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roller rockers

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by chevysrule, Dec 17, 2001.

  1. chevysrule

    chevysrule Registered Member

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    Okay, i bought my truck 2 years ago, its my first vehicle. the guy told me it had a 1/4 mile racing cam in it. I did a compression test and all of the cylinders read 123-125psi. The 400 motor has great horsepower but is weaker ont he torque side. I recently installed Crane hi intensity lifters (to bring back low end compression and vacuum) , crane roller rockers 1.5 ratio and a shift kit. since then the power is gone, i can hardly keep it running, and its extremely hard to start. can anyone help??
     
  2. KRAZIE87K5

    KRAZIE87K5 1/2 ton status

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    sure sounds like a timing issue to me... hard to start, doesnt run, no power... all the indicators that your timing is trashed...

    Check to make sure the dist. is in correctly, and then look for proper firing order 1-8-4-3-6-5-7-2, then look for spark plug gap .045 to .060 depending on your ignition coil. After that is all good, go for the timing gun. Set timing at 8* for starters, you can bring it up to 12* if you plan to run 93 all the time.

    You might also want to check that you have the correct plugs installed... I once bought a set of plugs that were too shallow, and didn't extend all the way into the combustion chamber.. (the end of the plug was still in the spark plug bore). This caused some funky power problems too... [​IMG]

    Other than that, I would have to lay hands on that bad boy! Thats all I have for now...

    <font color=red>GOT MUD???</font color=red>
    My license plate reads:<font color=blue> 8 YR SUV</font color=blue>
    454/TH400/NP205 - 14BFF/D60/w/ 4.10s - 36" TSLs<P ID="edit"><FONT class="small">Edited by KRAZIE87K5 on 12/17/01 11:08 AM.</FONT></P>
     
  3. chevysrule

    chevysrule Registered Member

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    I know that the plugs are fine. and highly recomend them (champion truck plugs) after the installation we re did the timing by ear. and i can actually still drive the truck. i plan on re-setting the lash and doing another compression test.
     
  4. wayne

    wayne 3/4 ton status

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    I would agree, it sounds like timing.

    See <a target="_blank" href=http://coloradok5.com/gallery/Waynes-Toy>Project Mighty Mouse</a> here.
    <font color=blue>Wayne<font color=blue>
    <font color=blue>Happy Trails<font color=blue>
     
  5. chevyracing

    chevyracing 1/2 ton status

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    It could also be that the valves are adjusted too tight. Make sure you have correct lash. Just out of curiosity, what is a 1/4 mile racing cam?

    John

    Like to go sloppin' 'round in da mud in a rapid fashion....=)

    <a target="_blank" href=http://coloradok5.com/gallery/albun31?&page=1>BLAZER PICS</a>
     
  6. chevysrule

    chevysrule Registered Member

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    I actually have no idea, i was hoping someone else would know. thanks for the help
     
  7. 79Jimmy

    79Jimmy 1/2 ton status

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    Sounds like the valves are lashed too tight to me as well. If the valves aren't closing all the way it hard to get very much compression. Let off a half a turn on all the rockers, asuming the were all adjusted the same, and give it a crank. Couldn't hurt![​IMG]

    James

    jimmy79@shaw.ca
     
  8. DesertDueler

    DesertDueler 1/2 ton status

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    1/4 is a mild RV cam. 3/4 cam is supose to be a 400 horsepower cam, but the last one we dynoes it put out a whopping 300 hp.

    86Jimmy 4"&35"MTRs,87 burb 4"&33"MT,69Firebird w/525 hp,and 70GTO live in PHX,AZ<a target="_blank" href=http://www.geocities.com/modifierperformance>My vehicles</a>
     

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