Another Oil Pressure Question

ChrisJC · Post by **ChrisJC** » Wed Jul 18, 2007 8:35 pm

I think Katanaman might be onto something. I would take the sump off and have a look at the pickup strainer. I have seen them just about 100% full of gunge, bits of instant gasket, sludge, swarf, you name it!

Chris.

Mike n Helen · Post by **Mike n Helen** » Sat Jul 21, 2007 8:17 pm

This afternoon I removed the input hose to my remote filter housing and poured some oill down the pipe. Removed the distributor and gave the pump a turn by hand using a home made priming tool. As soon as i did this oil came back out of the input pipe to the filter housing. I put the pipe back on and then did the electric drill thing to make sure the system was well primed. Checked on the oil pressure gauge and was getting about 1bar while doing this.

Put the distributor back and started the car, (note to myself, must ensure distributor goes back into orignal position otherwise car doesn't start properly

) straight up to 3 bar dropping to 1 bar after it had ran for a while, no top end knocking, great I thought.

Just been out to check it again, a few hours later, no oil pressure again, what's going on????? It's almost as if the system un-primes itself every time the car has been left standing. Has anybody else experienced this?

Mike n Helen

The Original Tom · Post by **The Original Tom** » Sat Jul 21, 2007 9:01 pm

Maybe your tea-strainer-block gasket is knackered?
The engine might run OK when it's just been primed, but over a period of rest then air can get into the system and 'un-prime' it.

Mike n Helen · Post by **Mike n Helen** » Sat Jul 21, 2007 9:09 pm

The Original Tom wrote:Maybe your tea-strainer-block gasket is knackered?
The engine might run OK when it's just been primed, but over a period of rest then air can get into the system and 'un-prime' it.

What's one of them and where can I find it??

Mike n Helen

The Original Tom · Post by **The Original Tom** » Sat Jul 21, 2007 9:28 pm

Inside the sump. The tea strainer is the slang for the oil pickup. It comes from the side of the block below the dipstick, and hangs into the oil. The end that is in the oil is covered in a fine wire mesh (good to clean it too as it'll be crapped up as mentioned before). The mesh looks a bit like an old tea-leaf strainer hence the name

The bit whre it mates to the block has a gasket - I also instant-gasketed mine to ensure a good seal. 2 bolts are only 10lb/ft IIRC.

Tom.

Mike n Helen · Post by **Mike n Helen** » Sun Jul 22, 2007 9:29 pm

Right, this morning having slept on this I tried the following. Before even turning the engine, I again disconnected the input pipe on my remote filter, removed the distributor and turned the oil pump drive with my home made priming tool. Within seconds of the drill turning the pump I had oil coming out of the pipe. This suggests the pump is still primed, so I reconnected the pipe and continued with the drill. Within a short period of time there was lots of oil pressure.

What this suggests to me is that the system itself is OK and it's the rate at which the oil is being pumped around the engine what is taking the time to fully pressurise when the engine is running. Is there such a thing as a high volume oil pump available, I've looked on a few website but can't see any??

Mike n Helen

Post by **katanaman** » Sun Jul 22, 2007 9:59 pm

the standard pump is a high volume pump but your barking up the wrong tree here. The point is that your having a problem that isn't normal therefore there is something wrong with your pump. You need to find what the problem is and fix it not go looking for some super duper high volume pump that still wont work because a 2p gasket is broken. The priming stick works better because it is spinning at much higher rpm than the pump would at idle or on the starter. This tends to bypass either air leaks or blockages that might be there.

Mike n Helen · Post by **Mike n Helen** » Mon Jul 23, 2007 9:07 pm

katanaman wrote: You need to find what the problem is and fix it not go looking for some super duper high volume pump that still wont work because a 2p gasket is broken. The priming stick works better because it is spinning at much higher rpm than the pump would at idle or on the starter. This tends to bypass either air leaks or blockages that might be there.

Are we talking oil pump gasket and/or sump to block gasket or are there others I should be considering??

Mike n Helen

Post by **katanaman** » Mon Jul 23, 2007 9:31 pm

the one that holds the strainer to the block and also a blocked strainer both are in the sump. Its unlikely to be a pump gasket as when you do get oil pressure it would leak out there. It could also be the front cover gasket but that's fairly unlikely.

Mike n Helen · Post by **Mike n Helen** » Thu Jul 26, 2007 5:46 pm

Had the car booked into the garage on Wednesday for a tune up, but after a discussion with the mechanic we both agreed it was a waste of time until I've got the oil pressure problem sorted. Left the car with them so they could have a look to see if they could see anything wrong.

They checked the oil pick up gasket on the bottom of the block, nothing wrong with that, but when they removed the remote filter houing off the pump they "found excessive wear on the gears and housings." I don't doubt for one minute what these guy's are telling me as I know they know what they're talking about, but I still can't understand why once the oil picked up everything ran OK if the gears and housing are so worn.

Anyway, I got them to put the car back together as I'm going to do the job myself, it looks like a new front cover, gears and housing are needed, can anybody recomend a good source??

