The quality of what you're calling stock parts just isn't what it used to be. Stock long block Gen III's are making upwards of 1000fwhp without breaking. I wouldn't call that crap. With .550 lift the LS6 ran just fine to 6600rpm in stock form without valve float. Good enough for GM to put a 3/36 warranty on it. Many beat the hell out of their LS6 and they just keep taking it. The intake valves on the LS6 are taller and yet sodium filled. The smaller intake valve of the 4.8L likely weighs around the same as the larger sodium filled LS6 valve. I doubt valve float was his issue.

 

im aware of what todays stock parts are capable of but in the end its still a stock part. for the cost of a set of springs vs rebuilding an entire motor. i would much rather run a better spring. a valve just doesnt break unless its cheap, valve float or it has contact

 

He posted that it broke at a cruise of 50mph, not likely valve float there. I doubt it was from contact since it broke above the valve guide and not below. All that makes sense is that it was a problem in the metal of the valve. A weak valve with a stiffer spring would have simply broken earlier on, not held up better.

 

like said either cheap, contact or float....if no contact or float then cheap part or damaged part

and things usually break when not beating on it. the damage is usually done prior and just at this point in the it shows its ugly face

 

I'd agree that the metalurgy of the valve is at fault, doesn't seem to be valve float or a spring issue.

 

If he would have had high quality aftermarket springs, the valve would have broke sooner. Stock parts FTW.

 

but doesnt that relate back to a junk/weak stock valve then right? so in this case stock FTL causse it hurt his motor

 

Damn, you caught me... lol ya, stock valve broke... but I bet more comp 918 aftermarket spring have broke than stock valves have....

 

yea not saying all stock valves are junk but seems like the most recent ones doesnt matter the head. there was a nice batch of 918s that were junk. i ran them in the past with no issues but it seems the batchs after that set were the junk ones....or its possible he knicked the valve when installing the new springs...

 

aaaahahahahahaha


maybe thats what i did. not sure how thats even possible, but it wasnt what happened. just a faulty valve.