Prospect Posted July 8, 2014 Report Share Posted July 8, 2014 Took Ruby (1966 TR4a with overdrive) down to Classic Le Mans via Tunnel. Car was not using oil previously (less than 1 litre in 500-1,000 miles only filled to 2/3 of the way up dipstick)) although never run at sustained speeds for more than 40-50 miles. On the trip to Le Mans (home to Le Mans 350 miles) running at around 3,000 RPM in very hot weather (26-28 degrees C) used 3 litres on the way down. No sign of blue smoke or excessive oil around block exhaust very dark grey, no oil on plugs - dark grey or usual suspects. On the way back with similar driving topping up every 100 miles used 3 litres again. Oil pressure behaviour only really noticed on the way back very weird, at 3,000 RPM showing 55 PSI, tick over (900 RPM) 30 PSI BUT on over run from 3,000 RPM goes up to 80 PSI ! Help for numpty please, any ideas or advice as to reason for sudden quantity of oil used and any thoughts on why oil pressure rising dramatically on the over run from higher revs. Are they associated and a clue to oil loss? Quote Link to post Share on other sites
Paul Harvey Posted July 8, 2014 Report Share Posted July 8, 2014 80 psi could blow oil through the crankcase breather and you wouldn't know anything about it. You should adjust the oil pressure relief valve to trigger at 60 psi which is a safety device This is simple job and you can get replacement spring and ball bearing for the valve if you have any doubts (they can wear leading to the symptoms you describe) Quote Link to post Share on other sites
peejay4A Posted July 8, 2014 Report Share Posted July 8, 2014 I wondered about the breather but as it's a 4A it would normally have a PCV valve and a blanked off crankcase vent. I did away with the PCV on mine and fitted the old style snorkel. I don't notice any difference in oil consumption between pootling and fast motorway cruising. I wonder if the overrun effect is due to surging. Is your dipstick too long and telling lies about the real oil level? Quote Link to post Share on other sites
Paul Harvey Posted July 8, 2014 Report Share Posted July 8, 2014 Irrespective of the breather arrangements, the oil pressure will never rise above 60psi if the OPRV is set correctly. It is such a simple and satisfying job to do I don't understand why people ignore it. After I did mine you can actually see a flicker on the oil pressure gauge as the valve kicks in and out at 60psi on start up (when the oil is cold.) Quote Link to post Share on other sites
BlueTR3A-5EKT Posted July 8, 2014 Report Share Posted July 8, 2014 (edited) From Standard Triumph Service Bulletin April 1954. The solution was an extended breather pipe. (if any one knows how to cut and paste a pdf on a pc let me know and I will place the picture from the bulletin - Doddle to do on a Mac with 'GRAB') SPORTS/2/B EXCESSIVE LOSS OF OIL FROM THE CRANCASE Date APRIL 1954 BREATHER PIPE It has been found that under sustained top speed condition that the oil splash in certain engines allows considerable loss of oil through the crankcase breather pipe, Part No. 201650. The crankcase was modified at Commission No. TS.972E. to incorporate in the casting a baffle to shield the breather pipe aperture. A new breather pipe, Part No. 202126., must be used with the modified crankcase. To deal with complaints of excessive loss of oil at this point, with cars prior to the Commission Number quoted, the end shield shown in the illustration can be quite easily fabricated and fitted. NOTE: These instructions are for information only and do not constitute an authority to carry out modifications at the expense of The Standard Motor Company Limited. Edited July 8, 2014 by BlueTR3A-5EKT Quote Link to post Share on other sites
Paul Harvey Posted July 8, 2014 Report Share Posted July 8, 2014 On a PC click on the Windows icon bottom left hand corner Type in 'snipping' to the search box An icon 'snipping tool' will appear in the results Click on this and you can highlight, cut, paste and save anything from anywhere which is on your screen at the time. Perfect for nicking pictures off the internet that can't be saved direct No doubt hated by Copyright owners everywhere Quote Link to post Share on other sites
peejay4A Posted July 8, 2014 Report Share Posted July 8, 2014 So Mr Prospect. Does Ruby have a crankcase breather or a PCV? Quote Link to post Share on other sites
Peter Cobbold Posted July 8, 2014 Report Share Posted July 8, 2014 Re: over-run and op rising. If the PRV valve is permanently open the over-run depression in the manifold will 'empty' the crankcase of air. If the oil pump is sucking some air on its inlet side - especilaly as oil level drops - the rise in op on the over-run might be explained. Quote Link to post Share on other sites
Prospect Posted July 8, 2014 Author Report Share Posted July 8, 2014 Many thanks to all for all the sage advice. Will try adjusting the PCV in the morning and give her a good run to see if that sorts out the issue. Pete, Crankcase breather appears to be a solid 1" pipe coming up capped off at the top and presumably open at the bottom, will check the bottom and see if I am right. Tony Quote Link to post Share on other sites
