Valve Lash Adjustment: running or not?

[Chevy454]

Interesting that there was only a 17hp difference. Also interesting that the hp peak was so high...my LS6 peaked around 5700 I believe, but that was with the Crane blueprint cam...the Comp piece listed above would certainly move the peak higher.

Ditto on the dyno...I see it as cheap insurance.

[bitfactr]

Thanks for posting the numbers Rick. Saves me searching for them tonight.

Some of the more loose rockers were probably around .015, maybe more. After reading your earlier post, I thought perhaps I should have set them all in the .014-.015 range, since the engine really never gets out of the low end. But the quieter engine, yet better sound, resulting from .012 is nice.

Though driveability felt like it needed a tune-up again, other than just resetting the idle. I'm guessing this isn't uncommon after valve adjustment.

Rob mentioned the tighter lash cam being more finicky. I'm wondering about the margin of error I have in the adjustment. I tried to set it where the .013 would not slide in, .012 would with drag, and .011 easily. So, in theory, my settings should all roughly be between .0115 and .0125.

At would point would a "too tight" adjustment be a problem (i.e. if a valve was set at .010 or tighter, what, if any, damage could occur?)

And, no, I'm not done cleaning it yet [img]<<GRAEMLIN_URL>>/smile.gif[/img]

[Chevy454]

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: bitfactr</div><div class="ubbcode-body">Thanks for posting the numbers Rick. Saves me searching for them tonight.

Some of the more loose rockers were probably around .015, maybe more. After reading your earlier post, I thought perhaps I should have set them all in the .014-.015 range, since the engine really never gets out of the low end. But the quieter engine, yet better sound, resulting from .012 is nice.

Though driveability felt like it needed a tune-up again, other than just resetting the idle. I'm guessing this isn't uncommon after valve adjustment.

Rob mentioned the tighter lash cam being more finicky. I'm wondering about the margin of error I have in the adjustment. I tried to set it where the .013 would not slide in, .012 would with drag, and .011 easily. So, in theory, my settings should all roughly be between .0115 and .0125.

At would point would a &quot;too tight&quot; adjustment be a problem (i.e. if a valve was set at .010 or tighter, what, if any, damage could occur?)

And, no, I'm not done cleaning it yet [img]<<GRAEMLIN_URL>>/smile.gif[/img]

</div></div>
Comp could tell you the exact tolerance number for that lobe, but .004&quot; +/- won't hurt a thing. We've played with lash a lot in our Pure Stock class, and although it's a different lobe, we've gone from .020 to .030+, and COPO Pete has deviated more than that on his ZL1...we're stuck with the stock cams, but that's not always the perfect cam, so you have to try and work around it.

[69Tom]

Guys, what valve lash measuring tool would you recommend?

This has been an interesting thread. Very informative.

Dennis, glad to see you're out exercising the car after all that work!

[bitfactr]

I bought two sets of feeler gauges; one straight, and a second with a slight angle at the last 3/4&quot;. I tried the latter first; they were a pain. The straight set worked better for me.

I did read about &quot;go/no-go&quot; feeler gauges, where the first 1/2&quot; or so is .002 less. I was constantly going back and forth between .011, .012 and .013. The go/no-go set would have been great to have. I'll be ordering a set for next time.

The other thing that consumed time for me was getting the bump-switch hooked up. It's difficult to reach the S terminal on the solenoid on a hot engine without getting burned, which I did. I'm considering some type of temporary, very well insulated, lead I could install while cold.

Thanks Rob for letting me know that I have some room for error without causing damage. I'm wondering now if the minutes I took in hooking up the bump-switch and popping the valve cover, was enough to have the engine start to cool and effect the adjustment. The rockers were still hot to the point I could only touch them for a split second with my finger tips, so I'm not too worried.

[TDW]

The other thing that consumed time for me was getting the bump-switch hooked up. It's difficult to reach the S terminal on the solenoid on a hot engine without getting burned, which I did. I'm considering some type of temporary, very well insulated, lead I could install while cold

I installed a small plastic block on the firewall of my Nova just for that purpose. It is an original GM part, but I don't remember what it was from. Basically, just a block with 2 studs and a mounting ear. I ran a #10 wire from the starter to one stud, the other stud is where I hook one of the leads on the remote button. The other lead on the remote just hooks to the Pos side of the battery. Works great.

[Chevy454]

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: 68Tom</div><div class="ubbcode-body">Guys, what valve lash measuring tool would you recommend?

This has been an interesting thread. Very informative.

Dennis, glad to see you're out exercising the car after all that work! </div></div>
I just use a feeler guage, plus a wrench, and an allen wrench...(I've got poly locks). I've always thought I'd buy a go/no-go guage, but once you get a feel for doing it with the feeler guages (that I already had), you can do it with your eyes closed.

[bitfactr]

Forgot. The multiple valve adjustment procedure that Belair62 mentions is like the procedure described in the '70's era manuals I have. I was going to go with that, as it should certainly work, but when I started to post, the EOIC method seemed a little more goof-proof for a first timer. But thanks for the info.