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I'm new and need advice on smoking 8v71TI's please!!!

aquacraig@shaw.ca

aquacraig@shaw.ca

Well-known member
Joined
Sep 14, 2008
Messages
243
Status
  1. OWNER - I own a Hatteras Yacht
Hatteras Model
53' MOTOR YACHT (1969 - 1988)
I own a 1972 53 MY in Victoria BC and there are not a lot of Hat owners here. The engines have about 1600 hours and start quick and clean. We cruise at 12-1400 rpm and oil pressure, temp etc all good with no smoke. WOT in neutral negligible smoke...but...WOT in gear and we blow a lot of white smoke. It is not steam but may be slightly grey. I don't know where to start. If it was compression, the engines should be difficult to start and would smoke cold. If injectors, I'd get dmoke at all rpm. My top rpm in neutral is about 2100 on both engines and I think this is a bit low. All advice appreciated and needed!
 
Thanx Mike. I've been through that thread a few times and am not seeing my specific problem of white smoke under load. Bill had suggested that I could have a turbo issue. Maybe wobbly blades that are indicative of bad bearings and blow by?
 
Are you achieving your normal RPM at WOT under load? Or, does it not want to push over something around 1500 or 1600 rpm?

That could be a turbo issue or it could be something as simple as needing the change your secondary fuel filters - the ones attached to the engines. That was my problem when I thought I had a bad turbo (unable to achieve rpm at WOT under load, smoking while trying to plane, etc.). It was a $7.15 fix which brought be great joy! :D
 
Blow-by would be blue smoke (oil burning). White is typically steam, either from a blown head gasket if there's a LOT of it, or simply steam from the hot exhaust having water in it (water cooling). Every large powerful turbo marine engine I've seen spews a good amount of steam at WOT under load.

When at WOT in gear...how far back is the "smoke" visible?
 
I love the filter answer! A tach on the flywheels was showing only aboutt 1900-1950 rpm WOT in gear. Not sure how that causes smoke but if you know the logic I'd like tounderstand. I'm sure it's not steam as no loss of coolant, oils not milky and the "smoke" does not dissipate until nightfall! We're talking a lot of global warming happening!
I guess my othe rquestion is if it could be a timing problem. Haven't checked that yet but with both engines behaving identical, I wonder if the set-up could be equally wrong on both?
 
Changing the fuel filters and making sure you are not sucking air with fuel would be a good start. Is the fuel fresh and of good quality? I have seen old degraded fuel cause a similar problem.
If all the above checks out,I would reset the injector timing and the racks.Pay close attention for wear on the rack yokes and clevise pins.
 
You could be right about the fuel being a problem. Some of our Northwest outlets are a bit iffy. I will ask the mechanic to check the racks and timing as I am suspicious about the last fellow that did this. Great advice! Craig
 
aquacraig@shaw.ca said:
I love the filter answer! A tach on the flywheels was showing only aboutt 1900-1950 rpm WOT in gear. Not sure how that causes smoke but if you know the logic I'd like tounderstand. I'm sure it's not steam as no loss of coolant, oils not milky and the "smoke" does not dissipate until nightfall! We're talking a lot of global warming happening!
I guess my othe rquestion is if it could be a timing problem. Haven't checked that yet but with both engines behaving identical, I wonder if the set-up could be equally wrong on both?
Click to expand...

2100 RPM at WOT in neutral and 1900 RPM at WOT in gear is way low for those engines. Are you even getting up on plane? If so, you should be doing 14.5 to 16 knots at 1950 RPM if your bottom is clean. There is (or was) an engine plate attached to each engine when it came from the factory that listed the WOT load and no-load RPMs for that individual engine. Hatteras usually took them off of the engine and screwed them to the forward bulkhead wall, but they could be anywhere. Look for them and find your factory RPMs. I don't know your individual engines, but I believe the WOT RPMs may be over 2300 no load and over 2200 loaded. You can also call Detroit Diesel with your engine numbers and get that info. For comparison, my 1978 53MY with 8V71TIs will go over 2200 RPMs up on plane with full fuel and water and gear aboard and will be doing 16 to 18 knots.

Doug Shuman
 
aquacraig@shaw.ca said:
I love the filter answer! A tach on the flywheels was showing only aboutt 1900-1950 rpm WOT in gear. Not sure how that causes smoke but if you know the logic I'd like tounderstand. I'm sure it's not steam as no loss of coolant, oils not milky and the "smoke" does not dissipate until nightfall! We're talking a lot of global warming happening!
I guess my othe rquestion is if it could be a timing problem. Haven't checked that yet but with both engines behaving identical, I wonder if the set-up could be equally wrong on both?
Click to expand...

It sounds like you may be over loaded you should turn around 2300 @wot in gear. That condition makes black smoke not white but sometimes when you combine the black smoke with steam it almost looks white.

I would forget about the smoke and find out why your not turning full RPM. Dirty bottom fouled props bent props wrong size etc. I bet when you solve that problem the smoke problem will go away also.

Brian
 
I will have a careful look for those plates and also go through my manuals to see what WOT should be. This boat was extended to 61 (from 53 ft) according to Hargrave design and re-propped then. Don't know what all that will mean but WOT in neutral won't change!.
 
If you use the serial numbers, shouldn't the detroit folks be able to look somewhere and find out what the engine was set up for...as far as rpms go? Maybe SAMS can get the serial #s if they can't be found?
 
aquacraig@shaw.ca said:
I own a 1972 53 MY in Victoria BC and there are not a lot of Hat owners here. The engines have about 1600 hours and start quick and clean. We cruise at 12-1400 rpm and oil pressure, temp etc all good with no smoke. WOT in neutral negligible smoke...but...WOT in gear and we blow a lot of white smoke. It is not steam but may be slightly grey. I don't know where to start. If it was compression, the engines should be difficult to start and would smoke cold. If injectors, I'd get dmoke at all rpm. My top rpm in neutral is about 2100 on both engines and I think this is a bit low. All advice appreciated and needed!
Click to expand...

First things first
Your no load rpms should be greater than 2300. This leads me to believe your tachs may not be accurate. Please call. between myself and my Detroit rep we may be able to set you in the right direction.
Mitch Iwan
Holland Propellers, inc.
616-355-2900
 
Before you deal with Holland Propellor, send me a PM.
 
I understand that this may be a prop issue but the low no load WOT rpm readings off the fly wheels, causes me concern. I think I should proceed with tune-up, timing etc. and re-check.
 
Your right. You're No Load WOT is checked and adjusted during the tune up. Get that done and you'll know your engines are good. Then check your WOT under full load. If you can't make that then look at the props.
 
Thanx 'Traveler". I spoke with my mechanic today and we're going to do the racks and timing as well as check the turbo play. I'm hoping I get some more info for you guys soon as your input has rwally helped so far. Craig
 
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