Smoking 8V-71 in a PD4106....

[bwze]

OK guys, I'm new to this arena and trying to make it up this steep learning curve. Doing pretty good so far. Anyway, I've got, what I would consider, excessive smoke in my exhaust. I was told this engine was rebuilt around 17k miles ago and have no reason to doubt what I was told. I've make a video of this smoking and posted it on YouTube so my helpful friends and fellow bus nuts can chime in on what make be the issue.......both positive and negative feedback accepted with open arms....

PD4106 Starting up.....

[Bill in KS]

I'm not a DD mechanic , just a gm bus owner.  When I picked up my bus and left the previous owners place it smoked like crazy.  My father-in law followed me aprox 10 miles and then we went different directions, later that day I seen him and he informed me I better prepare to do an inframe when I get home ( I was 900 miles from home).  After I had the Detroit Dealer run the rack, change my oil and filter put'n in a straight 40 weight motor oil. 
The next day my father inlaw followed me up to the Canadian border, at lunch he stated " I don't know what they did but it cleaned it right up "

After driving over 1000 miles and only burning / leaking a couple quarts what ever smoke I see at start up doesn't concern me much.

Bill in KS

[Busted Knuckle]

Billy,
I wouldn't be alarmed just yet! Idling causes a 2 stroke detroit to smoke. What you need to do is get that "Jimmy" out on the open road for a way and let'r purr on down the road! Most likely you'll find that it will clear up after some good running.
Even if it smokes like that at start up & idle every time if it ain't using excessive oil and smoking going down the road you are still in good shape!

Now as to the part about rebuilt about 17000 miles ago. That could be true, and it may not! Many many buses are listed as "rebuilt engine XXXXX miles ago" when trying to sell.
I mean face it which sounds better that or "It may have been rebuilt 500,000 miles or 20 yrs ago but we don't know!"


Without documentation a "recent rebuild" is a crap shoot that may or may not pan out!
 BK  

[bevans6]

well, you have some smoke.  What counts for me is less the smoke on a cold start and at idle, than when driving down the road with a warm engine.  Before you worry about the smoke, you need to get it warm and have a few miles on it, then you can see what's what.  You also need to consider the oil consumption, and if your blower seals are leaking, which is something fairly easy to check on that engine installation.  If it clears up when it's warm and run in a bit, with the correct oil and a new air cleaner and all of that, then you can run with that for a long time.

Brian

[bigjohnkub]

Because you are a newbie, i'm going to post what most others know. Proper oil, and a clean air filter are neccisities. Without going into lond discourse, Delo 100 40wt or shell Rotella 40 wt will make quite a difference in smoke. Try to use the search function on this board for previous discussions. It is quite helpful. On the other side of this coin, never be afraid to ask anything on this board. Some(like me ) are just old and grouchy, but have lived around Detroit's for years.

Big john

[bwze]

10-4 Big John.....I'm aware that the Delo 100 40 wt. is recommended for this engine......and the previous owner was running Rotella 15W40....it's nice to know that this may be the cause. I'm planning on changing oil and all filters next week.....thanks everybody....

[johns4104]

Just because a engine was rebuilt does not mean it was maintained or driven correctly.


John

[gus]

You can also find CF-2 oil in 30wt in blue TWO gl bottles at WM.

I use this in cold weather.

It is labeled "Heavy Duty Oil" or something like that and is quite a bit cheaper than Rotella or Delo.

[5B Steve]

    Also you might check if your getting some fuel in the oil, I had that problem and it was a cracked cross over line.


     Steve 5B..........

[pvcces]

bwze, one other thing that I haven't seen mentioned on this thread is that if your engine has a recent, high quality rebuild, it may not have been driven hard enough to break it in, yet. It is not uncommon for it to take 30,000 miles to break these engines in properly.

If you use oil analysis regularly, you will be able to track your wear metals, which should reach a minimum by 25 or 30 thousand miles. Because these engine pass rings over openings in the liners, they tend to smoke quite a bit more than four stroke engines.

Lastly, even if everything is the engine is perfect, they will smoke on start up if they idle very much. It's called exhaust loading and is normal in a heavy duty engine that is not working hard enough.

I don't know if you recently cleaned your engine, but that sure looks like you have a clean engine. With a cheap rebuild or no rebuild, I wouldn't expect the engine to look like it does. I wished ours looked like that. And ours is in good shape, getting 10 miles per gallon fairly often.

We had a 6N71 boat engine rebuilt with high quality liners. It smoked and was even hard to start.  And it misfired periodically at high RPM. After asking around about what to do, a rebuilder and a few other people told me to take the boat out and firewall it for a minimum of four hours.

I did it and the result was amazing. All the symptoms went away and it ran perfectly.

Don't make the mistake of looking for car behavior out of that two stroke. It's not going to act like one.

Good luck.

Tom Caffrey

[TomC]

Number one- the engine started right up when you hit the starter.  Two- it sounds like it is running rough-either needs a tune up, and/or new injector tips.  Three-change the oil to good CF-2 rated straight 40 weight.  That bit of blue smoke isn't that bad.  Run it and see what you come up with.  I think you have lots of miles left on that engine.  Good Luck, TomC

[bwze]

Thanks for all the replies guys....I feel a little better know. As I stated earlier, I plan on changing the 15W40 over to Delo 100 40 wt. next week along with all the filters. I hope this will clear things up a bit. 

Guess it's a good thing I have a sister-n-law that works for an oil jobber.....

Well, going out to try to get these park brakes to release. See this link for more details....http://www.busconversions.com/bbs/index.php?topic=18442.new;topicseen#new