cliff.b Posted February 28, 2022 Author Report Share Posted February 28, 2022 12 minutes ago, johny said: What pressures do you see on the gauge when hot at 2000rpm and tick over? I used to get the light flickering at low revs on hot days in traffic before replacing bearings/oil pump and improving cooling Since the tickover has been down to 600RPM the lowest I have seen the gauge show is 10lb. At 2000RPM with the engine as warm as it's going to get in this weather I haven't noticed it below 30lb. Link to comment Share on other sites More sharing options...
johny Posted February 28, 2022 Report Share Posted February 28, 2022 Also, without being personal, does your dipstick look like the ones for your car on sale with ebay? Link to comment Share on other sites More sharing options...
johny Posted February 28, 2022 Report Share Posted February 28, 2022 Think thats a pretty low tickover for a 4 pot... Link to comment Share on other sites More sharing options...
cliff.b Posted February 28, 2022 Author Report Share Posted February 28, 2022 1 minute ago, johny said: Also, without being personal, does your dipstick look like the ones for your car on sale with ebay? Pete has raised that as a possible issue. I will check and as he suggested, calibrate when next changing the oil Link to comment Share on other sites More sharing options...
cliff.b Posted February 28, 2022 Author Report Share Posted February 28, 2022 1 minute ago, johny said: Think thats a pretty low tickover for a 4 pot... The revs or the pressure? Link to comment Share on other sites More sharing options...
johny Posted February 28, 2022 Report Share Posted February 28, 2022 sorry, revs Link to comment Share on other sites More sharing options...
cliff.b Posted February 28, 2022 Author Report Share Posted February 28, 2022 1 minute ago, johny said: sorry, revs Ok, that's interesting. I set it at that while timing the new dizzy as the advance is supposed to start coming in above that. When I had finished, as it was ticking over nicely I just left it. Maybe I will raise it a little Link to comment Share on other sites More sharing options...
NonMember Posted February 28, 2022 Report Share Posted February 28, 2022 7 minutes ago, cliff.b said: the advance is supposed to start coming in above that I think you misread that. The advance starts coming in at about twice that - the distributor data is all given in camshaft RPM, not crank. Book figure for idle is 850RPM (and there's a note in some of the earlier owner's handbooks that "due to the modern, high efficiency design" these engines can't be expected to idle as low as older ones). Link to comment Share on other sites More sharing options...
johny Posted February 28, 2022 Report Share Posted February 28, 2022 Interesting as I was going to suggest 800 - 850 rpm but then saw the manual for the 1300cc twin SUs indicating 550rpm! Link to comment Share on other sites More sharing options...
cliff.b Posted February 28, 2022 Author Report Share Posted February 28, 2022 11 minutes ago, NonMember said: I think you misread that. The advance starts coming in at about twice that - the distributor data is all given in camshaft RPM, not crank. Book figure for idle is 850RPM (and there's a note in some of the earlier owner's handbooks that "due to the modern, high efficiency design" these engines can't be expected to idle as low as older ones). I will look back at the notes I used. I'm definitely seeing more advance at 1200RPM (crank speed) than tickover but then I had to change the primary distributor spring because, as supplied there was no advance at all below 2000 RPM. Now, after replacing the spring, I am seeing pretty much the advance curve I was expecting with much better performance and a nice smooth tickover, even at 600RPM. Maybe my distributor modding has unexpectedly resulted in that 🤔 Link to comment Share on other sites More sharing options...
Colin Lindsay Posted February 28, 2022 Report Share Posted February 28, 2022 1 hour ago, cliff.b said: My only concern really is if it indicates something not right or the start of an issue so interested in people's thoughts and if others have seen the same thing. Welcome to the wonderfully paranoid world of old cars... temporarily rig up an oil pressure gauge and then you'll understand why they call them worry gauges! I'd still like to think it's electrical, because that's the cheaper option; has anyone watched the oil warning light while you wiggle the wires about? Link to comment Share on other sites More sharing options...
