Caterpillar 3208 - one cylinder runs hot

Panhandler · Jun 1, 2016

All, as I'm typing this I realize I probably need to post on boat diesel, but I'm hoping you may know the answer. I have an old Cat 3208NA and one of the cylinders seems to run hot above 2000 rpms. I believe this because of infrared temp readings of the exhaust manifold. The exhaust also has the barest hint of white smoke. I'm thinking bad injector. Make sense?

I'm looking at the repair manual that came with the 3208 and there seem to be a bunch of adjustments that can be made to an injector. In other words, I probably can't just order a new one and pop it in because it will need adjustment, which is above my head and tool kit at the moment. Perhaps the most I could do is remove the injector and scrub the nozzle with a wire brush as suggested in the manual.

Any tips or experience with 3208 injectors? Any flaws in my thinking? Thank you!

Hawkeye · Jun 1, 2016

I've got 33 yr old 3208NAs with 2800 hours. I check with infrared gun and see some difference between different spots on the exhaust manifolds. The barest hint of white smoke is also not so unusual on these engines. I'll be interested in what others say but until proven otherwise I'd be willing to say that you don't have anything to worry about. How hot is the difference between 3 or 4 points on the exhaust manifold?

TG · Jun 1, 2016

I think a hint of white smoke is normal for 3208's. Mine do the same at idle when cold and then clear up after they warm up and under way. Long periods of trolling (hours) and they get a little loaded up and smokey so I rev up for a few minutes at 2000 rpms and blow them out then back down to my normal cruise at 1500 - 1700 or back to troll.

Check out the prices for injectors at Mylex International Fuel Injection Services

$30 for rebuilds, a smokin deal and they are ready to install.

gaston · Jun 1, 2016

Panhandler said:
All, as I'm typing this I realize I probably need to post on boat diesel, but I'm hoping you may know the answer. I have an old Cat 3208NA and one of the cylinders seems to run hot above 2000 rpms. I believe this because of infrared temp readings of the exhaust manifold. The exhaust also has the barest hint of white smoke. I'm thinking bad injector. Make sense?

I'm looking at the repair manual that came with the 3208 and there seem to be a bunch of adjustments that can be made to an injector. In other words, I probably can't just order a new one and pop it in because it will need adjustment, which is above my head and tool kit at the moment. Perhaps the most I could do is remove the injector and scrub the nozzle with a wire brush as suggested in the manual.

Any tips or experience with 3208 injectors? Any flaws in my thinking? Thank you!

Before you do anything else swap the injector to another cylinder the further away the better then take another reading

boatpoker · Jun 1, 2016

gaston said:
Before you do anything else swap the injector to another cylinder the further away the better then take another reading

+!

and don't forget to use only new washers as a good seal is unlikely if you reuse the old ones.

Ski in NC · Jun 1, 2016

You can not tell cylinder balance on a 3208 by shooting manifolds. The temp is going to vary mostly due to how skinny the water jacket is, and what the water flow is like inside. Also the rear cylinders have more exhaust flowing past, which tends to raise temp.

If engine sounds smooth with only a trace of smoke when warm, and if blowby is good... Motor on.

Panhandler · Jun 2, 2016

Thanks, all! The exhaust manifold reads about 220f on the port bow-most cylinder and about 190 on the others. Is this a normal temp differential? Thanks

Ski in NC · Jun 2, 2016

Are the manifolds sea water or fresh water cooled? I think some versions of the NA were sea water cooled.

Panhandler · Jun 2, 2016

Ski, according to the manual I have the seawater goes through the heat exchanger to the risers and out. I guess it's possible my engine could be different from the old manual that came with the boat... Is there an easy way to check whether the manifolds are sea water cooled?

boatpoker · Jun 2, 2016

If you have heat exchangers it s a closed cooling system.

Ted · Jun 2, 2016

A lot of engines from that era had what was referred to as "semi fresh water cooled".
The engine was fresh water cooled from the heat exchanger, but the salt water
went from the heat exchanger to the exhaust manifolds then out the exhaust.

I ordered a Cummins and was able to get "full" fresh water cooling.

Ted

boatpoker · Jun 2, 2016

Ted said:
A lot of engines from that era had what was referred to as "semi fresh water cooled".
The engine was fresh water cooled from the heat exchanger, but the salt water
went from the heat exchanger to the exhaust manifolds then out the exhaust.

I ordered a Cummins and was able to get "full" fresh water cooling.

Ted

So where does the exhaust cooling water come from in your "full" fresh water cooling ?
I don't think the OP said anything about having a dry stacked exhaust.

Ted · Jun 2, 2016

The water would go directly from the heat exchanger to the exhaust pipe. (riser?).
I used the discharged salt water for constant flow wash down lines.

Ted

pearlwindham · Jun 2, 2016

Does it run hot or is it running hotter big difference

Ski in NC · Jun 2, 2016

If it has sea water cooled manifolds, sea water will come out of the heat exchanger, go into the manifolds, then go right into the risers. If manifolds are fresh water cooled, a separate sea water hose will go into riser from heat exchanger.

boatpoker · Jun 2, 2016

Ted said:
The water would go directly from the heat exchanger to the exhaust pipe. (riser?).
I used the discharged salt water for constant flow wash down lines.

Ted

Sorry I don't understand,. I thought you said salt water did not go out the exhaust ?

I don't see the difference between what you are describing and a conventional closed system with salt water exhaust cooling system.

Ted · Jun 2, 2016

Salt water goes out the exhaust if required for cooling it, but NO salt water in the
manifolds

Ted

Baker · Jun 3, 2016

boatpoker said:
Sorry I don't understand,. I thought you said salt water did not go out the exhaust ?
I don't see the difference between what you are describing and a conventional closed system with salt water exhaust cooling system.

IN one, the manifolds are cooled by seawater. In the other, the manifolds are cooled by the freshwater cooling loop.

sunchaser · Jun 3, 2016

Boat Poker is spoiled. He and his clients live in fresh water. Those of us who don't were amazed at the benefits of coolant cooled exhaust manifolds that occurred well back in the last century.

Some of us who worked in yards in the Atlantic NE in fact remember cleaning out the various engines' salt water cooling passages before each winter's layup. It was a way of life. And oh the whining that took place when coolant cooled marine engines ensued!

Caterpillar 3208 - one cylinder runs hot

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