Lots of cooling and exhaust symptoms

[skhorleb]

Hi Don,

A previous owner of my 1974 C&C 30 Mk1 removed the water lift muffler and replaced it with a brass swing check valve. The exhaust system seemed to be working fine until one of the welded iron pipes rusted through. Then Murphy's Law kicked in. I replaced everything rear of the manifold with 1 1/4" brass pipe to prevent future corrosion problems...Every piece of pipe is within an inch length of the previously welded concoction. Attached is a drawing of what is currently installed...as a picture is worth a 1000 words.

First, I suspect the design is severely flawed. Fed up with trying to fix a series of problems without manuals I purchased your Service and Overhaul Manual. I was alarmed to find the previous owner had made such a significant modification...yet I was surprised it previously had worked. Hopefully your feedback will help me assess this design against the symptoms.

Second, I now have white smoke--not steam--rolling out of the exhaust pipe and it smells a bit like coolant. I believe it started right after I replaced the exhaust parts. Plenty of water still comes out of the tailpipe so I believe my seawater pump works fine. Removing the heat exchanger cap after it has been running for a few minutes and white smoke billows out of there too. I have observed bubbling in the coolant reservoir after the engine runs 20+ minutes. It seems I am losing approximately 1 quart of coolant every 30 - 45 minutes the engine runs.

Third, crankcase oil had a milky color to it so I changed that and have not restarted the engine since to avoid recontamination.

Fourth: As additional background (I am not sure if this is relevant or merely coincidence), I began having some overheating problems....so the thermostat was replaced with a new one (Moyer Product #CS TH_03.4_241). I also replaced the fresh water pump with an MMI 502. The temperature gauge and sensor is new too. The reading is very slow to get above 120 degrees, while the head seems to get incredibly hot within a couple minutes. (The galvanized fitting that the sensor threads into remains cool to the touch.

Needless to say, I have my hands full right now, not sure how much is self-inflicted, and how many different problems I am really dealing with. Here are my questions: 1). Is it most likely that the wet exhaust design is causing the white smoke and/or the water/creamy color in the oil? 2.) Do I need a water lift muffler? 3.) What is the difference between a water lift exhaust and a water lock exhaust (e.g., those manufactured by Vetus)? 4.) Is it normal that the head could be so hot yet the galvanized fitting that the temp sensor threads into would still be cool to the touch? 4.) Do you think the hot head is related to the exhaust system design? 5.) Should the brass exhaust system include a zinc anode to prevent corrosion?

Thanks Don.

[Don Moyer]

Steve,

Your symptoms of bubbles in the coolant expansion tank, milky oil, and the loss of coolant (unfortunately) are very consistent with a coolant leak into one or more of your combustion chambers, though I have no idea why such a failure would have occurred just after replacing your exhaust system. In any case, since your exhaust system has nothing to do with the freshwater section of your cooling system, I believe we can discount (at least for the
moment) anything behind the manifold in our investigation.

I also do not see the anomalous indication of a cool temperature sensor and hot head, perplexing though it may be, to be involved in the main problem at hand, so for the moment I would look past that particular symptom as well.

I recommend removing the plugs and inspecting each of the combustion chambers for evidence of coolant. Then perform a compression check.

If the compression check is satisfactory (85 psi or more on each cylinder), you'll have to perform a pressure-test of the head, block, and manifold. I'm attaching a pdf file containing a guide to pressure testing these components that has worked well for on-boat tests in the past. If you have any questions on the procedure, please check back in for clarification.

Again, I have a lingering concern that we might be missing something in this analysis because I still can't understand the coincidence of this (apparent) serious condition developing just because you worked on the exhaust system.

Don

[skhorleb]

corroded manifold stud

Don,

As always, thank you for your rapid response to my posting. I followed your advice. When I tested the cylinder compression I got the following values: #1 = 112 PSI, #2 = 112 PSI, #3 = 120 PSI, #4 = 120 PSI. Spark plugs were clean. Using q-tips, I found no moisture in the cylinders. Good news so far. I sprayed some Marvel Mystery Oil in each cylinder anyway.

