Adding Oil Cooler
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  1. #1
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    Default Adding Oil Cooler

    I have a somewhat modified 4CV to which I have fitted a by pass oil filter.

    I have obtained an oil cooler off a Kawasaki 1000 MC.

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    The oil filter consumes about 3-4PSI but the oil cooler could reduce this further. I have already stretched the oil pump relieve valve spring to increase pressure.

    Do I need to replace the spring with another and would the pump have sufficient capacity to push all this extra 'cooler' oil around?

    Any suggestions would be welcome by Kermit.

  2. #2
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    Quote Originally Posted by Colin Rose View Post
    I have a somewhat modified 4CV to which I have fitted a by pass oil filter.
    I have obtained an oil cooler off a Kawasaki 1000 MC.
    The oil filter consumes about 3-4PSI but the oil cooler could reduce this further. I have already stretched the oil pump relieve valve spring to increase pressure.
    Do I need to replace the spring with another and would the pump have sufficient capacity to push all this extra 'cooler' oil around?
    Any suggestions would be welcome by Kermit.
    Hi,
    The oil pump output is usually only critical at low RPM. At any RPM more than 1000 or so the volume is normally sufficient to get full pressure, open the relief valve and let the excess go straight back to the sump. Increasing the pressure does not change this. The pressure should be left alone unless you have some reason to tinker. A higher pressure does waste more power and causes the oil to heat up more A larger pump also does this too

    So, if the pressure drops excessively at idle then the volume output is too low, the pump is worn or the engine is worn and you have no spare volume. If the pressure does not drop much at idle then the pump volume may be sufficent to take off some for a bypass filter, the amount can be restricted to a small flow which is sufficient to ensure the oil gets cleaned over time. The pressure does not need to be increased at all for this. Stretching the spring or replacing it will not increase the volume pumped. I assume you are saying the pressure drop of 3-4psi occures now at idle with the bypass filter.

    If the engine is running OK with the bypass filter now without the pressure dropping too low at idle, then I would suggest putting the cooler into the line feeding the filter or the return line and there will be no change to the volume tapped off.

    There are more complicated ways but its probably not worth the effort.
    jaahn

  3. #3
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    Hi jaahn,

    I have a 20PSI pressure relieve valve in the return line to the sump and a 1mm hole drilled into the union to restrict too much flow. This is recommended in some old workshop manuals I have.
    At present I get 25PSI at idle at 800rpm and at 4K rpm about 35-40PSI (hot).

    The motor is in excellent shape and has only done 5,000k since a total rebuild including new pistons, bearings throughout, seals, full balance and JP forged pistons fitted to line bored liners bringing 905cc. A copper head gasket was made and thus far performs without any problems. At least I can reuse it time and time again with a little bit of heat.

    Cheers

  4. #4
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    Default oil ??

    Quote Originally Posted by Colin Rose View Post
    Hi jaahn,

    I have a 20PSI pressure relieve valve in the return line to the sump and a 1mm hole drilled into the union to restrict too much flow. This is recommended in some old workshop manuals I have.
    At present I get 25PSI at idle at 800rpm and at 4K rpm about 35-40PSI (hot).

    The motor is in excellent shape and has only done 5,000k since a total rebuild including new pistons, bearings throughout, seals, full balance and JP forged pistons fitted to line bored liners bringing 905cc. A copper head gasket was made and thus far performs without any problems. At least I can reuse it time and time again with a little bit of heat.

    Cheers
    Colin,
    Sounds like you have a reasonable set up now. Researched in the 'good old books' instead of the web!#$% you must be older like me?? I doubt if the mighty web would have any usefull information about this except where to spend 'big bucks' at a dodgey speed shop
    Perhaps just put the cooler into the return or feed line and it will be OK.

    If you wish to tinker then I could suggest increasing the volume flow a bit more for more cooling. So first increase the return line relief setting till it is above the pressure at idle so it does not bleed off untill the revs come up a bit. Say 30 psi. Perhaps stretch the spring or pack it with washers. Then increase the size of the hole a bit to get more flow through the cooler and filter.

    Engine sounds good. I hope you do not have to reuse that copper head gasket "time and time again".
    jaahn

  5. #5
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    Quote Originally Posted by Colin Rose View Post
    I have a somewhat modified 4CV to which I have fitted a by pass oil filter.

    I have obtained an oil cooler off a Kawasaki 1000 MC.

    The oil filter consumes about 3-4PSI but the oil cooler could reduce this further. I have already stretched the oil pump relieve valve spring to increase pressure.

    Do I need to replace the spring with another and would the pump have sufficient capacity to push all this extra 'cooler' oil around?

