Valve springs

[FreeBeeTony]

Are the valve springs on the stock GM Vortec heads on the weak side?
Am thinking I am developing valve float.

Could it be possible the springs are too weak?

Just a thought.

 

[Reel Poor]

Re: Valve springs

In general no, on your particular motor it may be a possibility. When you did the engine work did you have the heads reworked? Did they check spring tension? Did they shim the springs like is typically required when doing a valve job? What kind of symptoms are you experiencing?

 

[John_S]

Re: Valve springs

Tony,

I can't believe the valve springs are worn out in that short of time. This is only the 2nd season on the new heads, right? A roller cam will float before a flat hyd (heavier lifters) but that is still 1000 rpm above what you should be running. You are using stock cam and valve train components, so you shouldn't be causing coil bind.

I remember you had some problem with one of the roller lifters. Did you end up replacing the whole set? or just the one? I can't remember!
Have you tried readjusting the lifters yet?

 

[FreeBeeTony]

Re: Valve springs

Hi John...........you're right, this is the 2nd season.

I did adjust the lifters (on 1 side) because I noticed the same (original) problem again..........seemed to solve the problem.

Now I am noticing it again to some degree...........starts to miss at ~3200RPM........but if I continue to throttle up it disappears..........I know it's the same problem just don't know why it keeps coming back.

I only replaced the 1 lifter that was damaged at the end of last season.......maybe it's time to replace the entire set.........am going to adjust the lifters on the other side to see if this helps.

 

[FreeBeeTony]

Re: Valve springs

^bump^

 

[mkpj1]

Re: Valve springs

You have probably posted this before but what make you think it's valve or vavle train related and not ignition/electrical. Like losing spark at that RPM?

Ken

 

[FreeBeeTony]

Re: Valve springs

Had a similar problem in the past and found a bad lifter.........now the problem has re-appeared (slightly) and I am wondering if all the lifters should be replaced.

What causes lifters to go bad? I changed the oil to 10W40 (4qts) and a qt of MarvelMystery oil to see if it would free them up.............haven't really run it too much since though...........

 

[KaGee]

Re: Valve springs

It's beyond my thinking why you did not replace all of the lifters once you found a bad one. For that matter, why you did not do it from the beginning during your rebuild.

 

[FreeBeeTony]

Re: Valve springs

Looking back, yes, I should have replaced all 16 when I replaced the 1 but at that time I thought I found the problem.

 

[Limited-Time]

Re: Valve springs

A mis from valve "float" and the mis from a "bad" lifter are not the same, unless the lifter is hanging in the bore and holding the valve open. What exactly was wrong with the defective lifter you replaced?? I'm assuming it was collapsed, or collapsing under load. If its the same lifter as last time it may be time to have the valves looked at.

 

[mkpj1]

Re: Valve springs

Well I am still commenting when I don't know what you have....ie roller/flat tappet, ...engine, rocker arms etc.. I agree, should have replaced all and you should have replaced the cam considering the work compared to the cost. The cam could be moving forward and aft causing the problem too. How did you know the lifter was bad? Why was is bad? that's the question you need to answer.

I still am suspect though that it only occurs at a certain RPM. I guess I can see the valve train catching up after 3200 and the problem quits but still..... Ignition and electrical has been eliminated? Yes?