Next, I went to your directions for check the water jacket for a water leak. I decided to torque the manifold bolts just in case...and was surprised I could not apply 35 lbs pressure to the rear nut without it loosening up. New symptom--sloppy fitting on the rear manifold stud. Then your closing comment clicked with me: "we might be missing something in this analysis because I still can't understand the coincidence of this (apparent) serious condition developing just because you worked on the exhaust system."

Here is what may be the missing data from my previous report: When I previously replaced the exhaust system, I had to remove the manifold to drill out the broken off/rusted bolt where the exhaust pipe attachs to the manifold, re-tap the fitting, etc. I did not have any trouble tightening up the manifold the last time I reattached it, but recalled the rear stud came out with the nut rusted to it and the tip of the stud was corroded.

Nevertheless, when I took off the manifold today the front two nuts came off just fine...like the last time I unbolted it. Just like the last time, the rear manifold stud came out along with the nut rusted to it. One difference this time--Lots of coolant came pouring out of the fitting immediately when the rear stud was removed. See the attached picture of the 3 studs. They are shown in order--rear to front. Note the rear stud corrosion, it is a bit longer than the front two manifold studs, and the remaing threads are worn...I suspect of a different vintage--older.

I am suspicious that coolant began leaking around the corroded stud since it was last reinstalled, under pressure seeping into the exhaust side of the manifold. At the same time possibly some coolant is getting into the crankcase by way of the value stems.

Does the rear stud (obviously on the left) show enough corrosion to explain the milky crankcase oil, the white smoke coming out of the exhaust, and what seems like excessive heat that bubbles the paint on the head above cylinders # 1 and 2--because the coolant is taking the path of least resistance into the manifold instead of being pumped forward over the front two cylinders? Besides replacing the rear manifold stud, do you recommend any other actions? Thanks again Don.

Steve Horlebein

[Don Moyer]

Steve,

Congratulations, this is great news! Your defective manifold stud could explain all your symptoms. 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.

After cleaning everything up, I recommend installing one of our 7/16" repair studs in the block. You can actually drill out the last hole in the manifold to 7/16" and install the repair stud through the manifold. I'm attaching a pdf file with instructions that come with our repair studs to install them through a head. The instructions work for a manifold as well.

If you don't have easy access to 7/16" taps and a drill, you might consider our installation kit.

Don

[skhorleb]

Still having a little problem

Don,

I got the manifold repair stud installed after tapping the threads up to 7/16" and using JB weld on the threads. Also replaced the other two manifold studs and used red locktite on those threads. Thank God I had a stud remover! It worked great after a few doses of Kroil. I was concerned about tightening the studs too far into the engine block, stressing the existing block threads, so I left about 1/2 of a tread exposed. I trust this is not a problem. Let me know if I need to revisit seating of those studs.

I also used a new manifold gasket but applied no gasket sealer.

I started the engine and the white smoke was not coming out of the exhaust. I was thrilled!!! ....for a few minutes. After running the engine for a few minutes, a small amount of white smoke reappeared. A faint odor of coolant was in the engine compartment and a small amount of bubbling was observed in the plastic coolant reservoir. No visible water in the oil. I re-torged the 3 bolts on the manifold to 25 lbs twice after getting the engine up to 140 degrees each time. This did not totally eliminate the problem, but reduced the white smoke a little. There is also a little smoke rising from the aft portion of the manifold--below and from behind the manifold. It is all seems from behind the aft manifold stud, the repair stud. I put the engine under some load and the smoke rising from the back of the manifold got worse.

I hope one additional detail is the "smoking gun"... I recall that before I reinstalled the manifold I had the manifold flange sitting on a very flat granite counter top. (Don't tell my wife.) The manifold surface was not completely flat and noticed it was pitted on the rear port by the exhaust. It rocked a small amount toward the back end of the manifold, probably less than 1/32". Would that account for my remaining symptoms.

If so, would you recommend that I apply a bunch of Permatex Hi-Temp red silicone gasket maker, have the manifold surface machined to a perfectly flat surface, double up the manifold gasket, or do something else next?

Thank you.

[skhorleb]

coolant expansion tank bubbling and pitted block

Don,

Thank you for the sanity check during our phone call last week. The manifold surface has been machined. They took off a couple 1000th's of an inch to get it completely flat...Only cost me $30.

I checked the adjoining engine block surface for pitting. There is some significant pitting on the aft end of this surface (around the last 2 ports), but I am not mentally prepared to pull out the engine block to get that machined flat.

