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Thread: Lakes ????

  1. #1
    Squirtin Thunder
    Do you know if the '91 7.5L EFI (460) had a retard cam timing????
    Thanks
    Jim

  2. #2
    Squirtin Thunder
    OK the deal is my water pump is leaking and if I am going that far I was thinking of gaining a few extra hp by bringing the timing strieght up. It only has 451,000 miles on the engine and the water pump is original. I thought these things last forever?????????
    Jim

  3. #3
    LakesOnly
    Compared to what engine?
    In 1972, Ford effectively retarded the cam timing 8 degrees (by advancing the cam chain's crank gear by 4 degrees).
    http://www.reincarnation-automotive....k-sprocket.jpg
    http://www.reincarnation-automotive....k-sprocket.jpg
    Whether or not this applies to the computer-controlled FI motors is not known by me, but comparing its crank gear to the photos above will answer your question...I would think probably the later set.
    LO

  4. #4
    Squirtin Thunder
    Believe it or not I have called about three dealers and they all say that they have no idea. They just replace them if needed. This is my first '91 that I have even thought of changing the timing set on. I usually deal with older ones. At the dealership that I worked at in NC all I saw were the GM ones, Black Pontiac GMC, imagin that right.
    Thanks
    Jim

  5. #5
    LakesOnly
    ...water pump is leaking and if I am going that far I was thinking of gaining a few extra hp by bringing the timing straight up.
    Jim
    Jim, the cams on the later engines are ground differently...for a different power curve and so if you put the earlier timing set in with your 1991 smog cam, you will lose about 500 rpm top-end power (when compared to an early engine with the early set). Low end response will be improved, though.
    LO

  6. #6
    hondajoey
    I was told on a fuel injected motor you need to put the timing in the factory location thats is where the Computer is calibrated for, i changed a cam in my 350chevy with TBI and changed the timing set and the summit rep advised me to leave it in the strait-up location due to knock sensors.

  7. #7
    Squirtin Thunder
    Yes if it had knock sensors that could be true but the knock sensorf will know if it it knocking at 20degs advanced too.
    Lakes
    This truck has 3.55 gear in it the highest it has ever seen is 4000rpms. and with the 33" tall tire it would help a bit, to be a little advanced I believe.
    Put it this way the truck in overdrive turns 1900rpms at 75mph or so.
    In town the thing is chugging along. I do think the reson it has lasted me so long was that the gears are so high and that FORD has one hell of a base 460 (7.5L).
    Thank you
    Jim

  8. #8
    Squirtin Thunder
    Well I found that the '91 F250 7.5L (460) came from the factory with a double roller timing set and they are straight up. I did show signs of wear, after 451,000 miles I guess its OK !!!! The cylinder presure is still at 162psi average. Now that is eather the Valvoline Dura Blend or just one Hell-of a Engine Ford made. It is still hard to believe though. But the water pump sucks it should have lasted forever. This is my first water pump replacement on this truck.
    Jim

  9. #9
    058
    Only 451K?....just getting broke in. Be sure to take it back to the dealer for its 500,000 mile service.

  10. #10
    MudPumper
    You guys forgot...........JETBOAT

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