Wild oil pressure readings

O.k . Removed and polished the plunger with fine grinding paste to within an inch of it's life , no finger prints left ( handy for a job i've got lined up for later :shock: :LOL: ) Put it back together and primed it up . Will see what happens with it tomorrow , got to do a few miles .
Didn't really see anything that should make it stick , there was a small machining ridge i could just about feel with a finger nail , got that out .
Other than what i've done already i can only think of a weaker spring or an adjustable relief valve . I have seen them on ebay for about 60 quid . If they make them their must be a reason ???
 
Hi Tim .
As i said i took the relief valve apart checked everything and polished the plunger . It still seems the same , o.k one minute high the next . I really don't trust the gauge / sender and will borrow a spare sender of a friend soon . Failing that a weaker spring ? Have had a bigger issue to deal with this week though ,
viewtopic.php?f=22&t=14501&start=0
:cry:
 
Would it be better to try an oil pressure guage that is connected to the engine by a pipe ?(what's the word I'm looking for ?)
 
Hi Stina, I've got a hydraulic oil pressure gauge (garage tool, not an instrument gauge one) here if you want to borrow it to check your oil pressure. Obviously you'll only be able to check it while stationary.
 
Hi Tony , How does that connect , and can you still leave the original connected whilst using your one to compare readings ?
If so i could get it hot , connect it up and see what they both read at around 3000 rpm !
Stina
 
Hi Stina. It just bolts in where the sender goes, unfortunately, but I''ve also got a remote splitter, but I'm not sure what adapters I've got, I'll have a look tomorrow. I reckon you could fit ditto where your oil warning light switch goes; I reckon it's in the same gallery, so would read the same pressure though.
 
Hi , i know Stan Vultsman has his capilary gauge plumbed into the oil warning light switch through a " T " piece so he keeps the warning light . So what you say would work assuming i can physically get it in the space available down there . I'd be really interested to know if the gauge in the car is at the cause of of the high readings before i take things any further .
Stina
 
From what I remember, there's more room around the switch than the pressure sender, so should work. I do have a splitter here, but I''ll have see if it'll work/fit. I'll suss it out tomorrow. If I haven't got an adapter for the splitter, it'll be a nonstarter. We'll see. I'll try it on mine tomorrow, as I'm quite keen to see how accurate my gauge is too.
 
Hi Stina. The news isn't terribly helpful I'm afraid. First off, I can't find my gauge, secondly, the splitter I have has completely the wrong thread, so I'm a bit stumped. My splitter is also one with 4 ports, 1 in, 3 out, with a blanking plug, and is quite big, so it's almost definite it won't fit in the space available when fitted up with the gauge & switch. Sorry about building your hopes up. :oops:
 
Hi Tony , no problem , i have a garage full of equipment like that :LOL: Been looking at oil pressure gauges on ebay , will try and rig one up permanent , need to find the right fittings to come out of the oil light switch .
Still have that mirror when you want it :D
Stina
 
Got a theory , Thinking a previous owner may of fitted an uprated spring to the relief valve , and i may of unintentionaly replaced it with a new uprated spring . The oil pump kit advises a new spring and plunger , Standard , I'm going round in circles trying to figure out what is going on , the motor always had high pressure at high rpm , suggesting someone had installed an uprated spring ! I have cut one down and stretched it to the same length , but before i give it a try does anyone have a nice old original standard one i can try ?
As in compare the length , pressure against a known standard one !
 
Hi Stina,

I would be laying the blame straight at the feet of the replacement sender. Unlike the original Smiths units, the replacements as I have mentioned on a number of occasions are very unreliable, sprurious readings are just part of their job description.

When I had the 4.6 installed the original Smiths sender was refitted, but it had started to give problems some years prior, pressure falling without reason and then returning. So I fitted over the coming months not one, nor two but three replacements, each being replaced under warranty. They all leaked oil at the metal / nylon interface and their readings were wild and totally inconsistant. Very fortunately I came accross a NOS Smiths unit, in its original green and white box from 1971. Upon fitting it all spurious readings ceased to be, and accuracy and consistancy remains.

Given that the likelyhood of finding another original Smiths sender is extremely remote indeed, your best bet is to either replace the sender and gauge with a suitable replacement or indeed supplement the existing gauge with such. Another alternative might be to try and find a second hand Smiths sender, it may well be old but you can be sure provided it is working it will provide more accurate readings than the modern replacement that you have now.

Ron.
 
Hi Guys .
Well i eventually got fed up with wondering what the hell the oil pressure was doing , it was starting to spoil the fun of driving , constantly watching the gauge and wondering if it really was that high and doing any damage . So i rigged up an old capillary gauge that was kicking around the garage and just wedged it in the glove box so i could compare it to the gauge in the dash .
The readings are similar up to about 45 psi then the dash one keeps climbing , showing that the relief valve , oil pump etc is working as it should .
I decided to mount a gauge permanently where only the driver can see it .
I found a couple of gauges in some auto jumble at a show last weekend for four quid ( i didn't want the water temp bit of the one i had ) and the amp one i just bought for the holder . Took the oil gauge apart and used the best glass , surround etc from the bits i had and mounted it in the car .
Few pics , probably in the wrong order :D
 

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Hi Stina,

As I mentioned to you in my previous post, the sender is the problem. Your photo confirms that you have the replacement sender fitted, which are entirely unreliable as I indicated. The confirmation is in the oil capillary gauge readings. The oil pressure relief valve only comes into play when the oil pressure reaches the maximum safe level, which should be close to 60psi. Its function is a direct consequence of the resistance to flow that the oil experiences from within the engine, and until that pressure is reached, the pressure relief valve does not move.

Ron.
 
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