How long to run hollow valves?

[zerolm]

How long are guys getting away with running hollow stem valves between replacing them? I know that you will wonder about cycles, all I can say is that the engine turns between 7800 and 8000 in mostly 25 lap features, and some 50 lappers.. Average of 50 laps per night... How many nights under these conditions can I expect to run these without a problem? Thanks in advance...

[zerolm]

Oh yeah.. Flat tappet application, "Bee hive" springs... not sure of the seat or open pressure...

[zerolm]

I guess nobody has any experience with these...

[perfconn]

Because there is no pat answer.It all depends on how radical the cam is and other variables like seat presure.I know of one dude in alabama that has two seasons on his with a roller cam.

[rubbinsracin]

i know of a roller mod motor with a full season on it and starting this season with them. 7800ish rpm. fairly aggressive cam. ran 36ish nights last year and has at least 5 nights so far this year with no signs problem.

[zerolm]

Ok, thanks guys.. I'll try to get that info..

[dynoman14]

Who's hollow stems are you using? I have run Redress in Golfers Cup engine for 2 seasons. I have used GM valves in crate engines for 6 years ( my Dyno car ). Gotta make sure u don't get a lot of harmonics to kill seats. I would not run more than a season in a late model with minimal msint& lash adj.