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| Oil pressure drop https://www.ausmini.com/forums/viewtopic.php?f=2&t=80568 |
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| Author: | MattE [ Mon Mar 04, 2013 4:13 pm ] |
| Post subject: | Oil pressure drop |
Hi all, I've recently put my car on the road, which has a Metro 1275 turbo lump in it. Until now it's behaved well (I haven't split it off the gearbox). I believe it's a 1989 engine, and I got it in 1995, so has had 6 or less years on the road - could be quite good inside, but who knows!). Anyway until now oil pressure has been very good - 50-75psi, and not much less at idle. But today, didn't really want to do more than about 45psi, and 5-8psi at idle. Came home and checked the pressure relief - ball fitted, and rolled out into my hand - so that looks fine. Also dropped the oil, so I could check the sump plug magnet - usual collection of fine particles, and the oil is only 200-300kms old. Any ideas? Has there been a sudden internal failing of bearings/pump etc? Should I suspect the gauge (usual Smiths 0-100psi mechanical)? Perhaps the strainer has picked up just a touch too much crap? Is it worth pulling out the oil pickup pipe magnet (has been modded to accept a sump plug) to see if there is a lot of crap on it? Not an easy job, but may be worth the angst. Thanks in advance for ideas & opinions. Matt |
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| Author: | Lillee [ Mon Mar 04, 2013 4:26 pm ] |
| Post subject: | |
What brand oil? El Cheapo Castrol GTX2 used to do that to my old 1100 engine, whereas Castrol Edge 25W50 wouldn't. |
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| Author: | MattE [ Mon Mar 04, 2013 4:36 pm ] |
| Post subject: | |
I think it was Penrite, but can't recall what grade. That oil was about 3 years old, but I was holding off a little on the oil change, as it's only done those few k's - 200-300, and all in the last six or eight weeks. I'm going to put some Castrol GTX in tomorrow at this stage. Could it really just be about the oil? (That'd be nice!) |
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| Author: | Kennomini [ Mon Mar 04, 2013 4:46 pm ] |
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I doubt the oil would cause that unless it's a really thin oil (by mistake). My guess...If the engine hasn't been used for ages the oil may have gunked up in the sump then picked up into and partly blocked the pickup or something else in the oil feed system. Or maybe spun a main bearing blocking the oil path  .
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| Author: | MattE [ Mon Mar 04, 2013 4:56 pm ] |
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Thanks Kenno. Who knows what kind of crap could be lurking in the sump. Or perhaps was lurking in the sump. Would a bearing failure be immediately apparent? It's still driving quite nicely. I wonder if yesterdays blat at freeway speed is related? On the bright side, if it is internals, I get to see it all and make it good again. Just wasn't going to do serious work yet! Matt |
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| Author: | Convertible Mini [ Mon Mar 04, 2013 4:58 pm ] |
| Post subject: | Oil pressure. |
Before you start getting things and ideas put in your head why don't you just get someone who can screw in an oil master gauge in to the block Oil gallery and check the pressure on a known good gauge. Might be nothing but crook oil. |
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| Author: | drmini in aust [ Mon Mar 04, 2013 6:12 pm ] |
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Read my thread in how-to forum. This is a common problem with this mod. http://www.ausmini.com/forums/viewtopic.php?t=58088 If you run the ball and spring with nothing inside it the spring can bend & flick the ball sideways, and oil pressure drops as you found. Solution: cut a bit of 5/16" diameter steel rod 40mm long. Deburr the corners and put it inside the spring. Also check the spring is straight. If not buy a new one. I have 2 motors running with this mod and have done a dozen others. |
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| Author: | MattE [ Mon Mar 04, 2013 6:45 pm ] |
| Post subject: | |
Thanks a lot Doc. I'll definitely do this before anything else. Great stuff. Will let you all know how it goes. Cheers. |
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| Author: | phillb [ Mon Mar 04, 2013 9:28 pm ] |
| Post subject: | Re: Oil pressure drop |
MattE wrote: Should I suspect the gauge (usual Smiths 0-100psi mechanical)? Perhaps the strainer has picked up just a touch too much crap?
It might be worth ruling out. My gauge went low one time and that's what it was. I cleaned the tiny filter at the back of the gauge and it was all good. In fact the gauge was more responsive and reactive afterward. |
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| Author: | Lillee [ Mon Mar 04, 2013 10:10 pm ] |
| Post subject: | |
Oil change intervals are mileage based and time based. If its more than 6mths old, it needs a change |
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| Author: | drmini in aust [ Tue Mar 05, 2013 7:16 am ] |
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Lillee wrote: Oil change intervals are mileage based and time based. If its more than 6mths old, it needs a change
Don't believe this marketing BS hype by Toyota, Subaru et al. They make their $$$ by overservicing. Many cars have 12 month change intervals... and years ago, oil changes were just mileage based. |
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| Author: | Lillee [ Tue Mar 05, 2013 8:43 am ] |
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I was told that new oils are alkaline so that when they are run and slowly turn acidic it balances out. But if you don't run the oil and it sits there the alkalinity or for that matter (acidity after use) starts to eat seals and gaskets? Maybe old wives tale? Anyway at $24 a change (or $20 oil only), it worth doing at least 6 mths to save a $$$$ engine? or worth risking it to save $24? False economy... |
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| Author: | drmini in aust [ Tue Mar 05, 2013 9:18 am ] |
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Lillee wrote: I was told that new oils are alkaline so that when they are run and slowly turn acidic it balances out. But if you don't run the oil and it sits there the alkalinity or for that matter (acidity after use) starts to eat seals and gaskets?
Maybe old wives tale? Anyway at $24 a change (or $20 oil only), it worth doing at least 6 mths to save a $$$$ engine? or worth risking it to save $24? False economy... Do cans of oil have a use by date? No? I didn't think so... If you hardly use your car (which applies now to you and me) the oil will take yonks to get dirty. If it looks nearly clean, why change it unnecessarily. Even after 1500 miles (12 months for me) the oil isn't black. But I change it then. I reckon 6 months is overkill if you are just changing it on a time basis, OK if you have run a lot of miles up and it's due for that reason. The same marketing BS applies to timing belts (which don't usually snap btw, the teeth rip out when their polyester coating is worn through). Due to wear ie mileage, not time. I know this well, I used to have Fiat twincams... 
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| Author: | Lillee [ Tue Mar 05, 2013 9:34 am ] |
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lol ok, I just feel the need to change it because it "feels" dirty not to 
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| Author: | Panthersteve [ Tue Mar 05, 2013 9:53 am ] |
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drmini in aust wrote: Lillee wrote: I was told that new oils are alkaline so that when they are run and slowly turn acidic it balances out. But if you don't run the oil and it sits there the alkalinity or for that matter (acidity after use) starts to eat seals and gaskets? Maybe old wives tale? Anyway at $24 a change (or $20 oil only), it worth doing at least 6 mths to save a $$$$ engine? or worth risking it to save $24? False economy... Do cans of oil have a use by date? No? I didn't think so... Why don't you read the post and comment on that  Lillee never said it had a use by date, he said he had heard that if not used much the alkalinity of the oil affects things whereas if the vehicle is used more the alkalinity lessens as the engine produces acidic by products in the oil.
I don't know if this is crap or not but your answer did nothing to help understand if it is true or not 
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