Poor oil pressure ?
- Thread starter stealthyflatfish
- Start date
stealthyflatfish
Well-known user
Awaiting new filter Ross, B4 I run it again just incase that's the problem.
stealthyflatfish
Well-known user
The mystery continues, new filter fitted, AC Delco oil topped up.
Pressure sits at 35psi hot or cold idle or 3000 rpm ?
Pressure sits at 35psi hot or cold idle or 3000 rpm ?
stealthyflatfish
Well-known user
Guage goes back to zero when you switch engine off.
Chuffer
CCCUK Member
If its electric as opposed to caterpillary ( 
) it sounds like a gauge problem to me . Any chance you can borrow a remote gauge from somewhere to test your pressure sender unit with the engine running to get a real time read out of what`s going on . When I had a permanent 35 psi reading on mine , my race car buddy loaned me his remote gauge with a universal adaptor that allowed me to unscrew my connection to the sender , fit the remote and gauge hey presto ! correct GM pressure readings , That proved the sender was duff and not the gauge . Far less hassle than having the instrument panel apart
) it sounds like a gauge problem to me . Any chance you can borrow a remote gauge from somewhere to test your pressure sender unit with the engine running to get a real time read out of what`s going on . When I had a permanent 35 psi reading on mine , my race car buddy loaned me his remote gauge with a universal adaptor that allowed me to unscrew my connection to the sender , fit the remote and gauge hey presto ! correct GM pressure readings , That proved the sender was duff and not the gauge . Far less hassle than having the instrument panel apart 
johng
CCCUK Member
I have an old Smiths capillary type oil pressure gauge that you can have if you like, to check if the problem is the gauge or in your engine (can't guarantee it still works though, must be 40 years old!). Alternatively you can buy an electric type gauge with sensor for £20 on ebay, plus you might need a thread adapter to fit it in your block
Emc
Supporting vendor
Put a good extenal gauge off the block directly, that will give a correct reading, if this gives a higer pressure then 90% its the gauge.
Inside the factory gauge is a very fine copper coil which expands under pressure, however on cars that have stood the pivots inside clog up stopping free movement, the gauge can be disassembled and all the pivot points carefully cleaned to restore totally free movement . I have had to do this many times .
Inside the factory gauge is a very fine copper coil which expands under pressure, however on cars that have stood the pivots inside clog up stopping free movement, the gauge can be disassembled and all the pivot points carefully cleaned to restore totally free movement . I have had to do this many times .
stealthyflatfish
Well-known user
Thanks for the offer Johng, I'll sort something this end, I used to have a couple of oil gauges for work, unfortunately all that kit went back when I packed in. Typical.
Roscobbc
Moderator
? - What Can Happen to an Oil Filter When the Pressure Relief Valve Fails? -
? - Diagnosing a High Mileage Oil Pump
Puzzling isn't it? - when I installed my 'new' engine (albeit 10 years ago or so now) it had quite high oil pressure from day one. 'Off the scale' when cold, generally showing in excess of 80 lbs running and 50 lbs + at idle. No 1 big end journal eventually failed and broke-up in to multiple pieces. Oil pressure was still good however. Engine oiling priority means that the front main bearing is the very last to receives its oil supply. No. 1 crankshaft journal is second on the list. Hence why there wasn't a clue from the pressure gauge showing reduced oil pressure. The engine 'knocking' wasn't audible ay idle, and although the 'knock' could be clearly heard when revving it diodn't really gibe a clue to how bad no. 1 big end actually was - 30 thou + clearance. Have to say I'd be rather inclined to 'pull' the oil pan and do a visual inspection - try seeing if there is any excess movement on the 'rods - perhaps replace oil pump with another high volumne Melling item as a matter of course?
? - Diagnosing a High Mileage Oil Pump
Puzzling isn't it? - when I installed my 'new' engine (albeit 10 years ago or so now) it had quite high oil pressure from day one. 'Off the scale' when cold, generally showing in excess of 80 lbs running and 50 lbs + at idle. No 1 big end journal eventually failed and broke-up in to multiple pieces. Oil pressure was still good however. Engine oiling priority means that the front main bearing is the very last to receives its oil supply. No. 1 crankshaft journal is second on the list. Hence why there wasn't a clue from the pressure gauge showing reduced oil pressure. The engine 'knocking' wasn't audible ay idle, and although the 'knock' could be clearly heard when revving it diodn't really gibe a clue to how bad no. 1 big end actually was - 30 thou + clearance. Have to say I'd be rather inclined to 'pull' the oil pan and do a visual inspection - try seeing if there is any excess movement on the 'rods - perhaps replace oil pump with another high volumne Melling item as a matter of course?
stealthyflatfish
Well-known user
Any one know how to get a new oil strainer on a new oil pump, been struggling all morning, I know there supposed to be a tight fit but ridiculously difficult, any cheats ?
Roscobbc
Moderator
Are you talking about the 'pick-up' tube with the 'strainer'/gauze on the underside? - if so it 100% has to be a tight fit in the oil pump. It also need checking for its position in relation to the base of the oil pan. Too close and there is a risk of oil starvation - too far away and the same thing applies if running with a low oil level and corning hard.
The supplied pick-up tube was fractionally too large for the Melling oil pump I used - thats OK - simply use a flat file to remove some of the metal around the circumference of the pick-up tube where it goes in to the oil pump (until it fits). It should be welded in place to be 100% its 'air-tight' and it doesn't fall opff in use (it happens!)
stealthyflatfish
Well-known user
Ok guys, got the oil pick up/ strainer in, there's a video on YouTube from Melling explaining how to get it in.
It explains it's an interference fit and yes you do require a ( special tool suprise suprise ) but I used a plumber's spring loaded tap spanner with a jubilee clip around the jaws to stop them prying apart, then hammered it in resting the pump on a wooden block on the floor, ( two man job ) but it worked, video says not in a vice, no no no. It does leave a few dig marks on the soft pick up tube , but the pump that came out also had similar marks. If you are really picky you could grind the knerling off the tap spanner jaws so it's perfectly round.
While on the subject in answer to the earlier question of oil pump shaft movement looking down the distributor tube, yes there is horizontal movement on the shaft this is because it's a two piece shaft joined by a plastic joint in the middle so it has a certain amount of slop in it. and doesn't mean the oil pump or shaft is knackered. Hope this helps somebody else out with the same questions, right I'm of to tack pick up tube on, then check clearance to oil pan, with the help of some play doe.
It explains it's an interference fit and yes you do require a ( special tool suprise suprise ) but I used a plumber's spring loaded tap spanner with a jubilee clip around the jaws to stop them prying apart, then hammered it in resting the pump on a wooden block on the floor, ( two man job ) but it worked, video says not in a vice, no no no. It does leave a few dig marks on the soft pick up tube , but the pump that came out also had similar marks. If you are really picky you could grind the knerling off the tap spanner jaws so it's perfectly round.
While on the subject in answer to the earlier question of oil pump shaft movement looking down the distributor tube, yes there is horizontal movement on the shaft this is because it's a two piece shaft joined by a plastic joint in the middle so it has a certain amount of slop in it. and doesn't mean the oil pump or shaft is knackered. Hope this helps somebody else out with the same questions, right I'm of to tack pick up tube on, then check clearance to oil pan, with the help of some play doe.