Is anybody using a spring height micrometer when setting up their heads? I am having trouble finding one in the right height range and small enough to fit the spring base/pocket. I have an 1150 head and want to set my springs up by pressure and not at the assumed spring height.
I use a vernier. Ray.
Yeah, the tailshaft of the vernier gauge will fit the limited access of a 4 valve head.
I do the same thing and all you have to do is subtract the thickness of the retainer.
We use the spring Mic to set the spring tester. We check everything at assemblerd height, retainer spring and base, just the way it will be in the head.
Jay I am running the Pro springs in my GS head. Cams are G18/G14 (.425/.440). What minimum coil clearance at maximum lift is acceptable? I also found that I had a variance of approx .035 difference between my shortest spring (.755) coil bound height and my tallest (.790) coil bind height. That is a pretty big difference and could greatly affect my clearance to coil bind.
The person I bought this head from was running the standard HD valve springs with these cams. This does require the Pro springs correct? This is the first head I am assembling on my own.
Last edited by kms2402; 08-16-2012 at 09:15 PM.
You HAVE to get the springs INSTALLED height pressures close to each other. If you have different heights either some of the valves are sunk further than others or you have mixed sets of spring bases. Check the thicknesses on all of your spring seats & make sure they are the same or close. If they are then start measuring the amount the valve stems are off the spring seats. You will just have to shim the longer ones to get the spring installed height pressures close to the same. I shim all of mine to within 2 pounds of each other. And, YES, you will need the Pro springs with cams that big!
I am within 2 pounds on both my intake side and exhaust side. On my intake side I do have 2 valves that are shorter, and I have shimmed the longer ones to get the same installed height pressures. Worked out perfect and I have plenty of clearance to coil bind. The smallest is .047"
The problem I am facing is with my exhaust side. Partially because of the large lift on the cam and the shorter installed heights. However, the big problem I am facing is that when I went back to calculate my coil bind clearance I discovered that 3 were very marginal on clearance and 1 only had like .010"!! I pulled my springs back off the head and measured each spring at complete coil bind. What I found was that I have a margin of .0.040" in height between my shortest spring and tallest spring. My shortest spring is 0.750" and the tallest is .790", the others are somewhere in between. On my exhuast side all of the installed heights are within .005".
Its the height of the springs when coil bound, that are causing my problems.
What I have done is ordered another set of springs and I will just measure them and pick out the ones I need to get my clearance. I am shooting for at least .040-.050 clearance. Is this enough?
Last edited by kms2402; 08-18-2012 at 05:32 PM.
Com Cams sells a Hight mic for small engines.....Mike
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