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New C/B/M oil pump

I'm sorry to gloat, but I was pleasantly unsurprised when I stripped my first Hepolite (wassell) oil pump for the above title.
I will admit that I was a little upset when these first appeared on the market as my version has been drawn up for around 10 years now.
First appearance is they look quite well made. After stripping I was not so impressed.
The first thing I noticed was that the shafts are not ground. Then the shaft clearance in the body and end cover is excessive.
This is important because oil will drain back into the engine leaking up the drive shaft when it's left for some time.
I'm not going to run any physical tests as it's just not worth it on a circulating pump. (it doesn't need to make pressure)
Due to end float and excessive clearance on the gear tips in the housing a lot of oil will leak in these areas. Not the end of the world for a circulating pump, but I would expect better.
The pickup/end cap has no provision for a non return valve. Also I think it is made from mild steel. The poor quality 2BA set screws may also distort this cover.
Backlash in the gears is not worth worrying about as I feel the above points out weigh this.
Though I don't believe the tooth form will detract from it's performance, I don't like it. Also the teeth are poorly deburred.

My conclusion is, I really must offer you something better.

I won't fit one, but the choice is yours.

email (option): pes.sales@btconnect.com

Re: New C/B/M oil pump

Just looking for some good quality new bodies me

I have nos gears, top cap, bottom cap & bolts too

Jo’b

email (option): jonnyob1@googlemail.com

Re: New C/B/M oil pump

If I knocked up some bodies it could make use of your bits then John.
I'll do them in cast iron as I have a length of bar.

email (option): pes.sales@btconnect.com

Re: New C/B/M oil pump

The end plate was mild steel on the original pumps...Interestingly the ABSAF high output pump for the Gold Star also has no ball valve in the base plate...Ian

email (option): ian@wright52.plus.com

Re: New C/B/M oil pump

There are arguments for and against it Ian. One thing for sure is that it’s not easy to machine that fine grove that retains the clip. Personally I’d rather have it. I also like to use a shaft seal, but there is not a lot of room in this pump. I also think the shaft and gear arrangement lends itself to side thrust. I have a solution for this if I made an entire pump.

email (option): pes.sales@btconnect.com

Re: New C/B/M oil pump

Mark,

I have two of the Hepolite pumps and they are different from yours in the photo.

The gears in both my pumps have a black oxide coating, not bare metal like yours.

The fit and finish of the gears also looks better than yours.

I measured the gear shaft to pump body clearance and it was .0006" for the feed gears and .0007" for the scavenge gears. I would consider less than one thou not excessive???

I next measured the hardness of all the components.

The gears measure at Rockwell C scale 30.

The pickup end plate is definitely mild steel and measures Rockwell C scale 8.

The pump body also appears to be mild steel and measures at Rockwell C scale 12.

Cast iron for the body would probably be a better material than mild steel but as BSA made them out of Mazak and it does not wear out, maybe not necessary?

Before Hepolite started making new pumps I was going to make a new body and end plates out of bronze. But never picked what alloy I was going to use.


Anyway, I have put thousands of miles on one of the pumps so far with no issues.

Re: New C/B/M oil pump

I expect they use a number of subcontractors for making parts Bruce. I make a few bits for them.
The gears I have, have been hardened. Though an attempt has been made to clean them.
I clean (super finish) all my gears.
I'm pleased you had a better experience than me, I was a bit slow with the first batch.
Even the one I have would work, though I would not sell one without warning the customer.

BTW I have a few bronze end plates I made a long time ago. At the time it was so easy to buy a used pump I didn't think new would sell.

email (option): pes.sales@btconnect.com

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