This was some really interesting info (as is the case with most of
Jonmac's postings!), so I was sharing it with my brother, cousin, and
father, who are all Triumph owners (GT6 convertible, TR6, and Stag),
and the question came up - if an external oil feed was never intended
by Triumph in the original design, then what is that threaded hole for
on the back of the cylinder head? Anyone have any ideas?
Tim Holbrook
1971 TR6
--- jonmac <jonmac@ndirect.co.uk> wrote:
> I have two questions now that the machine shop has returned the head
> from my
> '76 TR6:
>
> 1) what color should I paint the head. Seems to me gloss black.
>
> Hole in one!
>
> 2) I will add the auxiliary oil feed to the head but received no
> instructions. Where/how are the connections?
>
> From the oil pressure switch 'T' piece (which you'll have to obtain)
> to the
> back of the head.
> However, if your head has been properly cleaned after machining and
> the
> rocker pedestals, shaft and oil drains in the shaft and rockers
> themselves
> are clear of accumulated sludge, you really don't need an auxiliary
> feed.
> Standard-Triumph valve gear only needs a continuous 'ooze' of oil and
> not,
> contrary to widely held opinion, a 'semi-pressurised' oil feed. I
> asked the
> following question only last year of David Eley, the engine's
> designer who
> is now well into his nineties and as charming and polite as ever.
> "Mr. Eley. Many enthusiasts seem to favour the fitting of an
> auxiliary oil
> feed to the cylinder head on your four and six cylinder engines.
> Would you
> like to comment?"
> His reply was as follows: "John, if I had felt an additional oil
> supply to
> the valve gear was necessary, I would have ensured a direct pressure
> feed
> from the pump. The only two ways the existing supply can suffer is
> from
> partially or fully sludge blocked oil ways within the valve gear
> itself, or
> worn grooves on the back end of the camshaft. If the pump is working
> as it
> should and the camshaft in good condition, then the internal supply
> will be
> more than sufficient. A reliable check is to leave the engine idling
> for no
> more than five minutes with the rocker cover removed. If flecks of
> oil are
> found on the surrounding panelwork, the oil supply is performing as
> it
> should, as designed and needs no further intervention."
> "May I quote you on that?"
> "By all means. Please convey to your friends that my four and six
> cylinder
> engines do not need an additional oil supply of the type you suggest.
> In
> fact, there is a danger that an excess feed to the top end could
> reduce the
> oil level that *is* needed in the sump."
>
> Draw your own conclusions.
>
> Jonmac
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