8V71TI Smoking At Startup? Likely new 53MY Owner!

[MikeP]

Just seems odd that every 53 hatt/8v71TI I have seen in NY and here act exactly the same way...

But in any case, it appears that my impression is totally wrong about the cold smoke from these engines under normal conditions. If there are 8V71TIs that don't smoke on startup, I'd have to conclude that the ones that DON"T smoke are doing it right and the ones that DO smoke, like mine, are doing it wrong!

So IGNORE the advice I gave earlier about the smoke being OK!

 

[Angela]

Do you think it has anything to do with the air temperature? Not trying to be a smarta$$, but I'd like to understand why the difference. There is another Hatt in my marina that never smoked either. I'm starting to wonder if it's geography - air/water temp that makes the difference. ??? For me, it doesn't appear to be seasonal, but we don't really have winter - it's just less hot during those months.

 

[SKYCHENEY]

Ang,
Don't you have 8v92's?

 

[MikeP]

Well if some 8V71Tis in your area smoke and others don't it seems clear that something about the smokers is wrong - compression, injectors, timing, etc., assuming all engines retain original type parts, not retrofitted, for example with smaller injectors for "fuel economy." They would, of course, be more efficient at low throttle settings.

Certainly the warmer the air/water temp, the better the cold start fuel atomization will be. But if some smoke and some don't in the same conditions then NONE of them should smoke if in proper adjustment/condition.

 

[Angela]

Ang,
Don't you have 8v92's?

Yes, 8v92TI

By the way...I drove her this morning and docked her all by myself! Still can't wipe the smile off my face. I'm still intimidated by her size and "tonnage" but it felt good to do it myself for a change. I know...off topic..but just had to share... Oh, and no smoke. LOL

 

[Nonchalant1]

Do you think it has anything to do with the air temperature? Not trying to be a smarta$$, but I'd like to understand why the difference. There is another Hatt in my marina that never smoked either. I'm starting to wonder if it's geography - air/water temp that makes the difference. ??? For me, it doesn't appear to be seasonal, but we don't really have winter - it's just less hot during those months.

Ang & Mike,

Yes - temp makes a diff. I have 8V71TIs that had 50 hours SMOH when I bought it and now have 700 hours on them, and when it's 75 degrees out for more than 6 hours and the engines are at 75 or more, they start with no smoke. When it's below 70, which it almost always is overnight, they smoke a little at startup. If it was 40 overnight, they smoke a lot at startup. Startup smoke is always white (probably unburned fuel). Every diesel engine will belch black smoke if you ram the throttle to high while the engine is running at low speeds (incomplete combustion).

They do always warm up enough at idle to stop smoking and never smoke when returning to the slip, even if idling for long periods.

8V71TIs are as different as their owners, they all seem to have a personality. If they could type threads in this forum, they'd bitch about how they get maintained, what kind of oil they're fed, or how they're overloaded too much of the time with bad props.

Doug

 

[MikeP]

I thought all the 92s were TAs, not TIs. Maybe it was because one of the 53 EDs we looked at had (6v) 92s and I know they were TAs, I assumed all 92s were TAs.

Yeah, I know what they say about assumptions!

Doug, which Tstats are in your engines. Mine are 160's which I consider part of the smoke issue at idle since the engines never get above that when idling, regardless of how long they idle.

 

[yachtsmanbill]

Hey Mike... ya gotta consider this; most diesel engines are just air pumps, using just enough fuel to keep them rolling over, which really doesnt produce much heat. I doubt if even you could get a 100 F T stat that the engine would develop that idling.
Mine smoke out the place when I start them and I know thats mostly from low compression. The star side fires right off and smokes for a few minutes, and once the oil pressure is good I set them at 1000 rpm and it clears right up.
The port side is a slow starter! Besides a few bad injectors, I hold the stop button for about 15 seconds while cranking to build up a little compression heat. Itll start with a few complaints and takes usually 3 tries before it stays running. It'll clear up on fast idle after about 45 seconds, but smokes so good that I need to look out the back door for the USCG before starting. They'd think there was a fire and HAFTA investigate. That side leaves a SLIGHT sheen from fuel out the exhaust which leads me to believe thats an injector issue.
A lot of DDs Ive run either wsmoke like hell OR have no smoke at start up. I think its the nature of the beast!
Not to be a harbinger of bad news Doug, but when youre idling at the lock over here, yours smoke a tad from idling with no load. You probably cant even see it when aboard, but thats DDs for ya! This much headway makes them clean as a whistle! ws

 

[stormchaser]

Anyone recently rebuilt/majored an 8V71TI? What did it cost? Looking for ROUGH estimates in case it comes to that...

 

[jmccubbin]

Guy's,

I'm looking forward to meeting the potential buyer on Tuesday....it is always interesting to read about your boat on this forum as everyone is so good and they have always helped me when I have had questions. If the sale goes through I hope he takes advantage of all of the minds that have collaborated here. You guys are awesome.

We have been doing a lot of work on the boat the past two years and it has been fun. We did replace injectors and serviced and cleaned out the entire fresh water side.....learning how to clean out the fresh water systems and heat enchangers was interesting as I would never have figured out how to do it all if it wasn't for all of the advise from this forum... By the way the motor's turn right over....with the puff of smoke....like they always have. I just had the boat out last Sunday and she ran nice. Weather depending I will run her this weekend as well.

