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Heavy black smoke, 6V71 non turbo

Former Wrench

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It has been awhile but I am fairly positive 1.460 is for regular timing, non turbo. I don't have my manuals anymore, but in the day I have rebuilt 3-400 of them Worked for a DDA distributor so I have changed a lot of engines from standard to A timing along with spending 6 months in the dyno room doing run-ins and tune ups.
Depending on which of the eight engine configurations, a lucky guess would be to pull the rear cam cover on the right side and roll the engine (1 1/2 in socket) until you see the cam timing marks line up. With luck you will be able, maybe a mirror on a pole, see the timing mark on the idler gear. An A timed engine is stamped with an A and is one tooth next to the standard timing mark
I once spent weeks retiming 60 new Carlo Rossi Winery Freightliners from standard to A timing and installing bigger injectors (12V71).
 

willie59

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Might not have anything to due with the smoke but what are you using for oil? Detroits like straight weight 40 or 50 SAE oil with the right additives. Somebody can probably point to a long thread here on that subject!

I preach that every time I see a Detroit thread. 15W/40 will destroy those engines. Use only SAE 40 with a sulfated ash content of 1.0% or less. Rotella SAE 40 won't do. Two good choices are Delo 100 SAE40 (not Delo 400, ash content too high) or Mobile Delvac 1240 SAE 40
 

RZucker

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It's not necessarily a Billy Bob but definitely a {whoodly dang} that one should worry about tinkering around under valve covers.

Truck Shop
It's not necessarily a Billy Bob but definitely a {whoodly dang} that one should worry about tinkering around under valve covers.

Truck Shop

I saw some weird stuff our old friend Carl did... :eek:
 

td25c

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Pop the valve cover off & identify the injectors first .


Sounds like the engine is running good & making power ?

Engine possibly overloaded for the task ?

# 65 injectors will put some smoke out when ya puller down on RPM .
 

td25c

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If you have access to a manometer or pressure gauge that reads in inches of mercury you can attach it to one of the airbox drains, those pipes that hang down on the side of the engine and tend to drip oil! Under full load at 2,100 RPM you should have between 5 and 8.2 inches of mercury pressure on those tubes. That is only equal to 2.5 to 4 psi so need a good gauge to read that low accurately.

Spot on Ken ! That's exactly where most of our Detroit's run on the boost pressure . 2.5 to 4 PSI . The 71's seem to run close to 4 and for some reason the 53's run lower around 2.5 to 3 .

The 8-V 38 builds 7 PSI around 4,000 RPM and I'm afraid to push him much past that . Don't want any " Black smoke " or oil slicks . :)
 

td25c

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About this " Billy Bob " Stereotype …….

Sensitivity training for all you fellers …….

LOL ! :D:p
 

old-iron-habit

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A simple test if you are in clean air. Pull the air cleaner off and give it a turn. Maybe some one crunched one in he past and put to small of a air cleaner on it and it is not getting enough air under load.
 

Hallback

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Great info fellas!
I'll be glad if Uncle Gus hasn't gotten his hands on it!
 

Bluox

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I preach that every time I see a Detroit thread. 15W/40 will destroy those engines. Use only SAE 40 with a sulfated ash content of 1.0% or less. Rotella SAE 40 won't do. Two good choices are Delo 100 SAE40 (not Delo 400, ash content too high) or Mobile Delvac 1240 SAE 40
So how does 15w-40 destroy a engine ? curious minds want to know .
Bob
 

td25c

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So how does 15w-40 destroy a engine ? curious minds want to know .
Bob


Same thoughts Bluox …. My experience is the Detroit Engine will run on any kind of oil as long as it's slick ?

If there was a tougher user friendly engine I would sure like someone to point me to it . :)
 

RZucker

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So how does 15w-40 destroy a engine ? curious minds want to know .
Bob

I cant explain the whole thing, But it was told to me that 2 stroke Detroits "shear" the molecules in oils. 15/40 just breaks down that much faster and crawls past the oil rings and gets up and creates deposits on the compression ring grooves that stick the rings.
I had a customer running 2 twin power Wabco scrapers with 12V71T engines that were burning 1.5 gallons per day per engine. After getting them off 15/40 and switching to 40wt Delo 100, they were burning 2 quarts a day per engine. That was in 90 degree temps. in the colder season it was 30wt.
 

willie59

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I cant explain the whole thing, But it was told to me that 2 stroke Detroits "shear" the molecules in oils. 15/40 just breaks down that much faster and crawls past the oil rings and gets up and creates deposits on the compression ring grooves that stick the rings.
I had a customer running 2 twin power Wabco scrapers with 12V71T engines that were burning 1.5 gallons per day per engine. After getting them off 15/40 and switching to 40wt Delo 100, they were burning 2 quarts a day per engine. That was in 90 degree temps. in the colder season it was 30wt.

That right there! It's the viscosity modifiers in multigrade oil (15w/40), two stroke Detroit's don't like that stuff. Use of 15W/40 in those engine will cause increased oil consumption and shortened piston/liner life, it just is what it is, those engines do not like 15W/40. Use only SAE40 with a sulfated ash content of 1.0% or less for best engine life
 

kshansen

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The 15W-40 Vs. Straight 40 thing could be similar to the difference between running a good long life coolant to straight water for coolant. Engine will run just fine with the straight water in the cooling system but.......give it time and you will start having problems!

Heck you could go down to the local greasy spoon grill and drain some of the oil from the deep fryer and put it in you motor and it would probably run okay for some time but I would not suggest doing that for a truck going cross county on the Interstate hauling an 80,000 load.
 

John C.

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I got sent to a school many moons ago where the Detroit people were pretty emphatic about straight grade 40 weight. Use multi-grade and watch your warranty disappear in the smoke going out the stack. They would suspect as soon as you gave symptoms and knew before the head was completely removed from the block.
 

kshansen

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I got sent to a school many moons ago where the Detroit people were pretty emphatic about straight grade 40 weight. Use multi-grade and watch your warranty disappear in the smoke going out the stack. They would suspect as soon as you gave symptoms and knew before the head was completely removed from the block.

I hope my remarks above did not sound like I was suggesting that using oil type not recommended by the manufacture was a good thing! Just that just because it might not cause a major failure in the first five minutes running that it still was not a good idea.
 

John C.

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No, I understood what you were saying. Sometimes you have to run what you got and other times you might need to cut a corner to make a dollar. What I was saying is that there might be a cost down the road to consider. I think we were on the same track.
 
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