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Discussion Starter #1
I'm preparing to do a valve adjustment procedure on '00 V6 VTEC.

Valve lash is adjusted (as documented in both the 'Honda Service Manual' and 'ALLDATA', and demonstrated in many online videos) by feeling for "drag" with an appropriate feeler gauge. My question: given the tolerances involved, how is it that this procedure does not require the precision of a strain gauge?

Here's a example typical of the language one may expect to read/hear detailing the most critical part of this job:
"Snug down the rocker "just" until you begin to feel resistance. You should be sliding the feeler gauge back and forth or side-to-side gently. The valve lash setting should not be tight... the feeling should be about the same as putting a table knife through a stick of cold butter. Not too hard, not too soft."

Seriously..?

A bazillion years of valve adjusting by eleventy-bazillion greasy digits and the procedure has never evolved beyond this sort of casual approximation..? I'm incredulous. Precision is implied; dire consequences warned. So why the conspicuous lack of any semblance of exactitude or required use of a seemingly purpose-built tool (e.g., strain gauge) for this job? I use a torque wrench to tighten the lug nuts on my Accord to 90lbs. I could simply tighten each nut by "feel" with a four-way to, say, three grunts of snugly goodness. But I risk a warped rotor. How then did "a stick of cold butter" become an accepted method to gauge tolerances of a thousandth of an inch within an interference engine?

In my purple-sky world, here's how I imagine the valve lash procedure reads:
"Attach the strain gauge to appropriate feeler gauge as spec'd by Honda valve lash setting. Slide the feeler gauge between the top of the valve stem and the rocker arm tip. Zero the strain gauge. Loosen the jam nut. Slowly tighten the adjustment screw while drawing the strain gauge back. Tighten the jam nut when the strain gauge reads [whatever Honda specs as the appropriate value a strain gauge tool should read when used in this application]. Move to next valve and repeat."

Bleh...
 

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Clermont, FL
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206 Posts
my guess would be that no 2 valves will have the same amount of wear. gaps will be totally different from my v6 to yours.
 

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Elvira - the car
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I'm preparing to do a valve adjustment procedure on '00 V6 VTEC.



In my purple-sky world, here's how I imagine the valve lash procedure reads:
"Attach the strain gauge to appropriate feeler gauge as spec'd by Honda valve lash setting. Slide the feeler gauge between the top of the valve stem and the rocker arm tip. Zero the strain gauge. Loosen the jam nut. Slowly tighten the adjustment screw while drawing the strain gauge back. Tighten the jam nut when the strain gauge reads [whatever Honda specs as the appropriate value a strain gauge tool should read when used in this application]. Move to next valve and repeat."

Bleh...
Exactly where are you attaching the strain gage? On the feeler gage tip, further back ? Are you contemplating the glue on type such as the Vishay strain gage ( bondable resistive film strain gauges)? Or something different.

I use the Vishay strain gages when performing tests on PCB's that hold computer chip sockets. The hold down clips for the chip strain the PCB (induce some warping). There is also a case when testing to check the stress applied when tightening bolts to hold a pcb down. But I'm actually measuring the "stretch" of the PCB.

I envision measuring the strain induced on the feeler gage caused by XX amount of stress applied during the adjustment screw step.

As far as why the feeler gage method of "drag feel" compared to the strain gage is still used, I'm just guessing here but the tolerance is about 10% of nominal (0.22mm gap on intakes +/- .02mm). Feel method is probably just fine.

Interesting discussion.
 

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Elvira - the car
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Maybe not as interesting as I thought !
 

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Discussion Starter #5
Maybe not as interesting as I thought !
Agreed.
The shade-tree mechanic is mostly intimidated away from performing a valve adjustment, and thus indifferent. And mechanics simply shrug off my concern with a dismissive "tech's just know the feel". <plaintive sigh>

Moving on then...
I'll use a good quality feeler gauge and my very distinctly personal, highly-subjective interpretation of "just tight enough" when I do this job on my Accord... and then observe the results.
 

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"Its better to HEAR them than to SMELL them" - Eric the car guy

...meaning you're better off a little too loose than a little too tight which can burn up the valves.

Putting a table knife through cold butter seems very tight imho. When I adjusted the valves on my '99 v6 I tightened them till I felt slight resistance on the minimum spec gauge. Now I'm not a trained technician so take that with a grain of salt (or two) but my engine has been running very quietly and smoothly for the 25k miles since then.
 

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Super Moderator
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^^ ETCG is awesome. I've learned many things from him that weren't originally posted here.

Seriously..?

A bazillion years of valve adjusting by eleventy-bazillion greasy digits and the procedure has never evolved beyond this sort of casual approximation..? I'm incredulous. Precision is implied; dire consequences warned. So why the conspicuous lack of any semblance of exactitude or required use of a seemingly purpose-built tool (e.g., strain gauge) for this job? I use a torque wrench to tighten the lug nuts on my Accord to 90lbs. I could simply tighten each nut by "feel" with a four-way to, say, three grunts of snugly goodness. But I risk a warped rotor. How then did "a stick of cold butter" become an accepted method to gauge tolerances of a thousandth of an inch within an interference engine?

Bleh...
 
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