Paul Harvey Posted July 8, 2014 Report Share Posted July 8, 2014 (edited) Tony - yep, that's the one - I'm not sure ST were entirely consistent in when they dispensed with these in favour of the PCV (my 4A had both!) - or maybe subsequent owners just changed back to the breather in preference as many of us do now. Â It is worth removing the whole OPRV arrangement by unscrewing the largest nut (the whole thing comes out) You can then dismantle and inspect the innards easily. The spring is known to wear on one side only (evidenced by a shiny section) and this can cause it to stick giving intermittent results. I just changed the spring and ball bearing for pennies and put it all back together using common sense and trial and error to get the right result (count the turns of the inner slotted adjustment bolt as you remove it) Edited July 8, 2014 by Paul Harvey Quote Link to post Share on other sites
peejay4A Posted July 8, 2014 Report Share Posted July 8, 2014 It sounds as though you have both PCV and a crankcase breather or did I read that wrong? Quote Link to post Share on other sites
BlueTR3A-5EKT Posted July 8, 2014 Report Share Posted July 8, 2014 Thanks, jpg of mod drawing now added to my orig post  Peter W Quote Link to post Share on other sites
Prospect Posted July 10, 2014 Author Report Share Posted July 10, 2014 Hi sage ones,Have now taken out and cleaned the pressure release valve - PRV? although spring does not look worn and ball is still rolling perfectly would like to replace. However puzzling as to which filter head I have. Catalogues ask for whether Purolator or Tecalemit and state name on side of head but no writing on mine just part ref. ELTN FP 3005/03 which presumably is some after market part - any clues anyone or is the suggestion just get a spring and ball for both Purolator and Tecalmit and see which fits best! Would it also make sense to take the filter head off and clean it whilst I am about it. Also clarification please for a numpty, I assume PRV is pressure release valve and PCV is pressure control valve related to the crankcase breather, is this correct? Really need the advice before a non engineer does something stupid. Tony Quote Link to post Share on other sites
peejay4A Posted July 10, 2014 Report Share Posted July 10, 2014 If you post a photo of the filter head we'll be able to tell you which it is. Â PCV is Positive Crankcase Ventilation and it's the circular thing between the carbs and the rocker cover. It's connected to the rocker cover and a take-off on the inlet manifold and keeps a slight negative pressure in the crankcase although if you have the snorkel breather under the fuel pump as well then I doubt that it's doing very much. Quote Link to post Share on other sites
BlueTR3A-5EKT Posted July 10, 2014 Report Share Posted July 10, 2014 (edited) Hi sage ones, Have now taken out and cleaned the pressure release valve - PRV? although spring does not look worn and ball is still rolling perfectly would like to replace. However puzzling as to which filter head I have. Catalogues ask for whether Purolator or Tecalemit and state name on side of head but no writing on mine just part ref. ELTN FP 3005/03 which presumably is some after market part - any clues anyone or is the suggestion just get a spring and ball for both Purolator and Tecalmit and see which fits best! Would it also make sense to take the filter head off and clean it whilst I am about it. Also clarification please for a numpty, I assume PRV is pressure release valve and PCV is pressure control valve related to the crankcase breather, is this correct? Really need the advice before a non engineer does something stupid. Tony  I think if all you intend to do is replace the PRV ball and spring you will need to measure the ball diameter. Replace like with like.Cheers Peter W  PS If you want a couple of inches of 'lead linger' to seal the lock nut with send me a SAE. I still have most of a roll left. Edited July 10, 2014 by BlueTR3A-5EKT Quote Link to post Share on other sites
AlanT Posted July 10, 2014 Report Share Posted July 10, 2014 When I did the OD, which has ball-bearings controlling oil flow, I had trouble getting perfectly round ones. Â Seems stupid, but they are easier to make non-round and hard to get right. Quote Link to post Share on other sites
Graham Harris Posted July 11, 2014 Report Share Posted July 11, 2014 Peter W, where did you get the lead linger? when i took my lock nut off the lead fell to bits so i found an O ring to replace it which seams to have worked , no oil leaks. I would have thought anything with lead in would be off limits these days? Graham Quote Link to post Share on other sites
Prospect Posted July 13, 2014 Author Report Share Posted July 13, 2014 Many thanks for all the advice. Have cleaned the oil filter head and refitted original ball and spring (ball perfectly round and have bought replacements in case needed) oil pressure now goes to just 70 psi, flickers then drops to 70 psi. Hopefully problem solved. Will do a full oil change and then take her out for a longish drive in the week to check all OK once caught up with all the jobs built up whilst at Classic Le Mans. Tony P.S. Peter W. Thanks for the offer of lead linger, have made up my own from a sliver of roofing lead rolled into wire size. Quote Link to post Share on other sites
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