[Healeys] Oil Pumps

Bob Spidell bspidell at comcast.net
Mon Dec 30 20:58:19 MST 2019

[If this is a double-post please disregard, my mail server is acting weird]

Well, this is distressing.  Using the Torrington thrust bearing would 
spare the thrust plate, but you'd still get the wear on the gears and 
stretched timing chain, no?  Given this, and the alleged problems with 
their 'constant clearance worm' steering box I'm beginning to wonder 
what's up with DWM/R.  They race, they have fancy new CNC machines and 
appear to be profitable; why would they be offering (possibly) defective 
parts (and advice)?

My dad and I rebuilt my BJ8's engine at about 80K miles; I bought most 
of the parts from Sports&Classics in CT--they still around?--and I 
bought whatever pump they were selling.  I always assumed since it was 
for a BJ8 it was the gear type, but when I rebuilt the engine again a 
couple years ago I disassembled the pump; it was the vane type!  I had 
some wear on the pump driveshaft, but it held up for 120K miles, and 
I'll likely not put more than a few thousand on the new engine/pump in 
my remaining years.  I'm also re-thinking my use of 20W-50 oil (but I 
have 3 dozen qts. so ...).

I know of a problem with aircraft engine oil pumps with 'sintered' 
gears; I believe this is a method of producing the gears by basically 
melting iron powder in a mold, anybody know if the gear-type Healey 
pumps use sintered gears?

On 12/30/2019 5:47 PM, richard mayor wrote:
> 100/6 rotor style oil pumps were an engineering disaster. While the 
> design itself is OK, the large physical size of the rotors in the pump 
> creates a lot of resistance and stress in other engine components. It 
> puts great pressure and increased wear on the oil pump driveshaft gear 
> and the  camshaft great. This back pressure also results in the 
> camshaft being driven forward more forcefully into the camshaft thrust 
> plate. It also stretches the timing chain.
> As this problem became apparent, Austin modified the camshaft thrust 
> plate with the addition of a circular oil groove.  When that was not 
> sufficient they changed the thrust plate to a bronze type of material 
> with a circular oil groove. Eventually they replaced the rotor style 
> pump with the gear style.
> I the photo I have attached, the plate on the left is the stock steel 
> thrust plate. The middle plate is a late 100/6 bronze style thrust 
> plate.  The thrust plate on the right is the result of using a Denis 
> Welch 100/6 "high volume" oil pump. The cam has ground itself into 
> that thrust plate about 1/8th inch.   Look closely at the oil pump 
> driveshaft in the photo and you will see that the gears have been 
> sheared off. The gears on a very expensive Denis Welsh camshaft are 
> also sheared off.
> Calling a 100/6 oil pump a "high volume" pump is like calling a 
> prostitute a "social worker". They both do the job but the 
> consequences can be tragic.
> My advice:  Do not use a 100/6 oil pump.  The gear style pumps are 
> more than adequate.  And, don't believe everything you read in the 
> Denis Welch catalogue.
> If you insist on using the 100/6 oil pump then you should get the 
> Torrington bearing camshaft thrust plate from Denis Welch as well.

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