riverstar Posted June 2, 2017 Report Share Posted June 2, 2017 When I replaced my broken guage with a new one (not refurbished) it shows 50psi at 750rpm and about 90 at 3500rpm on a hot engine, I have tried adjusting this using the screw on the relief valve but nothing happens should I continue trying or just leave well alone. The engine was rebuilt a few thousand miles ago and the old guage showed 70-75 at 3500 before it broke Chris Quote Link to post Share on other sites
peejay4A Posted June 2, 2017 Report Share Posted June 2, 2017 Personally I wouldn't try to correct a different reading as a result of changing an instrument by altering the relief valve. All sorts of problems could ensue. Which instrument do you trust? Personally I'd live with it but you could ask Speedy Cables or John Ostick if they can calibrate. Quote Link to post Share on other sites
HSM Posted June 5, 2017 Report Share Posted June 5, 2017 Would recommend Budenberg Gauge Co. for any recalibration, still in business after many years . Harvey S. Maitland Quote Link to post Share on other sites
leishmanrobert@hotmail.com Posted June 21, 2017 Report Share Posted June 21, 2017 Hello, I have just read your request for help regarding the oil pressure issue. I have exactly the same issue with my 3A which also had an engine re-build 3,000 Miles ago. I have just completed 900 miles around North Wales and regularly had the taco reading 4,500 RPM in very hot weather. My oil pressure gauge ( direct feed ) reads 90 PSI and at hot tick over reads 40/50 PSI. Too high for my liking at both ends of the gauge. Just spoke to Geoff, Head of Tech at Moss Europe and he suggests backing it off as you have done. I will try this and see if their is a change. If not, he suggests removing it and checking the ball bearing that sits beneath the spring as this may be pitted and need replacing. Apparently this can be done in-situ without the need to remove the whole unit. Have you had any success since your posting ? Robert Leishman. Quote Link to post Share on other sites
Graham Harris Posted June 21, 2017 Report Share Posted June 21, 2017 If the ball bearing was pitted and not seating properly you would have less oil pressure not more? Quote Link to post Share on other sites
PYU940F Posted June 21, 2017 Report Share Posted June 21, 2017 Hi Was the oil pressure too high from immediately after the re-build or has it slowly/suddenly developed? I think it is a dangerous strategy to adjust the oil pressure down because if the main culprit is a dodgy gauge you could be running around with 70 on the gauge and the actual pressure be a lot less. If you have been operating at high RPM in hot weather the oil temp will be getting pretty hot (do you have an oil cooler?) If no cooler your oil temp after a hour or so a the RPM/ temp you mentioned will cause the temp to be up around 215-220 degrres F maybe even more. At that temp I very much doubt if a TR oil pump could even deliver 90PSI. As we all know TR trouble shooting is a question of trial and error and this is why forums as such as this are so useful. For my money I would first try a known serviceable gauge and replicate the driving conditions for a comparison, then when you can trust the integrity of the gauge you can start the serious fiddling. I hope the spirit of this forum will allow somebody to send you a known serviceable gauge in a jiffy bag on your promise of an immediate return after it has been used for diagnostic purposes. My 4A is off the road for another 7 days but I do not think my gauge will fit. Cheers Simon Quote Link to post Share on other sites
stuart Posted June 21, 2017 Report Share Posted June 21, 2017 Hi Was the oil pressure too high from immediately after the re-build or has it slowly/suddenly developed? I think it is a dangerous strategy to adjust the oil pressure down because if the main culprit is a dodgy gauge you could be running around with 70 on the gauge and the actual pressure be a lot less. If you have been operating at high RPM in hot weather the oil temp will be getting pretty hot (do you have an oil cooler?) If no cooler your oil temp after a hour or so a the RPM/ temp you mentioned will cause the temp to be up around 215-220 degrres F maybe even more. At that temp I very much doubt if a TR oil pump could even deliver 90PSI. As we all know TR trouble shooting is a question of trial and error and this is why forums as such as this are so useful. For my money I would first try a known serviceable gauge and replicate the driving conditions for a comparison, then when you can trust the integrity of the gauge you can start the serious fiddling. I hope the spirit of this forum will allow somebody to send you a known serviceable gauge in a jiffy bag on your promise of an immediate return after it has been used for diagnostic purposes. My 4A is off the road for another 7 days but I do not think my gauge will fit. Cheers Simon A TR4 oil pump is quite capable of delivering more than 90 PSI . Stuart. Quote Link to post Share on other sites
BrianC Posted June 21, 2017 Report Share Posted June 21, 2017 Why assume that the new gauge is faulty? Maybe the old gauge which gave the higher readings was at fault even before it broke. How did it break - gradual deterioration or sudden failure? Quote Link to post Share on other sites
PYU940F Posted June 21, 2017 Report Share Posted June 21, 2017 Stuart You are absolutely correct, what I should have said was it was unlikely for it to deliver 50 psi at idle when the oil was extremely hot Quote Link to post Share on other sites
riverstar Posted June 21, 2017 Author Report Share Posted June 21, 2017 I have now adjusted the pressure down successfully. My old gauge failed suddenly so when I fitted the new gauge (not reconditioned) I had assumed that the increase in indicated pressure was due to the old one under reading. I could of course be wrong, it has been known before Quote Link to post Share on other sites
PYU940F Posted June 22, 2017 Report Share Posted June 22, 2017 Chris So you have adjusted the pressure down on the new gauge but your previous reading on the old gauge was 70-75 at 3,500 rpm. That sounds about right. If the old gauge was reading correctly before it broke then what you have done is adjusted your oil pressure down too low and in my eyes looks like the new gauge is over reading. It may be of course that your old gauge was under reading until it failed and your new gauge is reading correctly. As I mentioned before until you put a gauge in that you KNOW is reading correctly you will not know which is correct. Are you in Chalfont or Phnom at the moment as I am very happy to wiz over this evening with my gauge to the former but the later could be a bit tricky Cheers Simon Quote Link to post Share on other sites
peejay4A Posted June 22, 2017 Report Share Posted June 22, 2017 ...the point I made in post #2. Quote Link to post Share on other sites
riverstar Posted June 23, 2017 Author Report Share Posted June 23, 2017 Simon, thanks for the offer unfortunately I am in Portugal at the moment Quote Link to post Share on other sites
Aldpilot Posted June 23, 2017 Report Share Posted June 23, 2017 +1 for John Ostick. Look at JDO instruments http://www.jdo1.com/other_services.html He has just done my speedo and he turns them around in days. OP gauge is £65 plus return postage, which you will need to get by contacting him as you are in Portugal. Mike Quote Link to post Share on other sites
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