Valve Lash Adjustment: running or not?

[69Tom]

In addition to this thread, I have a question: on an engine that is driven regularly, getting normal street useage, how often should one adjust one's valve lash? Or is there no way to really say?

Just trying to get an idea how often I'll be wrenching on my L72
It's not that I have any problem with doing so--just want to get an idea as to what to expect.

[VintageMusclecar]

Once break-in has been completed, you shouldn't have to check the valves any more than maybe once a year, esp. with an OE cam.

[69Tom]

Excellent. I like the idea of a yearly adjustment. Perhaps I should get one of those too. [img]<<GRAEMLIN_URL>>/burnout.gif[/img]

[bitfactr]

Thanks to everyone who responded.

The engine I'll be adjusting the valves on is an LS6, stock rebuild, using a CompCams regrid of the original LS6 cam. (I have the cam card and can provide the numbers if it would be helpful, but the card is at home.)

If I understand the info given by napa68 about the adjustment for a &quot;30-30&quot; cam, the procedure will also work with my engine. I'm guessing the LS6 cam does not fall in the &quot;30-30&quot; category (please correct me if I'm wrong), and shouldn't require the &quot;30-30&quot; procedure, even though it would work.

I was going to follow EOIC method described by VintageMusclecar. It sounds like it would accomplish the same result (providing the LS6 cam isn't like the &quot;30-30&quot. It seems a bit more friendly for those less experienced.

Thanks,
Dennis

[napa68]

Speaking for myself, I like adjusting on a cold engine. I have found the specs they give for a cold engine hits the spec just right for a hot one ( I checked one of mine before and after)
Best of luck.

Tim

[69 Post Sedan]

The first time I set my valve lash, I do it when the engine is hot. Once it has cooled down, I check them and write it down. My Nova was about .002 difference when it was cold.

[bitfactr]

Great ideas and advice all around. Thanks.

I was all set the do the adjustment tomorrow morning. I just looked at the specs for my cam. It is a CompCams, Part # 11-671-4, Engine: CB Nostalgia LS-6+, Valve Adjustment: Intake .012, Exhaust .012. Again, the engine was rebuilt to as close to original specs as possible, and this cam was selected as being the closest.

The 70's era manuals I have, while not listing the valve adjustment for the 70' LS6 specifically, lists the other solid cam big blocks (ex. L78 from multiple years, the '71 LS6 from the Vette, etc.) with lash in the range of .024 - .028.

I didn't expect such a drastic difference in the lash on the contemporary CompCams regrid; it seems to be about half of the original. Should I be concerned about this?????

I don't have the specs on the original LS6 cam, so I don't know how different the CompCams regrid is, but I included the rest of the CompCams specs here:
Valve Adjustment: Intake .012, Exhaust .012.
Gross Vale Lift: Intake .544 Exhaust .539
Duration @ .015 Tappet Lift: Intake 276 Exhaust 283
Valve Timing @ .015: Open: Int 29 BTDC Exh 76 BBDC
Valve Timing @ .015: Close: Int 67 ABDC Exh 27 ATDC
Duration @ .050: Intake 239 Exhaust 246
Lobe Lift: Intake .3200 Exhaust .3170
Lobe Separation 112.0
Specs for cam installed @ 108.0 intake center line

Lastly, I read in another thread that it would be a good idea to disconnect the &quot;power&quot; wire from the distrubutor when using a bump-switch from underhood to crank the engine to be absolutely sure the engine doesn't start. Would simply disconnecting the coil wire from the distributor do the trick?

Thanks again,
Dennis