55 degree VJ

[bsfc9]

we commonly use 55 degree valve jobs on drag motors using titanium valves and copper-berylium seats. has anyone had any sucess using a 55 with stainless valves and iron seats?

[tk]

we commonly use 55 degree valve jobs on drag motors using titanium valves and copper-berylium seats. has anyone had any sucess using a 55 with stainless valves and iron seats?

Do you use 55 degree on exhaust or intake too?

I know 55 degree helps on exhaust but just curious about using it on the intake?

[speedtalk]

The current Nascar stuff I've seen has 50' on the intake and 55' on the exhaust - sb2 that is.

[bsfc9]

yea intake and exhaust, it really helps high lift flow(over .600 or .700) but kills low lifts. have only used it on drag motors. do us some 50's on circle track stuff though.

[Guest]

we commonly use 55 degree valve jobs on drag motors using titanium valves and copper-berylium seats. has anyone had any sucess using a 55 with stainless valves and iron seats?

Basically the idea of using the beryllium copper seats with the 55Dg valve job goes hand in hand. The reason for using seats made out of this material is to deaden the harmonics or resonensce of the valve as it closes. The reason the valve sees this resonensce is due to the fast closing ramps of a high lift cam. The higher the lift, the higher the seat angle, in order to achieve flow at the maximum duration. It's all about keeping the valve happy at very high closing speeds and spring pressures. So to answer your question, no a steel seat is not ideal for cylinder heads that require a 55Dg valve job, as these heads will obviously be seeing high lifts,RPM's, and fast closing ramps on the camshaft.

[bsfc9]

my experience exactly. i have talked recently, though, with some folks who use the 55 with steel valves andiron seat(on blower applications) with reported success.

[Guest]

my experience exactly. i have talked recently, though, with some folks who use the 55 with steel valves andiron seat(on blower applications) with reported success.

Yeah I guess I can see where that would work for a blower application. The exhaust sees alot of heat. Are they using an inconel exhaust valve too? I know its a must have with turbo applications.

[bsfc9]

special exhaust alloys were not indicated to me.