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  1. #1

    Default Time for bearings?or....

    Hey guys what's up.i have built two 302 engines.so I know a lol bit but I'm not a master.i have a 91 Gt that does this. Ok 4 knocks on start up,then quiet,then after I drive every now and then the oil gauge fluctuates fast.normal to 0 and back and fourth.my uncle gave it to me before he passed.i had been begging him for years.any who he never abused it at all.141,000 miles.i want to top end it (more power)but don't think it may be wise.whats wrong with it guys?


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  2. #2
    FEP Super Member
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    May 2003
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    What brand oil filter are you using ?
    Most brands do not have an antibiotic drain back valve , and will make the engine start with little or no oil after sitting .
    I use only an F1
    clowns to the left of me , Jokers to the right

  3. #3

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    I m not sure. I'll check and see

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  4. #4

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    Probably a stationary compressed (that valve open) lifter collapses and empties after sitting a while, then fills when you start it and run it a few seconds. The fluctuation sounds like an electrical issue, loose connection, etc. Doesn't ever read above the O?...
    Last edited by Walking-Tall; 07-20-2017 at 08:26 PM.
    Mike
    1986 Mustang convertible ---> BUILD THREAD
    Past Fox-chassis "four eyes":
    1983 Mercury Cougar LS
    1986 Ford Thunderbird ELAN
    1980 Capri RS Turbo

    Work in progress website ---> http://carb-rebuilds-plus.boards.net/

  5. #5

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    Motorcraft

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  6. #6

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    Its not uncommon for old worn engines to be 5-10psi hot, but it shouldn't knock at all after its been runnjng and up to temp. The oil light flicker and low pressure on the guage is probably just worn out sending units.

    My $.02, if it doesn't knock when warm, don't worry about it. Ive had 302's well above 200k miles, my last one was at 350k. It would knock a few times on start up, but after 10-15 seconds all the noise went away.

    Make sure you have oil preassure. If its over 5-10psi warm, don't let it bug ya.
    2 1986 cougars (both 4 eyed and 5.0)
    1 1987 cougar

  7. #7

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    5-10psi... lol...

    It's inexpensive peace of mind insurance to freshen the short block with cylinder honing, rings, bearings, gaskets, oil pump, and timing set... then you KNOW it'll be okay, and take "spirited" operation... especially with the lone fact of 141,000 miles... extra especially with this knocking... and extra super-dooper especially since OP said, "I want to top end it (more power)". Best practices for performance use (not abuse), engine longevity calls for 10psi per 1000rpm that you intend to rev it, meaning intentions of upwards or past 6000rpm should have 60psi of hot and revving oil pressure, which is a piece of cake for something with healthy bearing/journal and oil pump clearances.
    Last edited by Walking-Tall; 07-21-2017 at 12:50 AM.
    Mike
    1986 Mustang convertible ---> BUILD THREAD
    Past Fox-chassis "four eyes":
    1983 Mercury Cougar LS
    1986 Ford Thunderbird ELAN
    1980 Capri RS Turbo

    Work in progress website ---> http://carb-rebuilds-plus.boards.net/

  8. #8

    Default

    Guess i should have said 5-10psi hot at idle. Btw, spec is around 10psi per 1k rpm, so with a 700rpm idle, spec would be 7psi, so it makes sense to me. My guess is the "i have a high volume oil pump with 65psi at idle" speech is coming next.

    Oil preassure isn't nearly as critical as flow. If the oil is getting in all the places in needs to be, then you really dont have anything to worry about. Anything over 10psi per 1k rpm is just wasting power and wearing out seals.
    2 1986 cougars (both 4 eyed and 5.0)
    1 1987 cougar

  9. #9
    FEP Super Member erratic50's Avatar
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    The only exception to that rule is with stock style unmodified lifters. Here additional oil pressure keeps the lifters stood up which is good for more lift at the value which translate to more RPM.

    My dad would always run bearings right at or within 0.001 of *max* tolerance with a higher pressure bypass spring. I've seen 80 at 1000 idle rpm from his monsters a time or two but they've always lasted really well.

    if you go to a high volume pump go to a larger pan. Otherwise the oil will not get back to the pan fast enough for only 5 quarts to provide sufficient oiling. High volume needs a bigger pan and more oil. Learned that one the hard way.

  10. #10

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    thanks guys really appreciate the info was just trying to do the correct thing. I do want more power but don't want to do anything stupid.so again I should be gt40 safe?

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