mjb59
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Posts: 311
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Post by mjb59 on Mar 13, 2010 10:54:32 GMT
I'm in Australia. I have a 68 P5B coupe with a 3.9 motor. For some time it has occasionally shown very high oil pressure on the gauge, but usually only for a few minutes. I have been overseas for nearly a year and just started the car for the first time for a year. Now the oil pressure needle is as high as it can go and the oil pressure warning light is on. There is also a rattle from the top of the engine. Any advice as to what to do would be much appreciated!
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Post by Phil Nottingham on Mar 13, 2010 12:49:22 GMT
The V8 engine rarely suffers from high oil pressure.
Rattle on startup is common after standing but oil feed to rockers may be blocked or pump needs priming. Yous hould see oil oozing out of the rocker shafts when running. The rattle may take some time to disappear and should not return if all in order. But ensure oil and pressure does exist first first
Seriously blocked oilways may cause excessive pressure as could stuck pump relief valve.
However the standard oil gauge is never to be relied on -- substrute a known good one preferably the Bourden tube type.
The oil pressure switch is also likely to have failed - they are cheap and can be had from LR dealers so replace this too.
Is there much black/flaky sludge in the rocker boxes?
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mjb59
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Posts: 311
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Post by mjb59 on Mar 14, 2010 1:50:19 GMT
Thanks for your help Phil. I just changed the oil and filter but still the same problem - high pressure on gauge, oil light on and rattle from top end. I'm pretty new to the mechanical game, so this is the first time I've taken a rocker cover off.(Is there an easy way to get it out past all the other stuff above and around it?) Looking under the rocker cover I can't see any new oil appearing. The rocker area is very clean (recond. head and new short motor by previous owner 10,000 miles ago). So, high oil pressure, oil light on and looks like no oil appearing at top end. Where to now? If I need to take the oil pump out, what should I look for, and is it best to replace it with a new one? Also, can a relative novice replace an oil pump? My experience to date includes replacing the fuel pump and thermostat and a bit of tuning. What tool do you need to remove those bolts with the funny shaped endings on the pump? Very grateful for your advice! Michael.
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Post by Phil Nottingham on Mar 14, 2010 10:25:33 GMT
After removing the fixing screws the rocker covers can just be eased out of the way by removing air filter and carb inlet elbows but first you must replace the oilswitch to see if you really do have oil pressure. This just screws out of the side of the oil pump. There is not much point changing the pump at this stage - it may just be a sticking relief valve which is under a big nut on its side. the other big nut is filter bypass valve.
The rocker shafts just unbolt and then the oilway in each end of the head can be seen. This can be prodded out to clear it but its best to turn engine over on starter motor after removing the plugs to see if oil comes out - its very possible pump has lost its prime
The pump fixings are 8 point flats which a standard 8 point imperial socket will fit 5/16th AF- I think. Removal of cover allows pump geas to be removed. The garers and endfloat need checking for excess wear/scoring
It is just about a DIY job for inexperienced - it will then need priming by filling spaces with Petroleum Jelly (never grease) before bolting cap back on. There is plenty in SEARCH about this topic
If you intend working on these cars a factory WSM is essential though
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mjb59
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Posts: 311
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Post by mjb59 on Mar 14, 2010 13:39:26 GMT
Thanks again Phil. I'll replace the oil switch first and let you know. If it's a sticking relief valve, can I look at that without removing the pump? Will it be obvious that it's 'stuck' when I look at it? And can you buy replacement valves? Can a pump lose it's prime just by a long period of non-use? I do have a work manual but it's for the 3.5 not the 3.9. Much appreciate your advice.
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Post by Grimv8 on Mar 14, 2010 16:49:21 GMT
I read this cheat for priming the pump on another forum and the result came back good. hi mate, the pumps not primed,remove rocker cover,No1 pot No1 valve closed,take out the rock shaft retaning bolt then get a oil can(pump type) pump loads in as much as pos, replace bolt and cover,give it a go!!! Never heard this suggestion before but sounds an easy option
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Post by Phil Nottingham on Mar 14, 2010 18:57:41 GMT
These pumps do loose their prime after standing a long time especially if slightly worn - the valve can be removed in situ using an Eziout extractor after taking out spring but not sure how different the 3.9 is. If it comes out easily it was not stuck. Truning engine over on motor may shoot it out - remnove plugs
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mjb59
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Posts: 311
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Post by mjb59 on Mar 14, 2010 20:28:08 GMT
Thanks again. I'll replace the oil pressure switch and get back to you.