    Any suggestions would be welcome by Kermit.
    I fitted a new oil pump to the 4CV about 15 years ago, obtained from Ken at Caravelle. It has always had much higher oil pressure than before (60 psi or more at 3000 rpm or thereabouts). My car has a reground crankshaft and new white metal conrod bearings (I know.....) and new main bearings of course. Well that was 1970. It has always had regular, if not excessive, oil changes and the only time I looked at the bearings (replacing sleeve seals) they seemed perfect.

    Mine has the later sump (now) with the curved bottom not the square bottom, which accomodates the later oil pump, if I remember correctly. Maybe on further thought they all look the same.

    I wonder whether the pump I have came from the last of those Ventoux engines (I guess the 850 units fitted to the series one Renault 5 might be that) have a larger capacity (flow I mean, not just pressure) pump - by the time the Renault 5 was available, cars were cruising in France at more than 120 kph, and cruising at higher revs perhaps than the earlier cars. They might have decided on a bit more oil pump delivery capacity (rate, I mean).

    Might be worth a thought.

    That all reads a bit confusingly to me, but I'm sure you know what I mean.

    Does your 905 cc engine have the latest block type with the extra internal webbing? Jean-Pierre Delaunoy, of whom you probably know, uses the very latest type when building a 902 cc engine with those largest capacity sleeve kits.

    Cheers
    JohnW

    Renault 4CV 1950 (R1062)
    Renault R8 1965 (R1130)
    Renault Scenic Series II 2005 (wife's)
    Renault Scenic Series II 2006 (daughter's)
    Renault Scenic Series II 2007 (mine)

    CitroŽn CX Pallas 1980 (moved on to new custodian)

    National Co-ordinator, Renault 4CV Register of Australia

  6. #6
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    Yup, Kermit has the extra ribbed block which also came with the extra oil jet for the timing gear which the old manual said would reduce oil pressure and therefore did not quite recommend after market oil filters.

    Interesting an R5 oil pump could be a direct swap and would certainly be a worthwhile investment. As we know, using thicker oil isn't the answer.

    Just a question, if the R5 oil pump is the same physical shape how is capacity increased?

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    Quote Originally Posted by Colin Rose View Post
    Yup, Kermit has the extra ribbed block which also came with the extra oil jet for the timing gear which the old manual said would reduce oil pressure and therefore did not quite recommend after market oil filters.

    Interesting an R5 oil pump could be a direct swap and would certainly be a worthwhile investment. As we know, using thicker oil isn't the answer.

    Just a question, if the R5 oil pump is the same physical shape how is capacity increased?
    Hi Colin,

    I wasn't aware of an extra oil jet for the timing gear on those later engines - where is it exactly?

    I'm only hypothesising about the extra oil pump capacity - the high pressure at idle and at revs suggests it, that's all. It could have slightly larger gears in the same housing if indeed it does have a higher capacity. It may be that the gears are thicker/longer and I didn't notice a slightly deeper housing too. I must look into it. What I really should have done was to pull the sump off and checked it when I got high oil pressures at the start - but I was so pleased that the sump sealed that nothing short of disaster was going to get me to undo it again!!

    Yes, I'd go for better oil - even accept higher oil consumption with a slightly thinner oil to get the volume through. Interesting territory.
    JohnW

    Renault 4CV 1950 (R1062)
    Renault R8 1965 (R1130)
    Renault Scenic Series II 2005 (wife's)
    Renault Scenic Series II 2006 (daughter's)
    Renault Scenic Series II 2007 (mine)

    CitroŽn CX Pallas 1980 (moved on to new custodian)

    National Co-ordinator, Renault 4CV Register of Australia

  8. #8
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    Without having the technical ability to scan and post the info. The jet is is near the camshaft from the end plate and directs extra oil to the gear wheels. It can be installed by drilling an extra hole through the end plate from the oil line that goes from the bottom of the feed to the top (if that makes sense). There was a small oil jet at the bottom but according to the manual more oil was required at the top, hence the modification. My head is starting to hurt!!

  9. #9
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    Default Oil

    Hi,
    My worth. I use Mobil One. It always used to be considered the best when it was the 'only' synthetic. It used to say 'suitable for any engine' no qualifications. I think it still is! Perhaps there are others just as good but who could know with all the hype so I just use it.
    Of course there are now several grades because different cars recommend varying grades and you cannot put in the wrong grade without affecting the warranty. However the 5w-50 still looks good for the older engines to me. Thinner like a 5 when starting so it flows well and still equal to a 50 when the engine is going hard and hot. The other thinner grades are for later engines which are designed for better fuel econony and less drag.
    On the subject of the R5 oil pump. Perhaps the pressure was higher because the relief valve was set higher?
    jaahn

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