Puzzling Oil Leak

[Bambikiller240]

An OEM pump in Aus is $171.84 +GST =$189.03

AM = $117.30 +GST=$129.03

Wonder if there is a repair kit?

MOM

FWIW, The pump I bought from Motorsport Auto (aftermarket) was to outward appearances identical to the OEM unit. Made by same manufacturer, etc. They also appear on eBay from time to time.

I haven't seen or heard of a repair kit, although if there is a kit, and it has the right parts icluded (the seals you need) it would be the way to go.

[HKSZ]

If it still leaks try putting a self tapper screw in the small hole near the rear pivot.

You 'd be amazed how much oil sprays out, particularly under race conditions when the oil breather is restricted or blocked.

[Zedrally]

Well this raises the possibility that there is nothing wrong with the pump and tha cause is actually a blockage in the breather....

Roll on weekend....

[Zedrally]

Update....

Last night it was still pissing oil, so once again off came the pump.

I had never noticed the small "breather" hole near the rear of the pivot arm.

After a very close inspection and clean of the offending item, I applied a small amount of silicon sealent to cover the hole.

After a vigorous drive this morning, I am proud to report that the problem has been ultimatley been solved.

It does however leave two questions.

1. What was the purpose of the breather hole?

2. Was it originally filled?

If anyone has a new pump could you please check, as I tested for obstructions in the breather/crankcase emmission system and found it free flowing.

Further investigations have also found that a repair kit was available, exploded diagrams and instructions appear in the Haynes Manual.

I haven't tried to locate one as I'm not appearing to need one.

Cross referencing with a 330 series manual [260C] has opened up an interesting subject, I'll start a new thread [2bolt pump/3bolt] pump so it doesn't confuse this thread.

Cheers

MOM

[Bambikiller240]

1. What was the purpose of the breather hole?

2. Was it originally filled?

1. Usually things like that are meant to allow pressures to be relieved

2. No, it's supposed to be a hole.

[Zedrally]

BY allowing an open breather, it appears to be a contradiction to what the system is meant to provide.

i.e. a closed crankcase emmision system.

[Bambikiller240]

Every Z car pump I've ever had has had the hole you are referring to. Oil only comes out of it when a seal (or diaphragm) inside has failed, letting pressure (oil and air) from the engine into parts of the pump where it is not meant to be.

[Zedrally]

Ah yes Carl, I agree up to a point.

In this case there is no seal between the mating surface of the EDP and the breather hole.

The first seal you come across is after the breather.

The diagrams make it quite clear that the seal is after the pivot arm.

Oil mist/blowby is quite free to move between all these areas. And most probably provides lubrication to the underside of the diaphram.

It may be possible that there was an obstruction at the bottom of the pivot which prevented oil from draining back into the block and accumulating in the casting.

This however, I'm not able to now prove as a did a total clean of the interior of the casting, removing much oil etc before I was satisfied it was totally clean. In hindsight, I would have been more careful on the initial inspection and should have noted any surface irregularities

So I may never know the actual cause of this problem...

Thanks for the brainstorming....

[still doesn't provide an insight into why there is an open breather in a closed system, though. Maybe another thread some day, some time...]

[Bambikiller240]

What I was trying to say was that I don't think it is meant to be "open". That it only becomes "open" when something inside the pump has failed.

Similar to the hole on the underside of the water pump snout. (the one that weeps water when the water pump shaft seal has failed)

[Zedrally]

Well the only thing that could fail [and the pump still function] would be the oil seal below the diaphram.

I really don't know, I'll try to find a seal kit and do a re-build just to isolate any potential problems...

[LanceM]

Looking at my pump (240 3 bolt) it is wet with oil on the back side but not dripping. Considering it's position on the head I would think that it would only get splash oil in it, if you have a large quanity of oil leaking then I would consider that you have another problem such as you mentioned of something not letting the splash oil drain back and slowly filling the case to the leak point. Another point is that in the early 70's what was considered a "closed" system was not quite defined the same as today I don't believe... JMO

[biker]

ZedRally

Had the same oil leak as yourself - oil out of the small hole at the bottom of the pump which was hard to find until you get the pump off.

Had it repaired with kits twice with little success.

Gave up an bought a new AM pump from AutoOne in Briz. By memory it cost about $110.00.

Should have saved the money from buying the kit and just went out got the new pump.

biker