John Morrison Posted October 18, 2023 Report Share Posted October 18, 2023 This was a scary moment. Run on Monday, car running very well indeed pressure 70 at 3000 revs. Watching the gauge it gradually starts to drop, over the space of a minute or so to 20/25 at said 3000 revs. Pulled over by which time the gauge was reading zero, absolutely zero! bonnet up no signs of issue and all the time the engine sounded lovely also displaying no issues, so having satisfied myself there was nothing wrong with the engine, sent off for the meet. Oil pressure immediately back to said 70 at 3000 revs, and behaved for all of the rest of the day another 130 miles or so, with no further problems. So, any thoughts I'm looking to look in the filter head? John. Quote Link to post Share on other sites
Lebro Posted October 18, 2023 Report Share Posted October 18, 2023 Something temporarily holding the pressure release valve off it's seat Blockage in the pressure gauge pipe ? Bob Quote Link to post Share on other sites
Motorsport Mickey Posted October 18, 2023 Report Share Posted October 18, 2023 Unless you know your pump rotor has been "pinned" beware this ..."That sounds like our old friend of a seized oil pump vane. Check the oil pump vane on strip down, there was a bunch that were "staked" rotor to shaft which after a while in use became loose causing the rotor to spin on the shaft giving low pressure and then an engine seizure. I always drill and pin (small dia c pin is fine) through the rotor into the shaft for safety." Maybe a loose rotor vane on the oil pumpshaft slipping and then grabbing the shaft again and giving oil pressure...until it finally breaks the grip and seizes. Unless you definitely find a culprit might be worth dropping the oil and sump and oil pump and stripping to check. Mick Richards Quote Link to post Share on other sites
RogerH Posted October 18, 2023 Report Share Posted October 18, 2023 4 minutes ago, Motorsport Mickey said: Unless you know your pump rotor has been "pinned" beware this ..."That sounds like our old friend of a seized oil pump vane. Check the oil pump vane on strip down, there was a bunch that were "staked" rotor to shaft which after a while in use became loose causing the rotor to spin on the shaft giving low pressure and then an engine seizure. I always drill and pin (small dia c pin is fine) through the rotor into the shaft for safety." Maybe a loose rotor vane on the oil pumpshaft slipping and then grabbing the shaft again and giving oil pressure...until it finally breaks the grip and seizes. Unless you definitely find a culprit might be worth dropping the oil and sump and oil pump and stripping to check. Mick Richards +1 Roger Quote Link to post Share on other sites
stuart Posted October 18, 2023 Report Share Posted October 18, 2023 39 minutes ago, Motorsport Mickey said: Unless you know your pump rotor has been "pinned" beware this ..."That sounds like our old friend of a seized oil pump vane. Check the oil pump vane on strip down, there was a bunch that were "staked" rotor to shaft which after a while in use became loose causing the rotor to spin on the shaft giving low pressure and then an engine seizure. I always drill and pin (small dia c pin is fine) through the rotor into the shaft for safety." Maybe a loose rotor vane on the oil pumpshaft slipping and then grabbing the shaft again and giving oil pressure...until it finally breaks the grip and seizes. Unless you definitely find a culprit might be worth dropping the oil and sump and oil pump and stripping to check. Mick Richards Definitely worth the check for the time it takes as opposed to an engine rebuild! Stuart. Quote Link to post Share on other sites
Lebro Posted October 18, 2023 Report Share Posted October 18, 2023 +1 Bob Quote Link to post Share on other sites
Michel Higuet Posted October 18, 2023 Report Share Posted October 18, 2023 Logically very few chance the problem come from gauge, on the contrary gave a big warning signal, idem the relief valve, more chance the oil pump vane on his rotor shaft. Didn't knew the security trick of the C pin. If you don't like an adventurous life you wouldn't own a TR... Quote Link to post Share on other sites
Andy Moltu Posted October 18, 2023 Report Share Posted October 18, 2023 I'd be tempted to fit a warning light so that if you don't happen to be looking at the oil gauge at the time problems occur. I would suspect the oil pump. Could be a sticky PRV. Could be a dicky gauge but I'd bet against it from your description. Quote Link to post Share on other sites
