I would like to see it running again too. We only have 6 1/2 months until the track re-opens! Hopefully the snow holds off for a while longer.

Guess it's going to have a few cubes more displacement when it's back together.

Simply going with taller springs means accepting that the additional lift is good - not sure if that is the case?? The lift spec'd on the build sheet appears to be the same as stock LS7.

 

Actually, it seems pretty clear this way. .660 of room with .630 to .640 of lift. I read that the minimum recommended clearance is .100.





The shimming of the rocker mounts is to get the rockers at 90* to the valves at mid lift from what I read.

 

A few of the valves were pretty hard to pull/push through the guides and the grooves scraped the guide material on the way out. Not sure if they are slightly bent or what? There don't appear to be any ridges on the grooves.

 

If there aren't any nicks or cuts on the valve stems, they may be bent. Do you have a spare valve guide that you could try running over the valve stems to see if they bind?

 

No, but they were definitely binding once the ends of the stems were into or close to the guides. Not sure how they could get bent without something else being damaged as well.

 

Is it possible for the end of the valve stem to "mushroom"? I thought that they were so hardened that they either just bent or broke...but I'm no engine builder like my pop, I'm more of a diagnostic specialist (which is actually my title at work)

 

If there was any micro mushrooming I would say it has to be at the lock groove area as the valve tips seem to go in easy.

Something else interesting............I had a cam spec'd for these heads and it came back with the same actual lift numbers I ended up with and maybe 10* more on the durations. The heads that were supposed to be on the motor(large port, 2.20 intakes) don't see any more gain in flow from .600 to .650 lift so the 595/.600 probably would have been just right for them - and they would have flowed 30CFM more at the lower lift.

 

The reason that you open a valve past maximum flow lift is so that the valve stays at that lift for a longer time.

 

That makes sense. What I ended up with is heads that peak at .650 and a valve lift just under that. If I had received the correct 4.125 bore heads peak flow would be at .600 lift and the originally spec'd cam had a lift just under that. Just saying that these 4.0 bore heads could use a little more lift than the 4.125's and that's what they ended up with, whether by accident or intentionally. Not that the valve/spring setup was suited to that much lift.

I would think that a setup that achieves the best flow at the lowest lift would be preferable from a durability standpoint.

 

Started a little valve spring discussion over on Tech. Sounds like I should bump up the pressures somewhat. https://ls1tech.com/forums/generatio...osted-lsx.html