what' up with these CATs

[captian]

Thanks for all the feed back, my bottom is in good shape we run the boat often 2 to 3 times a week. I think it maybe a good idea to learn to live with it. If it's not broke then don't try fixing it, is how I'm going to leave this one. I'll just get a better cleaner. Any one with performance numbers on the viking 35's with 3208 CATs 320hp? Just want to know if things are running as well as I think or if I'm way off.

[WAHOONBOX]

IT IS THE SPORTSMEN IN MY WORLD THAT MAKE THIS SUB-FORUM THE NUMBER ONE FORUM IN THE WORLD


VERY COOL AND INFORMATIVE THREAD THAT WILL OBVIOUSLY TOE...I MEAN GROW

[Bullock1344]

I have 3208s 375 hp on a 1993 boat with about 2800 hours. They are turbocharged and I had the same problem with excessive soot on the transom. I know it can have several causes, but one of the things we had done was rebuild the turbos. We found DMS in West Palm Beach who will blueprint your turbos. The turbos we removed had about a 1/4 inch clearance and we closed that up. Now better performance, fuel efficiency and no soot. Dave has extensive experience and knows what he is talking about. You can reach him at 561-644-6537 during the day and 561-622-2587 at night.

[gottaflylee]

Did the sticking injector cause a change in engine performance? I think my engines are running fine?

Sorry to get back to you a little late on this, but no, it did not. As Deep C stated you could see a little somke when we run and throtle up after trolling all day. Now I don't- won't push them past 1950 ever so as to loss of performance, not that I can tell, but I have over 7000 hrs on the rebilds. When I was running the "Bite Me" out of Morehead, it had Cats in her, one of them ran cold, about 160 degrees. That motor would soot bad, the other motor would not soot at all that I could tell and it ran at 180 degrees. Hope this helps. Try the Grez-off to remove the soot, its works great with not much elbow work...

[captadamnj]

all out she'll do 25knots at about 2650 RPM

Check the specs on the engines. Today's 3208's are rated for 2800 rpm's. If you are only turning 2650, then you may have a fuel/air problem or the engine is overloaded by a prop with too much pitch/cup or any one of a number of other problems. But that number, if not to spec, is a red flag to me. Under load, the engine should turn full rpm's or close to it.

[Lured Away]

Read the article by Len Belcaro that just came out in Big Game Fishing Journal on the refurbish of his Cats - good article and talks about how resolved his soot poblem.

Here is a link to the first part of it. Great mag if don't get it.

http://www.biggamefishingjournal.com...o_article.html

[JD5652]

I'm not an expert on Cats, but black smoke under normal operating conditions on a diesel normally means lack of air to the engine. Now this might be dirty air seps/filters, poor turbo performance or a design problem on not getting the sufficient amount of air to the engines. As someone else said, either aftercooler or intercooler clogged will also do it. The black smoke then "clings" to the transom due to the "station wagon" effect of most sport fish style boats.

To test out the possible lack of air design problem, open the hatch to your engine compartment and run her as you normally would. If you see a significant reduction or lack of black smoke, then you have your answer.

To test out the air sep filter problem, either clean your air seps/filters or replace them and take her for a run.

While you have the air seps off, take a look at the compressor side of your turbo. Does it "look" dirty?? How is the clearance between the compressor blades and the housing. Should be less than 0.018. Grab the compressor wheel and try to move it "side-to-side". If it moves ANY, then your turbo bearings may be worn. Also, give the compressor wheel a spin with your finger, it should continue to spin for at least 5-6 revolutions. If not, then possibly worn bearings again. See pic for what a turbo should "look" like from the compressor side (new). Also attached are pics of of my old turbo from the compressor side and the other pic is the same old turbo from the turbo side where it goes into the exhaust elbow. Note the severe corrosion.

Do you have turbo boost gauges on the bridge?? If so, then the boost should be up to spec as per you Cat engine spec data. If not, hire a mechanic and have him install a temporary gauge and go for a sea trial.

Hope this helps....good luck!

[Split Bill]

Captian,
I think Capt. Adam nailed it. You said the engines will only turn a max of 2600 RPMs when you put the throttle to the pins? This is too low! These motors are specked to turn 2800 and should be able to turn that high. You are overloaded (or have growth or something) if they won't make those RPMs. I have the same motors and they will turn 2800-2850 and we cruise them at 2450-2500rpms. Your motor is smoking b/c it is overloaded! Probably either need to clean the bottom and running gear or get a prop with less cup etc.
Good luck with the issue.
Ed

[Wicked Deep Stix]

if you can only reach 2650 that is the first clue to start searching. It may be the props but first i would check a few things on the engine. Lack of air will cause black smoke and plenty of it but injectors/injector pump going bad or wearing out with also cause it because the fuel does not get proper atomization in the combustion chamber and the particles of fuel are uneven spray pattern and too large for the air to bond to correctly. you will get incomplete combustion causing smoke and lack of power even though the rack is wide open. Remember on diesel engines you are throttling the fuel where gasoline its the air intake. Also make sure your aftercoolers are clean as this will reduce the density of the air charge(less O2), make sure your turbos are in good shape. Remove the air cleaner and make sure the compressor wheels spin free and see if there is bearing play on the axis and radius. You could also have clearance issues on both the compressor and exhaust turbine. There could be carbon buid up on the turbine throwing it out of balance and insulating from the exhaust heat that causes it to spool. Also if you see soot on the intake side of the engine aka air side of the aftercooler you make have intake valves not seating allowing the overlap to be off decreasing compression, same goes for the exhaust valves. When was the last time the valves were set? in the end check what you can but get a cat mechanic if its a major issue.

[Agitated88]

I'm not an expert on Cats, but... The black smoke then "clings" to the transom due to the "station wagon" effect of most sport fish style boats.

I don't mean to hijack this thread, but JD's comment brought to mind a question I've had for a while. I have noticed on a few...VERY few boats the exhaust vents out the side vs. the stern. Is there a reason this isn't done more often?? Is it due to overall structural integrity of the hull or stringers, does it cause engine performance issues by creating extra bends in the pipe, or maybe it reduces floor space for box's, etc...just wondering. Obviously it would solve the sooting transom problem, and I've heard/read somewhere that this setup is even quieter. Thanks ya'll...good thread!!