gonna change valve stem seals on a 91 Z71 350 in the next day or so and need a question answered. Using viton umbrella type seals, should they go on all valves or just the intakes as the G.M. manual says and do I need to use the O- rings under the keepers?
Thanks, Dave.
The intake valve seal should be the positive seal that pushes right down over the valve guide. The exhaust seal uses the umbrella type that just rides on the valve stem. Make sure you use the small plastic sleeve to protect the seals as you push them down the stem. And "YES" you must use the o-rings under the keepers. And you must install the valve spring and retainer, compress them, and "then" install the o-ring right before you install the keepers. If you install the o-ring on the valve stem and then compress the spring, (as so many rookies do), you will push the o-ring below the spring retainer and it will not work properly.
Ian
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