Hamish Posted October 18, 2023 Report Share Posted October 18, 2023 45 minutes ago, Andy Moltu said: I'd be tempted to fit a warning light so that if you don't happen to be looking at the oil gauge at the time problems occur. I would suspect the oil pump. Could be a sticky PRV. Could be a dicky gauge but I'd bet against it from your description. TRE do a sensor and adaptor that I use https://triumphspecialtuning.com/product/low-oil-pressure-warning-switch-kit-tr2-4a-and-morgan-4/ With this led light that is v bright and effective https://www.ebay.co.uk/itm/281825852424?mkcid=16&mkevt=1&mkrid=711-127632-2357-0&ssspo=XAy7lhFxQQK&sssrc=4429486&ssuid=33-Tg7STSaq&var=&widget_ver=artemis&media=COPY Quote Link to post Share on other sites
Andy Moltu Posted October 18, 2023 Report Share Posted October 18, 2023 I have the TRE adaptor and put a bright LED in the dash. Prompted by our former chairman who lives in the same village rooting his 4a engine when his oil pump failed after a chunk of metal jammed it and sheared the drive! Quote Link to post Share on other sites
John Morrison Posted October 19, 2023 Author Report Share Posted October 19, 2023 Update on this, Pulled the filter head, and the oil pump last night. Nothing in the oil pump, is pinned to the drive shaft and tolerances fine (Bearing in mind this delivering 70 at 3000 revs) Adjustable relief valve had a small piece of something, not metallic thank goodness, stripped. cleaned, i.e. washed in paraffin the whole of the filter head, all OK. Likewise filter and filter bowl. There was a wear hole in the gauze mesh on the oil pump, so I'll fit anew one of those then put her all back together with a new filter and oil change, Just have to see how it goes. Can't see any downside in also fitting a warning light, so will will likely incorporate over the winter. Thanks all. John. Quote Link to post Share on other sites
graeme Posted October 19, 2023 Report Share Posted October 19, 2023 John I experienced a similar problem with my 4A, when the pressure dropped suddenly several times during a long run. On investigation, I found what looked like copper wire in the relief valve. Cleaned it and everything was OK. When I eventually dropped the sump, I found the oil pump filter gauze to be damaged as you found, it has a copper finish, so it got replaced as I assumed it was a part of this which jammed the relief valve. No problems since(15 years). Cheers Graeme Quote Link to post Share on other sites
John Morrison Posted October 19, 2023 Author Report Share Posted October 19, 2023 That's my route Graham - thanks for the reassurance! Regards John. Quote Link to post Share on other sites
BlueTR3A-5EKT Posted October 19, 2023 Report Share Posted October 19, 2023 Yep had that “muckin the prv” situation. Oil pressure dropped to close on nothing at tickover with it being sensitive to revs. 20 psi at 3k dropping to virtually zero at tickover Strip and cleaned the ball and spring, that solved the issue. Quote Link to post Share on other sites
John Morrison Posted October 20, 2023 Author Report Share Posted October 20, 2023 Following on from putting the TR back together, just wandering, does anybody know what thread the oil gallery plugs are? Thinking of sorting an extra warning light. John. Quote Link to post Share on other sites
Andy Moltu Posted October 20, 2023 Report Share Posted October 20, 2023 (edited) I think they are 1/8 BSPT but don’t take that as gospel. The regular oil pressure gauges are 1/8-27 NTP again might be wrong. Hence the need for an adaptor. Edited October 20, 2023 by Andy Moltu Correction Quote Link to post Share on other sites
BlueTR3A-5EKT Posted October 20, 2023 Report Share Posted October 20, 2023 (edited) The cylinder block thread where the plug screws is not BSP. It is 3/8” UNC. The pressure switch could be anything including BSP Picture of mine Edited October 20, 2023 by BlueTR3A-5EKT Quote Link to post Share on other sites
Andy Moltu Posted October 20, 2023 Report Share Posted October 20, 2023 TRenterprizes sell the adaptor but I've never seen them elsewhere so the other option is to make our own. Quote Link to post Share on other sites
Hamish Posted October 20, 2023 Report Share Posted October 20, 2023 I would think ( if you had the Tools/skills) you could drill and tap an original bolt to take a pressure switch. i guess like peters Quote Link to post Share on other sites
BlueTR3A-5EKT Posted October 20, 2023 Report Share Posted October 20, 2023 2 minutes ago, Hamish said: I would think ( if you had the Tools/skills) you could drill and tap an original bolt to take a pressure switch. i guess like peters It is home made item from a length of hexagon bar not a drilled and tapped bolt. No doubt when my brother spots this post I will be making him 2 for Xmas along with TR2 door pull escutcheons in stainless. As stated earlier find the pressure switch and measure its thread before starting the job. From £6.00 https://www.carbuilder.com/uk/search?q=oil+pressure+switch OR Adjustable type £30 https://www.med-engineering.co.uk/products/oil-pressure-switch Quote Link to post Share on other sites
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