Smoking Perkins 6.354T

[Gaylord Ballard]

Greetings all,
I have a 1977 Mainship with a Perkins T6.354. I crank it every week and it runs smoothly but it belches out a lot of blue smoke. I haven't noticed any significant oil burn but I don't know much about diesels. Is this normal?

 

[C lectric]

Stop cranking/starting it every week. At the most monthly would be enough. Many of us don't even do that.

Old engines such as this smoke upon startup. The design is old and little attention was paid to controlling smoking. The combustion chambers are cold as is the whole engine. The fuel does not burn well with cold combustion chambers. Without a load the engine will not warm up. What you are seeing is poorly burned fuel.

Also when you first crank the injection pump governor goes to full fuel. It sees cranking speed as under speed compared to idle speed so it jacks up the fuel rate untill the engine fires and come up to idle speed. Then it backs off the fuel rate to control the speed to idle. However, a bunch of raw diesel has been dumped into the exhaust and must now be cleared.

All this adds up to sheen on the water and smoke.
You are also dumping a bunch of it into the oil as cold pistons and rings do not do as good a job.

 

[sunchaser]

Celectric is correct. I might add -

What does cranking every week mean? At best it could mean you start it up every week, leave the slip in a few brief minutes and run the boat at 1600 to 2000 RPM for 30+ minutes. At worst cranking every week could mean letting it sit idling with no load resulting in unburned fuel and low coolant and oil temperatures.

So some use history would be helpful. BTW, diesels are designed to be run hard with coolant and oil temperatures at spec levels. Your old Perkins would love to see coolant temperatures of 175F and oil temperatures of 180 to 190F - not achievable when sitting at the dock or at very low RPM when underway.

 

[FF]

Most diesels need only one min or so if "warm up" before leaving and putting the engine under modest load.


Ideling with no load does nothing but slow harm.

 

[RT Firefly]

Greetings,
Mr. GB. Might need injector servicing. A poor spray pattern will also result in unburnt fuel. NOT a terribly expensive job in the greater scheme of things.

 

[Pete Meisinger]

Contrary to popular belief, and I know I will catch "flack" from the under informed.

Diesel engines do not like to sit at idle! In fact it can ruin a new or recently rebuilt engine.

Before you call me to task and cite instances of diesels you have owned which have idled for many hours without problems all I ask is that you seek out a qualified diesel rebuilding specialist and get their opinion.

Truck stops full of idling diesels are running to keep the driver warm as they sleep, or air conditioned. They are actually parking lots full of people ruining their engines.

If you are starting your Perkins weekly and let it idle until it gets warm you are well on your way to ruining the engine. Depending on how long you have been doing this murderous practice the engine may already be showing serious damage.

STOP DOING IT.

Save up that hour a week you are using to kill your engine, save up the minutes and once a month go out and run it hard for a day.

pete

 

[Xsbank]

Pete nailed it. Unless you put it in gear and run it up to operating temperature you are basically ruining...well...pretty much everything.

 

[DavidM]

I think you guys are missing a key statement by the OP: "it belches out a lot of blue smoke". Blue smoke is an indication of burning oil, not unburned fuel which produces white smoke.

So to the OP- is it really blue? I agree with all of the statements above if it is white smoke, but what is it?

David

 

[Ski in NC]

David- a cold diesel can make "bluish" smoke from unburned fuel. Kinda subjective regarding the color. Almost never related to lube oil. A worn out diesel might be losing lube oil, but it rarely shows up as blue smoke like an old gasser car/truck. A worn out diesel losing lube does not really smoke, it just makes slobber. It might smoke when load is applied, but not at cold idle.

 

[Xsbank]

Any symptoms that a cold clam-crusher diesel makes is specious. The only way to judge whether an engine is healthy is to warm it up under a load and run it at WOT. It will tell you if it’s worn or out of adjustment or prone to overheat and will test all the peripherals.

Please don’t argue over “WOT.” There is pages of information, debate and arguments on this site, just search.

 

[DavidM]

David- a cold diesel can make "bluish" smoke from unburned fuel. Kinda subjective regarding the color. Almost never related to lube oil. A worn out diesel might be losing lube oil, but it rarely shows up as blue smoke like an old gasser car/truck. A worn out diesel losing lube does not really smoke, it just makes slobber. It might smoke when load is applied, but not at cold idle.

I defer to the pro . I have only been involved with one truly worn out diesel a VW and admittedly it didn't make observable blue smoke. But it did puff like crazy from the vent- blowby from worn rings.

Perhaps the OP should do a simple redneck blowby test to use your terminology. Take off the oil filler cap and while under a little load in gear tied down at the slip, hold your hand over the fill port and feel for blowby. Light puffs is ok, but significant force indicates worn rings.

If that test doesn't show anything then focus on fuel related issues as above.

