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TR6 TR6 Smoking?

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veale001

veale001

Senior Member
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Hello again my friends,

I have taken alot of GREAT advice from some Triumph guru's on here and I wanted to ask another noobie question (Sorry Dr. Bill). I replaced the gaskets on my 175 Strombergs and adjusted the needles to a nice even mix and have the timing and plugs looking real good. The idle is around 900 and seems to have more power than usual. But after 2 or 3 days of limited driving I have seen a noticable amount of smoke coming from the exhaust and from the rear carb? Any recommendations or diagnoses?

Realted questions:

1)I used a synchrometer on both carbs to adjust, with the sych. wide open, and I do not seem to be getting a good amount of idle suction?

2)What exactly does the idle trimming screw achieve? I have read on the buckeye tutorials that it makes no difference except for testosterone to leave them closed?

Thanks again for helping me out,
W
 
veale001 said:
Hello again my friends,

I have taken alot of GREAT advice from some Triumph guru's on here and I wanted to ask another noobie question (Sorry Dr. Bill).
Click to expand...


Warren, NOOBIE is and always was a term of endearment. It was never meant to be an insult or disparaging remark. We were all NOOBIEs at one time or another.

Now, back to your question. See if Poolboy will respond. He has forgotten more about ZS carbs than I remember.
 
Hi Warren

1) What RPM are you using to adjust your carbs? By Sync wide open are you referring to the air flow through the sync tool?

2) Leave them closed at this point until we get them otherwise sorted out.
 
Thanks Doc!

Skip,
Ive been keeping the warm engine idle at around 900, anything less seems to strain the engine.

Yes "sync wide open" I meant to say I have the air flow at wide open on the tool itself and the meter is only reading 1/4 of the length of the shaft? Both diaphragms have been replaced... :confuse:

But back to the first question, the smoking exhaust. Its not the typical black smoke from a rich mixture type of problem. But a white smoke which Ive always heard was something to do with water or antifreeze getting in the mix? But I am a non-mechanic. :square:
 
I think he was referring to another post Bill
 
If you have white smoke and have antifreeze in the cooling system, smell the exhaust. If it is sweet smelling you have a water leak into the intake, the combustion system, or the exhaust. Do not sit there for a long time smelling the exhaust. Bad things can happen. John and I were trying to troubleshoot a miss in a Ford ambulance for about an hour. Pat walked up smelled the exhaust and stated that it had a cracked head. He was correct.
 
It did smell sweet!? What some good ways of deducing the point of the leak?
 
Warren,

First let's say that the "Noobie" issue should be settled once and for all as a term of endearment, contrary to what may have been posted a while back as another members opinion of the use of the word. With that being settled, remember that you are welcome here and your questions are welcomed and it makes no difference if you feel you are a mechanic or not.

Sooooo.....I guess that it's probably time to ask if you have had to add any anti-freeze lately? Actually, have you checked it lately?

On these engines, the head gasket will NORMALLY go before the head cracks, so if you do add coolant to top it off, keep track of how much you add per your driving habits, allowing that you have checked for any external leaks and found none evident.

The next step from there is to do a compression test. Generally, if and when head gaskets leak, they usually find a way to get a weak spot between two adjacent cylinders, which allows coolant to be sucked in during the intake stroke and hence the white smoke is created upon combustion. But another give away is that what leaks out in between adjacent cylinders can also allow a leak in when in a sealed system. By that I mean that when the engine has combustion, that gas pressure can sometimes be pushed back into the cooling system, resulting on a lot of bubbles in the radiator and bulging hoses.

All of that being said, it is not uncommon that a head gasket can leak at a single cylinder or the water jacket close to the combustion chamber/cylinder.

But as said above, if the exhaust smells sweet, you can be sure that the white smoke is burnt anti-freeze.

Let's start with the coolant level and the color of the coolant and go from there. Green is great, rusty is not so great, but flushable, black is not good at all, as something (oil & combustion) can be getting into the coolant.
 
