Idle shake

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I would like to see the plugs (in order) 1357-2468.
And raise the idle 100-150 rpms.
This is what I start with.
Then make sure all 8 are firing would be next.
Then I’d be all over that ignition timing (initial and total both)
You can screw with vacuum advance some other time.

It’s possible the really low idle and a mild cam could make a “shake” and cause a jumpy vacuum reading.
 
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RustyRatRod said:
What's the balancer look like?
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Round, orange. :). Pics below
TrailBeast said:
I would like to see the plugs (in order) 1357-2468.
And raise the idle 100-150 rpms.
This is what I start with.
Then make sure all 8 are firing would be next.
Then I’d be all over that ignition timing (initial and total both)
You can screw with vacuum advance some other time.

It’s possible the really low idle and a mild cam could make a “shake” and cause a jumpy vacuum reading.
Click to expand...
If I raise idle past 700-725 it really clunks when I put it into gear. Kind of uncomfortable lurch.

IMG_3504.jpeg


IMG_3503.jpeg
 
Sure-grip rear end or One Wheel Wonder? Will make a difference how much it will clunk when putting it into gear.

Sure-grip will have 4 spider gears taking up the slack.

Open Differential will have only 2 spider gears.


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George Jets said:
Sure-grip rear end or One Wheel Wonder? Will make a difference how much it will clunk when putting it into gear.

Sure-grip will have 4 spider gears taking up the slack.

Open Differential will have only 2 spider gears.


☆☆☆☆☆
Click to expand...
Cone type sure grip has 2 spider gears.
 
George Jets said:
Sure-grip rear end or One Wheel Wonder? Will make a difference how much it will clunk when putting it into gear.

Sure-grip will have 4 spider gears taking up the slack.

Open Differential will have only 2 spider gears.


☆☆☆☆☆
Click to expand...
Sure grip. I’ll investigate the clunk. Thanks for all the help
 
Post #24. Nope, you do NOT want misting or fuel exiting the boosters at idle. This would mean the main system is operating at idle, when only the idle system should be operating & supplying idle fuel to the engine.
A very common cause for this is a 'big [ger]' cam that needs more air & fuel to idle on.
 
Shep,
You said the idle rpm increased when you increased initial timing to 30*. Does not surprise me at all. With other symptoms, all indicative of a bigger cam. So is the increased idle speed to keep the engine running, part of the 'cost' of a bigger cam.

img267.jpg
 
Me personally, I would hesitate blaming the cam. what I hear it doesn't sound very aggressive. I run cams with 72° of overlap on the street and make them work well. I'm not saying it is in a contributing factor but I would be looking at Mounts,wires,cap,carb, ignition and other supporting cast first. Good luck and keep us posted.
 
Misfire maybe? Check plug wires with an inductive light move wire to wire looking for intermittent strobe...toss a set of new plugs in...
I like the way the paint is coming off your timing cover i thought it was just me and my 340 LOL!
 
Assuming the PCV is hooked up correctly and working, and all the air that the engine is seeing, is coming in thru the primaries past the throttle-blades, and that the VA is on the spark-port,

Just put the timing down to in the window of 10>14* and readjust the idle speed to 750 in Neutral; then reset the mixture screws as may be necessary.
If the exhaust gets stinky just bring in some bypass air.
If it still clunks; retard the timing or turn the idle-speed down.
After you get this done, you will need to vizit the Power-Timing.
Your cam is not a big deal. and once you get the idle worked out, she'll be a fun lil rocket.

Don't let tuning scare you.
I once had a 292/292/108 cam with 76* of overlap.
That thing ran just fine at 5* advance/550rpm in gear and pulling itself
across the concrete parking lot, at 930 ft elevation. (manual trans)

BTW
I don't hear anything wrong with your idle except maybe a lil fueling error on the transfers to mixture screw balance. Sounds pretty good out the back, too.
But, Ima thinking the engine is a wee bit noisy. Sorta like it has solid lifters. If so, than my first move would be to check the lash.
If not solids, I'd pop the VCs and check the rocker arm to retainer clearance and pushrod to tunnel clearance. etcetera. Cuz on my laptop it is quite noizy.
 
Thanks all for the great input. I work a ton and have a bunch of kids so will take me a few weeks to absorb and try all the suggestions but I’ll update when I get it sorted. If I missed a follow up question or didn’t make my issue clear, my apologies. I’m truly grateful for all the time spent.
 
I
Ironmike said:
I must be getting old. I don't see the problem...............
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I originally posted a short video of my vacuum gauge. I’m having a low vacuum/moving needle issue. The motor came with the car with no info I so was just looking for some direction. I’ve got a path forward now with troubleshooting and will hopefully get it sorted. Thank you for the time spent.
 
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