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Discussion Starter · #1 · (Edited)
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

 

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too slow , too complicated and too expensive , although one can never have enough tools, you don't want to carry a DTI on the road.


Just remember that the trumpy valve adjuster moves 2 thou for every flat of the screw.

After you find the heel of the cam loosen the lock nut, fingertighten the adjuster, back it off one flat for every two thou and lock up the lock nut........done, next valve.
 

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97s said:
Really? Takes me about 10 min to do all four. Precisely too.

too complicated
I don't agree. It's way simpler than dicking around with feeler guages. And more accurate.

and too expensive
You don't have $30 to spare on a test indicator which has TONS of uses around the shop?

you don't want to carry a DTI on the road.
Who carries a test indicator on the road? Why would you need to? Why would valve lash adjustment ever need to be performed when it wasn't scheduled maintenance?

Just remember that the trumpy valve adjuster moves 2 thou for every flat of the screw.
Given that there are four flats on the adjuster screw, you'd need a thread pitch of 125 for that to be true. .002 * 4 = .008 width of one thread. 1"/.008 = 125 . . .?

After you find the heel of the cam loosen the lock nut, fingertighten the adjuster, back it off one flat for every two thou and lock up the lock nut........done, next valve.
I do like your idea of using the thread pitch to set the lash without a test indicator or feeler guage. But, even with a thread pitch of 40 (which I suspect the adjuster screws are even less, maybe 32?) you'd get a travel of .00625 for each flat.

Am I missing something?

Respectfully,
Jason
 

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97s said:
too slow , too complicated and too expensive , although one can never have enough tools, you don't want to carry a DTI on the road.

Just remember that the trumpy valve adjuster moves 2 thou for every flat of the screw.

After you find the heel of the cam loosen the lock nut, fingertighten the adjuster, back it off one flat for every two thou and lock up the lock nut........done, next valve.
without a doubt, I can't remember the last time I used a feeler guage simply to adjust the valves on any machine I've owned...... save for a Benz diesel...... know the thread count...... do the math...... you're in biz

but then again, I find going to wild extremes to set static ignition timing pretty much a waste of my time as well..... since I can't recall any engine I've built performing best at the manufacturers specified tiiming setting.

And I know I've won when they require less advance for best performance.
 

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Hey Jason, are they giving you a hard time bro? Although I use go/no go feeler gages to check clearance on that stuff, in the shop an indicator is hard to beat for initial setup.

How ya been, missed readin about your exploits lately. Doctors totaled me out and bitch at me for still trying to work some. Just a few more troubleheads and I'm done. I can still make it a few hours a day in the shop. Sold my road bike and have been piddling around with my `47 Chief some.

Come see me when you're out and about..........always got a place to bunk.........jb
 

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I don't think anyone is giving anyone a hard time. Just pointing out it's a bit anal retentive, especially for a freshly overhauled engine...... whose valves will seat changing installed stem height...... and how much more will it close up when the head is retorqued? On a 2 and 4 engine..... well things can get out of hand pretty quick resulting in some burnt valves.

That manual just gives ya some baselines..... plenty of room to tweak them and thread count works very fast.

I do believe my short rod motor is currently set at 10 and 12.... picks up a bit of low end and it really needs it with it's tall gearing. The service manual doesn't tell you a thing about that or even rocker geometry.... so it's far from the the last word.

I don't have anything against Jason, he's been a guest in my home and shop. In fact, I dig what he does and wouldn't have any problem lending him a hand if need be.
 

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Yeah, so I'm particular when it comes to motors. Some people may argue that that level of attention is not necessary.

I know what works for me.

You should also see the way my bikes run.

Adjusting all four valves with a Mighty Mag and $20 indicator takes all of ten minutes including getting the inspection caps off.

In my world, if I can do something precisely in the same amount of time and effort as an approximation, I'll always choose the former. Every time.

Jason

p.s. - Thanks Hack.

p.p.s. - I'll send you a note JB.
 

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JasonMcElroy said:
Yeah, so I'm particular when it comes to motors. Some people may argue that that level of attention is not necessary.

