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Oil pump rebuild  Rating:  Rating
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 Posted: 06-21-2011 08:11 pm
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dmatth
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Yeah, plenty of oil. Our repairs were successful in reducing the amount of escaping oil.

So if the Pickup pipe goes out downward is there really no way to check it without removing the engine/sump?  Obviously there is some connection between the pickup pipe and the aux housing for the simple reason of supplying oil to the pump.  If I remove the aux housing will I have access to the pickup pipe enough to see if I can draw oil up it?

Is there any other simple gizmos like clips or such in the pump that could go wrong, without horrifying noise, but make the pump non-functional?

Doug

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 Posted: 06-21-2011 08:27 pm
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Greg Fletcher
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Contamination in the oil relief spring (inside the auxiliary housing) can create a no-oil pressure situation. A very small piece of stray silicon sealer is enough to make that happen.

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 Posted: 06-21-2011 08:29 pm
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subwoofer
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The oil pump consists of a rotor pressed onto the shaft and secured with a circlip, an annulus piece and the housing. I have never actually heard a really failed one, but I have seen a picture where the annulus had broken into 5 pieces or so. I would imagine it to be noisy.

Access to the top of the pickup pipe is easy once you have the aux housing off, the hole is 3/4" or so in diameter. To have a look at the pickup the sump must be dropped. I would not recommend trying that with the engine in place, although I think Dan (Florida) actually did it.

My priority would have been to check the condition of the sump contents, on my "new" engine the pickup filter screen was 2/3 covered in old gasket material and other gunk. It still had good oil pressure, but needless to say I cleaned it well. I think yours may be really clogged with old gunk.

Another idiot mode question: are you sure the gauge is working? Have you tried connecting another gauge?

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Joachim

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 Posted: 06-21-2011 09:43 pm
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dmatth
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Thanks for the suggestions!

Greg,
 I did clean out the spring/plunger in the Pump Housing.  Is there another something in the Aux Housing or are we talking about the same thing?

Joachim,
Thanks for the description. I guess the next step will be to remove the Aux Housing and see if i can draw oil up the pipe. Any idea how much/little effort should typically bring results?  As for the gauge, that was on my agenda for today thought I might send 25lbs of air pressure up the tube and see if the gauge needle moves.  Not feeling the the gauge is the culprit though since my test yesterday of removing oil cooler adapter seemed to leave the oil filter dry.

Another thing I thought of trying is to drive the pump with a power tool to see if I can get a response.

Doug

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 Posted: 06-22-2011 04:23 pm
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subwoofer
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I would hold back on removing the aux housing, I'm not quite sure taking it off would prove. Clean the relief valve again, making sure everything is squeaky clean. If you already have the cam belt off, try driving the aux shaft with some power tool to see if any pressure build. If you have had the distributor out, was the O-ring in good condition? The pump will not prime if the distributor is removed.

If you spin the aux shaft with a drill, try taking the oil filter and oil cooler sandwich off to see if it pumps oil at all. No back pressure should make the oil flow.

If there still is no sign of oil pressure, I'd drop the sump next.

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Joachim

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 Posted: 06-22-2011 05:17 pm
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dmatth
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I like the idea of not removing the aux housing (less work=more better), but I'm wondering if a clogged bleed hole could be a factor. Maybe with a mirror I'll be able to find the bleed hole with just the pump housing taken off.

I'll be tinkering tonight, hopefully with some results.

Doug

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 Posted: 06-22-2011 07:59 pm
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SpeedyMitch
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dmatth wrote: I'm wondering if a clogged bleed hole could be a factor
Hay Doug,

When I purchased my early JH last year it had never had the FSB applied to drill the air bleed hole in the Aux Housing. Without the air bleed hole it would take 20-30 seconds to build oil pressure. After drilling the bleed hole it now builds pressure in less than 5 seconds.

If your JH is taking longer than 30 seconds to build oil pressure I doubt it is a plugged air bleed hole.

Just my 2-cents (and worth every penny).

Speedy Mitch

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 Posted: 06-23-2011 12:58 am
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terryhowarth
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Hi all, I should have updated my problem months ago with the low oil pressure. As it turned out the PO had NEVER installed an olive into the pipe pickup at the block, all he did was ram some 1/2" plastic pipe down the oil pickup pipe and seal it with a piece of garden water hose & nut over that and sealing goop of some description. Then to top it off, a length of coiled metal spring about 12" long was shoved down that to stop the plastic pipe from being deformed by the engine oil heat. I removed the lot, fitted a new olive and nut and hey presto NO more oil pressure problems. might be worth checking it out as I'm sure there is more than 1 moron in the world.

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 Posted: 06-23-2011 05:06 pm
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dmatth
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SpeedyMitch wrote:

If your JH is taking longer than 30 seconds to build oil pressure I doubt it is a plugged air bleed


Good point. We've gone from good pressure (15-20 warm idle 45-50 running), to zero. So doubtful it's the bleed hole, I'll check it while I'm in there anyway.

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 Posted: 06-23-2011 05:16 pm
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Greg Fletcher
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The bleed hole may not be a big deal. It's great to put it in if that is not present when you are doing a rebuild, but my early Jensen Healeys never had it and they have always had excellent/instant oil pressure at startup. New oil pump rotors and engine bearings to spec will make a hugh difference compared to a high mileage engine.

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 Posted: 06-23-2011 10:41 pm
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dmatth
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So  last night I tested the gauge, (it's working), pulled the oil pump housing, (the bypass plunger and spring are free and moving, I'll grease em up anyway). This weekend I'll put the pump housing and dist back on and give it a spin test with power tool. Not feeling very optimistic.