I checked my manifold studs again. Actually they were fully seated--no threads showing. Hence no need to gently heat the manifold studs, remove them, and reinstall them flush with the block surface.

While I had the manifold off, I got ambitious: removed the freeze plugs, got the clogged water jacket drain opened up, gave the cooling portion an acid bath, and cleaned out as much crud (as possible) from inside the water jacket. "Installed new freeze plugs, sealing them with JB Weld.

The oil was changed again since it looked like a milk shake.

Finally, the manifold was reinstalled after applying lots of Permatex aviation sealer to both surfaces of the new manifold gasket. I did not anticipate the surplus Permatex would find it's way back to the carburetor via the scavenge tube. I ended up with a mess in my carburetor so the next time I will go a bit lighter on "the sauce."

After cleaning the carburetor a few times, the engine finally started. I could see Permatex bubbling along the block/manifold seam, so I torged the manifold nuts. 'Got it up to operating temperature a few times and re-torged the manifold nuts to 28 lbs. No more white smoke in the exhaust. No faint smell of coolant. No visible Permatex bubbling along the block/manifold seam. No more smoke rising off the aft end of the manifold. No leaking around the new freeze plugs.

However, I am still seeing some bubbling inside the coolant expansion tank. The bubbling is not profuse, but is steady like a slow boiling pot of water. I suspect I am still losing a little coolant somewhere, but I have not put the engine under load yet to verify. Would the pitted engine block surface account for the bubbling within the expansion tank or do you think I have some other source (e.g., bad head gasket) that is causing the bubbling?

A second question: If JB Weld were carefully applied with a putty knife to the block surface, smoothed out, allowed to dry for 24 hours and then hand sanded, would this be a reasonable alternative to pulling the engine and having the block's manifold face machined?

Thanks again for all of your help.

[Don Moyer]

Steve:

I don't really see the source of the bubbling in your coolant tank as coming from the pitted block to manifold surface around your aft manifold stud. There is really no pressure generated within the exhaust manifold which would be consistent with forcing air (exhaust gasses) past the gasketed surface between the manifold and block, through the threads of the rear manifold stud, and into the water jacket.

A slight leak in the head gasket which is bad enough to allow a small amount of compression to force into the cooling jacket, but not bad enough to allow coolant to flow into the combustion chamber, is the more likely cause of the bubbles.

JB Weld would have been a good product to use around the exhaust and intake ports to smooth out the pits in the block in that area. However, it appears that your use of Permatex (which is the more common sealer to use) has done the job.

Don

[skhorleb]

Time for a head gasket?

Don,

I was thinking that a bad head gasket would always have the tell tale symptom of low cylinder compression. My last compression test about 1 month ago yielded these stats...#1 = 112 PSI, #2 = 112 PSI, #3 = 120 PSI, #4 = 120 PSI. Please let me know if I am off base.

Last fall's attempt to remove the head (prior to purchasing the stud removal tool from MMI) was fruitless. Nevertheless, I recently obtained a complete gasket kit from MMI, so I am prepared....if needed.

Thanks again Don.

[Don Moyer]

Steve,

Sorry, but your unsuccessful attempt to remove the head suggests that your engine still has the original asbestos gaskets which, in addition to putting up quite a fight to remove, also tend to become quite brittle over the decades and will occasionally allow a bit of compression to "seep" into the cooling jacket. Your otherwise excellent compression only exacerbates this likelihood. Circumstantially, the compression readings between cylinders one and two could be an indication of this analysis.

The question really is: how important is this issue? I don't think it necessarily rises to the level of needing immediate remedial action unless you were planning a long trip. There's no way to know for sure, but I suspect that many raw water cooled engines would produce a few bubbles if they had their cooling water hose submerged into a five-gallon bucket of water for a few seconds while running under load.

In a roundabout way, it is more of a concern that if the bubbling is not being caused by a seeping head gasket, then it could be an indication of a more serious problem, e.g. a hair line crack in the block or head. If you find it easier to pressure-check the block, head and manifold than to remove the head, my guess is that you'd find some coolant being forced into one or two of the combustion chambers.

In summary, if you do decide to pursue remedial action, I'd start by removing the head, particularly since you have the stud removing tool and gaskets.

Don