Fondle

iTrader: (4)

So i have a junk yard 5.3 with a tc78 on it. the motor has somewhere near 100k miles i am assuming with stock heads/cam/valve springs. I have had this motor turbod for around 10,000 miles now, at first the car felt great and dynod 451/502 on only 6psi of boost, but now it feels weak and i get a "slipping" feeling

Not sure what this "slipping" feeling is, i have a mcleod twin disk in with around 6,000 miles on it, so I don't see how it could be this. but something isnt right. 1st gear feels fine, but when i am in boost in other gear it doesn't feel very powerful, and it feels like something is slipping. Its not violent , but it just feels like the car loses power and isn't running very strong. My initial thought was the clutch or tranny, but i feel if it was a tranny issue it would be a pretty rough ride if something in the tranny was slipping

It seems like the problem occurs more if the motor is hot and has been running for a while. I hear alot of issues about valve float and so this is something i could possibly be experiencing, but how do i know? What does it feel like to have floating valves?

99SS-T

iTrader: (5)

Well when you have valve float it feels like **** when you get near your peak. Basically it just makes less hp.
You mention slipping. if you wanna test to make sure that there isnt any slipping just get it in 3rd use the brake to keep ya from accelerating on the highway and hit the gas till boost is at max. if the revs dont come up then you can stop worrying about the clutch.
I had bad valve float in mine when i first put everything on. I would bet when you did your first dyno run that you were already down on power from shitty springs and prolly bent pushrods. I know mine was. Well worth taking it apart and replacing them.
GL

Fondle

iTrader: (4)

well today its starting get make a loud bang noise once every 5 minutes or so, coming from the passenger side valve cover. but also every so often when i try and get on the gas it will have am issue where it wont accelerate like it should, and it sounds like the motor isnt actually increasing rpm like it should, like the belt is slipping or something.. which is weird

DavidPHumes

iTrader: (1)

I would pull the valve covers off and take a peek.

Vexzer

iTrader: (1)

My experience with valve float is that it occurs at peak RPM, feels like a high-speed miss, like fuel starvation. In your application especially, I don't know why it would happen at low RPM. Pull some plugs, check fuel & retard by knock sensor. Pull valve covers.