I had my engine guy machine .100 off the valve guide boss on the heads for retainer clearance due to ZZP XP cam. I bought ZZPs viton valve seals and gave them to the builder to install. He said they would not fit over the valve guide boss. He installed valve seals he found on his own. Now 20k later the engine is burning oil. I took off front valve cover and found a seal that has tore and is now at the top off the valve stem. My question is this. Did he take too much off the boss and now the taper of it is too wide for a seal to slip over? Is there other seal options for this?
