[Healeys] Oil Pumps

Bob Spidell bspidell at comcast.net
Mon Dec 30 21:48:19 MST 2019

Correction: Sintering does not actually melt the metal--in this case 
iron--but uses heat and compression to form shapes.

On 12/30/2019 7:58 PM, Bob Spidell wrote:
> [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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