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TR6 TR6 Light exhuast problem

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tr6web

tr6web

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Hey all. Seems my 6 has decided to give me a little smoke problem coming out of the exhaust. It;s just light, but it's continual. It used to just smoke a little on start up and go away. Anybody have some advice? I'm not great at carb tuning if you think that's the problem, so any advice on that would be great.
 
Definitely not black or steam. If I had to choose a color, it seems like grey, mabye some white. Can you help me?
 
Mike, it sounds as though you may have a valve seal problem or possibly worn guides. Is it worse at start up? Does it seem to puff a bit more when you shift, or decelerate?
Jeff
 
Doesn't get any worse while driving. It's smokes a little on start up and gets better while driving. Just doesn't go away like it used to. If you think it is a valve seal or guide problem, could you fill me in on what you mean? I'm not too familiar with these areas. Thanks, Jeff.
 
Mike, if the intake valve guides are worn, the engine will suck oil around the valve stem into the combustion chamber, where it will burn and cause white smoke. There is usually a small rubber seal on the intake valve to prevent the oil from being sucked in. I'm not sure on the TR6 if it is an umbrella type seal, or simply an O ring. The umbrella type seal pushes down over the top of the valve guide, and seals around the valve stem. The O ring just fits around the valve stem itself.
How do the plugs look? If any are oily, you've at least isolated the problem to that (those) cylinder(s).
Jeff
 
Hello Tr6web,
you can forget the valve seals, there are non on a TR6. Is the smoke there when the engine is really hot? if so it probably is some oil but what is the oil consumtion like?
If it is not too heavy I would forget it until it gets very bad. Replacing the valve guides is a job for a machine shop unless you have a well equiped workshop yourself, or know someone who has.
A possible source of smoke is a leak in the brake servo drawing brake fluid into the engine, worth checking to see if you are losing brake fluid.

Alec
 
Alec, thanks for the correction on the valve seals. The books don't show any on my GT6 either, but when I tore the original head down, there were O rings on the intake valves, and the PO (from new) said he didn't install them. Mysterious. /ubbthreads/images/graemlins/smile.gif
But, they would be easy to install, to possibly help in the case of worn guides.
Jeff
 
Mike B--Alec is correct; no stem seals on the six (although you can retrofit them if you turn-down the guide tips). If you have the external oil feed line to the head, remove it and see if the smoking lessens. To confirm if your guides are excessively worn, hook up a vacuum gauge to a T-fitting in the brake booster hose. If the guage is wildly erratic at idle and steadies off-idle, your guides are worn. I wouldn't mess with head work until you start laying a smoke screen or your oil consumption goes offscale.
 
Thanks all. Rick, oil consumption is normal and it's only light smoke, so I guess you're saying that's kind of normal for an everyday TR6? Seems like it's always been like this, just a little more than usual as of late. Then again maybe since I'm really into getting it back into shape that I am a little more picky now. I woudn't want to attempt the head, etc. unless I have to.
 
Hello Jeff,
there are after market modified guides that have seals but they are rare. Generally no seals. On my 2.5 P.I. which runs at a very low idle vacuum of about 7 IHg I get some smoke but also have an extra oil feed to the rockers.
As it uses little oil I don't worry about it.

Alec
 
Yea, guess you could say the smoking would be normal for any engine with some time on the clock. Since you said you're into getting your six into shape, I would plan for an engine rebuild in the next few seasons because that's what smoking exhaust is telling you to do. At the same time, you should consider bumping the fun factor with some mild engine mods (increased compression, taller cam).
 
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