valve train

[oldsnowman]

i don't know about the valve floating thing...these are very high rev engines kind of like a motorcycle:) overhead cams type engines don't have the problems that the push rod V8's do...most push rod engine have a hydro lifter that runs on the cam to the push rods, this is where most of valve float comes from. the other cause is weak valve springs, but if you have weak valve springs, you would have had other problems by now. the lifter, in a high rpm setting, gets pumped up with oil and can't bleed down fast enough and hanges the valves open:( as far as i know these 660 engine are "cam & carrier" and are manually adjusted so just like having solid lifters like they put in drag cars so they can take the high rpm load.:D NOW i am not saying you should take your mini truck down the highway and see how fast it will go, this is just information. the newer trucks with electronic spark have rev limiters so the engine will stop you before you do damage. things to help keep your mini truck running good is to make sure your cam belt is good, and that your timimg is right...one more thing, low octane fuel will cause detonation:eek:
hope this helps someone :D
wyatt

[Mighty Milt]

i think you are spot on when you note that the newer motors have rev limiters that will kick in before you float a valve. that's a pretty safe bet.

it has been my experience that the only time you get valve float is when you rev the engine beyond the capabilities of the valve spring regardless of lifter type. i have floated many a VW valve spring when running solid lifters. i had way too big of a cam for the stock valve springs. keep in mind this was in my "grenade" motors that we put together from the core pile just to blow up. i remember having a 1600 with a huge cam (.600 lift & 310* duration) and leaving the line at the drag strip i just held the pedal to the floor and launched as high as it would rev ;)

but on my good motors i ran chevy small block springs with 2 additional inner springs to keep 2" valves from floating at 9,000rpms