I have a catalina 30 with an atomic 5411 diesel. The last time we were out I had some wires melt down that were sitting of my exhaust manifold. Upon further inspection I noticed that the exhaust manifold flange is completely corroded and falling apart. Also a bit of water is seeping between the flange and the manifold. It appears that a previous owner was having problems with this as there is JB Weld between the pipe and the flange and which along with rust may be the only thing holding this baby together. My question is what temp should that manifold be approx. Do I have water flow problems? If so any idea where? There seems to be adequate water coming out of the exhaust and none of the water hoses seem to be too warm. Is the manifold clogged? My other question is if I can solve the overheating problem can I get through the summer with this shody patch job and a bit more JB Weld or should I slap down the $200-$800 in parts and replace the manifold/flange? The Manifold seems to be okay but the studs are so corroded I'm not sure if it can be salvaged until I tear into it.
atomic 5411 exhaust manifold very hot
- Thread starter Tang07
- Start date
- Status
engine
The 5411 is a small Universal/Kubota diesel which does have a relatively hot exhaust and it is common for the manifold extension to corrode over time, particularly in salt water as this is a raw water engine - no heat exchanger. The so-called Atomic 4 is a gas engine - not sure what an Atomic 5411 is???
The 5411 is a small Universal/Kubota diesel which does have a relatively hot exhaust and it is common for the manifold extension to corrode over time, particularly in salt water as this is a raw water engine - no heat exchanger. The so-called Atomic 4 is a gas engine - not sure what an Atomic 5411 is???
Universal engines made the Atomic 4 gasoline
engine as well as all the Universal diesels (54xx etc). It must have been around the same time as they were making the Atomic 4 that they dubbed some of their diesel engines as 'Atomic' as well (clever marketing ploy). I saw the 'Atomic' nameplate on a friends boat that had a 5431 diesel in it. I like my old Atomic 4 gas engine but think it was stupid of Universal to use that 'tag' on their diesels as well (it means nothing - the model number is everything).
engine as well as all the Universal diesels (54xx etc). It must have been around the same time as they were making the Atomic 4 that they dubbed some of their diesel engines as 'Atomic' as well (clever marketing ploy). I saw the 'Atomic' nameplate on a friends boat that had a 5431 diesel in it. I like my old Atomic 4 gas engine but think it was stupid of Universal to use that 'tag' on their diesels as well (it means nothing - the model number is everything).
exhausted
Those exhaust pipes on 5411's are prone to rusting and will need to be replaced. It's not hard if you're somewhat handy. You need to remove the whole exhaust pipe. Dose the pipe/flange connection liberally with a penetrating oil and let it sit overnight at a minimum, two or three days with increased dosing would be better. Remove the rubber hose that goes into the water-lift muffler and get that piece of brass pipe with the water nipple brazed into it. You want to keep that. The rest of the pipe is common black iron pipe nipples and elbows. Don't buy it from Catalina, they'll charge you an arm and a leg for it. If you can't break the pipe loose from the flange, you'll need to remove the two flange nuts and get the flange off. They will need copious amounts of penetrating fluid too, but it's even easier to cut the nuts off with a hack saw or a chisel. Don't damage the stud threads, you'll need them. Get the whole thing out of the boat and onto a bench with a mounted vice. Remove the two important pieces; the flange and the water injection piece. Take the rest of it to your local home improvment store and buy the nipples and elbows to make up another one. Reassbemble it into the same shape, but don't tighten the connections all the way, you need some wiggle room. Put it back in, and get the hose (new piece) back onto the water muffler and the water injection piece. Work back until you can get the flange in place. Tighten the nuts (stainless ones) onto the studs, then tighten everything as much as you can. Don't worry about getting it all the way. The pipe will leak a little at first, but the interior soot will soon seal it off. Rewrap with a new fiberglass insulator, and there you go. (My pipe never ran that hot and I left the insulator off for years, only replacing it when I sold the boat)Have fun.
