Valve seal

[71chmark]

The Felpro gasket set I got for my 440 has 2 different kinds of valve seals. 8 with a good size cup comparable to the old ones already on my 346 head.  The other 8 have barely any cup to them and don't even seat over the guide.  I figured there was a mistake but when I went to order more there was intake and exhaust.  I don't understand because the guides and stems all seem the same and the old ones were all the same.  The shallow cup seals wouldn't even stay on the guide where as the deeper cups seated nicely(or does that matter?). Can someone learn me?

[422STROKER]

I just ran into this this weekend!  I think one is for the intake(larger) and the other for the exhaust(tighter).  I had a second set of tighter ones from another gasket set and was wondering if it would be better to use all tight ones?  Maybe someone w/a little more exp will check in.

Tom

[matt63]

My understanding is that they are different for intake vs exhaust. I believe the intake seals are the tight ones but I am not 100% sure (you don't want to suck oil down the intake guides?).  There are better seals nowadays but they require machine the guide bosses.

[422STROKER]

Thanks Matt63 I did a little reading and your right but it is recommended that a positive seal be used on both valves.  Due to the exhaust pulling oil past the standard umbrella seal which doesn't seal tight.

Tom

[matt63]

I've got some new style positive seals that do allow a small amount of oil past them unlike some of the seals that stop all of the oil.

[Chryco Psycho]

the guides do need some oil or they will wear very quickly , it i sa balance bettwen limiting the oil to keep from burning oil & providing adequate supply

[422STROKER]

Would using the provided seals(tighter ones) hurt if I used them on both valves?  I took the heads apart this past weekend and each head had one style on it.  Kind of like they didn't check the other package before they started.  Gonna reassemble them this weekend after cleanin up the casting flash and any real rough spots inside the chambers/runners nothing crazy.

Tom

[Chryco Psycho]

generally no but it could starve the exhaust with positive seals on both

[422STROKER]

Thank You


Tom