marki Posted December 31, 2015 Report Share Posted December 31, 2015 Afternoon. My oil pressure gauge reads about 8lb under and I want an accurate one. Does anybody know if the new ones from Moss etc are any good or of a retro electronic one ? I know I could just ignore it but it annoys me. Cheers Mark Quote Link to post Share on other sites
Stevecross Posted December 31, 2015 Report Share Posted December 31, 2015 HI Mark Just wondering how you know it is under reading by 8lbs. None of these gauges were IMO 100% accurate when they were made. As far as I am concerned as long as the gauge reads 0 when the engine is off ,goes up to an acceptable figure when started and drops a bit when hot it is doing it's job. The same as the fuel, temp & charge gauges. Don't know if the new Moss ones are good or not but there are lots of companies around that can recalibrate for you. I have used Speedy Cables in the past. Good product but don't really live up to the first part of their name! Cheers Steve Quote Link to post Share on other sites
marki Posted December 31, 2015 Author Report Share Posted December 31, 2015 Hi Steve. A friend owns a local garage and has a calibrated test kit and the Engine was tested on a Dyno run. My existing gauge was so called overhauled by The Gauge Shop, wouldn't bother with him again. Mark Quote Link to post Share on other sites
oldtuckunder Posted December 31, 2015 Report Share Posted December 31, 2015 Hi Steve. and the Engine was tested on a Dyno run. Where did they take the readings from? you will find different parts of the oil gallery are at fairly significantly different pressures (even on a new engine). Quote Link to post Share on other sites
marki Posted December 31, 2015 Author Report Share Posted December 31, 2015 Hi Last port on the right I think. Quote Link to post Share on other sites
oldtuckunder Posted December 31, 2015 Report Share Posted December 31, 2015 Hi Last port on the right I think. And where is your guage attached? Distributor pedestal? Quote Link to post Share on other sites
RogerH Posted December 31, 2015 Report Share Posted December 31, 2015 Hi Mark, I feel you are on a fruitless task. Even if you have the gauge re-calibrated how long will it remain in calibration. They are very crude instruments and age plays a big part. Assuming you get it to read correctly what will happen if it reads 8psi lower one day. Will that mean engine out and another rebuild. Nothing else on your car is calibrated or even remotely set to an exact value - it doesn't need it. You could get hold of a few used gauges and one may be better than the rest - but what does it prove. Roger Quote Link to post Share on other sites
marki Posted December 31, 2015 Author Report Share Posted December 31, 2015 Hi Roger. I know you're right and I should ignore the gauge, as all my friends have said. It would have been nice though. I was just wondering if the electronic ones are more accurate and no chance of nasty oil leaks in the cab. Mark. Quote Link to post Share on other sites
Stevecross Posted December 31, 2015 Report Share Posted December 31, 2015 Hi Mark If you are really concerned with accuracy then take your car to the garage who did the dyno. Get them to plug a certified pressure gauge into your cars normal oil pressure output and then compare the figures Don't know how many classics you run but the more you have the less you worry about the details. The "ain't broke so don't fix it" rule becomes more true the more of these old girls you run! Happy New Year Steve Quote Link to post Share on other sites
RogerH Posted December 31, 2015 Report Share Posted December 31, 2015 Hi Mark, leaking oil is a different problem. I'm sure the pipes have been known to come off or the internals to leak but it is very rare. There are electronic gauges out there not have not had one myself. Getting one to mimic the other gauges will be a challenge. Roger Quote Link to post Share on other sites
Graham Posted December 31, 2015 Report Share Posted December 31, 2015 Mark If accuracy is what you are after then ……..http://www.demon-tweeks.co.uk/motorsport/gauges-auxiliary/stack-pro-control-oil-pressure-gauge REALY expensive but had the kit in my race car and it is very good ATB Graham PS stuck the lenses in the dishwasher worked at treat ! Quote Link to post Share on other sites
Don H. Posted December 31, 2015 Report Share Posted December 31, 2015 Electronic oil pressure gauges are easily done. I've used VDO for cars in the past, with a simple dash gauge and a two-output sending unit (one on/off output for oil pressure warning light and the other variable for the gauge). Amazon has the VDO gauge alone for about $28. http://www.amazon.com/VDO-350104-Electrical-Pressure-Diameter/dp/B000CCDLEI But all of these gauges are "indicative", not "prescriptive". They'll give you information and YOU decide what to do with it. High precision just doesn't seem to be that important, especially since your dyno work has given you values you're happy with. You're mainly looking for a departure from normal, and it seems your current gauge would deliver this. I would fear an unending cycle of frustration trying to seek "perfection" in measurements. Where does it stop? Have you looked at your voltmeter, ammeter, speedometer, tachometer, fuel level, and so on for how precise THEY are? Quote Link to post Share on other sites
