turb0racing

im assembling heads for a 267 chevy SB and the felpro gasket kit came with viton and nylon valve seals. i haev 2 questions should i put the nylon on the intake or exhaust? And where do the orings go, the kit came wiht 16 oring seals, do i put then in both the nylon and viton seals or just the umbrella nylon seals? And do they go above or below the umbrella seals?

Damon

The o-rings go on the valve stem on the lower groove (locks use the upper groove) of the valve stem. The o-ring seals the retainer to the valve stem so the whole retainer acts kinda like an big umbrella. No oil can just slide off the top of the retainer, down the valve stem and onto the top of the valve guide.

When installing the o-ring it's important to assemble it in the proper order. You have to put on the spring and retainer, compress the spring while holding the valve up. Put the o-ring on the bottom groove of the valve stem and the locks on the upper groove and THEN release the valve spring. This traps the o-ring inside the retainer- where it's supposed to be. If you put on the o-ring first (the WRONG way to do it) and THEN the retainer the o-ring will pop out of it's groove and slide down the valve stem as soon as you compress the valve srping- where it won't do any good at all.

I almost always install the o-ring IN ADDITION TO any other valve seals down on the valve guide. It's almost impossible to have too much vavle seal protection. The valve guides require such a tiny amount of oil to stay alive it's rediculous. Dry it up as much as you can!

turb0racing

Thanks damon! So now you helped me get the o-rings sorted out, but should i put the positive seals on the intake or exhaust? The engines going to be a low boost twin turbo motor with small restrictive .48 t3 turbine housings. I was thinking because of the high exhaust pressure it would be better to seal up the exhaust more with the viton positive seals. Then just have nylon umbrella seals on the intake. Does this sound good to you?

Aron213

the positives go on the intake, the nylon goes on the exhaust. Its actually ok to have a little oil on the exhaust guide to help lubricate it. You see when a intake valve opens, the engine is sucking and if you have a weaker seal there it will suck right past it, now when the exhaust valve is opening the pressure is being blown out, and in a round about sense, not going to be pulled down the guide.