Valve Springs

[Purestock3]

I think my valves are floating.

Springs have about 10-12 races on them. They are Stock Z28 valve springs

Turning 6500

I'm thinking about changing them, but I'm not sure about the shimming height.

The machine shop origionally shimmed them.

Can I just Swap the springs and leave the shims???

If not......whats the method for measuring/checking for correct height?

Any input would help

Thanks

[Truck99]

If the springs were set up at the machine shop for a particular installed height and your new springs are the same brand/type as the old springs, I would leave the shims in to keep your installed height the same.

 

Depending on your cam lift, you could also shim the existing springs a little more to bump your seat pressure back up, but I think the other plan (new springs) is a better one. Those "z28" springs aren't good for too many races at 6500.

[Purestock3]

Thanks

I doubt I can get the same "brand", but I'll probably get the same type for now.

Need to do some research.

I know there are much better springs out there, but I just haven't gone that direction yet.

I guess it's about time.

 

Thanks again

[Purestock3]

O.K.

Got some new valve springs on the way, but they are not the same.

Gonna shim the ones I've got to help me get through this weekend.

Thanks for the info.

Any idea how much I might try to shim for this weekend??

Your guess is probably better than mine.

lift---->.390I .410X

1.5 rockers

Stock length push rods.

6500 rpm

Thanks

[Truck99]

I really can't say without knowing your current installed height and current seat pressure. It's purely a guess, but you could PROBABLY shim them like .030 and be OK for a week, but that's just a guess.

[poorboy]

Dareger I seriously doubt that you are floating the valves. I would bet that you are way over the RPM range for that cam. I'm assuming you are loosing top end power.

[Purestock3]

I'm definately out of range for my cam. WITHOUT A DOUBT

 

But this just started happening.

Also...I'm not totally convinced that my valves are floating.

Changed my fuel line last week...fuel was getting too hot...now I'm back to the stock metal line

My origional problem went away, but now I've got a miss. (had a different problem before this)

I might have some stuff in my carb from the old metal line.

Getting a new one from L&L this week. And new plugs

I dunno....something is wrong though. \/ \/ \/

 

----(valve springs, fuel delivery, carb, plugs, head gaskets)---- gotta be one of these

[HiTech]

weak springs can start out running good the first few laps and when they get good and hot the bottem drops out motor go.es flat and nomatter what you do the car wont pull .if you add shims rotate the motor full open valve to make sure they dont bind .

[Purestock3]

Turns out it was the Carburetor/fuel delivery

Ran good untill I ran over 42's Tire.

For some reason engines don't run well with a Smashed/Flattened Exhaust pipe

[railer]

I got a new timing chain & cam ran 3 races on it tore the motor down found that the new chain was already streched out .Got a true roller set and that corrected almost the same problem u r having maybe?