have a chevy street rod with a stock 350 with edelbrock 600 cfm electric choke.Start the car, idles in park with just a very slight shake. Put it in drive and it shakes so that the steering wheel shakes too. Take of and it gets up to speed with plenty of power. Even with the shaking though, it won't stall. Thanks for any help or info.
Oh yeah, what does overdrive have to do with it? Did this just start happening? If you rev the engine in neutral, does the steering wheel shake? I suppose it could be a trans/driveline issue but have no idea what trans you have.
Yep, sounds like something is out of balance in the motor. More info, has it always done this or just started doing it. Don
Could be the torque converter, do you have any info on the tranny? What kind ? Rebuilt ? Stock converter?
I was thinking torque converter also. Could be a cracked flywheel or loose, missing tc bolts. Unless its manual, then it could be pressure plate or flywheel bolts or? The shake in the steering mention makes me want to start at the front of the car and work back. Hell, if it only happens under way, it could be wheel bearing or loose bent wheel. Need more data.
sorry, the "overdrive" was a typo. Meant to say when you put it in drive with the your foot on the brake.k, the steering wheel does not shake if it's idling in park. The trans is a 700 R. also when it's in park, you can crack the throttle and it revs up fine. When take off it doesnt shake no matter what the speed. when you come to a light and have to stop. It starts to idle rough(shake), but take off again and it runs fine.
What have you done or been working on the engine lately. Did this start right out of nowhere or did it progressively get worse. We need the whole correct story. Have you checked for loose bolts or nuts?
I would think a dead cylinder or bad booster would show up at idle, always. This could still be a lot of things. Just wondering, when it acts jerky at a stop, if you shut it down and restart it, does it straighten up?
I'd have to ask what you did or what you changed just before the vibration started or has it had the vibration since you have had it? Somethings that come to mind are: Plug wire up against the header or burnt and shorting out at different times. Plug wire loose in the cap or loose on the plug, Check each to see if they are tight and the wires are fully on the plug and fully in the cap. Cracked cap, especially if it seems to act up when it's a bit damp out. #'s 5 & 7 plug wires crossed. The wrong base gasket under the carb? The wrong flex plate? The wrong dampener? You can document that it is a 350 with a 350 crank and not a 400 or some version of a 383 stroker? In the late 70's my brother bought a sharp looking jet black mid 70's Chevy 4x4 that had 400 emblems on it and that he thought had a 400. After a trans job and flexplate change he developed a vibration similar to yours that ended up being caused by the 400 flexplate being installed on a 350 Target motor that the original 400 had been replaced with. If it vibrates with no load but seems to quiet down and smooth out when you put it in gear and get a load on it check the converter bolts as that is pretty common. Those are just some of the things I've run into over the years that caused a similar vibration. And none at the same time. has it got the right flexplate in it?
Neutral balance flexplate on an externally balanced engine will do it or vice versa, externally balanced flexlate on an internally balanced engine?
On the off chance it's not actually the engine that's shaking, I had a U-joint go once where when I let off on the throttle at speed, it would vibrate pretty bad and shake. Was the one on the trans yoke if I remember right.
sounds like a plane old miss to me. That 350 idle fine, not stall, bit act just as you describe & will still get up and go quite well on 7 cylinders. You have to start there (miss or dead cyl) anyways before you go chasing anything else.
I agree!! There is no load at idle when it's under a load, as in OD, then it breaks down. Don't chase obscure fixes until the easy ones have been eliminated first. I'd be checking the plugs first.
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