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update on engine troubles - steam/water in exhaust

Posted: Sun Dec 31, 2017 9:38 am
by North
update - unfortunately, after redoing the gaskets in the water cooled manifold and turbo, and then running the boat a few more times, still using water as coolant, the problem reappeared intermittently - never any visible steam out the exhaust, so the new gaskets may have helped some.. but there was still some water/coolant getting in the exhaust.

well, I finally got around to pressure testing the coolant side (should have done this long ago...lessons learned..).
As suspected, it would not hold pressure and you could hear air in the exhaust (listening at the turbo). After eliminating the block coolant passages, testing only between the water cooed exhaust manifold and the water cooled turbo, it still would not hold pressure and could hear air through the turbo.
Finally, took off the exhaust manifold and then you could hear air in through the exhaust ports of the manifold. Then knew about where the leak was and once i blocked off the turbo and filled the exhaust chambers of manifold with water, i could clearly see where the crack was in the manifold - behind one of the frost plugs in the manifold . I knocked out the frost plug to get a better look and confirmed crack with a dye penetrant - you can see red areas in pic...
wish i would have done this before pulling the head and spending time and money on gaskets,etc but at least know i know what i need.
The engine performs well so i don't mind spending about $400 on a new manifold- there are chinese aftermarket ones on ebay for that much but also some claiming to be genuine cummins oem for only a bit more.
if there was better clearance and visibility to the crack i would try mig or tig with silicon bronze or brazing - but i think i would have to cut out an "access" hole to get at it to clean /grind and then repair that as well once the crack was repaired. It may hold but i don't want it to fail next summer or soon after and then still need a new i will likely get a new one.

Re: update on engine troubles - steam/water in exhaust

Posted: Sun Dec 31, 2017 10:01 am
by Bill Edmundson

I don't know how many times that I've spent money to save money only to go back and spend the money later!


Re: update on engine troubles - steam/water in exhaust

Posted: Sun Dec 31, 2017 11:12 am
by North
thanks for the input Bill. I know the engine runs strong, and knock on wood... if i replace the manifold, i think i should have many hours of use - the engine is old, and will have small issues, but i think it is worth the investment.

Re: update on engine troubles - steam/water in exhaust

Posted: Sun Dec 31, 2017 9:02 pm
by kens
Good to hear from you, I been wondering how things are going.
How is your new prop running?

I consider marine wet exhaust as expendable. pricey but expendable.
I have had them rusted, leaky, freeze cracked. They never seem to last.
The main thing now is "is the engine hurt" ?
Cylinders OK?
If the OEM part is only a few dollars more, I would not skimp money on the manifold.
Damage to the cylinders is far too valuable to skimp money on the manifold.

Re: update on engine troubles - steam/water in exhaust

Posted: Mon Jan 01, 2018 5:41 am
by North
Hi Ken - nice to hear from you.
i think the engine is fine - i had the head off and cylinders looked good - made a mistake and assumed i would not get the exhaust bolts out easily (in the field) to troubleshoot the water leak so i chose to take the head off (complete with exhaust and turbo). I had suspected a potential head gasket issue or cracked head but it all looked ok and cylinders look good/ normal.
and, the kick in the pants was that when i took the whole unit back to the shop, the exhaust bolts came out easily....should have tried while on the boat... in the end, all it cost me was some effort, a couple hundred for gaskets and all went back together well - and, i know the engine pretty well now...
I found pretty worn / bad shape gaskets at the manifold water inlet and turbo connections, so i thought that would fix the water in exhaust issue. Sadly, it didn't but at least now i know the issue and can buy the part at a reasonable price (for a marine anything...)

one note - guy in ebay with great reputation claims part is OEM/ genuine cummins and specifically NOT aftermarket....but. there is another guy in ebay asking twice as much who states it is aftermarket, abeit made in USA... cant trust anything nowadays - even the made in USA stamped in the casting... could very well have been cast in China or anywhere. there id a grinder mark in both sellers picks where the last digit of part number was changed so may have been a large lot sale of aftermarelt or OEM "seconds" perhaps...

i will likely try and weld in at least the outboard sections of floor in aluminum this winter - like to see some progress.....

Re: update on engine troubles - steam/water in exhaust

Posted: Mon Jan 01, 2018 4:14 pm
by Ozzieboat
It maybe worth your while to have a look at Not cheap, but will last a lot longer.

Re: update on engine troubles - steam/water in exhaust

Posted: Thu Jan 04, 2018 9:34 pm
by North
thanks - the link shows some very nice manifold products, but i didn't see any listed Cummins engines. I imagine they would be as much as I paid for the complete engine anyway... new one from Ebay is on the way for $400USD