Hi Magnus
The only other suggestion I can offer, that hasn't already been suggested, is
that there are 2 types of camshafts for the C series engine.
One camshaft, typically used in low revving C Series sedans, and possibly
early 100/6's etc has 13 teeth to drive the oil pump. The oil pump gear and
the camshaft gear on the cam are the same size. This camshaft drives the oil
pump faster.
The other camshaft, typically found in later C Series engines and most 6 cyl
Healey's, has 12 teeth to drive the oil pump (and still 13 to drive the
distributor). Easily identifiable because the two gears on the camshaft are
different diameters. It drives the oil pump slower than the "sedan" cam.
Typically, the sedan cams have little wear on the lobes, and typically have
never been reground. So the initial reaction when you look at a pile of old
cams is you select the one with the best lobes, that hasn't been reground...
Often, a sedan cam.. And that's where the problem starts...
If you use a sedan cam, with a Denis Welch hi volume pump, you will have huge
oil pressure. And if you rev the engine at around 6,000 or more for any
prolonged length of time, the oil pump gear on the cam will strip and you'll
have no oil pressure, as the cam gear that drives the oil pump has very poor
lubrication, and you are driving the oil pump faster....
At least 3 people encountered the stripped oil pump cam gear problem at
Bathurst in 1998 and 1999.
Of course, this all only applies to reground, original BMC cams. The
remanufactured, gun drilled cams solve the whole cam lubrication issue. E.g
the Denis Welch remanufactured cams. They make the cam part of the lubrication
system, lubricating the gears and the lobes by oil ways in the cam.
Hope this helps
Chris
P.S Patrick Quinn. I'll write this up for you as an article. ;-) Promise
Sent from my iPhone
On 16/05/2013, at 7:13 AM, Magnus Karlsson <magnuskarlsson@bornet.net> wrote:
> I have a problem with an engine that I just restored completely. The oil
> pressure gets too high when revved over 2500. The pressure reaches all the
way
> up too 80 psi, which of course is way too much. The strange thing is when
the
> engine is cold and you rev it, the pressure will not rise above 60 psi.
Quite
> contrary to the normal behavior. The oil pump is a new Denis Welch unit,
the
> oil pressure release valve and spring are new, all bearings in the engine
are
> new, all parts have been machined to the right tolerances. I4ve tried with
a
> used release valve and spring that is quite softer than the new one.
Resulting
> in the same high pressure.
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