NonMember Posted February 28, 2022 Report Share Posted February 28, 2022 44 minutes ago, cliff.b said: I'm definitely seeing more advance at 1200RPM (crank speed) than tickover Well, I was quoting from memory and don't have a 1500 manual to hand, but the earlier Spitfire curves begin to advance around 1000RPM (crank). The Vitesse 6 and Herald 1200 do have a more aggressive "busy advancing while still at idle" curve, which strikes me as a bad idea because it'll lead to instability. Link to comment Share on other sites More sharing options...
cliff.b Posted February 28, 2022 Author Report Share Posted February 28, 2022 27 minutes ago, Colin Lindsay said: Welcome to the wonderfully paranoid world of old cars... temporarily rig up an oil pressure gauge and then you'll understand why they call them worry gauges! I'd still like to think it's electrical, because that's the cheaper option; has anyone watched the oil warning light while you wiggle the wires about? Next time I take the car out I'm going to temporarily disconnect the wire to the oil pressure switch, do the braking test and if the light still comes on it must be an electrical issue. I do have an oil pressure gauge fitted and even when the light came on it still registered about 10lb, but if I rev the engine I can see there is a delay in the pressure rising and then falling so quite possibly not sensitive enough to show a momentary dip. Link to comment Share on other sites More sharing options...
cliff.b Posted February 28, 2022 Author Report Share Posted February 28, 2022 5 minutes ago, NonMember said: Well, I was quoting from memory and don't have a 1500 manual to hand, but the earlier Spitfire curves begin to advance around 1000RPM (crank). The Vitesse 6 and Herald 1200 do have a more aggressive "busy advancing while still at idle" curve, which strikes me as a bad idea because it'll lead to instability. That makes sense and anyway, I am now very happy with the way the car is running. I think I will increase the tickover a little though, probably to about 800RPM as that seems reasonable. Be interesting to see if that has any impact whatsoever on the oil thing. Presume there would be about 1/3 more "sucking" going on 🤔 Link to comment Share on other sites More sharing options...
johny Posted February 28, 2022 Report Share Posted February 28, 2022 At least youve got some ideas. Let us know the outcome as its a bit unusual and my money is on it being a real drop in oil pressure... Link to comment Share on other sites More sharing options...
cliff.b Posted February 28, 2022 Author Report Share Posted February 28, 2022 1 hour ago, johny said: At least youve got some ideas. Let us know the outcome as its a bit unusual and my money is on it being a real drop in oil pressure... Will do, although I probably won't be going out again until next weekend. Weather taken a turn for the worse and too busy 😒 Link to comment Share on other sites More sharing options...
Graham C Posted February 28, 2022 Report Share Posted February 28, 2022 Sorry coming to this late, I would say this down to the oil moving in the sump when hard breaking, I have owned my Spit 1500(1981) since 1984 and always had this problem. Fitted a pressure gauge via a T joint off the engine where the oil sensor is and that drops in pressure. You tend not to notice it so much when you have fresh oil in the engine. That is my experience of owning a Spit 1500 and lose of oil pressure. Graham Link to comment Share on other sites More sharing options...
cliff.b Posted February 28, 2022 Author Report Share Posted February 28, 2022 3 minutes ago, Graham C said: Sorry coming to this late, I would say this down to the oil moving in the sump when hard breaking, I have owned my Spit 1500(1981) since 1984 and always had this problem. Fitted a pressure gauge via a T joint off the engine where the oil sensor is and that drops in pressure. You tend not to notice it so much when you have fresh oil in the engine. That is my experience of owning a Spit 1500 and lose of oil pressure. Graham Many thanks for the feedback. Have you noticed if oil level has any effect? Just wondering if the oil age is relevant or just that it's completely full after you have changed it. And also, considering the recent comments, interested to know what your tickover speed is like lol. Link to comment Share on other sites More sharing options...