Those exhaust pipes on 5411's are prone to rusting and will need to be replaced. It's not hard if you're somewhat handy. You need to remove the whole exhaust pipe. Dose the pipe/flange connection liberally with a penetrating oil and let it sit overnight at a minimum, two or three days with increased dosing would be better. Remove the rubber hose that goes into the water-lift muffler and get that piece of brass pipe with the water nipple brazed into it. You want to keep that. The rest of the pipe is common black iron pipe nipples and elbows. Don't buy it from Catalina, they'll charge you an arm and a leg for it. If you can't break the pipe loose from the flange, you'll need to remove the two flange nuts and get the flange off. They will need copious amounts of penetrating fluid too, but it's even easier to cut the nuts off with a hack saw or a chisel. Don't damage the stud threads, you'll need them. Get the whole thing out of the boat and onto a bench with a mounted vice. Remove the two important pieces; the flange and the water injection piece. Take the rest of it to your local home improvment store and buy the nipples and elbows to make up another one. Reassbemble it into the same shape, but don't tighten the connections all the way, you need some wiggle room. Put it back in, and get the hose (new piece) back onto the water muffler and the water injection piece. Work back until you can get the flange in place. Tighten the nuts (stainless ones) onto the studs, then tighten everything as much as you can. Don't worry about getting it all the way. The pipe will leak a little at first, but the interior soot will soon seal it off. Rewrap with a new fiberglass insulator, and there you go. (My pipe never ran that hot and I left the insulator off for years, only replacing it when I sold the boat)Have fun.
Running Fine Now
Thanks for all your replies. I went back Sunday night with my heat gun and the engine ran fine at 145-150 operating temp under load. There might have been a temporary blockage or perhaps the thermostat. My exhaust pipes actually seem okay, like I said before it is the flange that is crumbling and a small coolant leak has developed between the flange and the header. By the way this 5411 which originally was sea-water cooled only now has a heat exchanger and a closed anti-freeze system. That all seems to be operating normally -- measured all hoses with a heat gun. I might be able to save the manifold and I'll probably look into replacing the pipes when I do this job. For now I'm going to add a oil pressure/temp sending unit and make sure it doesn't overheat again and work on this project when the rains come.
Thanks for all your replies. I went back Sunday night with my heat gun and the engine ran fine at 145-150 operating temp under load. There might have been a temporary blockage or perhaps the thermostat. My exhaust pipes actually seem okay, like I said before it is the flange that is crumbling and a small coolant leak has developed between the flange and the header. By the way this 5411 which originally was sea-water cooled only now has a heat exchanger and a closed anti-freeze system. That all seems to be operating normally -- measured all hoses with a heat gun. I might be able to save the manifold and I'll probably look into replacing the pipes when I do this job. For now I'm going to add a oil pressure/temp sending unit and make sure it doesn't overheat again and work on this project when the rains come.
When you have the time .....
consider to open/disassemble the entire raw water cooling circuit .... and look for large 'plateletts' of 'slab rust'. Slab rust is quite common in exhaust systems (expecially in Universal engines) made from cast iron. Heres how 'slab rust' occurs, how it forms, what to do to prevent it: Cast Iron when its made is poured into a mold and the metal inside when it cools 'stratifies' .... like an 'onion' with many layers or zones in the cast iron. HOT cast iron is quite resistant to corrosion in seawater because the HOT cast iron quickly forms a protective form of rust (black/blue rust or ferrous rust). Keeping the cast iron WET will allow the black/blue rust to remain intact which will protect the deeper layers of the casting. IF the cast iron is allowed to 'dry-out' the ferrous rust quickly will change into destructive *red* or ferric rust . IF the ferric/red rust begins to penetrate into the 'stratifications', red rust being less dense than cast iron will develop extreme pressure between the 'stratifications' and large/huge plateletts of the stratiafication will begin to form, come loose and ****occasionally block**** the raw cooling water circuit !!!!! When a slab breaks loose the force of the moving water will sometimes hold the slabs across the passageways and the flow will be reduced or stopped altogether. Most times when there is a slab blocking the passageway when you turn off the engine, the flow stops and allows the slab to fall to the bottom of the passage so when you startup up again the flow is restored and the overheating problem 'magically' disappears ...... until the slab gets lifted and sometime later again blocks the passage. How to prevent slab rust: Never turn the engine off .... thats what the USNavy does !!!! Never allow the engine to drain entirely (like during a winter lay-up) but instead use an antifreeze with a rust inhibiter and 'hold' the antifreeze IN the engine. The goal is to always keep the engine internals 'wet'. Run the engine HARD, LONG whenever possible .... so that any forming 'red' rust is converted back into 'black' rust by the high operating temperature. An engine that is used HARD and LONG will last a long time; one that used occasionally and or allowed to 'dry-out' will soon destroy itself due to 'internal corrosion'. Marine engines hardly ever 'wear out', instead they 'rot' away. Dont de-salt or 'pickle' the engine with muriatic or other inorganic acids .... instead use a commercial boiler descaling compound that doesnt destroy the protective black/blue rust (Marsolve or RydLyne, etc.). What to do if you have the signs and symptoms of Slab rust: open the raw water circuit and go into the part (usually the exhaust manifold) with a stiff wire and break up all the slabs, invert the manifold, etc. and shake out all the broken up slabs and reinstall (you should do a pressure hold test on the manifold to be sure that there are no pinholes between the exhaust gas side and the raw water side - which will allow water to drain into the cylinders and destroy the cylinder walls, etc). Reinstall the manifold and RUN the engine HARD and at full operating temperatuare for a minimum of 2-3 hours (to quickly begin to rebuild the ferrous protective rust layers). The 5411's exhaust system is easily cleaned out and the slabs broken up by a quality 'radiator shop' who will use ultrasonic methods in the cleaning-out process ..... but then you need to run the engine HOT when you get the parts back so you redevelop the protective ferrous rust layers (or simply put the part into a pot on the stove and BOIL for 3 hours !!!!!). (boiling your tools that you keep on the boat will also form the blue/black rust and keep them from 'red' rusting). Dont ever let a cast iron block engine or an engine with a cast iron exhuast manifold 'dry out'. Fill the sucker with antifreeze WITH anti rust compounds when laying up for the long term storage. Run the HELL out of the engine whenever possible so it get up to HOT. betcha 99% that your 'pisser' 5411 has its exhaust manifold full of 'slab rust'.
