Active Active   Unanswered Unanswered

Help needed - Engine still running hot

Keeping your powerboat under power is a lot easier with good advice. Post your power systems questions here.

Moderators: Don Ayers, Don Vogt, Al Benton

Rugger8
Posts: 318
Joined: Sun Dec 28, 2008 2:40 pm
Location: Dutchtown, NY
Contact:

Post by Rugger8 » Mon Dec 14, 2009 9:05 pm

Still not sure as to what the exact cause of the piston malfunction was, so let me talk about what I did today. I went to the boat and took off the elbow from the exhaust manifold. I then poured water into the the aft end of the exhaust manifold, just like it would normally come in from the water pump. Well the water poured out the bottom of the manifold. This chamber is supposed to be for exhaust gases and not exiting water. So, that would indicate to me that the inside of the exhaust manifold is rotted out in a spot that allows the water to pass between the two chambers. I then connected everything back together and started up the engine. Before that I disconnected the hose to the theromostat, like Jim advised. Water did not come pouring out of there, in fact, some water was coming up from the thermostat housing, but not the other way. So obviously, this is not right, and again, this I think points to a faulty exhaust manifold. Does this make sense or am I missing something?

Finally, I ran the engine for roughly 5 minutes to move the boat to her winter home (different slip). After I got her settled in, I went down and took spot temperature readings of the head. Above cylinders 4-6, the temp was around 180 degrees. Above cylinders 1-3, the temp was 205-210 degrees. Please let me know what you guys think.

Thanks,

Jeff

dalesparrow
Posts: 7
Joined: Sat Nov 29, 2008 11:17 am
Location: Gorham, Maine
Contact:

Post by dalesparrow » Mon Dec 14, 2009 10:15 pm

your manifold has two water chambers one on top and one on bottom here is how it goes - water comes from the water pump and enters the bottom of the manifold,from there water can go to one of two places either through the thermostat housing into the top of the manifold or through the block/head and then into the top of the manifold.From the top of the manifold water goes through the exhaust elbow and out the exhaust. The thermstat decides which way the water travels.When engine is cold thermostat allows water to go from the bottom of the manifold directly to the top of the manifold through the thermostat housing without going through the engine, as engine warms thermostat keeps water from going from bottom manifold to top of manifold through the thermostat housing instead forcing water to go through the engine before entering the top of the manifold

THE RAZZ
Posts: 583
Joined: Thu Apr 20, 2006 9:52 am
Location: OAKLAND, CA
Contact:

Post by THE RAZZ » Tue Dec 15, 2009 2:26 am

Dale,
Thanks for the reminder re cooling flow in a WB......I'm limited to the K series. The thermostat should be the first part replaced. Start with the cheap stuff first.

Melting a (aluminum) piston requires temps over 1200 degrees. I can't see 1200 degrees from water jacket/gasket problems.

I'll put my nickel on detonation caused by timing too far advanced.

Jerry
1942 17' barrelback 71923
1987 21' CC Stinger

Gord
Posts: 160
Joined: Fri Mar 13, 2009 12:06 pm
Location: Medicine Hat Alberta Canada
Contact:

Post by Gord » Tue Dec 15, 2009 11:47 am

Jeff who is setting your timing and what method are they using. Are you running points or are you using a Pertronix cube. If points is your system 6 volt or 12 volt.

Timing: pull spark plug #1 and bump the starter till you have the piston on top dead center on the compression stroke, take off distributor cap, the rotor should be pointing directly where #1 spark plug wire is attached to the distributor cap, if the rotor is ahead or behind that point then loosen the distributor and move it a little. Before taking the dist cap off you may want to determine where # 1 plug wire is attatched to the cap, take a Sharpie and make a mark on the distributor housing right below where #1 wire is attached. Now when you take the cap off and you are on TDC on the compression stroke the metal part on the rotor should be directly in line with the mark you made on the dist housing. If the rotor is exactly 90 degrees away you are on TDC of the exhaust stroke. If you do not know how to find TDC on the compression stroke take #1 plug out put your finger on the hole so its sealed, bump the starter till you feel the compression pushing on your finger, take a flash light and look into the spark plug hole and bump the starter till the piston is right at the top of the cylinder. That is now top dead center on the compression stroke.
Once you have the rotor in the right position and are on TDC to advance the timing turn the distributor the opposite way the rotor turns. to retard the timing turn the didtributor the same way the rotor turns I would start by moving the dist about an 1/8 of an inch at a time the opposite way the rotor turns. Do not go to far.

