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Oil Pressure At Idle

Discussion in '"Stock" Alpine' started by serIIalpine, Apr 19, 2007.

  1. serIIalpine

    serIIalpine Donation Time

    After driving my SerII today for about a half hour my indicated oil pressure at idle was less than 10 lbs. At revs it was around 40. I'm running 20w-50 oil and when cold the pressure ranges from 25+ to 50+.

    Is this OK????



    62 SerII
  2. jumpinjan

    jumpinjan Bronze Level Sponsor

    It sounds okay, but why do you run such heavy oil?
  3. serIIalpine

    serIIalpine Donation Time

    It's coming up on summer here in LA and when I do get to drive my car it's usually either in Bumper to pumper traffic or as fast as the the little 1600cc engine will make my Alpine go for hours at a time in the mountains north of Los Angles.

    Also, the oils I am using Royal Purple in the specific 20w-50 spec is very high in Zinc and Phosphorus. These are supposed to be good for older engines with solid lifters etc..

    By the way this is what tech support at RP said:


    That doesn't sound right. What kind of oil filter are you currently
    running and is your pressure gauge before or after the filter? Do you
    have anything blocking your pressure sending unit? You might want to
    check for Teflon tape. Are you using a stock gauge or an aftermarket
    gauge? If it is aftermarket gauge when did you install it?

    Have you driven the car since? The way you talk you put the 75 miles in
    one trip and you could have had a air pocket. I would be interested to
    see if this does repeats.

    Get back to me and I will go from there to try and help you.

    Have a great day.

    Kyle Neal
    Technical Sales Representative
    1 Royal Purple Lane
    Porter, TX 77365
    281-354-8600 office
    713-705-9556 cell



    '62 SerI
  4. jumpinjan

    jumpinjan Bronze Level Sponsor

    Anytime this heavy oil issue comes up, I wonder how your rocker arms are doing with that thick oil. Another thing I heard is that the thicker oil doesn't help the rings and will make them stick more. I don't know if thats correct or not. Is there enough oil getting up there? What is your oil pressure using 30 oil?
    I remember when R/P came on the scene about 1992. I would say that its a good oil to use.
  5. V6 JOSE

    V6 JOSE Donation Time


    He lives in So. Cal., where the temps get to over 100 degrees regularly. In the summer these older cars can use the more viscous oil, because it thins out when it gets hot. The heavier oils do not hurt either the rings or rockers. Where did you get the idea that heavier oils would gum up the rings??

    It is hard for those that do not live in the South West, to understand the kind of stress engines are under during the summer heat, especially in stop and go traffic. I have always used 20/50 oils in all my engines, with no negative results.

  6. Nickodell

    Nickodell Donation Time

    Eric; the figures you give are puzzling. If you're getting pressures that are only limited by the bypass valve at high revs, you should be getting more than 10psi at idle, unless you have the idle set way down - 500rpm or less. I don't know about you, but Matilda needs at least 800rpm to idle smoothly, and at that speed, on a well worn 1725 (e.g. wear steps in the cylinders) I still get 25psi or so with hot 10w40 oil, and bypass pressure at 1500 and up.

    I only know of five reasons for l.o.p:

    1) Worn mains and/or big ends;
    2) Too much wear clearance in the oil pump;
    3) Clogged filter, or other blockage upstream of the gauge pickup (downstream would tend to give higher, not lower, readings);
    4) Faulty gauge;
    5) Too low a viscosity oil.
    6) Faulty bypass valve;


    1) Only you know. And that would reduce pressure all through the rev range;
    2) Ditto
    3) Absolutely ditto. In fact, this would more likely cause poor pressure at higher revs where the flow restriction would be more significant than at low;
    4) Again, one would expect problems all through the range, and other symptoms like the needle momentarily sticking as it rises or falls in response to a change in revs, or failing to return to zero;
    5) Obviously, not in this case;
    6) Possible, if the plunger has stuck at the point where just a little of the return port is exposed. At low revs most of the pressure would be lost, but a strong pump output might keep it up at high.

    And you were wondering what you were going to do to occupy yourself this weekend:D
  7. serIIalpine

    serIIalpine Donation Time

    So I went out and took a spin in the early evening and here's what's going on:

    At idle when cold: 15-20 lbs
    3000 rpm+: 50+ lbs

    Warmed up the idle pressure drops to the very left of the scale. What is this 10-15 lbs??