Mike n Helen

IRG · Post by **IRG** » Fri Jul 27, 2007 9:29 am

Mike,

What age is your engine ………. Pre or post SD1 ?

If its pre SD1 then it will have an early lower volume pump ………… this can be upgraded to a high volume pump by the addition of an after market kit and / or booster plate. . Its easy to tell……….does the pump drive have a male of female the fits into the dizzy. Early pumps always had a drain back problem from new and were difficult to prime when worn.

If your engine is post SD1 then it already has the high volume pump (male drive main gear). It is very unusual for main housing to wear unless the engine has been very badly treated. More often than not the problem is with severe scoring on the pump cover and worn gears. The gear clearance between the tops of the gears and the cover is critical. When rebuilding these engines I always pay a lot of attention to the pump cover ………….. you can, if well practised and its quite a lot of effort ……….. resurface the cover using small sheet of plate glass and some 400 grade wet n dry lubed with paraffin. If the cover is really bad then a good machine shop will surface plane it for you, but only get them to take off enough to remove the score marks. I would expect, that work on the cover and replacement gears (cheap) will fix the problem. For more info on fixing the cover ……… see page 5, post 86 of my current rebuild here ….. http://forums.lr4x4.com/index.php?showtopic=14006&st=80

HTH

Ian

Paul B · Post by **Paul B** » Fri Jul 27, 2007 4:08 pm

Mike n Helen wrote:... I don't doubt for one minute what these guy's are telling me as I know they know what they're talking about, but I still can't understand why once the oil picked up everything ran OK if the gears and housing are so worn.....

As has been explained in several other posts about Rover oil pumps, the pump is above oil level, so it has to suck air first to suck oil up, so once it is 'wetted' with oil it has a perfect seal and pumps like a good 'un, but once the motor is turned off and the hot thin oil drains away, the pump has no seal. So, next time you come to start it there is no way the pump can suck air fast enough to get the oil up to itself again. Crap design.

You need a new pump if it is as bad as they say.

badger · Post by **badger** » Fri Jul 27, 2007 7:27 pm

Been following this thread - one thing I haven't seen mentioned so far is the oil filter itself. The filter should have a non-return valve built into it (on a std filter it's the rubber disc that sits underneath the row of inlet holes in the top surface of the filter), if this is either missing (due to an incorrect filter) or damaged in some way, then it will allow oil to drain back if there is the slightest wear in the pump/housing. It's very purpose in life is to prevent back-flow after shutdown.
I had this issue some years back with a rather potent 3.9 in a landrover, with a brand new timing cover, pump cover and gears. It was fine unless it sat for more than 2 or 3 weeks unused at which point it rattled the tappets like crazy for roughly 10 seconds after startup. It was traced to a bad batch of Perkins (!) filters that the MOD were using at the time, where the internal non-return valves weren't seating correctly. (Don't ask how I came by them.....!) It wasn't an issue for the MOD as they only had a handful of V8's and they never sat idle for more than 2 days at a time. I replaced the filter with a Unipart one and the problem vanished instantly.
Anyway, enough of my rambling, just thought I'd pass it on, maybe something worth checking?

Paul B · Post by **Paul B** » Sat Jul 28, 2007 1:06 pm

badger wrote:Been following this thread - one thing I haven't seen mentioned so far is the oil filter itself. The filter should have a non-return valve built into it (on a std filter it's the rubber disc that sits underneath the row of inlet holes in the top surface of the filter), if this is either missing (due to an incorrect filter) or damaged in some way, then it will allow oil to drain back if there is the slightest wear in the pump/housing. It's very purpose in life is to prevent back-flow after shutdown.
I had this issue some years back with a rather potent 3.9 in a landrover, with a brand new timing cover, pump cover and gears. It was fine unless it sat for more than 2 or 3 weeks unused at which point it rattled the tappets like crazy for roughly 10 seconds after startup. It was traced to a bad batch of Perkins (!) filters that the MOD were using at the time, where the internal non-return valves weren't seating correctly. (Don't ask how I came by them.....!) It wasn't an issue for the MOD as they only had a handful of V8's and they never sat idle for more than 2 days at a time. I replaced the filter with a Unipart one and the problem vanished instantly.
Anyway, enough of my rambling, just thought I'd pass it on, maybe something worth checking?

But that seal would be on the outlet side of the pump, wouldn't it, and would be to make the system 'pressure up' quicker once started?

If the pump is so worn that it can't get a seal then you'd have no oil to pressurise the system regardless how good the seal was on the filter.

Unless I am visualising the pump incorrectly. It is a couple of years since I had mine in bits.

I have a complete SD1 lump sat in the garage that I keep threatening to pull apart and have a good rummage around in. It was supposedly fully rebuilt but 'wouldn't start', so it sounds interesting already.

badger · Post by **badger** » Sat Jul 28, 2007 4:52 pm

Doesn't matter where in the line the NRV is, it will prevent oil drain-back through a worn pump!