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GM B-Body Forum, 77-79 Caprice/Impala Forum

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    Mechanical engine question

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    HeavyChevy77
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    Mechanical engine question

    Post  HeavyChevy77 on Thu Mar 23, 2017 12:16 am

    Put a edel intake with soft fiber gaskets as I was mistakenly using blue felpros and had vac leaks due to aluminum intake/iron head and the gasket to stiff to seal
    Swapped it immediately better never retuned the qjet but was driving very well so drove it a week ran great I was happy but knew it needed a tune up
    Days before I work on it again it would idle kinda lopey and coming to a smooth stop got lopey and gen light would flicker with low lopes.
    So had a msd dizzy to go in put it and this where my mistake happened I got 4&6 backwards and not sure why I know the firing order off the top my head but still mental lapse on my part.
    Tried to tune it but saw I kept having a 1/2"hg drop steady with rpm thought my valves were just worn (fails paper test)  but knew something was off as it would puff vapor or compression thru carb on acceleration so eventually had found my mistake fixed it and revved fine next day check it though and still did the puff not as strong though . So knew something is wrong
    #6 Comp test 50 psi. Wet 55psi
    Check rockers #6 intake visibly loose when wiggling lots of spring in lifter
    Loosened rocker Removed pushrod dizzy got a bendable magnet and remover the lifter which was bad I could bottom it out with my finger tips
    So ordered new intake gasket and lifters
    But I'm gonna get one lifter from autozone to install and confirm the failed part.


    my question is would I need break in oil for one lifter or would the assembly lube be sufficient
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    Re: Mechanical engine question

    Post  GM B-Body Forum on Sat Mar 25, 2017 12:10 am

    To be honest i wouldnt even mess with installing just that one to see if its bad, sounds like that hydraulic lifter collapsed and was giving you all that play in the pushrod, id def check that cam and lifter out, to make sure there isnt a wiped lobe, and if so get ready to install another cam and lifters. But to answer your question, yes break in oil! along with the assembly lube. Shoot with these flat tappet cams id run break in oil all the time, but i actually use Joe Gibbs Driven Hot Rod Oil HR5 10w40, and used their break in oil for both of my cam swaps and no problems with over 22,000 miles in 5 years.

    On another note, im trying to figure out why you have such low compression on that one cylinder, even with a worn lobe or collapsed lifter you should have normal compression unless one of the valves arent seated fully, or a plethora of other things lol


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    1979 Caprice Sport Coupe, 400hp Vortec 350, Th350, GM 8.5 w/disc brakes, 3.90 gears Detroit Truetrac, 2.5" stainless duals w/ x-pipe, Dynomax race bullets.
    1984 Caprice Sedan, 305 motor, 700r4
    1978 Caprice Sedan, 305 motor, th350
    1993 L99 Caprice, 4.3 v8, 4l60 trans
    1972 Ford F-100, 302 windsor, c4 trans
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      Current date/time is Sat Oct 21, 2017 10:42 pm