User avatar
evansjw44
Posts: 1865
Joined: Wed Jul 05, 2006 8:46 am
Location: Grosse Pointe Farms, MI
Contact:

Mainfold

Post by evansjw44 » Tue Dec 15, 2009 1:47 pm

If you pulled off the exhaust elbow you exposed the ends of both water jackets. The elbow seals the end of the lower (inlet) jacket and has a passage that takes the water from the end of the upper (outlet) jacket and routes it into the exhaust discharge. So if you put water into the water inlet pipe fitting where the water pump and oil cooler connect it will just run out the end of the lower jacket. Still, a pressure test for the manifold is in order to verify it is in tact.

I should ask if this is salt water of fresh water. Salt water eats manifolds alive so I wouldn't be the least bit surprised if you manifold is perferated if its used in salt water.

In addition to salt eating cast iron manifolds, there is a second mechanism that will perferate a cast iron manifold. Its a simple chemical reaction between water vapor in the exhaust gases and exhaust steam reacting with rusty scale on the manifold surface. Carbon monoxide in the exhaust gas reacts with iron oxide (rust) in the presence of water vapor to form iron. The iron ends up as loose scale and is expelled in the exhaust. The freshly exposed manifold iron rusts and again reacts. Eventually a the casting is erroed and perferates. Thats why so many CC iron exhaust elows failed and were replaced with bronze.
Jim Evans

THE RAZZ
Posts: 583
Joined: Thu Apr 20, 2006 9:52 am
Location: OAKLAND, CA
Contact:

Post by THE RAZZ » Tue Dec 15, 2009 1:55 pm

Gord,
Nice innitial set up.

On the K series we use the timing light on the flywheel. Is that possible on the WD?

With the K idling, rotate the distrubutor 1/8" and the engine slows 100 rpm. Move the other way 1/8" and the idle increases.

In a runabout (unclear in a cruiser) when wide open and planing....rotate the distributor until the engine first "rattles."

At idle turn the distributor making the idle slow 100 RPM. Back to full throttle. If engine "rattles" repeat above. If later you hear a rattle. Immediately go to idle and reduce idle another 100 RPM. You'll find the most advanced timing WITHOUT detonation.

Once set you should be good to go for the season. RATTLE-ADJUST without delay.
Jerry
1942 17' barrelback 71923
1987 21' CC Stinger

THE RAZZ
Posts: 583
Joined: Thu Apr 20, 2006 9:52 am
Location: OAKLAND, CA
Contact:

Post by THE RAZZ » Tue Dec 15, 2009 2:01 pm

Jim,
Really nice applied metallurgy discussion.
JT
1942 17' barrelback 71923
1987 21' CC Stinger

Rugger8
Posts: 318
Joined: Sun Dec 28, 2008 2:40 pm
Location: Dutchtown, NY
Contact:

Post by Rugger8 » Tue Dec 15, 2009 5:40 pm

ok, thanks everybody. I will try and answer the questions as best I can and unfortunately, I am not going to be able to do all the tests I want to because I had to winterize the engines before I head to Michigan (parents house) for the holidays. So, much of the repairs are now going to have to wait until the spring and warmer weather.

But to answer the questions. Jim, the boat was used almost exclusively in salt water prior to my purchase. Mostly in NJ and North Carolina. The boat is now in mostly freshwater. Also, the last bolt was stuck when we took off the manifold. We were able to finally get it out, but not easily. Well, when we put the new bolt in, you can actually see the bolt if you are looking inside the manifold from the elbow forwards. I was told that these bolts were supposed to be sleeved. So, at the very least, it appears that the original bolt rusted to the sleeve and both came out at the same time. Anecdotal, but some evidence of corrosion within the manifold.

Gord - As for the timing. I have a distributor and points. The former owner was helping me with that and he did put his finger over cylinder #1 to test for the compression. The boat is running on 12V. But I will re-read your posts when it comes back to time to fix this again. unfortunate time lag, but just don't want to risk it the way the weather is turning right now.

Separately - does anyone have a source for thermostats for this engine. The thermostat are set for around 140 degrees because the owner was running in salt water and wanted to avoid salt build up. From my understanding this is an inefficient burn temperature and the engines should be running more like 170-180. In any case, I need to get new thermostats anyhow, but also could be a cheap thing to test.

