Guys I cannot figure out why i have a decent amount of vibration at 60ish mph. What could cause this? Its pretty bad. Rear view mirror is not usable and you can see / feel the car shake. New rear and front suspension. wheel and tires are new. Also my 289 has no power. never really has. I have a 62 fairlane with almost the same 289 and it pulls way better.
vibration ,tires balanced correctly ??? , universal joints tightened on the rear yoke and seated correctly on yoke ? , and are the joints new? just a few things i would check trans tail shaft bushing ?? , t
At what speed does it start? Have you driven fast enough to see if it stops? Sounds like a hub/wheel/tire issue to me. Maybe harmonic balancer or flywheel (28oz vs 50oz). Can you get it up to speed, then put it into Neutral and coast, to separate whether the issue is wheel or engine? Joseph
I didnt think of that joseph but thank you I will try that tomorrow. Hey if my pinion angles are super far off can that be robbing horsepower? I recently raised the reat of the car with shackles. also the ront went up a bit with new springs / shocks.
I'm not sure about any HP loss. When I bought my '67 F250, the PO did a "poor man's lowering." He cut the front coil springs several inches. But he didn't change the hubs, so the angles were all wonky. The biggest thing was that the weight was riding on the inside of the tires. Once I replaced the coil springs, life was good again. My take is that if you're wanting the changed ride height, you really want the kits so your tire geometry doesn't change, but that takes $$$. Just my two cents, Joseph
My understanding is that the trans and rear pinion angles need to be the same or you will get shake due to mismatched rotational speed of the UJ's
check for a warped brake drum or rotor. That drove me nuts for a while on my 79. Found out the new parts were warped from the factory. So just because it's new does not always mean good. Bent wheel or wheel weight missing. Belt slipped in tire will cause this too.
I'd look at whether the vibration disappears or lessens in neutral, whether the damper has slipped if it does, and if it doesn't, the driveshaft, axleshafts and the tires/wheels. Have someone follow behind you on the freeway, shoot some video of the wheels on both sides. The camera's frame rate can sometimes make wobbly wheels more visible.
If it is speed-specific it is almost certainly wheel/tire related, or driveshaft. Try rotating tires. Also possible too much toe set but that should show quick tire wear.
I forgot about driveshaft alignment. When I did my FE/C6 in the truck, I was told that the front U-joint and rear U-joint needed to be 90 degrees off from each other. But they also had a sliding U-joint at the front end, because the beds were so long, so you could change the front/rear alignment. I don't know if our 'cheros have that or not, since our beds are relatively short. Joseph
I had a car I was working on a while ago where they didn't set the rear U-joint into the yoke correctly...… Had a wicked vibration at about 55-60 mph. I pulled the driveshaft, greased both U-joints, reinstalled the driveshaft (correctly this time), and NO MORE VIBRATION!!!
Nothing in your first post relates to drive line or engine problems other than low power, I would take it back to the tire shop and have them recheck the balancing. Start from work done prior to the problem, keep it simple.
I would check the u-joints to see if either end is worn. Vibration may be the first clue that you need new joints. A worn rear sleeve bearing in the trans can also cause it. You can check all of this without removing any parts, just give each joint a good shake -- any movement at all means a bad bearing. Raising the front end won't affect the drive angles. Doubt the raising rear with 2" shackles would affect it much either.
X2 on u-joints, especially if they have a "few" miles on them prior to the rear lift. As u-joints wear they get a particular "set" (if you look at the u-joint cap and/or trunnion you would see something resembling "witness marks") to them and not have a vibration issue, make the u-joint have to travel during their operation more than this "set" and you can introduce vibration. A good friend who owns a 4x4 driveline shop near me told/showed me this, he deals with these type of issues just about everyday. I do realize a lifted 4x4 probably introduces more degrees of u-joint operation travel change than just a 2" shackle lift, but still something to look at. Hope this helps.
On my '61 (entirely different engine & transmission, but still...) I used to have an awful vibration as I would transition 45mph. It would go away and be fine, but on side streets, etc. it was awful. I tried a bunch of things including having the drive shaft balanced, new U-joints, etc., all to no avail. Turned out to be the rear transmission mounts. Once I replaced those, the problem immediately went away and has never returned. Brad
