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Thread: R2 cranking pressure

  1. #1
    President Member Ron Dame's Avatar
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    R2 cranking pressure

    The shop manual calls for 160 -170 PSI. This 59,000 mile engine shows 123-132 PSI, hot, all plugs out, and throttle open. Oil in two holes made no change, at that point I stopped trying. I'm at 2100 feet altitude, but I doubt it would make that much difference. What is real life cranking pressure on an R2?
    Ron Dame
    '63 Champ

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    Ron, Motors says 160 PSI, now if the origional steel head gaskets were replaced with composition head gasket that could explain the difference. Valves not sealing as well after how many years? Valves properly adjusted? Lou Cote

  3. #3
    Speedster Member greyben's Avatar
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    Considering the readings are reasonably consistent it seems unlikely that any wear would be so even across all 8 cylinders. On the other hand the readings you are getting are about what would be expected in an engine with dished pistons.
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  4. #4
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    Check your valve adjustment. Note what you've got now and then set them to spec. If they're at all tight, if you've had exhaust valve seat recession, that can lower the cranking compression.

    jack vines
    PackardV8

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    Stock cam?
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  6. #6
    Golden Hawk Member StudeRich's Avatar
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    Quote Originally Posted by greyben View Post
    /Cut/On the other hand the readings you are getting are about what would be expected in an engine with dished pistons.
    However if still stock, an R1 and R2 Both have Flattop Pistons with stock R2 Heads about; 9 to 9.5 Compression Ratio.
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  7. #7
    President Member Ron Dame's Avatar
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    Put the borescope in and see I have flat top pistons, but lots of carbon
    Ron Dame
    '63 Champ

  8. #8
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    Just as a double check, measure stroke to ensure you have 289 crank. You never know...

    If you have a thick dark layer of 'carbon ' it is likely bad rings as you could be pumping a lot of oil.
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  9. #9
    President Member TWChamp's Avatar
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    Usually engines with bad rings will be clean around the outer part of the piston tops.

  10. #10
    President Member Ron Dame's Avatar
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    Best as I can tell from comparing what little I can see to a feeler gauge, the gaskets are around .035". It's not at all accurate, but the best I can guess.

    Quote Originally Posted by dynolou2 View Post
    Ron, Motors says 160 PSI, now if the origional steel head gaskets were replaced with composition head gasket that could explain the difference. Valves not sealing as well after how many years? Valves properly adjusted? Lou Cote
    - - - Updated - - -

    I'm really not using any oil, and the plugs stay clean.
    Quote Originally Posted by TWChamp View Post
    Usually engines with bad rings will be clean around the outer part of the piston tops.
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  11. #11
    President Member Ron Dame's Avatar
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    I adjusted the valves to .026"cold today, all were a bit tight, from .023 to .025. Yesterday, the compression was tested with the engine warm, today, cold. Not much difference, maybe 5 pounds. And though it cranked fine, I had forgotten to recharge the battery.
    How much difference between hot with a fresh battery and cold with a not too bad, but not too fresh battery should I expect? I hate the idea of putting the plugs in, warmong it up, and pulling them again, but I guess I better get used to it.
    Ron Dame
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  12. #12
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    Sounds like composite head gaskets instead of shim. There is usually a small portion on the outside edge of the heads where you can inspect. If there are 2 pieces of steel with a filler, they are not the shim gaskets. Could lower compression to about 8.5.
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  13. #13
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    Quote Originally Posted by Ron Dame View Post
    I adjusted the valves to .026"cold today, all were a bit tight, from .023 to .025. Yesterday, the compression was tested with the engine warm, today, cold. Not much difference, maybe 5 pounds. And though it cranked fine, I had forgotten to recharge the battery.
    How much difference between hot with a fresh battery and cold with a not too bad, but not too fresh battery should I expect? I hate the idea of putting the plugs in, warmong it up, and pulling them again, but I guess I better get used to it.
    All the Shop Manual specs are for cold cranking compression.

    And yes, having a fully charged battery cranking over fast does make a noticeable difference on some engines.

    jack vines
    PackardV8

  14. #14
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    Any chance you have a bad gage? I have seen the ones with the rubber hose between the plug hole adopter and gage go bad, and flex out when cranking.

  15. #15
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    If you checked it cold it is probably okay. Warm it up to operating temp 160 deg and check again. It'll be higher. If there is no blow-by or excessive oil consumption, I wouldn't lose a wink of sleep over it----it wouldn't be worth dropping several grand into it just to raise compression 20 psi.

  16. #16
    President Member Ron Dame's Avatar
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    Quote Originally Posted by Jeffry Cassel View Post
    If you checked it cold it is probably okay. Warm it up to operating temp 160 deg and check again. It'll be higher. If there is no blow-by or excessive oil consumption, I wouldn't lose a wink of sleep over it----it wouldn't be worth dropping several grand into it just to raise compression 20 psi.
    A recharged battery helped a bit, I'm trying to decide whether just to check the oil pump and bearings, or pull the heads and look. I do want to get the old pressure closer to nominal, even though it's theoretically ok at 10 PSI per 1000 RPM. I guess best practice at this point will be to pull the heads and see what is up. I must say, nasty as the outside is, everything under the rocker covers is very clean. The engine uses no oil to speak of and doesn't smoke. Of course it leaks.
    Ron Dame
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  17. #17
    President Member TWChamp's Avatar
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    I agree with Jeffry. I'd leave it alone and just fix any leaks.

  18. #18
    Speedster Member Endl98's Avatar
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    I just rebuilt my R2 and I have 175 psi cranking pressure, but I did install a R2+ camshaft. tho id think that would of lost a little on cranking.
    1 Family owned 63 Studebaker Avanti 63r-1705 White with Orange interior , R2 4 speed.
    Just purchased 63r-3623 R2 was a auto now dressed to a R3 with a4speed.

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