I have tried to tell the potential buyer all the things that we have accomplished and what still needs to be done....all basic little things....but at this price he is getting a nice deal, I believe.

Tommy Huggs is also a great DD guy and the surveyor he is using is also top notch. I'm looking forward to see what comes of it. If anything major does pop up which I would be surprised by but at that point I will probably need to think about finishing everything and keeping the boat at these price points.

Again thanks to all of you and I do hope the buyer likes the boat pending sea trial and survey! She has been a good boat.

Jim

 

[bonnevillebarbie]

Jim,
We are definitley looking forward to meeting you. We all know how everyone has an opinion and wants to be as helpful as possible. Please know we are truly looking forward to this. Its easy to get worried and flustered when there is an unknown. Thanks again and see you soon. Amanda and Dave

 

[jmccubbin]

I'm looking forward to meeting the two of you as well. Your lucky you did not have to do the refrigerator replacement....that was a project! and by the way the thing I love about this forum is that everyone has all of those opinions....you will be well served by them...most of these guy's are really good. See ya Tuesday.....Jim

 

[MikeP]

Maybe part of this is a personal difference on how much smoke is "smoke." When I say our boat smokes idle, once warmed up from cold start it cannot be seen from the boat but it can be seen if you are off the boat and looking at the right angle and if you look within a couple feet of the exhaust outlet. You won't see any smoke say, 10 feet from the exhaust. But since there is some visible smoke, my description is that it smokes at idle.

When warmed up at cruise or at idle after cruise, there is none at all, from any angle no matter how close you look at the exhaust area, both from the dingy and from just a few feet away with scuba gear. But back in our marina in LI, with nearly a 30 minute ride at idle (no wake) from the bay to the slip, she would be lightly smoking again at the slip (not visible from the boat but from the dock) and eng temps would be down below 160.

I had often thought about checking the injectors but the boat runs so well that I just did complete tuneups and left it at that. It starts instantly from cold in any temp though it will hunt for maybe 10-15 seconds with air temps in the 40's.

I BELIEVE this smoke thing is all based on eng/air temp but since my experience in DDs is rather limited compared to others here, I can't in good conscience, be as dogmatic as I might...no...as I WOULD be with gas engine issues!

 

[SKYCHENEY]

Early 92's were TI's. Later they were all delivered with aftercoolers.

 

[Brian Degulis]

I don't think that start up smoke on a turbo engine has much to do with the coolers. I think it's all about compression new 71N compression is 565lbs minimum is 515lbs New turbo is 475lbs minimum is 425. So you can see that because the turbo runs a lower compression ratio the pressure developed on a new turbo engine is still 40 lbs lower than the minimum for a natural.

So your turbo engine running without a load (no boost pressure) has the compression of a natural that's trashed.

Healthy DDs don't smoke? I'd say with turbo engines young healthy DDs don't smoke. They can and should be healthy with 800 to 1200 hours but they're going to smoke on start up. They shouldn't fog the marina and they should clear up in a few minutes or when you drop them in gear but unless they're near perfect smoke is normal.

Brian

 

[captddis]

My 92s @ 3000+ hr only smoked for 15 seconds and just a light wisp unloaded. When the previous owner bought it from my customer @ 2500 hr it still had 440# compression. I have a neighbor with a Viking with 1900 hr 450 hp 671s and only a puff on start up. I can go on..... I stand by my statement. A healthy Detroit will not be a smoker.


PS that 43 year old Chris Craft I was working on has 5400 hr 671s that had not run in the last 2 years, lit them off no smoke!

 

[SKYCHENEY]

My 92s @ 3000+ hr only smoked for 15 seconds and just a light wisp unloaded. When the previous owner bought it from my customer @ 2500 hr it still had 440# compression. I have a neighbor with a Viking with 1900 hr 450 hp 671s and only a puff on start up. I can go on..... I stand by my statement. A healthy Detroit will not be a smoker.


PS that 43 year old Chris Craft I was working on has 5400 hr 671s that had not run in the last 2 years, lit them off no smoke!

My 3800hr 6v92TA's don't smoke either. No block heaters. I always get comments on how clean they are. Lucky? Maybe. I don't really know.

 

[MikeP]

Interesting... based on the input here if I was as much of a diesel guy as I am a gas guy, I would be seriously pursuing this in an effort to see why my 71 TIs smoke while others apparently don't. OR, if I was still only a 5 minute walk to the boat instead of an 8 hour flight (with stop), I might pursue it as well.

But since neither of those things are true, my engines act like everyone elses here, and the compression on the lowest cylinder in the two engines is 470 PSI, I'm not going to expend any effort on it. Though I would prefer seeing NO smoke!

Maybe I'll consider replacing all the injectors as I have been saying I'm going to do for 2-3 years.

Nah, probably not...

 

[captddis]

If you have 470# compression obviously the engines are sound. Checking injectors might be in order and go over the tune up real well. One thing that gets overlooked is checking the rocker arms for wear, worn injector rockers will cause smoke. Max wear is .007. I use the dial indicator for setting injector height, you can get it exact that way. Dave

 

[Finalee]

My 6v92s at 1000 hours do not smoke until temps drop below 50. Then only briefly at start up.