Uh!oh!...Smoking?..In some states where the smoke is coming from its a worrying thing.which pipe is it coming from?
just kidding. :nonono:
 
I can tell you about the idle trim screw. It's related, in a way, to the temperature compensators.
As the engine warms there is a bimetal leaf (like a thermostat) that opens an air port to admit more air into the mixing chamber of the carb. Within that air port there is yet another drilled port; the volumn of air thru that port is controlled by the idle trim screw.
It's not much air, because the port controlled by the idle trim screw is very small to begin with; couple that with the fact that a wide open temperature compensator is only able to admit the amount of air that can pass thru the 1/4" diameter hole located on the carb's air filter mounting flange that lies between the top and the right threaded bolt holes for the air box (filter housing)attachment bolts.
It's said that the ear cannot detect changes within the range of adjustment that the idle trim screw provides. I'd agree with that and that's why it's safe to fiddle with it and not affect much.
Supposedly once the engine has broken in the service tech was to close the port by clockwise rotations of the screw.


.
 
Thats not smoke its the Ghost of Lucas past'



TR631-1.jpg
 
Hmm, you sure they weren't supposed to open the idle trim?

Both the trim and the temperature compensator allow a small amount of extra fresh air to bypass the venturi; so it doesn't pick up it's share of fuel. Thus they both have the effect of leaning out the idle mixture a bit (the temperature compensator only when it gets hot). This lowers carbon monoxide at idle; but as noted the difference is hard to detect without a CO meter.

And since they allow only a small, fixed amount of air to bypass the venturi, they have essentially no effect with higher total air flow (ie off-idle).
 
UPDATE:

Was checking out the level in the radiator and noticed the tube for the overflow bottle had come loose and was hanging near the block. So I reattached it, but after re-reading some posts wondered if the back pressure had popped it off? My intial thoughts was some fluid had gotten on the block and was burning off but that wouldn't cause it to come from the tailpipe?? The radiator is full and is perfectly green? HELP!

SIDENOTE:
What is everyone's feeling about Colortune for checking the mixture? Worth the 60 bucks?
 
Well, this is good news, because you can't keep burning anti-freeze and not have the level go down in the radiator.

Sooooo...what is making the white smoke that smells sweet come out of the tailpipe?
 
TR3driver said:
Hmm, you sure they weren't supposed to open the idle trim?

Both the trim and the temperature compensator allow a small amount of extra fresh air to bypass the venturi; so it doesn't pick up it's share of fuel. Thus they both have the effect of leaning out the idle mixture a bit (the temperature compensator only when it gets hot). This lowers carbon monoxide at idle; but as noted the difference is hard to detect without a CO meter.

And since they allow only a small, fixed amount of air to bypass the venturi, they have essentially no effect with higher total air flow (ie off-idle).
Click to expand...
I can quote in part what the Stromberg Manual says.
"A new engine may be run with a comparatively weak mixture, when the idle trimming screw will be fully unscrewed, the maximum bleed being controlled by the size of the drilling (an extension of the passage to the temperature compensator). As the engine 'frees off' during the running-in period the screw may be progressively screwed in until it is seated and the air bleed is blanked off, giving a richer mixture.)
That's what I was going by.
 
Sooooo...what is making the white smoke that smells sweet come out of the tailpipe?

Could it be that the fresh air intake is picking up the steam from the evaporating

AF and sending it thru the combustion system

just a thought
 
Well, that certainly seems clear enough. I just thought it would be the other way around; using a (slightly) richer mixture for a "stiff" engine. Live & learn, I guess.

BTW, the Volvo manual I have handy says the idle trim is used to adjust idle rpm. But it also talks about the damper oil "flawing", so maybe something got lost in the translation :laugh:
 
Tony, if enough evaporates, you will have to add something to replace it. He said it was clean and full, so where is it coming from. To make steam would require a leak, either internal or external.
 
While I don't know what the problem is, it might be worth noting that exhaust normally has a fair amount of water in it (a by-product of combustion), and sometimes incomplete combustion can leave sweet-smelling compounds in the exhaust.

The smell of oil smoke also varies a great deal depending on what oil you use.
 
I agree Randall, that's why I said if the radiator level isn't going down, the problem has to be elsewhere.
 
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