    As I get on the gas the pressure rises almost as fast as the revs up to 50+ lbs.

    My guess this is ok. Yes, no, maybe???

    I just don't remember the pressure getting this low at idle but I would imagine that if it rises and holds at speed I'm OK.




    '62 SerII
  8. alpine_64

    alpine_64 Donation Time


    1. Are you getting any rattles at startup?
    2. IIRC you are runnign twin DCOES.. how rich are they running, with DCOE's if you are caught in traffic i think they are probably fuelling up. Smell the oil on the dip stick, does it have a fuel smell?
    Change your oil and filter, see if this helps, if so i think its a rich fuel misture ruining the oil.
    3. oil psi relife valve, is it sticking maybe?
  9. serIIalpine

    serIIalpine Donation Time

    No rattles at start up.

    I use a wix filter with a anti-reversion dohickey.

    The oil is brand new and while I have one plug that's a little sooty the other three are all fine.

    My carb adjustments are off and will be corrected tomorrow.

    How can I check the oil relief valve?



    '62 SerII
  10. Pumpkin

    Pumpkin Donation Time

    oil pressure


    How can I check the oil relief valve?


    Eric, the way I checked mine,,

    Take the bugger off, clean You can boil it out in a pan,, OH YEH,use the good ones hanging up.. ;) I go to goodwill or like place and get old stuff, works good. If you have a GASBBQ doit out side.. They clean up real good, also put in about 1/4 cup of dishwaser liquid soap ..

    And I used a standard pencil with an erasure,. Apply pressure with the erasure and press hard If it moves very easy, may be worn, If you cannot press it down then it is probably stuck with poop, also inspect the internal as well as you can.

    Also I tried another gage,, (after I went through all the above) worked real good. I ran it for quite some time with the newer gage on the tranny house..Now installed properly.

    Other than that PLAN B:eek:
    My 2p
    Chuck in portland
  11. serIIalpine

    serIIalpine Donation Time

    I have the later series oil filter plate with the screw on type filter.

    I undid the oil pressure relief valve and all that came out was the spring.

    I need to remove the whole apparatus to remove the PRV don't I?



    '62 SerII
  12. Alpineracer8

    Alpineracer8 Donation Time


    More than likely, if all you got was a spring, you removed the oil bypass valve rather than the pressure relief valve. My car is a Series I vintage racer with a Series II 1600 but, like you, I'm running the later model Series V oil filter/cooler set up and the block under the spin-on filter plate houses both a bypass valve and a pressure relief valve. Unless your PRV has been modified for higher pressure, you would have to practically tear it up to get the spring and piston out.

    To answer you immediate question, yes you should remove the entire assembly to be able to get at the PRV easily. It's easily removed and the gaskets are readily available from Sunbeam Specialties. Once you've removed the PRV, look at the relief hole in the side of the tube and see if you can see any daylight under the piston inside; i.e. can you see all the way through it. If you can, you just found your problem. If not, take a small instrument, preferably something with a blunt end, and stick it up the open end of the valve and push on the piston and spring. It should move freely and with absolutely no hang-up whatsoever. If the piston is reluctant to either push in or return, then again you just found your problem.

    The problem is that the piston and the tube on these valves are both of similar metals...brass. Brass is a soft metal and, therefore, wears easily. It's been my experience, too, that being a soft metal it wants to gall easily. I was experiencing the exact same problem on my race car that you are describing and, once I took that valve out, I found that the piston was sticking and not closing off the relief hole. I took it to a friend of mine who is an accomplished machinist and took the valve apart, took out the brass piston, honed the brass sleeve, made a new piston from steel and reinstalled everything. My valve now works like a charm. It appears to be a simple matter of putting steel with brass rather than brass with brass. The ultimate fix would be to make an entire tube and piston from steel but the cost would have been too high. What I had him do, however, is working perfectly.

    Best of luck and keep us all up on what you find,
  13. serIIalpine

    serIIalpine Donation Time

    So I pulled the pressure relief valve and found that it was indeed stuck open.

    I pushed it in and it came right back and seated properly.

