wikkonado

Recently got my '69 Toronado up & running, but the engine shakes at idle, a lot.
It sounds fine when I rev it up, nice & smooth.

Video here:

http://www.youtube.com/watch?v=6lLC8ofdFwY

Misc:
Carb was rebuilt, new plugs/wires/dist/rotor/points/fuel pump/water pump.

What RPM should this be at idling? (need to get a gauge).
The shake smoothes out when I adjust the idle higher, of course.
I was thinking the 41yr old motor mounts may be suspect.

Does it look as bad as I think it does?

Thanks!

extreme1

Motor mounts seem pretty soft, I have a lumpy cam in my cutlass and it doesn't move the much at idle...

silverriff

The 455 in my Cutlass does that too. I thought it was the harmonic balancer being trash, because it clearly wobbled, but even after replacing it the shakes didn't stop. I'm sure that my motor mounts could stand to be replaced too. But the thing is that I would think if the mounts were bad, speeding up idle or revving it would make the shaking worse, but as you stated wikkonado, it gets better....

citcapp

A stock 455 with a stock to mild cam should idle smooth. Check you firing order. sparkplugs and plug wires. A bad plug wire or sparkplug could be grounding out and is more noticeable at idle. Check sparkplug gap too

Bluevista

Edit: Never mind, citcapp is way faster and smarter than me.

My 350 jumps around a little, drives me nuts, I think the carb may have problems now but I can live with it. The carb was rebuilt but that don't mean nothin'. I got it almost all smoothed out by going to a larger plug gap, like I should of with the Pertronix ignition and coil to begin with. Adjusting the idle mixture screws about a thousand times, with a vacuum gauge and tach hooked up. 2 barrels are a pain, seem much more sensitive to adjustments but who knows. I advanced the timing about 4 degrees and it runs better all around, may have a little balancer slip because you put it to specs and it chugs like a dog, whatever it is I like it.
Mine idles at 600 in drive, it should have the specs on the sticker above the radiator if it has a sticker. It still drives me a little nuts, runs like a bear otherwise. I would say most people would say I'm crazy if they saw it idling now.
I would check the carb baseplate gasket and other places for a vacuum leak too, wires on correctly, PCV valve. I have new motor mounts so I know that's not it but could be on yours. If it has any kind of performance cam it will idle rough but then you don't worry about it. I like the Ram-Air cam in my GTO, shakes your fillings out.

silverriff

Yeah I will just start telling people that's how it is supposed to be. My problem is that I am really just assuming that my whole engine is stock, because I am too lazy and unskilled to open it up. One thing I know is that I did a really sloppy job of making my "custom" wires. It was that orange retro musclecar wire kit from either Jegs or Summit. I cant remember how many times I would have the boots/clamps pull off the wires when I was trying to install them. I just used the free cheap *** wire crimpers that came with the kit, and they were worthless. In any case I will check my wires, probably just replace them. I have a virtually brand new set of the E3 diamond fires that are pregapped to .040 and as far as I can tell you can't regap them. If I could do it over again, I definetly would have just gotten the cheaper stock plugs. Anyone want to trade some Diamondfires for a good wire set??

OLD SKL 69

If you have a vacuum gauge, connect it to a source of manifold vacuum and start the engine. Should be getting around 17 to 20 with a steady reading. That can help identify any potential issues, such as a sticking valve, late timing, and carb idle mixture.

wikkonado

I'll check the plug gaps again (delco r45s), I set them to .30, per the chart here - http://www.carnut.com/specs/gen/olds60.html
Is that too low?

Wire order is correct, and vacuum was reading a steady 15 at idle as well.

OLD SKL 69

Idle should be around 700-750rpm.

A couple of ideas:
1. Make sure the vacuum advance is working (if it's original, it's a good bet that it stopped working)
2. If the vacuum advance is working, bump up your initial timing 2 degrees at a time and see if it makes a difference.
3. With the vacuum gauge hooked up, try adjusting the carb idle mixture screws to make your mixture richer. If that is your issue, the vacuum reading will go up and the idle should smooth out.

OLD SKL 69

That is correct.

stan 65 cutlass

there should be two screws on the front of the carb. air fuel. only work at idle. should be about 2 turns out to start. start on one side and turn out while listening and watching, engine should rev a little higher and smoother, now do the other screw. should smooth out a bit morethen readjust idle and retune the screws again

coltsneckbob

There are a variety of reasons for engine shake at idle. Carb adjustment, engine timing chain, proper plug adjustment and cleaning, good wires, points, lifter springs, compression leaks, vacuum leaks, bad gas, clogged fuel filter and on and on.