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364 Posts
this was posted on the HAMB awhile back.......figured id move it over
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I was setting the valves on my preunit the other day and was talking to my bud Jason McElroy
he is completely rebuilding a trump engine for me and asked if i was still settin them with feeler gauges
i said yeah...why you got a better way?
what follows is his explanation
thought id share the love
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setting valve lash using feeler gauges is both a pain in the ass and is less accurate than using a test indicator. Especially on early motors like this one that do not have the inspection/adjustment caps down near where the adjusters contact the valve tips.
First step is to ensure that the tappet for the valve you are adjusting is on the heel (or smallest diam.) part of the cam.
Two ways to do this
1) The common way: Turn the motor by hand with your hand on the opposite valve (L for R, not I for E). When the opposite valve is fully open, the valve you are trying to adjust is most likely on the heel of the cam. The heel of the cam has a pretty wide angular range, so finding it does not require great precision.
2) Use the test indicator to find the highest point on the adjuster screw (valve is FULLY closed)
after ensuring the tappet is on the heel loosen up the adjuster locknut and set the adjuster screw to what you believe to be close to the desired lash (or play). In JG's case, the desired values were .002 loose on the intakes and .004 loose on the exhausts.
I usually stick a small magnetic (Mighty Mag) dial base on the bottom of the gas tank or on some part of the frame to do this. For doing motors on the bench, I made up a short piece of flat stock that is drilled to install across the top-mount (head-steadies for you Brit linguists) studs. I use a larger adjustable dial mount with this setup. You can see a little of it in the pic.
With a small screwdriver or pick, I move the rocker up as far as it will go then down as far as it will go, noting the travel indicated on the dial. The test indicator pictured is graduated in half-thousandths. Move the indicator aside, adjust the screw, tighten the locknut, and remeasure until you get the desired lash.
While to the uninitiated this method may appear to be more involved, it is MUCH faster (by a factor of ten at least) than fucking around with bent-up feeler guages trying to squeeze past the rocker arm through the adjuster cap opening.
Doing all four of JG's on the bench took under ten minutes and resulted in precise adjustment.
You can probably pick up an inexpensive test indicator and Mighty Mag base for under $50 from Enco, MSC, or another tool supplier. Once you do it this way once, you'll never go back.
jason
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
I was setting the valves on my preunit the other day and was talking to my bud Jason McElroy
he is completely rebuilding a trump engine for me and asked if i was still settin them with feeler gauges
i said yeah...why you got a better way?
what follows is his explanation
thought id share the love
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
setting valve lash using feeler gauges is both a pain in the ass and is less accurate than using a test indicator. Especially on early motors like this one that do not have the inspection/adjustment caps down near where the adjusters contact the valve tips.
First step is to ensure that the tappet for the valve you are adjusting is on the heel (or smallest diam.) part of the cam.
Two ways to do this
1) The common way: Turn the motor by hand with your hand on the opposite valve (L for R, not I for E). When the opposite valve is fully open, the valve you are trying to adjust is most likely on the heel of the cam. The heel of the cam has a pretty wide angular range, so finding it does not require great precision.
2) Use the test indicator to find the highest point on the adjuster screw (valve is FULLY closed)
after ensuring the tappet is on the heel loosen up the adjuster locknut and set the adjuster screw to what you believe to be close to the desired lash (or play). In JG's case, the desired values were .002 loose on the intakes and .004 loose on the exhausts.
I usually stick a small magnetic (Mighty Mag) dial base on the bottom of the gas tank or on some part of the frame to do this. For doing motors on the bench, I made up a short piece of flat stock that is drilled to install across the top-mount (head-steadies for you Brit linguists) studs. I use a larger adjustable dial mount with this setup. You can see a little of it in the pic.
With a small screwdriver or pick, I move the rocker up as far as it will go then down as far as it will go, noting the travel indicated on the dial. The test indicator pictured is graduated in half-thousandths. Move the indicator aside, adjust the screw, tighten the locknut, and remeasure until you get the desired lash.
While to the uninitiated this method may appear to be more involved, it is MUCH faster (by a factor of ten at least) than fucking around with bent-up feeler guages trying to squeeze past the rocker arm through the adjuster cap opening.
Doing all four of JG's on the bench took under ten minutes and resulted in precise adjustment.
You can probably pick up an inexpensive test indicator and Mighty Mag base for under $50 from Enco, MSC, or another tool supplier. Once you do it this way once, you'll never go back.
jason
