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Discussion Starter #1
I just had the head resurfaced and the valves ground and now I am trying to set the clearance. On the exhaust side I cannot get any and I mean any clearance. I have used the same shims that I took out so I think I should have some clearance as I do on all the other valves. Do I have the machine shop grind the top of the valves or how do I get some kind of clearance so I know what size shims to use? Really need help cause I want to get it together soon. Thanks!!
 

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You need to install shims that are thinner than the shims currently installed. Do you know what size shims are in there now? Do you have any shims that are thinner?
 

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Start by assembling the head with NO shims. Measure the valve clearances, which should be too big. Exhaust valve clearance is usually set at around .020 - .021". So, subtract .021 from whatever clearances you get on the exhaust side - that's the thickness of shim that you need.

Sometimes after a valve grind the valve stems move too close to the cams to accommodate a standard thickness shim. I.e., no standard shim is thin enough to give the necessary clearance. In that case, it is necessary to grind either the valve tip or shim. Or install new seats.
 

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I just went through this myself. Check the clearance between cam lobe and tappet without the shims. Subtract the stock clearance this should be what size shims you need just as alfajay says. If you try to shave the valve stems becarefull because the skirt of the shim may now ride on the valve keeper and not the valve stem. This happened to my head and although I only needed to replace one exhaust valve, while all the clearances for the rest were within spec to start, after the head work was done and they shaved the valve stems I needed to redo all the shims and needed to shave the skirts so the shims would rest on the stems not the keepers.
 

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Having too many shims to begin with, I never had to resort to the no-shim clearance check. I'll install the thinnest shim available, 0.059", and go from there. This method has the advantage of determining the clearance using only one blade of a feeler gauge (depending of course of the type feeler gauges one has).
If the clearance in the no-shim method is larger than the thickness of your thickest single feeler gauge (0.080" minimum for the exhaust), then multiple blades will have to be stacked together. Having stacked blades can reduce the accuracy of the reading which may result in having to adjust a valve (or valves) a second time.

If the clearance is too tight even with the thinnest shim, the preferred method is to replace seats/valves as necessary.
A method used in the field a number of times to obtain proper clearance is to grind a shim a bit thinner (0.050" being the minimum thickness). If still insufficient clearance, then up to about 0.010" can be taken off the valve stem while still retaining sufficient shim to keeper clearance.
 

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Discussion Starter #6
Thanks for the advice! I will check as advised as now I think I can get the proper clearances. The info on how to get the correct is great. Thanks to all again. Michael
 

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Having too many shims to begin with, I never had to resort to the no-shim clearance check. I'll install the thinnest shim available, 0.059", and go from there. This method has the advantage of determining the clearance using only one blade of a feeler gauge (depending of course of the type feeler gauges one has).
If the clearance in the no-shim method is larger than the thickness of your thickest single feeler gauge (0.080" minimum for the exhaust), then multiple blades will have to be stacked together. Having stacked blades can reduce the accuracy of the reading which may result in having to adjust a valve (or valves) a second time.

If the clearance is too tight even with the thinnest shim, the preferred method is to replace seats/valves as necessary.
A method used in the field a number of times to obtain proper clearance is to grind a shim a bit thinner (0.050" being the minimum thickness). If still insufficient clearance, then up to about 0.010" can be taken off the valve stem while still retaining sufficient shim to keeper clearance.
I agree whole heartedly except that after my head rebuild the valve stems were shaved so I could not get accurate readings of the clearance(prior to the rebuild all but one valve were in spec on clearance but none after!) without grinding the skirts of each shim first so it was easier to pull the shims and to stack feeler guages. My feeler guage unscrewed so I could stack them easily but as you stated I was off slightly on a couple. When the new shims came in I shaved the skirts and remeasured and had to shave a few shims for proper clearance.
 

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...the valve stems were shaved so I could not get accurate readings of the clearance...without grinding the skirts of each shim first...
This is why a max of only 0.010" can be taken off the stems. Any more than that risks the shim skirts contacting the keepers (which, as you know, now requires that the skirts be shaved too).
 

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If the shims needed are thinner than what's normally available, the seats and/or valves have likely been cut too far. If the shim skirts hit the retainers, something's not right. There are some "long skirt" shims that are maybe for V6s? If have run into those periodically, and been fuddled on getting consistent valve clearance readings.
If need be you can make thin custom shims on a valve stem grinder, or grind the valve stems slightly, but then you're courting having the shims hit the retainers. About the thinnest you can go, the Bay Area gurus say, is .030". A well-done four-cylinder valve job will result in shims in the .065" to .085" range.
Andrew
 
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