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Post by Warwick on Mar 14, 2010 23:47:12 GMT
I'd be giving the oil pump a good run using an electric drill before going to the trouble of removing the timing cover Michael.
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Post by enigmas on Mar 15, 2010 1:01:37 GMT
I'm with Warwick on this. Don't remove the pump. Remove the distributor and prime the pump with an electric drill and simple priming tool (Warwick can probably best explain this device)
You can tell when it is primed because you will feel and hear resistance in the system. If you have the rocker cover off one side you'll also see oil ooze out of the shafts.
The pump may have dropped prime because: A. You're using a thin synthetic oil. B. The pump and base plate were not properly setup (read too much clearance) when the 'modified' engine was done.
If you prime as above...you'll know lubricant is flowing to the vital components because you'll see it exiting the rocker gear.
** DO NOT RUN THE ENGINE WITHOUT OIL
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Post by enigmas on Mar 15, 2010 1:09:54 GMT
Here is the tool I use for priming the V8 oil pump. (No grease or vaseline involved...for adults only)
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mjb59
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Posts: 311
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Post by mjb59 on Mar 15, 2010 9:08:52 GMT
Very grateful for everyone's advice. I replaced the oil pressure switch today. Same result- oil pressure light on and pressure high on gauge. So now I have a spare oil pressure switch! I'm using 'Castrol GTX 20/50 for older engines', not a synthetic. Looks like the pump prime is next. To ask a stupid question, when I have designed a pump prime tool (which seems it can look like a screwdriver, a golf club shaft or an intimate part of a Dalek) do I need to still pack the pump with vaseline? Or will the drill do the job alone? Also (again, be gentle, I'm new to this) do you drill clockwise, counterclockwise or doesn't it matter? How long should the drill prime process take - seconds or minutes?
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Post by enigmas on Mar 15, 2010 11:15:25 GMT
It's quite straight forward and easy mjb59. Your using the correct weight for oil but take a look at the Oils ain't Oils thread for an insight into ZDDP (Penrite Classic Light lists this additive on their oil pack) roverp5.proboards.com/index.cgi?board=general31&action=display&thread=2579Remove the distributor and use the simple tool that Warwick has described. No you don't need any vaseline unless it makes you feel better (I'm sorry I couldn't restrain myself on that one) The beauty of this method is that you won't need to dismantle the pump or do anything else. Prime in the same rotational direction that the distributor rotor turns. It shouldn't take more than a minute probably much less. Remember your only spinning over the oil pump...nothing else. You simply engage the oil pump slot with the screw-driver end of the tool (that you've made following Warwick's instructions). You'll need an electric drill with some grunt. Don't use a cordless they don't spin fast enough. Hook the drill to the rod and secure firmly (you may want to square the end that fits into the drill chuck) Press the trigger...it will spin quite fast and free until it picks up the oil from the sump...and then you will feel a resistance (the drill will labour) as the oil is picked up and pumped through the galleys of the engine priming everything. Remove one rocker cover...you should see oil exiting the rocker gear when the engine is primed.
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mjb59
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Posts: 311
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Post by mjb59 on Mar 15, 2010 20:16:43 GMT
Thanks Enigmas. Do I need to take the plugs out whilst I'm priming? (and if so why?) I will take a walk to the garage and the ailing Rover now. I may be gone for some time..... I'm still new to this forum and not sure how it works. If I give an update on this in a day or two, do you guys automatically get a message to look at this thread? What I'm saying is, don't go away!
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Post by enigmas on Mar 15, 2010 21:53:07 GMT
No mjb59, the priming tool only spins over the oil pump...nothing else. ~ Vince
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Post by Phil Nottingham on Mar 15, 2010 23:05:17 GMT
There is no automatic reply nofication on this forum and not all unread threads are highlighted on the summary page once the first one is read
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Post by Warwick on Mar 15, 2010 23:24:00 GMT
Never fear Michael, because it's such a narrowly focused forum, there aren't that many new posts that it isn't hard to see what's new since last time you logged on. Also, there always seems to be someone who knows the answer to your question logging on not too long after you ask it.
