Specification Comp 26921
10-22-2003, 05:37 PM
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Specification Comp 26921 Has any body got the specifications on the new Comp 26921 Valve Springs.
All that seems to be available is that they are dual's with a 1.300 Dia and good to .650 lift.
But at what spring pressures opened and closed.
All that seems to be available is that they are dual's with a 1.300 Dia and good to .650 lift.
But at what spring pressures opened and closed.
10-23-2003, 09:38 AM
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Re: Specification Comp 26921 Kind of off topic but at what spring pressure does it become an issue? And why does spring pressure matter so much? I can see why needing too much pressure would place undue stress on components, but I would have thought they would have designed around this. Do the larger cams have such ramp rates as to overtax springs at a higher installed pressure/height? Just tryin to learn here, just gettin into valvetrain stuff.
10-23-2003, 11:16 AM
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Re: Specification Comp 26921 do these springs set up at 1.770" or 1.800". if they set up at 1.770" then 135 on the seat sounds good, but 400 at .550" of lift. if you run a big cam with those springs there is going to be some serious pressure. hell, my cam with .570" lift would be over 400 lbs. is it just me or does that seem excesive for a hydrolic roller cam?
10-23-2003, 02:21 PM
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Re: Specification Comp 26921 Couple of points Comp has released them for LS1 motors in particular so we would presume they would know what they are doing. When you start running high rpms in a modified car with to little spring pressure you will get valve float and loose power. Yes the spring pressure is high and you would need to run the correct components to make the valve train work.
10-23-2003, 03:46 PM
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Re: Specification Comp 26921 You want enough spring pressure to stabilize the valve when closing, not enough pressure and the valve bounces off the seat. IMO you should run no less than 135 on the seat and no less than 350 open. That being said I have run as much as 180 on the seat and 480 open with no problems. In the mustang world there is a class called renegade and they are 306 CID that run hydr. roller cams no more than .550 lift. We have hydr. roller cams that will make power at 8500 rpm and it must have a seat pressure of at least 160 and open 400. You can run that much on a stock lifter given it is good shape, comp "R"'s being my choice of lifter to do such. BTW we run 165 on the seat with stock lifters and rocker in our car, but comp "R"'s are going in with the new heads.
