Cat 3208 TA black smoke

[SeaEric]

I have had an intermittant problem with one of my engines, a Cat 3208 TA rated at 355 HP, 1800 hours. Running at the high end of cruise speed RPM's, about 2350/2400, my starboard engine will put out a huge cloud of black. If I back off 50 RPM's it clears and runs normally. Temps, pressures are all OK on the gauges. When I run that engine up to WOT (2800) by itself, it doesn't seem to have the same top end power like to port engine at WOT. I'm guessing that the turbo either stops spinning for some reason, or slows down.

I had a mechanic aboard yesterday who tells me that he thinks the after coolers need cleaning. He allows as how if the after coolers are partially blocked, the air flow from the turbo is restricted and this will cause the black smoke. He also ran his finger across the bottom of the area where the shaft for the turbo passes through and there was oil there. He said this is caused by the increased pressure, it forces oil out at the bearing.

Mechanic also tells me the after coolers should be cleaned every 600 to 700 hours. I don't know the past history of this service on my boat so I'm inclined to go ahead if only to begin a baseline for proper maintenance.

Does any or all of this sound logical? It did to me as the mechanic explained it, but maybe he's just a better salesman than I am!

[captddis]

Eric,
My money is on the turbo. Had a 38 Bert with the 355s that would do the exact same thing. I used to clean the aftercoolers every 3 years. They get oily, Using a CCV helps as the breather does not go into the air filter.
Pull the turbo cartridge and I bet you find something.

[Genesis]

I'd clean the coolers if you haven't, just to get a baseline.

I bet you have a turbo on the way out. Don't ignore this - if it grenades on you while under power it can start a fire below decks or do serious damage to the engine.

[SeaEric]

The mechanic is due Monday AM. He has the parts on hand to do the coolers on both engines and is to look at/test the turbo on the stbd while we're at this. If it needs a turbo, it needs a turbo and I will certainly replace/rebuild, whatever is appropriate. I whole heartedly agree Karl, the cleaning is worth the baseline on maintenance. Thanks guys!

[TomT13]

I have the same exact engines in my 1985 36C. My mechanic indicated I should run them around 2400 to 2450 rpms as my cruise speed. I noticed you run that at your "high" rpm cruise speed. High engine idle is 2800 as you noted. I also do not know if the previous owner ever cleaned the after cooler. I am not getting smoke but I will be doing that during this winter lay-up after reading your post. As for the turbo cost, I had a problem with the cross over manifold that holds the turbo last year. A hole developed between the exhaust and water jacket side of the manifold. We took the turbo off and were going to get a new cartridge for it while we had it off. Then I saw the cost is almost as much as a new turbo. I wasn't having a problem just figured I would do some preventative maintenance. The cost changed my mind and I put the turbo back on without changing anything. Good luck with your problem I am interested in your progress. Hopefully it will school me on what to keep an eye out for.

[(Nobody You Know)]

Ok, good. Where do you (I) get instructions on the proper way to clean the turbo coolers???? (or can anyone with knowledge of the task advise?)

Thanks,
Capt'n Bill

PS: as I live many miles from my boat I do not have access to the Caterpiller Owner's Manuel as provided.

[captddis]

Cleaning is not hard, but is tedious! It takes forever to get the air side clean. I clean until the cleaner fluid runs clear. Or you can take them to a radiator shop. The rubber seal on the inside is a bit of a pain but the o ring seal around the retainer is a real B---h!!! I use some spray adhesive on the o ring.
You also need to push the core in with the opposite end facing up a little in order to get the core on the pin. The center seal will go down but not up, so keep it up and let the core come down to fit the pin. Pay close attention to the outer o ring, if it is not seated in the right place it will spray a nasty black mung. Dave

[SeaEric]

Well, here's the latest. Mechanic showed up this morning, one day late due to parts delay. He took the aluminum end plates off without the expected breakage. He says that the blockage on the stbd "problem" motor is quite complete. The restriction has been causing the air filter element to be slowly consumed by the turbo, with the parts then spit out into the after cooler. So far, no turbo damage but if this went on much longer it would not have been good.

There are some plastic runners on the edges of the after cooler elements that the mechanic claims Cat hasn't used since 1984. There is an updated rubber part that is a retro fit to the plastic. What this dating means is that since these motors were new in 1982/1983, the after coolers have never before been cleaned! I'm glad I decided to do this job now.

He is cleaning the coolers in an acid bath, and then blowing them out with air. He will then pressure test and re-install either tomorrow afternoon or Thursday morning. I'm really looking forward to the seatrial. I'm hoping for improved fuel economy and maybe a little extra "snort" at the top end RPM.

Part of this job also includes replacing my NAPA spin on fuel filters with Fleetguard primary and Cat OEM secondary spin ons. The complete re-do on the fuel system is still in the future planning stage, but is getting closer.

I'll post the results of the seatrial, or maybe Dr. Jim will- He has asked to come along for the boat ride.

[jim rosenthal]

Absolutely. I am getting NO boating time in these days with mine up on the hard in VA.

[SeaEric]

The weather has finally straightened out enough here on The Chesapeake that we can seatrial the repairs this morning. The mechanic and Dr. Rosenthal are meeting me at 10 this morning for a boat ride. We shall report back the results.