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  1. #1
    Join Date
    Mar 2010
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    Very little oil pressure when idling but ok with revs up - help

    Hi All

    When I fire up the Cob, Rover V8 - I get a reading of around 45 pressure but the drops to around 10 at idle but once I have engine warmed up I'm getting around 25psi at 2000 revs and zero on tick over at 750rpm.

    I fitted a new oil pump with the updated high oil pressure components around 8000 miles ago and it's ran perfect - used to have around 30psi when hot and this dropped to around 20psi at idle.

    Any ideas what's causing current low pressures?

    Car runs well and engine performs well other than this worrying problem.

    dave
    Last edited by perky2; 31-05-17 at 05:54 AM.

  2. #2
    Join Date
    May 2004
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    Cowbridge, United Kingdom
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    Don't panic RV8's always have low oil pressure at idle.
    They run on low pressure compared to most other engines.
    I suggest you change your oil and filter again, maybe you have a bit of crap on the relief valve causing the drop.
    Kev Davies
    South Wales Area Rep. UKCC Membership Secretary
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  3. #3
    Join Date
    Sep 2014
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    aberdeenshire Scotland
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    Correct Rovers always had poor pressure on idle, when we finished our car and it was at 1.5bar at idle my pall said that is good pressure for a Rover (Rover mechanic from the seventys)

    Dont worry about it, but as Kev said just change oil and buy a good quality filter, not sure if you know, but they are also bad for loosing prim so when you change the filter have your new one full of new oil ready to screw on.

    Cheers
    Shuggie

  4. #4
    Join Date
    Aug 2004
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    A chap who used to come into the pub where I worked was a freelance Ferrari mechanic; people used to fly him to Arabia to do a service.

    He told me that it is quite normal for some of those cars to have the oil light on at hot tick-over.
    Cheers

    Myles D-W

  5. #5
    Join Date
    Mar 2010
    Location
    west yorks
    Posts
    12
    thanks Chaps i am aware that RV8 is low pressure high volume compared to other engines but you seem to be missing an important piece of information from my post - until now i had good pressure even when hot - any idea then why the sudden change?

    dave

  6. #6
    Join Date
    Apr 2004
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    on the edge...almost falling off
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    Oil pressure relief valve stuck?? Try banging on the castiing where the valve floats to try and unstick it.

  7. #7
    Join Date
    Dec 2004
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    Staines Middlesex / Abu Dhabi
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    Something as simple as what oil SAE or manufacture you used when changed out and noticed the difference ?
    Did you change from mineral to synthetic ? I seem to remember sometime it was a recommendation to not use synthetic oils in American V8's but cannot remember if Ford or Chevy or both ?
    Perhaps get a thicker viscosity oil for when its hot if it concerns you ?
    Do you have an oil low pressure light as well ? When warm/idle does the light come on or flicker or remain off ? If remains off ( is it around 8psi they switch on ?) then perhaps its your pressure sender that's giving a false indication with warmer thinner oil ?
    I would be happy with it as long as it comes up ok under load ?
    Chris Lutman -427SC Coupe / MG Tojeiro "LOY" replica

  8. #8
    Join Date
    Mar 2010
    Location
    west yorks
    Posts
    12
    Thanks again Chaps

    I hacent changed from 20/50 grade.

    As already stated nothing changed from good oil pressure to low oil pressure.

    Tony Ill try the hammer effect. I had thought that replacing the spring and valve but suspect to do so is a removal of the whole unit?
    Dave

  9. #9
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    It's been a while but from memory there is a large nut at the back of the casing which goes direct to the pressure relief spring!
    BIG TONE


    Mercedes SL owner, definitely NOT a kitcar owner like you lot!


  10. #10
    Join Date
    Feb 2007
    Location
    West Sussex
    Posts
    8,457
    Its not difficult to pull the whole thing apart as its on the side of the engine, so you could always replace the spring.
    Has the engine been sat unused for a while? Wondering whether re-priming with vaseline help?
    Crendon Chassis No.49
    Huddart FE428 + toploader

    Not listed in the Shelby Register.

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