|
|
Post by martiny on Nov 9, 2017 16:23:50 GMT
Yeah, I'm not clear on whether it's part of the oil pump assembly or not but somewhere just beyond the oil pump itself there's a spring loaded valve that just lets oil escape back into the sump if the pressure is too high. On cold starts when the pressure's near max I sometimes see the needle jump a little which I assume is the valve letting some oil go.
|
|
|
|
Post by wannabe on Nov 9, 2017 17:26:26 GMT
Yeah, I'm not clear on whether it's part of the oil pump assembly or not but somewhere just beyond the oil pump itself there's a spring loaded valve that just lets oil escape back into the sump if the pressure is too high. On cold starts when the pressure's near max I sometimes see the needle jump a little which I assume is the valve letting some oil go.
Ooh, interesting stuff, thank you 
There must be one of those 'exploded diagrams' on the internet somewhere that shows that - I will get trawling...
Mine is never near max so perhaps I shouldn't worry  lol
|
|
|
|
Post by wannabe on Nov 9, 2017 17:48:06 GMT
Ooh, ooh, found it!
It's here:
www.mellens.net/mazda/Mazda-Miata-1991-1993/1991_engine.pdf
in the Service Manuals on mellens:
www.mellens.net/mazda/Mazda-Miata-1991-1993/index.html
www.mellens.net/mazda/
Bottom of page 29 / top of page 30 says:
Figure 15, at the top of page 31, has the exploded view of the oil pump, showing the Pressure Relief Valve - it looks to me like it's just a cap on the end of a spring, which opens under pressure lol The text may say it's not adjustable but the Oil Pump Specifications table lists 'Pressure Spring Length' as 1.791in / 45.49mm, so it looks like (potentially) it may be possible to remove the sump and then clean/replace the spring. without removing the whole oil pump?? Bit of a mission, though... lol |
|
|
|
Post by wannabe on Nov 17, 2017 19:17:50 GMT
Gah, I swear my car is actually female - do the same thing on different days and get a completely different response...  lol Every day I've driven it recently, I've had that low oil pressure in the earlier pic on idle (c.800rpm). Today, same thing when I set off, maybe getting up to almost 3bar under load. I stopped for petrol and 10 minutes later I set off, at which point I was holding a firm 1bar on idle and reaching almost 4bar under load! WTF!! Just random... lol |
|
|
|
Post by atlex on Nov 17, 2017 21:53:45 GMT
wannabe - what oil are you running ? Those are decent pressures you're seeing, not terrible, not perfectly ideal. Have you considered doing an early oil service with some decent fully synth ?
|
|
|
|
Post by wannabe on Nov 18, 2017 23:04:34 GMT
wannabe - what oil are you running ? Those are decent pressures you're seeing, not terrible, not perfectly ideal. Have you considered doing an early oil service with some decent fully synth ? Asda Fully Synthetic 5W40  To be fair, it does need a change. I can't remember if it was last done for the MOT, as if not, it could be almost a year since a change! Finding the time to get to the garage is a PITA, but I should have the ability to use a driveway soon, rather than a car park, which will make things easier. It is probably pretty fresh in reality, though, given how much oil it drinks in normal use and how regularly I have to top it up lol I am ordering some Shell Helix fully synth 5W40 shortly, which I hope will make a difference! Thank you for the help |
|
|
|
Post by warpspeed on Mar 11, 2021 0:24:30 GMT
Its always a good idea to check the oil pressure gauge, and the way I do it is to connect it up to an air compressor.
It takes time for the compressor to build up pressure in the tank, and you can cut the power at any stage to maintain a steady reading on both your oil pressure gauge, and the pressure gauge on the compressor air tank.
If both read the same you can be pretty certain that all is well.
|
|
|
|
Post by dadbif on Mar 11, 2021 8:25:34 GMT
Nobody has mentioned the oil filter, if it gets clogged, most have a bypass in them ISTR, or used to, so your oil pressure will drop with an old filter and rise with a new one.
In days gone by, when cars had a pressure gauge as standard, I used to note when my oil pressure dropped during normal driving and do my oil and filter change accordingly.
On the level discussion, mine reads the same on the stick, I always fill so one side is just above max and the other side just below.
Seems to be the popular decision on most MX5/Miata forums.
|
|
|
|
Post by wannabe on Mar 13, 2021 21:06:01 GMT
Thread from the dead! lol The oil pressure issue ended up being an easy fix - the connector that slides onto the metal tab on the oil pressure sensor moves around, it seems, and when the connection is poor, the oil pressure gauge reads low Wiggle it a bit and make sure it's pushed on properly, bob's your uncle - decent pressure on the gauge (Well, 1-bar idle, 4-bar under load when stone cold.) |
|
|
|
Post by dadbif on Mar 13, 2021 22:11:35 GMT
Take the connector off, squeeze it slightly in a pair of pliers, refit it. No more loose connection.
|
|
|
|
Post by wannabe on Mar 14, 2021 1:09:29 GMT
Take the connector off, squeeze it slightly in a pair of pliers, refit it. No more loose connection crush it like a 2-year-old crushing Wotsits into their hand, swear profusely, order a new connector for a million pounds, bodge it into the system using a chocolate block and half a reel of electrical tape, wish once again that you were not a mechanical danger with tools. Edited for accuracy  |
|
|
|
Post by dadbif on Mar 14, 2021 8:18:50 GMT
It’s only a bloody Lucar connector !!! Don’t turn it into “head gasket 2, the nightmare continues”
😜😜
|
|
|
|
Post by Zed. on Mar 14, 2021 10:46:49 GMT
It’s only a bloody Lucar connector !!! Don’t turn it into “head gasket 2, the nightmare continues” 😜😜 one Common Denominator.....  Rich. |
|
|
|
Post by dadbif on Mar 14, 2021 21:33:06 GMT
I begin to worry about you...
|
|
|
|
Post by wannabe on Mar 18, 2021 22:51:32 GMT
You're only beginning to worry now? lol |
|
lol
lol 
le sigh