Trumpy Posted December 30, 2022 Report Share Posted December 30, 2022 (edited) Hi folks while the car (Tr5) is confined to the garage I’m on a quest to find some extra oil pressure. Before I remove the sump to check the big end/main bearings I thought I’d have a look at the easiest parts . The PRV looks fairly worn along it’s stem (, I’m guessing it’s the original.) but I’m wondering if the sealing face will have bedded in and fitting a new one may make things worse? If indeed the valve is leaking! Anyone have any experience of the prv . Also , should it have the washer on the stem ? Thanks, Dave . Edited December 30, 2022 by Trumpy More info Quote Link to post Share on other sites
roy53 Posted December 30, 2022 Report Share Posted December 30, 2022 The washer is a trick to increase pressure I had high pressure and solved it by fitting a complete new setup I guess the spring became stiffer i would try a new one . Cheap fix if it works for you Roy Quote Link to post Share on other sites
john.r.davies Posted December 30, 2022 Report Share Posted December 30, 2022 I had exactly the same last winter with a rebuilt engine, trying it again and again with various mods, in the workshop. Eventually, took it out on the road and it stayed cooler oil pressure up! I have an electric fan, but maybe not enough without movement. John Quote Link to post Share on other sites
Trumpy Posted December 30, 2022 Author Report Share Posted December 30, 2022 I suspected the washer had been added to stiffen the spring . The hot engine has oil pressure within Triumph tolerances at 2000rpm and above but it drops a bit low at tickover when hot . The light doesn’t come on but the pressure switch is only 5psi . I guess Triumph consider any thing above this sufficient so mine at about 10psi would be ok , just about . I’ve still to check the gauge is accurate but the prv is so easy to check I thought I’d have a look . I see Rimmer’s have a new body and up-rated spring so I’ll try that first . D Quote Link to post Share on other sites
Waldi Posted December 31, 2022 Report Share Posted December 31, 2022 I replaced valve and spring; I “lapped” the new valve in, also radially, because its movement was not smooth in the bore. I re-used the body. No rings, as say above. Waldi Quote Link to post Share on other sites
Mike Collins Posted December 31, 2022 Report Share Posted December 31, 2022 That plunger shaft looks very worn to me, there are impressions of the spring coils and a ridge half way down. Can you feel the ridge with a fingernail? I would certainly replace it. Mike. Quote Link to post Share on other sites
Trumpy Posted December 31, 2022 Author Report Share Posted December 31, 2022 The ridge is machined onto the stem and the new valve stem is the same in that respect. The spring has worn the stem considerably though and a washer had been added . The wear on the stem probably makes no difference but Rimmer’s have a new uprated spring , valve and body for £25 so worth trying. Quote Link to post Share on other sites
Waldi Posted December 31, 2022 Report Share Posted December 31, 2022 What does “uprated” mean exactly? Quote Link to post Share on other sites
BlueTR3A-5EKT Posted December 31, 2022 Report Share Posted December 31, 2022 What oil are you using. Is it a quality 20/50? You will need to try the PRV first. Cost is under a tenner. Pt nos. 132107, 131535, 6K433 If that does not help it is sump off, check and repair or replace the oil pump. Check and replace if required big end bearings and main bearings. Do the thrust washers on the crank while you are in there too https://jamespaddock.co.uk/oil-pressure-relief-valve-3 Quote Link to post Share on other sites
roy53 Posted December 31, 2022 Report Share Posted December 31, 2022 2 hours ago, Trumpy said: The ridge is machined onto the stem and the new valve stem is the same in that respect. The spring has worn the stem considerably though and a washer had been added . The wear on the stem probably makes no difference but Rimmer’s have a new uprated spring , valve and body for £25 so worth trying. The stem has no ridges Quote Link to post Share on other sites
stillp Posted December 31, 2022 Report Share Posted December 31, 2022 1 hour ago, Waldi said: What does “uprated” mean exactly? About 20% added to the price, usually. Pete Quote Link to post Share on other sites
John L Posted December 31, 2022 Report Share Posted December 31, 2022 The adjusting washer on the valve looks like the hole in it doesn't match the radius on the stem, the spring may be holding the valve at an angle perhaps, I guess it should sit flat to the valve head? I have been having lower oil pressure when hot, so have increased the pressure a little more with a washer on the valve. the new valve I got was slightly smaller in diameter to the original on the head, but the seat in block looks fine. John Quote Link to post Share on other sites
Trumpy Posted December 31, 2022 Author Report Share Posted December 31, 2022 Hi all , many thanks for the replies. uprated spring is stiffer ( and twice the price) but both together cost less than a decent pint so no worries. both the old valve and new valve stems have a slight ridge, Maybe both pattern parts ? The new valve felt to mate firmly to the internal Seat and pulled away with an audible ‘pop’ so hopefully seals well . The old spring has compressed shorter than the new one by about the width of the washer (as shown in pics) . I have left that off . Took the car out for a run to warm the oil and then left it ticking over for 20m in the garage and turned the fan stat up to 100* . I think it was up to full summer running temp and the pr gauge shows a definite improvement with 50psi at 2000rpm and high teens at tick over . This hopefully means the old valve wasn’t seating properly and reducing pressure through leakage. I’m running 20-60 penrite oil btw . Quote Link to post Share on other sites
