[Healeys] Oil pressure in a BJ8

[Bob Spidell]

Richard,

DW sells the rotary pump specifically for engines that mostly run at 
relatively low revs (i.e. street/touring cars); and the gear pump for 
engines that run at higher revs (i.e. racers).  DP you think the gear 
pump can be a problem in engines that rarely run over, say, 4,000RPM?  I 
can't believe the DW people aren't aware of the backpressure issue.

I might be buying a new pump soon.

Bob


On 9/1/2016 6:30 PM, richard mayor wrote:
> Chris,
>
> I hate to be negative about your good oil pressure but I fear you may 
> have a problem.  I am assuming that you have the "high pressure" oil 
> pump from DW.
>
> Based upon that assumption, I can tell you that it is the rotary style 
> of pump that was used on the 100-6 engines. There were many problems 
> with this pump.  It has a very large capacity and as such it results 
> in a lot of friction, or back pressure in the system. Namely, it put 
> stress on the camshaft gear, the driving spindle gear, the timing 
> chain and the camshaft thrust plate.  This was a common problem with 
> the early 100-6 motors.  One fix was to machine an oil grove in one 
> side of the the trust plate. Then an oil groove on both sides. Then a 
> bronze thrust plate with oil grooves. Timing chains stretched.  Cam 
> and driving spindle gears received excessive wear.  That is why the 
> switch was made to the gear style pump.
>
> The rotary style of pump is actually a very good design. Nissan used 
> it in the Z car motors but it was 2/3rd the size of the Healey pump so 
> there was much less back pressure.
>
> Many of us racers have used the DW "high pressure" oil pumps and 
> discovered that at some point, all of the teeth on the cam and driving 
> spindles have been ground off to such an extent that we have lost all 
> oil pressure.  On a shelf with my "offerings to the god of speed" I 
> have a camshaft thrust plate that has a groove that has been ground 
> into it almost  1/8th of an inch from the resistance of the oil pump 
> forcing the camshaft into the trust plate. I am sad to admit that it 
> took me the loss of 2 race motors to finally grasp why this was 
> happening and before I switched back to the 3000 gear style pump .
>
> Jeff Jonk did an excellent article about these pumps and the damage 
> they cause in the Healey Marque publication about 10 years ago.
>
> Richard
>
> On Tue, Aug 30, 2016 at 3:53 AM, Chris Dimmock 
> <austin.healey at gmail.com <mailto:austin.healey at gmail.com>> wrote:
>
>     Hi all,
>     Recently someone asked about oil pressures, and the oil being used.
>
>     My BJ8 engine was totally rebuilt in 1998.
>     Today, my wife and I went for a drive up the M1 motorway and I
>     kept an eye on oil pressure. Water temp was 185 degrees all the
>     time. Air temp was ~22 degrees Celcius.
>     Lovely day for a drive to the Hunter Valley!
>
>     Hot idle. After 70 minutes at ~70 mph, idle @ 850 - 900rpm = 40 lbs.
>     Oil pressure at 2,000 rpm hot driving = 50 lbs
>     3,000 - 5,000 rpm hot oil pressure = 60 lbs.
>     My wife said we wouldn't make our 3rd wedding anniversary if I
>     pulled 6,000 in overdrive top..... ;-)
>     Denis Welch oil pump.
>     Fresh Penrite HPR 40 oil and filter last weekend.
>     Draw your own conclusions. Mine are:
>     the thermostat is perfect, and
>     so is the oil pressure relief valve.
>     Best
>     Chris
>

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