David

 

[Gaylord Ballard]

I would like to thank all of the contributors to my diesel education. I have learned a lot and appreciate it. Assuming I haven't damaged the engine irreversibly I will change my habits. Thanks all.

 

[STB]

My last boat had 6.354MGTs. My current boat has 6.354s.

/White/ lingering smoke with a diesel smell can be normal for any turbo version of these engines at idle, especially after a cold start and until warm up. The injector pump is old school and the curve cant be fully tuned to what a turbo needs, so it over fuels at low RPMs. The white smoke and maybe even slight to a little slicking is just unburned diesel.

A little bit of grey wouldn't surprise me, either, turbo or not. Basically, in a not-new old school engine there are plenty of relatively normal ways things can get a little inefficient with combustion for a little carbon to show up in the exhaust at idle, e.g. build up, slightly low compression, etc. If it is really dark, there is likely a more significant problem or restricted airflow (but then it would likely get. worse underway). If valve timing hasn't been checked -- it is fast and easy and might help a little.

Really dark smoke is never normal, except for the turbo version, under heavy acceleration as the engine RPMs need to speed up to get the needed air in.

Smoke that is clearly very blue is /never/ normal for those engines. They do not commonly burn oil. Having said that, a /little/ blue when cold is likely nothing to worry about. It could easily be aging oil control rings or valve seals, and those usually go a very, very long time in boat use before getting really bad. And, valve seals can be replaced in boat if they are a problem.

Another common issue on those is the oil seals in the turbos. If those are the issue, they tend to get bad fast and are usually inexpensive to have rebuilt. Check the turbo for oil (and play) and rebuild if either. This smoke is often seen as dark grey.

Can you post a picture?

 

[STB]

Oh, also, check the oil level (with the engines off). If they are over filled, they get messy.

Lastly, in some warm places, some folks with middle age engines have reported that going to straight SAE 30 or 40 from multigrade improved their smoking problem. I suspect the higher weight base oil gave more margin to slightly worn control rings, but dunno'.

I've also seen engines smoke more when the oil was very heavily diluted with Mystery Oil.

 

[RT Firefly]

Greetings,
Mr. GB. "...damaged the engine irreversibly." I very much doubt it. Lots of little and simple things to check. You'll be just fine.

 

[rochepoint]

Qe have a Perkins 6.3544M naturally aspirated engine that smokes like crazy on cold start, we had the injectors checked as well as other things. I was told to quit starting it at the dock unless we were going out and not to just let it idle. Start it and go, just not high RPM's until it warms up. Now if I do start it at the dock I throw it in gear at 1200 RPM, as soon as it goes into gear the smoke decreases to next to nothing. The previous owner just use to idle around fishing all the time, I was told by some trucker friends that was a great way to glaze the cylinder walls, since I change my ways 20 years ago it has gotten way better.

 

[BruceK]

Greetings,
Mr. GB. "...damaged the engine irreversibly." I very much doubt it. Lots of little and simple things to check. You'll be just fine.

Could be glazed bores due to the excessive unloaded idling.
I did that to my genset by not realizing the eutectics compressor had died. Fixed it with Nulon Oil additive snake oil,at double strength.

 

[jleonard]

I had one of those in my ex an old 34 Mainship. They smoke at at startup. Period. That's what they do. It's old iron.
They will smoke until the operating temperature gets to about 140 degrees F.
That is their design temperature when all the clearances get correct.

 

[STB]

Photos here would really help. Here are three photos of the same boat idling at the slip along the way of fixing an injection pump timing issue at the auxillary gear shaft. Perkins 6.354, TC series (old school, no turbo).

So, smoke can be normal. But, well, only normal smoke is normal.

 

[Wayne]

Just a thought - If the turbo is frozen and won't deliver the required air, the engine will smoke - billowing black smoke as the throttle is advanced. Celestial required a turbo overhaul as a result of always just cruising at hull speed, which did not load the Cummins 6BT5.9M engines adequately. Mechanic was able to free the turbo successfully. He said I needed to run the engines under "continuous max load" for 15-30 minutes/day (when cruising) to eliminate carbon build-up in the turbos and valves. An expensive lesson!

 

[Pack Mule]

Mine smokes at cold start for sure. I know this sounds crazy but when I took the advice of someone here on the forum and switched over to a genuine Perkins oil filter, it helped a little. Maybe just in my head but I think it helped.

 

[Mrwesson]

Photos here would really help. Here are three photos of the same boat idling at the slip along the way of fixing an injection pump timing issue at the auxillary gear shaft. Perkins 6.354, TC series (old school, no turbo).

So, smoke can be normal. But, well, only normal smoke is normal.

Mine looks like this except the 3rd picture .

I basically just ignore it and just use the boat.

 

[STB]

Yeah. The 3rd picture is the really good side of normal for a NA 6.354 range 1-3. It really doesn't get better than tha idling cold at the slip. The turbo models produce much more white smoke cold idling at the slip. And the range 4s seem a bit cleaner.