BlueTR3A-5EKT Posted December 31, 2015 Report Share Posted December 31, 2015 As an apprentice I spent some time in the calibration and standards dept. It was then I chose to check my TR2 oil pressure gauge and re-set its calibration if needed. It was not far wrong at 50 psi, not half a needle's width out. The man in charge thought it was about as good as it got for such a cheap construction and design of instrument. The tool used was a 'dead weight tester' Yours for about 1500 quid on ebay. I'd live with what you have - remember you are viewing the needle from one side and that may be distorting your observed reading. Cheers Peter W Quote Link to post Share on other sites
marki Posted December 31, 2015 Author Report Share Posted December 31, 2015 Hi All. I might try a cheap gauge and have a play, found this one... looks right. Hi Graham, pleased the lenses worked ok. Thanks for the replies, Mark. Quote Link to post Share on other sites
ianc Posted December 31, 2015 Report Share Posted December 31, 2015 Regardless of how the reading is indicated, by a pointer (as on the TR's gauge) or electronically, the device producing the necessary movement inside the gauge is almost certain to be the same, so you are no more likely to get an accurate reading with the electronic than with the old-fashioned gauge. That said, the old-fashioned gauge may have suffered wear in its moving parts, but whether that will be significant can only be proved by connecting to a dead weight tester, which is the device used when calibrating instruments for use in power stations, chemical plants and the like, where accuracy really does matter. As has been stated above, repeatability is far more important to the owner of a classic car. Ian Cornish Quote Link to post Share on other sites
stillp Posted December 31, 2015 Report Share Posted December 31, 2015 What are you going to do though, if the gauge reads say 5 psi under what you want? At what point are you going to decide the engine needs a rebuild? Think of it as an indicator, rather than a measuring instrument. Pete Quote Link to post Share on other sites
Paul Down Posted December 31, 2015 Report Share Posted December 31, 2015 In my experience the good old plumbing type oil pressure guages are a great deal more relable than electronic guages. On my TVR S3 the electronic sender was replaced three times due to oil leaks. A common problem. Quote Link to post Share on other sites
Drewmotty Posted January 1, 2016 Report Share Posted January 1, 2016 Automotive oil pressure gauges tend to be of the "no oil pressure, some oil pressure, loads of oil pressure" type and really that's all that you need as what we should be looking for is changes and trends rather than impirical values. Ultimately oil pressure is not a guide to lubrication as totally blocked galleries will give maximum oil pressure and zero lubrication. By the time the oil pressure is seen to drop off in normal driving the motor is already goosed. Quote Link to post Share on other sites
rogerguzzi Posted January 1, 2016 Report Share Posted January 1, 2016 (edited) Hello Mark You could use one of these as a test I think Accuracy Class 1.6% is close enough? = about 1psi at 70 psi http://www.ebay.co.uk/itm/63mm-DIAL-HYDRAULIC-GLYCERINE-FILLED-PRESSURE-GAUGES-HORIZONTAL-30-to-10-000-PSI-/131053837654?var=&hash=item1e836add56:m:ms2VU6yGjSDlclL-jLTcc-g Then you could worry yourself into an early grave? Roger Ps I bought a high pressure one to set the overdrive pressure on a J type Edited January 1, 2016 by rogerguzzi Quote Link to post Share on other sites
Tonyloz Posted January 2, 2016 Report Share Posted January 2, 2016 Hi Being a retired instrument engineer I've calibrated a few in my time! For what it's worth I'd use the gauge as a trend indicator if it starts to read different to the norm then I would investigate further If you must have an acurate reading then get it calibrated using a dead weight tester The mechanical gauges are easier to calibrate, the electric versions rely on a stable voltage supply Quote Link to post Share on other sites
peejay4A Posted January 2, 2016 Report Share Posted January 2, 2016 Me too Tony, a long time ago. Also of note is that calibration at one point isn't enough. The error on a bourdon gauge isn't going to be linear. That said I calibrated the voltmeter on Eric at the 12v position only but even that doesn't take into account ambient temperature. Quote Link to post Share on other sites
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