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Thread: valve spring clearances

  1. #1
    curt
    help, correct me as necessary please . Im spending the day putting a cam in my boat when i should be putting upwith a lack of power until winter. but i just cant stand the smoothness of a stock cam .anyway i ordered a complete cam kit from on of our fellow posters when it arrived I read all the literature 20 times and assembled the missing parts so today I started the r/r of the cam. All went well until i started changing the valve springs with the stock spring retainer and stem seal i have plenty of clearance with the isky retainer there is less than 0.500 " and the double spring will not clear the stock stem seal i bought teflon seals that are smaller but cannot get them on if i could I think i would have enough room without a trip to the machine shop . is there some secret to this ? this is a gm402 all original all stock 10 hours old I'm putting in an Isky292 mega hyd. with 0.590 lift at the valve are the double springs really necessary I want to be able to WOT @5700 an am concerned with float or breakage the stock parts are new gm pices. any help is much appreciated squirton!

  2. #2
    blowngas
    Originally posted by curt:
    help, correct me as necessary please . Im spending the day putting a cam in my boat when i should be putting upwith a lack of power until winter. but i just cant stand the smoothness of a stock cam .anyway i ordered a complete cam kit from on of our fellow posters when it arrived I read all the literature 20 times and assembled the missing parts so today I started the r/r of the cam. All went well until i started changing the valve springs with the stock spring retainer and stem seal i have plenty of clearance with the isky retainer there is less than 0.500 " and the double spring will not clear the stock stem seal i bought teflon seals that are smaller but cannot get them on if i could I think i would have enough room without a trip to the machine shop . is there some secret to this ? this is a gm402 all original all stock 10 hours old I'm putting in an Isky292 mega hyd. with 0.590 lift at the valve are the double springs really necessary I want to be able to WOT @5700 an am concerned with float or breakage the stock parts are new gm pices. any help is much appreciated squirton!
    save yourself some headaches--go ahead and pull the heads,(since the intake is off) take to a decent auto machine shop along with the new springs,retainers, and locks, give him the specified installed height---he may have to resize the seal dimentions to use a smaller teflon seal than u have--ps-use a good new head gasket (felpro, ect)for your specific engine and application--do it right and u shouldn't have any additional problems---best of luck

  3. #3
    wideopen545
    have them check the lower spring cups thats were your spring sets the 402 bbc had two different heads car and truck if you have the truck you need spring cups to keep the spring from walking around been thier thought it might help tim

  4. #4
    FLYTE RISK
    Agree with all the above, but if you are going that far go roller only way to go save that set up for your hauler....

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