Smoking 6bta

[David Wesner]

Keel cooled JWAC 6BTA, CPL CPL953. Tach is 200 high. Unknown hours WOT is 2750 RPM photo tach. 32’Novi, 17,000lbs,2.57:1 gear with a 23×26 high cup wheel.

After 1300 RPM she starts smoking, black to brown. The engine is not the easiest to start in the cold, I crank it without fuel for 10-20 seconds then start and she will start 20-30F. Spring/Summer temps it has no problem starting. Blowby appears fine, no test done to measure…but it doesn’t look bad.

Aftercooler and injection pump do look like they have been worked on at some time. I believe this engine did ingest an air filter due to an exhaust leak at one time. Exhaust leak has been corrected and I have installed a filter minder which reads fine. I also checked the air manifold with a vacuum gauge to see if there was any restriction in the aftercooler. Nothing notable observed. I also have run with the engine hatch off to verify air supply not being an issue.

At first I thought I might be overpropped. But, with some reading I understand this engine to be a lower boost at low to mid range and high EGTs are common.

How would you attack this issue? My thoughts tend to go looking at the injector pump settings and timing. I do need another wheel and I would significantly reduce pitch. The main reason being I cannot use the top part of the RPM range anyway because of the displacement hull and the engine would be happier also.

Topic

[Peter McKibbin]

Similar Symptoms

Glad to see you resolved the issue David.
Going the same route with two 6BTA JWAC engines in a new to me boat.
Max I can get is app. 1600 rpm with a huge amount of black smoke.
Traveled from Batam, Indonesia, to Port Klang Malaysia (app. 300 NM) at a painful 1250 RPM.

Using Seamax instruments and exhaust temp was constant at app. 850 deg, not yet wired up boost gauge.
Am thinking that vessel, Baha Cruiser 310 SF, had petrol Volvo’s originally and were changed for 6BTA’s.
Suspect that props were not changed and it is over geared as per article in Tony’s Tips.
Talked with Austral props and settled on replacements which are four blade 18″ X 15.5″ with 1/2″ Cups.
Original props are three blade 18″ X 22″ with 1/2″ Cups.
Props will be changed during current haul out.
Hope to have it back in water mid may.

Turbos are good, no sign of raw water entering from riser and exhaust has decent drop as per Tony’s Tips.
Fuel tanks cleaned, lines and filters replaced prior to trip, app. 2,000 ltrs of hi spec fuel used since.
About to use a can of brake cleaner on each after cooler as they have an light coating of oily soot on inlets.
Engines have unknown hours however top ends were rebuilt a few hundred hours before I got them.
Blowby from engines does not seem excessive, no noticeable drops of oil of sludge under vent hose.
Can anyone suggest where this light coating of oily soot could have come from ?
Thinking it could indicate leaking turbo oil seals.

Peter McK

[David Wesner]

Fixed

Turned out being an injector that wasn’t seated correctly. Number 5 injector was not sitting all the way into the injector seat.

Engine runs smooth with zero smoke now.

[David Wesner]

bump

[David Wesner]

Isn’t this supposed to be a G, instead of an H at TDC? Does this mean that the pump gear is timed to C instead of D?

[David Wesner]

https://quickserve.cummins.com/qs3/portal/service/manual/en/3666087/

From the quickserve site.

Section V, air intake system

[Tony Athens]

48 PSI ??????????????????

Where did you come up with that number?

Certainly not from the chart you posted..

BTW, can you post a link to where you found that chart ?

Tony

[David Wesner]

my bad inches of Hg….

[David Wesner]

Doing some research it appears the turbo should be putting out upward of 48 psi….Is this correct?

Tony…did you recommend another turbo for the CPL953 from another CPL??? One that was better suited to reduce EGTs

[David Wesner]

installed a differential pressure gauge to the after cooler, reading is zero delta. I’m pretty confident it is not a clogged after cooler.

Checked and adjusted valves. All close except for #4 exhaust was tight. No change in exhaust.

Next on the list is Injectors??? Any thoughts on checking the ball check in the injector pump for the fuel advance? I have heard this can cause smoking in the service manual.

Thanks

[Stephen Oliver]

If you look at holsets ‘counterfeit’ guide – then having a hex nut on the compressor side is a sign of a counterfeit turbo… normally its a multipoint nut. Its probably worth giving Holset a shout and giving them the pictures / serial for them to check..

Steve

1 user thanked author for this post.

David Wesner

[Tony Athens]

Never seen a turbo tag like that-It certainly does look like it came from Holset?————–Looks kinda “aftermarket” ? But this is a very early engine and I must admit, in those days I did not pay a lot of attention the the tags on the turbos.

Tony

1 user thanked author for this post.

David Wesner

[David Wesner]

Turbo, injectors and injector pump are also suspect as to being original or correct parts for this engine. A lot of unknowns.

[David Wesner]

How do I ensure I have the correct turbo installed for this engine?

PN 170-032-0125
SN H1146954

Thx D

[David Wesner]

OK. I appreciate your insight.

If I saw more debris and junk on the inside of the cooler I would be more convinced that this was case. Yes, visual on the inside is difficult, but was able to “look” inside with the phone pic. Just hard for me to believe without testing and no indications of being dirty. But, I get it.

D

[Tony Athens]

“I believe this engine did ingest an air filter due to an exhaust leak at one time. “

You would not see this , and there is a possibility ultrasonic cleaning will not get it out unless it dissolves it 1st.

Based on your posts——————–NOT getting air in the issue. It’s either this, or the turbo will not come up to speed, or a combo of both

Tony

[Tony Athens]

“I believe this engine did ingest an air filter due to an exhaust leak at one time. “[/size][/size][/size][/size][/size]

You would not see this and there is a possibility untrasonic cleaning will not get it out unless it dissolves it 1st.

Tony

[David Wesner]

I get it. Looked inside, looked clean. Cleaning produced little debris.

I can get it ultrasonic cleaned but I’m not confident it is the fix. Third picture is inside.

D

[Tony Athens]

You don’t get it.. You are looking at the exit side of the aftercooler.. It’s the input side that clogs & it cannot be visually inspected……………………….The output always looks clean.. …………No different than an air cleaner.

Tony

[David Wesner]

Took it for a run today. Still smokey. Any thoughts?

I saw a post somewhere that mentioned injectors not being seated caused black smoke issues. Although, I cannot think why this would be the case….could I have an injector issue.

Thanks.

[David Wesner]

inside the manifold it was very clean except for a small area collecting soot in the center.

[Author]

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