    Does this need a cleaning or a dismantling and rebuild? And if so, how?
    My valve appears to be all steel. The piston is held in place by a ring inside the end of the valve. The end seems crimped to hold it in place.

    Take a look here and let me know what you all think.:


    Thanks again for evryone's help.


    '62 SerII
  14. RootesRooter

    RootesRooter Platinum Level Sponsor

    Your PRV looks like the style used on the later Arrow Range.

    First time I've seen one of that style stick open. I've used one (purchased with the matching base from SS over a decade ago) on my Series V for at roughly 100K - no problems so far.

    I wonder if you have some foreign matter that's jamming the piston? When the brass style PRV goes bad (at least the 4-5 on my Alpines), it first showed itself by sticking open at higher rpms (with pressure quickly dropping from 45 to 20), unlike your experience at low rpms. When removed for inspection, the brass piston had always managed to pop off the ridge and fully close, again unlike your situation.

    When you depress the piston, can you see any kind of ridge or scoring on the inside of the cylinder? Is there any 'catch' when you release the piston?

    If no defect is apparent, I'd be tempted to clean it out as best as possible with gas or solvent, re-install it and keep one eye on the guage at all times. If the valve is indeed bad, the symptoms will likely re-occur within 100 miles.

    Dick Sanders
    Kent, WA
  15. Nickodell

    Nickodell Donation Time

    Eric; SO it was #6! The valve in the photo is exactly the same as on Matilda (1967 SV), and I had the same problem a few years ago. Scared me until I heard no expensive noises, so as I was only 2 miles from home I drove back very carefully, one eye on the o.p. gauge, which showed about 20psi.

    What I found was that varnish from the oil had built up over the years, causing the valve to stick. I fixed it by placing it with the open end up in a can of lacquer thinner, which is a very powerful solvent, and chucking an old pushrod in my bench drill. Then I exercized the valve a few dozen times, to get the solvent to wash the valve walls and piston. When I was sure it was moving freely again I replaced the solvent with oil and exercized the valve again to get rid of the solvent, then changed the oil once last time and repeated the process.

    I have had no problems since.
  16. Wombat

    Wombat Donation Time

    This was discussed on an earlier thread. Someone (I forget who) posted a Rootes service bulletin about the relief valve. The earlier valves were prone tp wearing and sticking. The later valves were supposed to rectify this. The later valves could be identified by a small raised area in the centre of the hex head. Can't see this on your photos, but if it is there you have the "good" one. If so clean it, exercise it and reinstall as others have recommended.

    Still, I doubt if even the most optimistic Rootes engineer would have expected a 40+ year life out of them.
  17. RootesRooter

    RootesRooter Platinum Level Sponsor

    If memory serves, the pictured PRV isn't the replacement discussed in the bulletin. The service bulletin (issued sometime in 1966) suggested replacing the current PRV with an earlier version used on Series IV's. Both were brass. I "think" the raised dimple indicated the prone-to-wear version.

    The pictured PRV uses a different base, is wider, and is threaded at the opposite end from PRV's normally found on Series V's.

  18. serIIalpine

    serIIalpine Donation Time

    So I cleaned up said PRV lubed it and put it back in the car.

    Here's what happened: When cold the idle pressure is just below 50lbs. (realize that it's in the upper 50s here in LA today and I'm using 20w-50)
    I drove it down the street and at full revs I'm getting 60+ lbs and the idle pressure is just below 50lbs. The engine temp only got up to 165 degrees.

    Are these pressures OK or is my PRV sticking the other way now?

    It seamed to move ok when I pushed it in manually. It wasn't super smooth but it did move the full range easily.



    '62 Ser II
  19. Nickodell

    Nickodell Donation Time

    What you report is abnormally high. Did someone in the past tamper with the spring to raise the pressure? If not, it may indeed be sticking closed now. In any event, unless you want a blown filter sealing ring or something else I would replace the PRV ASAP IMHO.
  20. serIIalpine

    serIIalpine Donation Time

    So I took the PRV out once more and checked it's movement and everything seemed cool so I took the car on a 150 mile drive (See: Southern California Drive on Sunday) and while it remained pretty cool out and the engine never saw 170 degrees the oil pressure never went above 55lbs and never below 45.

    Sounds pretty good to me.

    You all missed a GREAT drive.

    Thanks again.


    '62 SerII

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