oil pressure 1982 v6
Discussion
the oil pressure on ne sits at 3 on a smiths guage when the engine is cold. when hot on idle it sits under 1 goes up to 3 when accelarating. its got 20/50 in it and the level is constant. thought it might be the sender but would that affect it when hot only? new filter and oil change under 500 miles ago.
i expect a pressure drop when not accelrating but is such a drastic fall normal? if not whats the cause?
ps had a lively drive around east lothian today. performance isnt affected.
cheers guys
marcus
i expect a pressure drop when not accelrating but is such a drastic fall normal? if not whats the cause?
ps had a lively drive around east lothian today. performance isnt affected.
cheers guys
marcus
Hi Marcus...Not sure about smiths gauges but my Stuart warner gauge used to show between 38-40 on the gauge and sometimes it would drop slightly and return once warm..I now have a higher pressure oil pump that reads 30-40 when cold and then 70 when warm...It does vary with acceleration so i think you are ok...Cheers...Ziga
cheers mark, norman.
my idle speed when hot is quite low, around 500/600 rpm. i was sitting with my foot on the accelerator to keep the revs around 8/900 which kept the oil pressure at about 1.5bar.
It probably is ok but i prefer to see the needle sit a bit higher, like 2 bar or so on idle.
marcus
my idle speed when hot is quite low, around 500/600 rpm. i was sitting with my foot on the accelerator to keep the revs around 8/900 which kept the oil pressure at about 1.5bar.
It probably is ok but i prefer to see the needle sit a bit higher, like 2 bar or so on idle.
marcus
Oil Pressure..... Some myths and misunderstandings.
OK - I'm sure some posters will disagree, but this is what I learned/was told over the years, so I'm passing it on, good or bad. Anyway discussions are always good, so go for it.
For an ordinary road going engine, oil FLOW is more important than pressure, to make sure the various bearings have a good, constant supply of clean oil. So the engine simply needs enough pressure to maintain the flow.
The highest loads are [typically] not the main bearings, but the cam lobes and/or tappet faces.
The oil can actually 'burn' on those high load surfaces, so the oil flow cools as well as replenishes. Oil has quite a big cooling effect, as well as the radiator.
An engine drained of oil whilst running can carry on running happily for an amazingly long time, something like 30 minutes, before it siezes, depending upon how 'tight' it is - provided that it can maintain an oil film on its bearing surfaces, it's OK.
So as long as there's flow, idle pressure can be very low, even say 5 psi, and most engines are happy on load at 40psi or more....[perhaps not true for some modern designs ?]
ON Ford V6, Essex and Cologne, if the oil pressure drops slightly when you hit the throttle, and recoveres when you take your foot off, then you need new main and big end bearings soonish.
OK - I'm sure some posters will disagree, but this is what I learned/was told over the years, so I'm passing it on, good or bad. Anyway discussions are always good, so go for it.
For an ordinary road going engine, oil FLOW is more important than pressure, to make sure the various bearings have a good, constant supply of clean oil. So the engine simply needs enough pressure to maintain the flow.
The highest loads are [typically] not the main bearings, but the cam lobes and/or tappet faces.
The oil can actually 'burn' on those high load surfaces, so the oil flow cools as well as replenishes. Oil has quite a big cooling effect, as well as the radiator.
An engine drained of oil whilst running can carry on running happily for an amazingly long time, something like 30 minutes, before it siezes, depending upon how 'tight' it is - provided that it can maintain an oil film on its bearing surfaces, it's OK.
So as long as there's flow, idle pressure can be very low, even say 5 psi, and most engines are happy on load at 40psi or more....[perhaps not true for some modern designs ?]
ON Ford V6, Essex and Cologne, if the oil pressure drops slightly when you hit the throttle, and recoveres when you take your foot off, then you need new main and big end bearings soonish.
Edited by RCK974X on Wednesday 24th July 21:29
Remember 2.8 idle speed adjustment is *NOT* the tiny screw on the top, but the bigger screw head adjuster UNDERNEATH the main throttle inlet. Sometimes not easy to spot, espcially if you've not adjusted it before.
If your 2.8 idles happily at 600rpm, then you should know that your injectors must be in good condition, as lower idle speed tends to get lumpy first (i.e. low fuel flow is hardest for injectors to atomise cleanly).
If your 2.8 idles happily at 600rpm, then you should know that your injectors must be in good condition, as lower idle speed tends to get lumpy first (i.e. low fuel flow is hardest for injectors to atomise cleanly).
RCK974X said:
Remember 2.8 idle speed adjustment is *NOT* the tiny screw on the top, but the bigger screw head adjuster UNDERNEATH the main throttle inlet. Sometimes not easy to spot, espcially if you've not adjusted it before.
If your 2.8 idles happily at 600rpm, then you should know that your injectors must be in good condition, as lower idle speed tends to get lumpy first (i.e. low fuel flow is hardest for injectors to atomise cleanly).
AH I've learnt something new......must look "underneath" and mine WILL tickover (just) at 5-600rpm but under "normal" conditions it is 7-800 so maybe it does need a bit of a tweak upwards.If your 2.8 idles happily at 600rpm, then you should know that your injectors must be in good condition, as lower idle speed tends to get lumpy first (i.e. low fuel flow is hardest for injectors to atomise cleanly).