It probably wouldn't hurt to give a brief description of why priming is necessary and how the pump works. I'll repeat this in Vince's other thread.
The pump is a basic gear pump. These have two messed gears that fit snugly side by side inside a chamber. One is attached to the drive shaft. As it spins it turns the one beside it.
As the gears spin, oil is drawn in and pushed around and out the other side by the teeth of the two gears, acting like paddle wheels on an old river steamer. If there was only one gear, the oil would simply be paddled around and around in a circle, with the teeth. But because there are two meshed gears they spin in opposite directions. The oil is paddled around by each gear but it can't complete the circle since its passage is blocked by the meshing teeth. i.e. No more gap between the paddles. So it has to leave the pump and more oil is drawn in on the suction side.
The problem is that this type of pump doesn't prime very well as it relies on the viscosity of the oil to seal all the points where air can leak past the gears. Once full of oil they work very well but they don't pump air very well so they have trouble drawing oil up from the sump when they are empty.
If you tried to fill the pump with oil before you installed it, it will have drained out again before you get the chance to start the engine. This is where the vaseline comes in. If you fill the pump with it, it stays there. When the engine startes and the pump starts spinning, it pumps out the vaseline and draws in the oil behind it. Filling the pump with vaseline if it is removed from the engine is still the best thing to do, but if it is still installed, it's inconvenient.
Using the drill method gets the pump running fast enough that it can pump enough air to draw up the oil and prime itself.
The reason you can't let the engine do the pump priming is that it doesn't spin fast enough to prime the pump quickly enough to lubricate the engine. Starting the engine with an empty pump will eventually prime the pump but the oil arrives too late to prevent engine damage.
Hope that makes sense.
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mjb59
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Posts: 311
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Post by mjb59 on Mar 16, 2010 1:06:17 GMT
Brilliantly clear explanation and thanks very much for it. I've had this car for 8 years and had to do very little with it as the previous owner had sorted it. I'm sure my confidence will improve the more I do, and I'm very grateful for the advice. I'm off to find an old screwdriver.
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Post by Warwick on Mar 16, 2010 3:41:21 GMT
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mjb59
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Posts: 311
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Post by mjb59 on Mar 16, 2010 10:19:06 GMT
Happy to give an intro when I'm able to drive it out of the garage and take some pictures. It's burgundy over silver birch WITH NO OIL PRESSURE...........I'll get back to you post pump prime.
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Post by David on Mar 16, 2010 10:46:44 GMT
If you 'Bookmark' a thread you will be notified of updates/replies. How do I bookmark a thread?Main page>>>Any board>>>Any thread. When you enter a thread, you should see a "BOOKMARK" button on the top and bottom of the thread. Click on that thread to bookmark. If you have done it correctly, the "REMOVE BOOKMARK" button will appear.
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Post by johnwp5bcoupe on Mar 16, 2010 11:17:01 GMT
Happy to give an intro when I'm able to drive it out of the garage and take some pictures. It's burgundy over silver birch WITH NO OIL PRESSURE...........I'll get back to you post pump prime. If you have a genuine 3.9 you wont need a screwdriver as it is a tang on the pump not a slot (slot is on the distributor)
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mjb59
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Posts: 311
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Post by mjb59 on Mar 16, 2010 20:17:38 GMT
Thanks John. I'm still to take the distributor out, maybe tonight, but I'm pretty sure it is a genuine 3.9 short motor. If the pump has a tang, not a slot, any idea what I would use to prime it? (I'm sort of disappointed - I've assembled all the stuff to make Warwick's beautifully simple pump primer!).
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Post by johnwp5bcoupe on Mar 16, 2010 21:04:22 GMT
I have a high volume pump on mine I used a long bolt and ground the head round then filed a slot in it to match the tang
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Post by Warwick on Mar 17, 2010 0:41:10 GMT
Aaaarrrggghhh!!!
Sorry Michael, I should read back through posts more carefully. I completely missed the bit about it being a 3.9. My apologies. I'd better go back and edit my earlier post so as not to also confuse those who come later.
That's 2 balls-ups in the one thread. I must be becoming feeble of mind. Must have been that last birthday which caused it. I've never tried the Bookmark button. I just assumed that it was like a browser bookmark and it made it easier to find particular threads later on.
John, Is the standard gauge happy reading the output from the sender on a 3.9?
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