Madrox

Ok. Two questions I am having on an engine rebuild that I am in the progress of. Truck is an 84 Ford F150 302.

1st: Valve Stem Seals. Bought a set of intake and exhaust from advance auto and they look like the rubber boots you would put on the bottom of a chair with a hole in them. The ones in the head now look like a nice rubber boot with 2 springs to keep them taught. I was told 2 things, one being that the ones I got are meant to go over the old ones, and the 2nd was that the ones from advance look like they would creep up the valve stem and not seal properly and I needed to get ones like the ones on there now. Pic below for comparison.

2nd: Got a crane cam with 236 lift and 520 duration. The engine has a 4 barrel holley, headers, new pistons with plus 6cc and a holley high performance fuel pump. Will this be too much cam for this engine? Can I run 87 with octane booster every 2nd fill up? The engine has new cam bearings, rod bearings, main bearings, pistons and piston rings.

I know the pic sucks, but hopefully you can tell what it is.
Thanks in advance.

Kattumaram

Take a look at this:

http://www.summitracing.com/search/B.../?autoview=SKU

It may help you feel more comforable with the valve seals for your 302.

BTW: The compression ratio will primarily determine whether the engine will run on 87. Much over 8:1 may need a higher number.

Madrox

That does make me feel better about them, but does anyone know if these are designed to replace or simply go over the old ones?

Good old Bill

There might be a clearance issue using both types together. Personnally, I would go to Ford and use the ones they sell. For more years than the average members age, the umbrellas were used, two choices, hard plastic or softer rubber. Both worked just fine and yes they did walk up on the valve stem as the valve opened. Which is why I question using both, with the type with the springs being pushed on over the guide and then installing the unbrella seal, is there clearance when assembled and the valve is full open or will it be smashed in normal operation? Check it out.

Madrox

I called Summit Racing's Tech line today and spoke with a technician that said the umbrella type is fine, the only downside is that over time the rubber gets fragile and cracks up. He said if I could get the positive seal it would be a better, longer lasting seal.
I called around and finally came across a somewhat local machine shop that had the positive seal type Valve stem seals I was looking for, and they look far better to me than the umbrella style. Heading to put them on right now.

Thanks for the answers!