[Healeys] Oil pressure

Austin Healey pajtamuvek at gmail.com
Wed May 15 23:10:32 MDT 2013

Thats quite strange.
My only suggession is that the relief valve is a bit tight in its bore. Are
there any scoring marks on the relief valve(s)? Maybe You could try
polishing some 0.1mms off the valve and retry it.


2013/5/16 Chris Dimmock <austin.healey at gmail.com>

> 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 at 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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