a welder to reattach the expansion chamber.

Parts should be here this afternoon, and the machine shop should be finished today as well, so with any luck, we'll have her back together this weekend.

The source of the water leak remains a mystery.... y'all see anything in these pics?

Thanks.

[keelcooler]

Looks like your getting flow down the dry section. Test your stand pipe with water, deflector cap may be the problem, or an internal hole in dry pipe.

[sastanley]

I kinda agree with keelcooler...before you weld up that new hot section, maybe we need to help re-engineer it..gotta any pics of that?

I added about 6 inches of lift on my hot section over the winter, as there were reports of water intrusion (cranking too long) on more than one occasion by the PO. I made as big an upside down "U" in my hot section as I could. Although I have a plastic Vetus muffler, I used about 5" of exhaust hose as my connection...no welding. There are pics elsewhere on this site..I'll post a link to them so as not to load up Don's server with double pics.

Let's see if this worked. This was pre-installation mockup, but gives you an idea.

[Mark S]

Shawn, do you have a picture of the fully installed exhaust taken from the same vantage point? I'd like to see that.

Mark

[hank]

Thanks, I keep thinking this has to be coming from the exhaust also. I tested the dry section and the manifold but didn't see any problems.

[hank]

So - the machine shop worked the head and manifold. The head is fine, but the manifold is not. He found a 1/2" bad spot in the water jacket at the #4 exhaust port. With air pressure applied to the water jacket, a soapy solution showed a small air leak. The metal in this spot is pitted and soft, he recommended replacing the manifold rather than attempting to weld this spot. I tend to agree with him. Here's a pic. That blue spot is the head of a pin stuck in the metal.

So... mystery solved? Weld or replace?

On the bright side - the new valve, springs, gaskets etc arrived - so I can get started on the the head..

[hank]

sastanley, I'm glad you brought up this question of exhaust design. Most of the posts on this forum discuss a water lift exhaust system. We have a standpipe system. Here's a diagram I found of the design. I posted a diagram earlier in this thread of the expansion chamber. Earlier versions of the expansion chamber had the outlet pipe half way up the expansion chamber, and so, the chamber held water, but the later version,which we have, has the outlet pipe on the bottom so it doesn't hold water, so less corrosion.

This seems to me to be a good design, its drawback is that it requires some height - my expansion chamber rises to the top of the port lazarette!

I understand that in waterlift systems, if the engine doesn't start quickly, the water pump continues to fill the water tank, and eventually that water can back up the dry pipe to the engine. I don't think the standpipe exhaust system will draw water to the manifold if overcranked. Is that right? What do y'all think?

Hank

[keelcooler]

Hank, I think you found the offender. Get the new manifold. As your picture outlines, no sags allowed from stand-pipe discharge to transom.


You are right cranking should not fill up your stack and back flush. Also no need for vented loop in this system.