Graham C Posted February 28, 2022 Report Share Posted February 28, 2022 Oil level will have an affect. It is sometime since I drove the car regularly. However whenever I brake hard I always watch the pressure gauge dip and return. As to tickover revs I follow the book and aim for 700/800 rpm. Which from memory was on the label underneath the bonnet. Always thought 1000rpm plus was to high. As to losing oil pressure always took care with driving on when pressure built back up again, just be aware and top the oil. When driving regularly always changed the oil/filter twice a year and not always with expensive oil. I will wait for others to say that was the reason for lose of oil pressure. Graham Link to comment Share on other sites More sharing options...
cliff.b Posted February 28, 2022 Author Report Share Posted February 28, 2022 Thinking about this further, I'm guessing that in most cases if someone is forced to brake hard, the last thing they are looking at is their oil light 🤔. So maybe it can happen but few people notice. I am visualising Triumphs all over the country now making random emergency stops as owners check their own cars out 🙂 Link to comment Share on other sites More sharing options...
cliff.b Posted February 28, 2022 Author Report Share Posted February 28, 2022 (edited) 4 minutes ago, Graham C said: Oil level will have an affect. It is sometime since I drove the car regularly. However whenever I brake hard I always watch the pressure gauge dip and return. As to tickover revs I follow the book and aim for 700/800 rpm. Which from memory was on the label underneath the bonnet. Always thought 1000rpm plus was to high. As to losing oil pressure always took care with driving on when pressure built back up again, just be aware and top the oil. When driving regularly always changed the oil/filter twice a year and not always with expensive oil. I will wait for others to say that was the reason for lose of oil pressure. Graham Interesting stuff 👍 And yes, 1000 rpm is too high but before I changed my distributor it was the only way I could keep it reasonably stable Edited February 28, 2022 by cliff.b Add text Link to comment Share on other sites More sharing options...
PeteH Posted February 28, 2022 Report Share Posted February 28, 2022 1 hour ago, Graham C said: I would say this down to the oil moving in the sump when hard breaking On some "Marinised" Engines the sump is divided with baffles, with smallish holes, to mittigate this effect. During pitching and rolling. Road tankers are Baffled to stop Surge. Which has caused accidents when not fitted. Pete Link to comment Share on other sites More sharing options...
cliff.b Posted February 28, 2022 Author Report Share Posted February 28, 2022 10 minutes ago, PeteH said: On some "Marinised" Engines the sump is divided with baffles, with smallish holes, to mittigate this effect. During pitching and rolling. Road tankers are Baffled to stop Surge. Which has caused accidents when not fitted. Pete Some years ago I had a Ford Cougar with a transverse V6 engine and was told that during production they added a sump baffle after cases of oil starvation during fast cornering. Link to comment Share on other sites More sharing options...
cliff.b Posted March 8, 2022 Author Report Share Posted March 8, 2022 At last I have had a chance to get out again and investigate further. Firstly, I had noticed that where the car was when I topped up the oil was sloping more than I had realised, so I found somewhere flatter to check again and found it still wasn't full. It took another couple of "glugs" out the can to remedy this and then out for a drive. After a number of high speed braking tests I have found that the light still comes on briefly, but only if if I do a severe emergency stop, hard enough to make the front tyres squeal, from 60MPH. If I brake just as hard but leave the clutch engaged then the oil light doesn't come on at all. I am therefore concluding that it is not an electrical fault but was probably a combination of slightly low oil level and the reduced scavenging at tickover speed during a degree of oil "slosh". I'm not unduly worried as I never intend to brake that hard during normal driving but even so, the oil light was only on for maybe a second at tickover revs and no load. If I do have to brake that hard though I will try and remember to not push the clutch until just before stopping. As the slight extra oil top-up did improve matters I still need to check the dipstick out, which I will do at next oil change. Anyway , apart from all that, it's been a lovely day to take the car out for a bit of testing. That is until I had to fill the tank 😱 Link to comment Share on other sites More sharing options...
PeteH Posted March 8, 2022 Report Share Posted March 8, 2022 Cliff, Topped off swmbos car this morning, quarter tank 26quid!!. The big one will be the Motorhome. I expect that will be pump cut off and restart a full fill used to be just under the ton mark. Sign of things to come. Thanks Mr Putin!. Pete Link to comment Share on other sites More sharing options...
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