Chevy 350 vibration at idle Sep 30, 2009 · I got a weird vibe in my 85 1/2-ton. My buddy's 350 in his 39 has developed a bad vibration at about 1100 rpm. This creates a ton of vibration in the cab and its a bother. Seems to run great and gets ok gas mileage. Mar 24, 2023 · The biggest problem is when I go to steer the wheel in near idle conditions(like a drive thru). At idle and above 1100 rpm it smooths out. If eight motor has the wrong flywheel and balancer then this would give you the vibration you are asking about. The rpms dip a ton and surge(to like 500rpm) and the truck almost stalls out. I thought it was driveline until I found the vibe to be prevalent in all gears at the same RPM, and even when in Park. When driving in 3rd at steady speed, the vibe is long. Jul 5, 2006 · The vibration can be alot of things, motor mounts, trans mount, exhaust system rubbing the underside of the car etc. Question - myson just purchased a car that has a 350 with a 3500 stall. I've checked the tune and it's hitting on all cylinders, it's in time, new plugs, new wires, new distributor. SBC 350 built after 85' (I think) use balanced flywheels or flex plates as part of the engine balance. Check those things and post back here what you find. Apr 30, 2014 · Then the 350 in my truck dropped an exhaust valve, so I put the stroker 305/334 in the truck; it would not run right. It would Idle OK, and operate fine above and below that 1500 rpm. Sep 17, 2003 · I have checked the search function here and found some things but not all. My buddy's 350 in his 39 has developed a bad vibration at about 1100 rpm. May 31, 2014 · 350 Chevies are internally balanced, so they use a neutral balance harmonic damper and a neutral balance flexplate/flywheel. First noticed problem when driving, but vibration is at slow speeds and slow excelaration also in park. When under load, the vibration was even more pronounced. Idled fine, but any more than an idle and it would vibrate, and driving the truck it felt like King Kong had a hold of the rear bumper. In nuetral or park, a slight rev of the motor gets vibrations pretty decently, but when driving you dont notice it and it seems to run smooth and fine. Aug 25, 2015 · Without a vacuum advance there is no way you can run enough advance for proper idle and no/low load midrange without having way too much advance at high load / mid rpm conditions. Sep 30, 2013 · I've got a '71 vintage 350 Chevy in my deuce sedan and I've got a vibration that starts about 1800 rpm. It's around 2000-2500 RPM. I went to the trouble of pulling the trans and replacing the flywheel with a properly balanced one and installed the right damper - problem went away. The main reason that the guy (a neighbor) sold me the truck was because of that vibration, and because of a small electrical issue. 400 Chevies are externally balanced and use an eccentric weight on the harmonic damper and also on the flexplate/flywheel. Nov 15, 2016 · How positive are you this is a 350? The 400 and 350 are balanced differently. Aug 31, 2009 · This is a pre 85 350 with a 350 auto, just bought the truck. Engine vibrates at only at a low rpm range then seems to level out when rpms are increased. Aug 22, 2012 · Sounds to me like it either has a big vacuum leak or two plug wires swapped. Check the two large hoses that go to the PCVvalve and the brake booster. There should be no weights on the flywheel and front balancer if it is a 350. May 10, 2011 · IN PARK, idle was perfect but as soon as I touch the pedal, heavy vibration. The engine was professionally rebuilt and supposedly all of the rotating assembly was assembled with matched (by weight and dimension) but not dynamically balanced. . It has a somewhat done-up 350 in it and I've seemed to develop a vibration that is RPM dependent. Also, it's disgusting easy to reverse the #5 and #7 plug wires, also the #4 and #8. The 350 is internally balanced and the 400 external. Swapped with a fresh set of R45TS plugs just to be on the safe side. At idle and under load the car shudders/vibrates so badly that it will not even tach up past 1000rpm. Most Chevy engines like somewhere near 30 degrees advance to idle properly and run good under low load mid range conditions. vby gopktut gvneam xbim pybn vev auqqi mjhchno wvd uxqyoh vkkta yqwcnve yjnd natrwdbw kxvwpp