After that I guess the next step is to pull the Aux Housing and see if I can draw up any oil manually (I'm thinking high tech – tubing, duct tape and shop vac).  If not, then there must be something wrong/clogged at the pickup pipe.

Then it's time for that garden hose clamp, tubing and a long spring  q:)

This is driving me bonkers. There aren't that many parts to the system. A pool of oil, a pump and some passages. Is it possible for a blocked passage to stop the pump from working?

Oh BTW, when I put stuff back together I've been making paper gaskets and using a bit of gasket sealer instead of using Permatex silicon. Greg got me worried about goop squishing out to the inside and fouling stuff up.

Doug

Last edited on 06-23-2011 11:02 pm by dmatth

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 Posted: 06-24-2011 06:09 am
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subwoofer
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The only place blockage before the rotor is likely is the pickup filter screen. The pickup line is such a massive diameter for anything to clog.

My money is on the filter screen.

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Joachim

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 Posted: 06-27-2011 12:50 am
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dmatth
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OK, so its got to be the oil pump.
today we lubed up the bypass plunger with molly/graphite grease, and put the pump housing back on.  I had a right-angle drive for a power drill and put an allen driver in the chuck and used that to the drive the pump at 1200 rpm with the oil filter off, (figuring that the oil pump sprocket is twice the size of the crank sprocket that would be equivalent to 2400 engine RPM). Not a trickle of oil pumped out.  We removed the Aux housing and using the shop vac, duct tape and plastic tubing, we easily were able to draw oil up the pickup pipe. (at least I don't have to pull the engine again.)
So what can go wrong in such a simple mechanism as an oil pump? All I can think of now is if the inner rotor is somehow no longer being driven by the shaft.  Even worn rotors might drop your pressure some but we went from good pressure too zero.

Doug

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 Posted: 06-27-2011 02:14 pm
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subwoofer
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Are you positive the distributor is mounted correctly and the O-ring intact? If there is an air leak there, the oil pump may not prime. Others have tried getting oil pressure with the distributor removed and failed.

Edit: Idiot question mode again: You are sure you are spinning the pump the right way?

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Joachim

Last edited on 06-27-2011 03:56 pm by subwoofer

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 Posted: 06-27-2011 05:53 pm
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pbahr
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Joachim beat me to the question about an air leak.........
YELODOG

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 Posted: 06-27-2011 07:50 pm
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dmatth
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Well.... Yes, I'm positive we were spinning the pump the correct way, and yes the "O" ring on the dist is intact but no way of knowing if it is sealing other than the evidence that car does not seem to have been leaking oil at the dist mount, but then I guess once it looses its seal there would be no oil pressure nor oil to leak. (?)  There is a very small hole at the back of the housing behind the inner rotor and drilled parallel to the drive shaft that I presume is the bleed hole from earlier discussions, it is blocked but appears to have been blocked for some time (really solidly blocked), and another larger hole (maybe .080 - .125 dia) angled up and looks to terminate at the gasket.

Edit: We did have the dist mounted but without the cap in place.

Looking at the rotors... If I saw these at a junk yard I'd buy them. No discernible signs of excess wear (car has 104k mi).  The housing where the outer rotor spins shows some sign of scuffing but so little that there is no ridging between where the rotor spins and where it doesn't.  The rotor fits with maybe (haven't measured yet) .010 clearance to the outside wall.

Any ideas on how to bench test the pump??  Would I be able to spin it and just feel if it was drawing a vacuum?

Last edited on 06-27-2011 08:09 pm by dmatth

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 Posted: 06-28-2011 07:09 pm
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dmatth
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New update:
Talked with Delta Mortorsports today to order gaskets to put this thing back together and here's something that might be an issue: The gasket for the Pump housing is a "Precision" part at about .004" thickness. So my homemade paper gaskets may be the most recent problem.  This still doesn't explain the sudden loss of pressure but hopefully with the right gaskets I can get this thing back on the road. The pessimist in me still wants to bench test before installing though. Don't want to mess up a $7 Aux Housing gasket until I am confident it's going to work.
Thanks all, I'll let you know how it works.

Doug

Last edited on 06-28-2011 07:11 pm by dmatth

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 Posted: 06-28-2011 08:47 pm
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subwoofer
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I am at a loss here. There really are only two possible reasons, either it is drawing air somewhere, or something is clogged solid.

For bench testing, you could possibly turn the aux housing over and pour oil into the oil intake while spinning the pump just to see that oil makes it to the other side, but I'm not sure if that will prove anything.

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Joachim

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 Posted: 07-09-2011 12:05 am
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dmatth
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Here's the final chapter:
Put everything together with the proper gaskets and Eureka, Oil pressure, Lots of it. Fired up with a cold start pressure at about 55lbs. So it seems obvious that the gasketing after my initial cleaning was the problem. However the mystery remains as to what caused the initial loss of pressure. My best guess would be the Oil Pump Housing gasket (the .004" mylar one) or the Dist seal, both of which were replaced. (The housing gasket came off in pieces)

On another note, yes you can bench test an Oil Pump. I set the whole assembly on a workmate bench, used a piece of thick wall 3/4" OD plastic tubing, wrapped some electrical tape around one end so it fit snug in the oil pick up and the other end in a container of oil, taped off the upper hole to force the oil toward the filter passages, and use my DeWalt cordless with a 6mm alan driver in the chuck to drive the pump.
On the first attempt the tubing was too long (in the real world the pump only draws up about 8-10"). With a shorter tube I was able to make a huge mess on the lower shelf of the workmate.
Thanks everyone for your input!
Doug

Attachment: IMG_1374.JPG (Downloaded 67 times)

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 Posted: 07-09-2011 11:32 am
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subwoofer
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Good to hear that everything worked out in the end!

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Joachim

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