Last night I FINALLY got around to working on my project again and installed the new valve springs/retainers/keepers that I've been putting off getting done for a while now. While I was installing them, I measured the installed height of every spring and found heights ranging from 1.765 to 1.800 with a desired install height of 1.800. This is the first time I've actually checked installed spring heights myself and am wondering: Is this an acceptable variance?

The heads are low-mile factory 5.3 heads, if that matters. What are the typical ranges that some of you have found when doing spring swaps?

 

When you measured, did you give the valve stem tip a little tap with a hammer to seat the retainer and locks?

 

What kind of springs and whats your max RPM? If they are low rate springs, it may not be significant. Example 918 Beehive is 313 lbs/in and at a range of 0.035" = 11 lbs variation in your spring loads, which is about the tolerance of a new spring anyway. If you're running to 6k I would say you'll be fine, if you want to run over that, shim the larger heights to the lowest so you match everything. Shims are relatively inexpensive.

Bravo on the due diligence.

 

No, I just cranked the mic firmly, backed it off again, and then seated it again while "feeling" to make sure that the mic was seated as squarely as possible on the seat.

 

2003 z06 cam, ti retainers/keepers, 918 springs. Might be "overkill" to some(then again, maybe not), but I just want to know that I'm not going to be prone to valve float under boost and higher rpms. Anyway, that's the setup in case it matters.

 

Stock C5 Zo6 cam?

Your fine.

 

Yeah, it's .551/.541 lift..not real big, obviously....but is it something to worry about on an engine that will see 10-12 lbs of boost?

Thanks.

 

If you can measure the coilbind distance of the springs, it'd be a good idea to shim it up closer to coil bind. Say about .060" from coilbind. You'll get more out of your springs that way, but it's not really necessary I guess.

I always tap the tip with a hammer, just to seat the retainers and locks better, and I usually only see a small variation, like .010" at most. More than that can be corrected with shims.

 

Thanks for the info everyone. I guess that I'll re-check the ones that are the farthest off tonight, and see if I can get a different/closer reading. If so, I guess that I won't worry about it.

 

I would be tempted to check spring pressures aswell. Some engine builders will check pressures before they are installed and then shim all to correct height and leave it at that. Others I know will install all springs first and then check pressures after install and shim accordingly. This takes longer but u can get more accurate.

Personally I like to use a micrometer and get them all to 1.800" then install way u can get them all close to bind.

Joel...

 

That is a lot more then I have ever measured. Most of mine were +/-0.005". Did the retainer fit correctly in the micrometer, i.e., the beehive retainers may not sit on the correct measuring surface of the micrometer.