consider to open/disassemble the entire raw water cooling circuit .... and look for large 'plateletts' of 'slab rust'. Slab rust is quite common in exhaust systems (expecially in Universal engines) made from cast iron. Heres how 'slab rust' occurs, how it forms, what to do to prevent it: Cast Iron when its made is poured into a mold and the metal inside when it cools 'stratifies' .... like an 'onion' with many layers or zones in the cast iron. HOT cast iron is quite resistant to corrosion in seawater because the HOT cast iron quickly forms a protective form of rust (black/blue rust or ferrous rust). Keeping the cast iron WET will allow the black/blue rust to remain intact which will protect the deeper layers of the casting. IF the cast iron is allowed to 'dry-out' the ferrous rust quickly will change into destructive *red* or ferric rust . IF the ferric/red rust begins to penetrate into the 'stratifications', red rust being less dense than cast iron will develop extreme pressure between the 'stratifications' and large/huge plateletts of the stratiafication will begin to form, come loose and ****occasionally block**** the raw cooling water circuit !!!!! When a slab breaks loose the force of the moving water will sometimes hold the slabs across the passageways and the flow will be reduced or stopped altogether. Most times when there is a slab blocking the passageway when you turn off the engine, the flow stops and allows the slab to fall to the bottom of the passage so when you startup up again the flow is restored and the overheating problem 'magically' disappears ...... until the slab gets lifted and sometime later again blocks the passage. How to prevent slab rust: Never turn the engine off .... thats what the USNavy does !!!! Never allow the engine to drain entirely (like during a winter lay-up) but instead use an antifreeze with a rust inhibiter and 'hold' the antifreeze IN the engine. The goal is to always keep the engine internals 'wet'. Run the engine HARD, LONG whenever possible .... so that any forming 'red' rust is converted back into 'black' rust by the high operating temperature. An engine that is used HARD and LONG will last a long time; one that used occasionally and or allowed to 'dry-out' will soon destroy itself due to 'internal corrosion'. Marine engines hardly ever 'wear out', instead they 'rot' away. Dont de-salt or 'pickle' the engine with muriatic or other inorganic acids .... instead use a commercial boiler descaling compound that doesnt destroy the protective black/blue rust (Marsolve or RydLyne, etc.). What to do if you have the signs and symptoms of Slab rust: open the raw water circuit and go into the part (usually the exhaust manifold) with a stiff wire and break up all the slabs, invert the manifold, etc. and shake out all the broken up slabs and reinstall (you should do a pressure hold test on the manifold to be sure that there are no pinholes between the exhaust gas side and the raw water side - which will allow water to drain into the cylinders and destroy the cylinder walls, etc). Reinstall the manifold and RUN the engine HARD and at full operating temperatuare for a minimum of 2-3 hours (to quickly begin to rebuild the ferrous protective rust layers). The 5411's exhaust system is easily cleaned out and the slabs broken up by a quality 'radiator shop' who will use ultrasonic methods in the cleaning-out process ..... but then you need to run the engine HOT when you get the parts back so you redevelop the protective ferrous rust layers (or simply put the part into a pot on the stove and BOIL for 3 hours !!!!!). (boiling your tools that you keep on the boat will also form the blue/black rust and keep them from 'red' rusting). Dont ever let a cast iron block engine or an engine with a cast iron exhuast manifold 'dry out'. Fill the sucker with antifreeze WITH anti rust compounds when laying up for the long term storage. Run the HELL out of the engine whenever possible so it get up to HOT. betcha 99% that your 'pisser' 5411 has its exhaust manifold full of 'slab rust'.
- Status