Missing Problem

[ratter]

His symptons are exactly what valve springs cause.

I would feel bad for him if he paid $1200 + labour and it did not fix his problem.

[flutterpast]

thanks guys ill get a price to get the springs done and see what happens. I asked my mechanic about valve float and he said it probably wouldnt be that but yeah not sure.its strange though I can put as much boot in as I want when its getting traction.. it only happens when ive been smokin it on the brake

[notol]

just a thought, but could it possibly be coils?

[Sasha]

His symptons are exactly what valve springs cause.

Ahh fair enough. Perhaps you are right, its just that I have only heard people talk about this happening and never seen it. Theres plenty of other OHC engines with bucket type lifters that don't suffer. I thought it may effect the immediate idle quality after a high rpm ramp if it was going to have an effect at all, aparently im wrong. I definitely didnt think it would last for 2 mins as flutterpast describes. But oh well.

[ratter]

When the valves float, they are basically bouncing around out of control and the rocker arms are no longer contacting the cam shaft, when this happens the lifters have no load on them and then some will pump full of oil. When the lifter is full of oil it will hold the valve off it's seat so basically dropping compression on that cyclinder. This is why the car will run rough, after a few minutes of running the lifter will then bleed back down and things will go back to normal.

This is the good scenario, the bad one is if the valves bounce hard enough, the collets can dislodge and the valve falls into the combustion chamber, colliding with the piston and doing lots of damage.

[Sasha]

Thanks for the explanation ratter, it makes sense. I can understand the correlation between valve bounce and lifter pump. It was just hard to imagine these engines suffering valve float where the stock rev limiter is set. So it must be a hit and miss wether your engine has a batch of weak springs as there are plenty of BA's around that are making between 300 and 350 rwkw without any symptoms on stock springs.

[ratter]

When you increase boost you are effectively lowering the seat pressure on the inlet valves, because the extra boost is pushing against the inlet valve, so for example if you had a spring with 160 lb seat pressure, with 15 lbs of boost you effectively only have 145 lb of seat pressure

[flutterpast]

notol at first I thought it might be coils but it seems strange that faulty coil packs would cause the oil light to flash so I dunno