This time it's an inlet valve clearance question please.

[MLCstag]

There's much talk about inlet valves being 8 to 10 thou but then there's the yellow Triumph book with 6 to 8 thou. All my inlets are 6, bar one at 7 so should I get the shims ground down to allow an 8 thou clearance or leave them?

I'd like to know if anyone else is living with 6 thou? My car is a 72 Mk1 with what I believe is the original engine with 40k on the clock and not much sign of previous fettling. It's not really running perfectly and doesn't like warm tick over as it speeds up (carb overhaul next on the list). Can this be down to tight inlet valves and should I open them up whilst I'm changing the chains?

Any engine experts out there, help please!

Brian

[GDPR]

Checking as part of a service, its 6 thou, I wouldn't bother to change it - I tend to have 2 feelers out, a 6 and a 10. If the 6 goes through and the 10 doesn't, that is good enough.
Usually find tickover is only adversely affected at 4 or below.
If I am doing a head rebuild, then I work to exact clearance.

[jleyton]

There is an incorrect valve clearance figure shown somewhere in one of the manuals

It may have been in the Haynes or Unipart manuals, and it might even be the metric measurement, but I do remember the wrong figure somewhere.

Cheers

Julian

[Westfaling]

Brian
I would expect clearances to increase with wear so I wouldn't be changing anything. I suppose the valves could pocket themselves into the head more with use decreasing clearance but I would not have thought so.

[MLCstag]

Thanks for the advice, it fits with my thoughts so I'm going to leave undisturbed using the "If it ain't broke don't fix it" philosophy. I have enough servicing and faults to look at anyway.

Brian

[Seaking]

There is an incorrect valve clearance figure shown somewhere in one of the manuals

It may have been in the Haynes or Unipart manuals, and it might even be the metric measurement, but I do remember the wrong figure somewhere.

Cheers



Julian

Julian Both my ROM and Haynes both quote 8 to 10 thou.

so are they both wrong???
Cheers Glenn

[Westfaling]

The
Rimmers site quotes the figures in metric
Inlet 0.15 - 0.2mm which equals 6-8 Thou
Exhaust 0.41 - 0.46mm which equals 16-18 Thou
The Leyland Service Notes I found here also use these figs
www.vitessesteve.co.uk/.../Triumph-Stag-2997ccV8EngineServiceTraini...

I'm sure this will have been discussed here before. Someone - far better than me at searching on the Forum - will likely post a link soon.
Am I the only one who finds the search function to be rubbish??...

After my moaning I just found this post

http://www.stag.org.uk/forum/showthread.php?7064-Valve-Clearance-Data-Beware&highlight=valve+clearance

I don't think it's a metric conversion error because the service training notes quote both metric and imperial and the conversion is correct.
Nick

[Westfaling]

Guys
Is there a definitive answer 6-8 or 8-10 Thou??
Nick