Z320 Posted December 31, 2022 Report Share Posted December 31, 2022 In my opinion the oil pressure follows this: hot it is according to the hydraulic resistance / quality of the engines oil system, cold it is limited by this release valve, this opens a bypass, it is the higher resistance. If your engine suffers from low oil pressure it should not be possible to lift it by adjusting (possible on the 4 cylinder TRs) this „limitation“ valve. But last summer this happened to me: after long distance driving on the Autobahn with 100-130 km/h suddenly the pressure dropped down from usually 5 to 2 bar! On the remaining 40 km home on country roads it was on 1-2 bar, no problem at all, but scary anyway! A test drive next day was same-same. So I took the valve out, had a close look on everything, cleaned it and found nothing suspicious, held it against the sun, let it over night out at full moon, shaked it with my right hand over my left shoulder, and with the left hand over the right. Fitted it back the way I put it out - and the pressure is up to 5 bar again since then. I have no explanation, but it could be good to put the valve out to clean it Quote Link to post Share on other sites
ianc Posted January 1, 2023 Report Share Posted January 1, 2023 Z320: I had always thought that Germans were very logical and down-to-earth people, so am intrigued by your regime for fixing problems. Please can you give us the magic words (presumably in German, but a version in English would be helpful) which must be recited when the object is held against the sun, left out overnight at full moon, then shaken with the right hand over the left shoulder, and with the left hand over the right. Ian Cornish Quote Link to post Share on other sites
Bfg Posted January 1, 2023 Report Share Posted January 1, 2023 Quote Link to post Share on other sites
Andy Moltu Posted January 1, 2023 Report Share Posted January 1, 2023 Unless the valve is worn and or sticking or the spring soft it should not cause low oil pressure. Clean the bore it runs in and replace the valve and spring. Don’t fit an uprated spring as increasing pressure beyond a certain point won’t improve lubrication. How long is it since the engine was rebuilt? The low pressure may just reflect wear. If it is relatively newly built, was the oil pump replaced as there are a number of repro ones that were supplied out of tolerance and simply won’t pump enough to maintain pressure when the engine is hot. If the PRV proves not to be the cause things to check include: Check the gauge. Take the rocker cover off and check the grub screw is in place. They can work loose and come out. Take the sump off, inspect the pump and bearing shells. If worn but the crank journals look ok you can replace them. (Probably worth doing even if the shells are not not worn as tri-metal bearings are available again) Quote Link to post Share on other sites
boxofbits Posted January 1, 2023 Report Share Posted January 1, 2023 2 hours ago, ianc said: Z320: I had always thought that Germans were very logical and down-to-earth people, so am intrigued by your regime for fixing problems. Please can you give us the magic words (presumably in German, but a version in English would be helpful) which must be recited when the object is held against the sun, left out overnight at full moon, then shaken with the right hand over the left shoulder, and with the left hand over the right. Ian Cornish I think the magic words might be to ‘ do the Hokey Cokey’ (if only I’d had a relief valve at that New Year party last night…) Quote Link to post Share on other sites
Z320 Posted January 1, 2023 Report Share Posted January 1, 2023 My mantra was: “itcantworkbuthopefullyitwill-itcantworkbuthooefullyitwill“ 2 reasons why I did it against my own logic: - the pressure dropped at once while it was always good in any case - it was the most simple possible thing to do Quote Link to post Share on other sites
Trumpy Posted January 1, 2023 Author Report Share Posted January 1, 2023 Update! Took the car out for a decent 50 mile run today, all seemed fine but as the oil temp increased the pressure gains I thought I had achieved disappeared . So back to square one ! Next step I suppose is sump off and check pump and bearings . Whats this grub screw mentioned by Andy Moltu ? I’ve owned the car for 2 1/2 years and 2500miles . It supposedly had new mains and a new pump shortly before then , receipts back this up . Not big end bearings though. Or maybe I should just wait for the next full moon . Quote Link to post Share on other sites
BlueTR3A-5EKT Posted January 1, 2023 Report Share Posted January 1, 2023 (edited) It is the cross headed screw seen here in the rear rocker shaft pedestal. Locates the rockers shaft to the pedestal and if loose or missing allows oil to !P! Out Edited January 1, 2023 by BlueTR3A-5EKT Quote Link to post Share on other sites
Trumpy Posted January 1, 2023 Author Report Share Posted January 1, 2023 Thanks , I’ll check it out first . Quote Link to post Share on other sites
Waldi Posted January 2, 2023 Report Share Posted January 2, 2023 Before you dismantle the engine I would check the oil pressure with a known good gauge. Waldi Quote Link to post Share on other sites
Ralph Whitaker Posted January 2, 2023 Report Share Posted January 2, 2023 12 hours ago, Trumpy said: Thanks , I’ll check it out first . Whilst you are in there checking the cross head screw check for play in the rocker shaft itself. They are often neglected and if worn can allow a surprising amount of pressure loss, especially on tickover, as your oil pump has a lot to do in a six cylinder engine. Also what is your tick over rpm, a six will idle quite happily at very low revs and it may be below the reccomended idle speed. Ralph Quote Link to post Share on other sites
Tim D. Posted January 2, 2023 Report Share Posted January 2, 2023 Is the rocker shaft really an issue with oil pressure as it has a metered dose from the machined flat on the camshaft. And at best is just a dribble feed. Tim Quote Link to post Share on other sites
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