SuperTech Dual Spring users????
03-05-2010, 06:46 PM
#2
I haven't seen the SuperTech valve gear (please post pics) but most valvetrains I'm familiar with use seats and shims for 2 different purposes:
Valve seats locate/center the spring on the guide and protect the soft AL cylinder head from getting marred by the hardened spring steel of the valve springs. Valve seats are typically not run/needed on iron heads.
Valve shims are used to set the installed height of the valve spring to the spec provided to you by the mfg (SuperTech). Production tolerances, different valve lengths and high vs. low valve seats can all impact installed height of the spring. Supertech should have provided you with an install height spec (which needs to be checked on each of your 16 valves) and the valve spring pressure both with the valve closed (spring at installed height) and with the valve open (max lift of cam).
If I was building a nice new motor I'd check each valve spring with a machinist's square to ensure it was not tweaked or bent and also check each spring to make sure it had the specified pressure at both closed and open heights. Once the springs are known to be good, then I'd take the time to measure and adjust installed spring height (with shims on top of the valve seats) and try and get all the installed heights as close as possible. YMMV
Valve seats locate/center the spring on the guide and protect the soft AL cylinder head from getting marred by the hardened spring steel of the valve springs. Valve seats are typically not run/needed on iron heads.
Valve shims are used to set the installed height of the valve spring to the spec provided to you by the mfg (SuperTech). Production tolerances, different valve lengths and high vs. low valve seats can all impact installed height of the spring. Supertech should have provided you with an install height spec (which needs to be checked on each of your 16 valves) and the valve spring pressure both with the valve closed (spring at installed height) and with the valve open (max lift of cam).
If I was building a nice new motor I'd check each valve spring with a machinist's square to ensure it was not tweaked or bent and also check each spring to make sure it had the specified pressure at both closed and open heights. Once the springs are known to be good, then I'd take the time to measure and adjust installed spring height (with shims on top of the valve seats) and try and get all the installed heights as close as possible. YMMV
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03-05-2010, 07:33 PM
#3
The supertech seats go on top of the stock ones. But as sn95 said, you might still require shims to get the correct installed height. Otherwise you will have different seat pressures all over the place. The make a special micrometer for this, and it will only fit inside the outer spring, which is ok.
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03-05-2010, 10:28 PM
#4
The supertech seats go on top of the stock ones. But as sn95 said, you might still require shims to get the correct installed height. Otherwise you will have different seat pressures all over the place. The make a special micrometer for this, and it will only fit inside the outer spring, which is ok.
) but you can improvise with other tools if you don't have one or want to buy one. Most shim kits are an assortment of .015, .030 and .060 thicknesses, so you're not going to get installed height set to the .001 for all valves. Some dial calipers can work, an inside mic can work or you can use a telescoping gauge and measure its height with calipers or a mic. Make sure you use hardened/tempered shims too. Ordinary shim stock may not hold up under the high spring pressure and heat.
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