I know what works for me.

You should also see the way my bikes run.

Adjusting all four valves with a Mighty Mag and $20 indicator takes all of ten minutes including getting the inspection caps off.

In my world, if I can do something precisely in the same amount of time and effort as an approximation, I'll always choose the former. Every time.

Jason

p.s. - Thanks Hack.

p.p.s. - I'll send you a note JB.
Well if precision is the real issue.... since the speed of doing such.... either on the roadside or in the shop sure isn't...... doesn't take me ten minutes or anything close...... and I can damned near, which is the best you can hope for with a cheap indicator, nail them by feel/sound...... been doing it for years.

I suggest obtaining a good dial indicator and comparing them.

Starrett has a really fine digital that has resolution to 50 mil........ and is very repeatable..... unlike any of the cheap chinese indicators I own...... and very solid bases are available for them.

I own both and a 20 buck indicator is worth every dollar it costs...... and no more.

I think you'd really dig what's currently on the lift here and the next one drawn up in inventor...... pretty whacky for sure.

Let me know if I can help you in any way and I wouldn't mind having someplace to send the copious amounts of work I just don't have time to do.

Tell John and Ichabod I said hey.

Now what would be nice....... is to just once...... buy a brit that has extensive records logged. I've never even had anyone that's bought one of my bikes ask for it's log books which record everything that's ever been done, all critical info, and when.

Isn't that odd?
 

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Discussion Starter · #9 ·
i for one appreciate your precision Mr. Mc

please be as anal as you want on any of mine in the future
 

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Re: and a side note ..

While we're all talking about this . . .

I've got a question maybe some of y'all can clarify for me:

My understanding of setting valve lash to a particular value when COLD is so that you can reach a no-lash condition at running temps. I thought that factors such as cylinder and valve train materials and masses and expected temps were considered in determing a COLD value.

If, in fact, the goal is to reach no-lash at running temps, why not just set the valves when the motor is at running temp to no-lash?

Thanks in advance for your insights into this matter.

Jason
 

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Re: and a side note ..

JasonMcElroy said:
While we're all talking about this . . .

I've got a question maybe some of y'all can clarify for me:

My understanding of setting valve lash to a particular value when COLD is so that you can reach a no-lash condition at running temps. I thought that factors such as cylinder and valve train materials and masses and expected temps were considered in determing a COLD value.

If, in fact, the goal is to reach no-lash at running temps, why not just set the valves when the motor is at running temp to no-lash?

Thanks in advance for your insights into this matter.

Jason
I have always belived that cold lash was set on a new build to get the motor running. Then after running temp has been reached and or cam has been broken in, go back and set lash hot, not a fun job with a hot valvetrain and hot oil! I also was under the asumption that valve lash specs. given were for warm motors. most of my exp. is with small& big block chevys. with my triumph,I have drilled and taped a hole in the side of the cover and slip the feeler gague in there... works for me
 

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As for lash specs, there's a bit more to it. Reciprocating mass, cam timing, oil film layer stackup (cam, pushrod ends, rockers, etc) and thermal expansion all play into it. It's not that simple.

For initial Triumph twin setup, set the engine so the other valve is fully open (as described above). Loosen the adjuster for the closed valve and screw down till it touches. For intakes, back it off a quarter turn. For exhaust back it off 1/3 of a turn and lock it.

It will get you very close, if to the very outside of the range. If you do the math based on the appropriate threads per inch, you'll see why.
A slappy valve is a happy valve!
 

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a quiet triumph is like a 'ticking-time-bomb':eek: ! color of the pipes at the top bend going from :confused: gold to blue:confused: , another time of great concern!

anyone subscribed to the english magazines, CLASSIC BIKE---[ outstanding on-line-forum ] or CLASSIC BIKE BUIDE or THE CLASSIC MOTORCYCLE ? www.motorsportpublication.com is the american distributor.

over-there the hobby is well organized and well informed. the after market vendors are outstanding! afterall they rode these bikes for day-today-transport til late in the 1950's

redryder---just spent his two-cents!
 
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