Hope everyone has a great holiday,

Jeff

davidvn
Posts: 72
Joined: Thu Sep 06, 2007 9:23 pm
Contact:

Post by davidvn » Wed Dec 16, 2009 2:16 am

Hi
I confess I did not read all the posts so this may have been covered.
The thermostat system in your engine is a bypassing type. If you take the thermostat out the engine will overheat. It needs the top portion of the stat to shut off the bypass flow after the engine warms up. There is a correct replacement available. Some steam is normal in exhaust systems, but if the temp is to high there is a adjustment to the temp control system that can be made. Please feel free to give me a call
Regards
David VN
201 445 8685

Charles Wilson
Posts: 39
Joined: Thu Oct 05, 2006 6:47 pm
Location: Sandpoint, Idaho
Contact:

Post by Charles Wilson » Wed Dec 16, 2009 1:45 pm

Boy- who ever figures this one out should get "The Old Cracked Block Award" mounted on a wall plackard for your den. Is this the longest "fix it" thread or what. I'm not a mechanic but have messed around some. I speed read the thread and see you guys have explored lots of the possibilities. Your first post says you had the engine rebuilt. Was the Camshaft and timing gear replaced in that rebuild? Or was the old Camshaft rebuilt? Sometimes the wrong camshaft or gear can wind up in the wrong engine application. They fit but are cammed wrong or the position of the lobes is advanced or retarded. Parts numbers, origional and after market replacements can get tricky. Your rebuild guy may have made an innocient mistake or oversight? Can you verify you have a right one through the rebuild parts billing records without tearing anything down? This seemingly would not explain the differential cylinder heating you are getting but seems like your are down to the nibbens here. If it ran ok before the rebuild, what did they do in the rebuild is the question.


Merry Christmas to you all,

Charles aboard Miss Chris with his bumpers out.

P.S. Has anyone delivered Santa in a town event in a trailered Chris? I suppose some of you Southern guys do it in the water!
"The fender guy" in Idaho.

Rugger8
Posts: 318
Joined: Sun Dec 28, 2008 2:40 pm
Location: Dutchtown, NY
Contact:

Post by Rugger8 » Sun Dec 20, 2009 1:40 pm

Well, I took the thermostat out and put it in a pot of water and then heated it up on the stove. The thermostat opened up when the spot temperature got to around 150 degrees. So, that seems to be ruled out. As for the camshaft, it was not a complete rebuild, so the camshaft stayed in and was not changed. The bearings on the camshaft all looked good. So, still likely the exhaust manifold, but I won' be able to confirm that until the spring. too cold now and engines winterized. But I will update as I find out more info.

Jeff

Rugger8
Posts: 318
Joined: Sun Dec 28, 2008 2:40 pm
Location: Dutchtown, NY
Contact:

Post by Rugger8 » Sun Apr 18, 2010 9:54 pm

Well, this is a long time since I gave an update, so I figure I would let everyone know what I have been up to. Going on the assumption that it was the exhaust manifold being either plugged in the water jackets or rusted through between the two cavities, I decided to take an exhaust manifold off of a spare engine I have. I then sent it to Dave Van Ness, who heated the manifold up to 850 degrees and then essentially sand blasted the manifold (sand was not the abrasive, but you get the point). I also ordered a new thermostat at the same time. Well, today, I replaced the exhaust manifold with the new old manifold and gave her a test. She ran at 140 degrees consistently. And whereas before, the head above cylinders 4-6 ran cool, and cylinders 1-3 ran 210, the whole head ran at 130-150 degrees consistently. Also, installed new temperature gauges that had been rebuilt by Kocian electronics. So, now I not only have a working engine, but also working temperature gauges. Finally we dewinterized the second engine, and she started right up.

So, to celebrate, we took the old girl on a hour long test trip up the Hudson! A beautiful day that was capped by a complete rainbow on the Hudson, where we could see the whole arch from beginning to end. Hopefully this marks the end of my troubles with the engine. 8 months later, I now know a lot more about my engines, so that is a great thing, but mostly I am just relieved to have solved this issue that has been hovering over my head for so long. Thanks to everybody for your help!

Jeff

THE RAZZ
Posts: 583
Joined: Thu Apr 20, 2006 9:52 am
Location: OAKLAND, CA
Contact:

Post by THE RAZZ » Tue Apr 20, 2010 9:03 am

Jeff,
Thanks for the followup. Nice work.
Jerry
1942 17' barrelback 71923
1987 21' CC Stinger

Post Reply

Who is online

Users browsing this forum: No registered users and 2 guests