GaryM
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| posted on 15/2/06 at 07:56 AM |
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Xflow valve question
Hi
What would cause an inlet valve to get so much carbon deposit on it?
 
Inlet Valve
Cheers
Gary
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stevec
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| posted on 15/2/06 at 08:32 AM |
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Possibly oil getting down past the stem seals.
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britishtrident
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| posted on 15/2/06 at 08:51 AM |
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Inlet -- oil and 30 years of low speed town driving -- cheap fuel won't have helped.
[Edited on 15/2/06 by britishtrident]
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GaryM
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| posted on 15/2/06 at 08:58 AM |
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I've used my digital verniers to measure the valve stems to see if they are worn and they appear OK.
How would I check whether the valve guides are worn?
[Edited on 15/2/06 by GaryM]
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David Jenkins
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| posted on 15/2/06 at 08:59 AM |
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I'd second the 'oil down the valve guide' option. It's a very old engine and the guides will have worn.
Worth getting fixed? Depends on how much oil you're using. If you're not using very much, then I'd leave it alone. If
there's thick smoke coming out of the exhaust every time you blip the throttle, then you'd best get it done! 
If you plan to convert the head to unleaded, then don't worry - they'll have to change the guides anyway if they are worn.
David
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02GF74
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| posted on 15/2/06 at 09:40 AM |
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quote:
Originally posted by GaryM
How would I check whether the valve guides are worn?
Internal micrometer would be the best but very few of us have these.
So the way I would do it is
a) insert single strand of wire in the gap between valve stem and guide; then measure diameter of wire
b) rock the valve from side to side mesuing amount of wobble; using trigonometry work out wear (assumes vavle stem and guide have worn evenly) <--
not tried this since it makes my brain hurt!
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nitram38
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| posted on 15/2/06 at 10:01 AM |
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If you have the engine apart, get the valve guides replaced. Sometimes the oil is caused by the valve stem seals being worn out. If you have a new
head gasket set, then new ones should come with it.
[Edited on 15/2/06 by nitram38]
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britishtrident
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| posted on 15/2/06 at 12:15 PM |
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As it came from the factory xflos don't have valve guides --- the valves ran straight in the head -- less than ideal but it worked and was
cheap.
Because of the hole in the head wears more than the valve, way to check for wear is try in a new valve and see how much it wobbles.
Remedial action usually means taking the head to an engine grinder ! and asking him to fit guides.
In the old days valves with oversize stems were some times used the hoe in the head was reamed out to suit.
[Edited on 15/2/06 by britishtrident]
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