Good info. The vibration is most notable at idle...often time shaking the dashboard. It will also start off strong then calm down as the engine rpms settle a bit. A quick rev will come with a slight hesitation. Driving the car while accelarting through the gears, I can feel a slight vibration and hesitation of power, but the wheel remains steady. It just feels like it's sluggish. Also, on the highway the car will cruise 80mph no problem, with no steering wheel vibes. The most I feel comes through the accelerator pedal...and also through the clutch pedal.
All motor mounts have been reinforced. Aluminum subframe bushings. New tie rod ends and steering rack 20k ago. Tire's are 5k old. Pretty much everything else checks out well...
That info reinforces the dowell theory.
So, when there is no load on the engine it vibrates? How about:
heavy accel...Less vibration?
Coasting(with engine braking)...more vibration?
Coasting(in neutral-engine near idle speed)...same vibrations as idling at a stop?
Engine braking...less vibration?
Idle...more vibration...as stated.
When there is a load on the engine, vibrations are offset by higher cylinder pressures and higher rotating speeds and the mass of the car. Let me explain...as the engine increases in speed, the balanced part of the assembly has more influence over the imbalance. The pistons moving faster, the crank counterweights moving faster, the flywheel moving faster...all those items are large masses...as they move faster, the effects of the missing weight(where the dowell should be) are diminished. There are a bunch of reasons for this and I can't remember all of them but, I do know that there are harmonics involved. The missing weight imbalance is small but can be felt at low engine speeds...it's like a sound...at low frequencies(bass) you can FEEL the vibrations. As the frequency increases you can still hear the vibrations and the speaker is still moving a bunch of air, but the troughs and peaks of the sound wave are harder for us to make out...because of the mass of our eardrum(and our brains and nervs)...it just too darn heavy to move at the same speed as the soundwave at super high frequencies....like that; the mass of the rotating mass in the engine and the mass of the car, help to buffer the vibrations at higher engine speeds. (the crank will feel the vibrations but we wont...it's still bad on the engine)
This is why a WHEEL imbalance comes on at 60 and goes away some at 80 and will come back at some other frequency(wheel speed). the intensity AND frequency combine to determine if there is enough imbalance to start the chassis shaking.
I know that was hard to read...im at work and can't string more than 1 or 2 minutes of writing together...
quote: The most I feel comes through the accelerator pedal...and also through the clutch pedal
these are LIGHTWEIGHT things connected directly to engine...this is why you can feel it...no mass to buffer the vibes...is this a rod or cable shifter...if its a rod shifter you should feel it on the shifter **** too...not so much if it's a cable shifted trans.
edit: you have a 93...rod shifter...put an empty coke can on top of the shifter ****...can you hear and feel it through the can?
