[Healeys] Oil pressure in a BJ8

[richard mayor]

DW used to advertise that the rotary style pump was good to 6000 RPM but
higher reving engines should use the gear style.

All I can say is .... don't you believe it!!!!

My question to you is why would you want to use a component from a 100-6
engine that has caused so many problems?  No one ever lost an engine
because of the gear style pump.

On Fri, Sep 2, 2016 at 4:46 AM, Bob Spidell <bspidell at comcast.net> wrote:

> 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>
> 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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