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TOPIC: 1966 122S Idle Speed

1966 122S Idle Speed 2 months 2 weeks ago #1467

  • mrains
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George

Valve adjustment methodology makes sense. For Rule of Nines, I understand the math but logistically, how do I eyeball the valve fully open while moving the crankshaft? Is this a two person job? Is there any problem with moving he crank backwards and forwards to determine the exact spot where the valve is full open (and no more)? Seems like that's the toughest part. Need to know on the two person thing; my wife is not a player on this.

Thanks for the front end information.

By the way (have to ask); any relation to a Don Dill (deceased many years ago) who was my high school swim coach in Chicago area?

Mike Rains
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1966 122S Idle Speed 2 months 2 weeks ago #1469

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mrains wrote:
George

Valve adjustment methodology makes sense. For Rule of Nines, I understand the math but logistically, how do I eyeball the valve fully open while moving the crankshaft? Is this a two person job? Is there any problem with moving he crank backwards and forwards to determine the exact spot where the valve is full open (and no more)? Seems like that's the toughest part. Need to know on the two person thing; my wife is not a player on this.

Thanks for the front end information.

By the way (have to ask); any relation to a Don Dill (deceased many years ago) who was my high school swim coach in Chicago area?

Mike Rains

All us Dill folk are related - escaped from a penal colony near the Canaries in 1256 AD, pirated a Viking schooner and wrecked on a sandbar then waded ashore and founded the city of New Orleans (first called Pickleville). After centuries of mixing with the local mound dwellers we...

Valve adjustment simplified...

Suck, squeeze, bang, blow and firing order 1,3,4,2 with distributor cap off, rotor on, sparkle plugs out, a large ratchet on the crank pulley and battery negative post disconnected.

When #1 piston is approaching TDC to begin the power stroke both valves are fully closed, the rotor is pointing toward #1 terminal and the timing mark is near zero degrees.

What a great time to adjust valves #1 and #2!

As the 4-cycle engine is rotated in the "normal" direction the #3 piston is approaching TDC to begin its power stroke. The rotor is pointing towards #3 terminal and we don't care where the timing mark is pointing. Both valves are closed on #3 cylinder and ready to be adjusted.

Not sure #3 is at TDC?

Insert a WD40 straw into the #3 plug hole just enough to let the hidden end of the straw rest on the top of the piston. Now "rock" the engine a bit CW and CCW watching the visible end of the straw. It will wiggle up-n-down as you rock the engine and its lowest down point is TDC.

Now that both valves are adjusted on #3 (remove straw!) we'll rotate to #4, adjust valves then do #2.

BTW, in your opinion, does the piston stop at TDC with the engine running?

George Dill
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1966 122S Idle Speed 2 months 2 weeks ago #1470

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I like this valve adjust approach better. Never though about straw technique. Course haven't done any valve adjustments for many years.

Not sure about your TDC question. The piston of course reverses direction at TDC.
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1966 122S Idle Speed 2 months 5 days ago #1497

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Update on my tuning efforts.
I did a drop test on the SU pistons; ran across test on thread and hadn't considered. My drop test showed slightly under 5 seconds for both SUs. Based on this, I removed the ATF in the damper and put in 30 wt oil. Engine definitely accelerates better now; had been having a bit of stumble.

I plan to go over most things one more time(valves), dwell, timing, then carbs. The car is running good on the road but my idle is still a bit shaky when stopped.
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1966 122S Idle Speed 2 months 5 days ago #1498

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"...but my idle is still a bit shaky when stopped."

Shaky hot idle is very difficult to remedy as major changes in engine operating temperature greatly affect carb behavior especially at closed-throttle.

By this time the mixture nuts on the twin SUs should move one flat just by your shaking your head - left for rich and right for lean.

The next hot and shaky idle opportunity reach behind the air filter and turn the mixture nut six flats to rich. As soon as both nuts have been twisted blip the throttle. If the idle gets even more shaky start over and try six flats leaner.

Some place in between those twelve flats resides a smoother idle.

This exercise is best done AFTER you have redone the valve adjustment, timing, etc. as stated above.

Got any road trips planned for this Amazon?

George Dill
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