Vacuum & Timing questions w/video

[Ryan_M]

I've been chasing some gremlins with the help of the incredibly patient Scoutpilot but wanted to throw these videos out to the masses here on the forum.

I have some new gadgetry and am trying to figure out how to best respond to what it's telling me.

Video 1:

[media]http://youtu.be/HYnQ8QmUzz4[/media]

...and a follow-up:

[media]http://youtu.be/k-jn6EjJMC8[/media]

[1955CJ-5]

You might try changing the timing while it's running, and see where the vacuum gauge starts bouncing...

But I can't imagine why timing would make the vacuum bounce...valve timing yes, ignition not really, unless there was some pre-ignition before an intake valve closed....but then it would knock....I think....

I had another thought....you might try shorting each spark plug in turn while the needle is bouncing and see if it stops when you short out one particular cylinder....you may not learn any thing but who knows.....

[Ryan_M]

The needle begins to flutter right about -10 TDC. When I leave it at -20TDC like in the video it starts hard like they do when the timing is too far advanced. I've backed it off and left it at -10TDC. The needle still flutters slightly but it stays well withing the green area of the dial.

[1955CJ-5]

Didn't you have some unusual or missing timing marks, or was that the M-38?

[Ryan_M]

Timing mark location has been conquered.

http://www.cj3apage.com/cgi-bin/yabb2/YaBB.pl?num=1379296876/30

[1955CJ-5]

OK...just thought maybe 10* was the new 5*.....

I guess when you drive it you will know if that solved the flutter/stumble...

As you mentioned in your first video, new test equipment new problem..

I've never hooked up my vacuum gauge so the needle is steady and pegged at "0"...

[Ryan_M]

I finally got this resolved after an epic journey over on the 2A page. For anyone interested reading the gory details of carb adjustment here it is:

http://www.thecj2apage.com/forums/vacuum-timing-questions-w-video_topic32818_page1.html

Should you doze off half way through my incessant questioning, at least jump ahead and check out Scoutpilot's feature film on the topic. Very informative stuff:

[media]https://www.youtube.com/watch?v=jcjB0iGEEmQ&feature=youtu.be[/media]

[athawk11]

I have been watching the progression at the 2A.� Always something new to learn with these old Willys.� I watched the video and had a revelation.� I finally understand how to adjust the plunger.

Bottom line Ryan...your pain has been my gain!� .� Thank you for fighting that fight.

That ScoutPilot fellow is worth his weight in gold. I wish he was my neighbor.


Tim

[Ryan_M]

I finally understand how to adjust the plunger.

I'm still not entirely sure that I understand how bending the throttle rod affects the amount of plunger movement. I had 17/64" before the adjustment and 17/64" afterwards. I can definitely see how it affects the relationship to the metering rod once the connecting rod bend is made and the metering rod re-set. Short of a real extreme, I can only see the same pump throw no matter how the throttle rod is connected. Maybe it has to do with the relation to where the metering rod bottoms out in the jet as a result of this new setting?

I don't know. All I know is everything works better now and I like that.