It will also bump start off very little speed (like under 5mph!) so i think the engine is running very well. (it also pulls well since I had the MOT guy adjust my fuel mix! before that it was so lean it passed the emmisions test for a catalytic converter car!)
I love my wedge.....
That top screw is just too bloody obvious, and begs to be fiddled with ... it's actually the 'closed' stop for the main throttle plate - I think it has to be there because the plate has to have quite a strong spring on it, and so plate would slowly eat a groove in the body otherwise.
Mine was a bit lumpy at low end, and I did get 6 new injectors for it. The difference was very noticeable at low rpm and light throttle - much smoother. Much more even idle.
You can adjust your own mixture by the way - all you need is an extra long 3 mm hex key, and it fits into a hollow tube sticking out between the metering head and the main air cover. Beware though, just putting the key in actually affects the mixture !! Clockwise -> richer, anticlockwise -> weaker. There used to be a tool for sale at Halfords etc many years ago, probably not any more !
Mine was a bit lumpy at low end, and I did get 6 new injectors for it. The difference was very noticeable at low rpm and light throttle - much smoother. Much more even idle.
You can adjust your own mixture by the way - all you need is an extra long 3 mm hex key, and it fits into a hollow tube sticking out between the metering head and the main air cover. Beware though, just putting the key in actually affects the mixture !! Clockwise -> richer, anticlockwise -> weaker. There used to be a tool for sale at Halfords etc many years ago, probably not any more !
RCK974X said:
That top screw is just too bloody obvious, and begs to be fiddled with ... it's actually the 'closed' stop for the main throttle plate - I think it has to be there because the plate has to have quite a strong spring on it, and so plate would slowly eat a groove in the body otherwise.
Mine was a bit lumpy at low end, and I did get 6 new injectors for it. The difference was very noticeable at low rpm and light throttle - much smoother. Much more even idle.
You can adjust your own mixture by the way - all you need is an extra long 3 mm hex key, and it fits into a hollow tube sticking out between the metering head and the main air cover. Beware though, just putting the key in actually affects the mixture !! Clockwise -> richer, anticlockwise -> weaker. There used to be a tool for sale at Halfords etc many years ago, probably not any more !
Yes I have that allen key, just had no easy way of being 100% sure what the mixture was like, the MOT guy had his "probe" so could set it much better. You aso need to be careful IF you try to adjust it with the engine running as it can cause bits to break if not careful so when i was playing I always adjusted it after stopping the engine.Mine was a bit lumpy at low end, and I did get 6 new injectors for it. The difference was very noticeable at low rpm and light throttle - much smoother. Much more even idle.
You can adjust your own mixture by the way - all you need is an extra long 3 mm hex key, and it fits into a hollow tube sticking out between the metering head and the main air cover. Beware though, just putting the key in actually affects the mixture !! Clockwise -> richer, anticlockwise -> weaker. There used to be a tool for sale at Halfords etc many years ago, probably not any more !
And did you mean 6 injectors or 7 (or did you not replace the "cold start" one?)
Hi Marcus...Here is a pic of the idle screw...My throttle body is upside down due to the fitment of the blower..
Also be careful when fiddling about with the mixture screw as its easy to turn it too much and forget where you started..You only need to turn it in 5mm increments..A good test is to rev the car to about 2500rpm using the throttle linkage and let it fall back to idle..If it falls back to the correct idle then its ok..If it drops below and then comes up then its not right..I have a set of long reach hex drivers which are very handy, Its wise to leave the key in there whilst you are turning it and make a note of where it was to start with as its easy to lose track if you take it out..The car will also stall if you push down on the allen key whilst its in the adjuster..That is perfectly normal..It is better done with the aid of a gas analyser but it can be done by ear...Cheers...Ziga
Also be careful when fiddling about with the mixture screw as its easy to turn it too much and forget where you started..You only need to turn it in 5mm increments..A good test is to rev the car to about 2500rpm using the throttle linkage and let it fall back to idle..If it falls back to the correct idle then its ok..If it drops below and then comes up then its not right..I have a set of long reach hex drivers which are very handy, Its wise to leave the key in there whilst you are turning it and make a note of where it was to start with as its easy to lose track if you take it out..The car will also stall if you push down on the allen key whilst its in the adjuster..That is perfectly normal..It is better done with the aid of a gas analyser but it can be done by ear...Cheers...Ziga
Wedgeinald - Ah right. I mentioned the key because I used to hear a lot of people saying that the system wasn't adjustable.... and No, I didn't change the cold start injector, as engine had no trouble starting from cold, just a rough idle, now gone.
Zig - Agree with all that. I actually cheat - you can *gently* push the key down, which weakens mix, and pull key up to richen. I reckon there is enough movement that way to trim mixture by hand (and experience). Pushing key should cause idle to drop off quickly, and lifting should cause a rise in RPM, then a fall shortly after. Anyway I still reckon I can smell a weak fuel mixture at the tail pipe !
Zig - Agree with all that. I actually cheat - you can *gently* push the key down, which weakens mix, and pull key up to richen. I reckon there is enough movement that way to trim mixture by hand (and experience). Pushing key should cause idle to drop off quickly, and lifting should cause a rise in RPM, then a fall shortly after. Anyway I still reckon I can smell a weak fuel mixture at the tail pipe !
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