Thread: valve seals for modded heads

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?

I ran Viton seals on heads that were milled .100". No oil burning issue. Sounds like an install error on his part.

Intense has the modded seals as well... Not a bad job, but PITA because you shouldn't need to be doing it.

I would take one intake and one exhaust spring off and Mic the valve stem (o.d.) and talk to intense, make sure the i.d. Of the seal is good to go...

I've done the .1" off the valve guides and not had a problem with getting viton seals to work. They do have a problem with popping off though. Prj sold tighter fitting seals that stayed on better.