Vibration??

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funhntt

funhntt

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73 Duster 225. The car starts and idles great. chokes up and kicks down, runs smooth. When you put it in drive the car vibrates, very noisy!! Eveything shakes and rattles. Let off the brake and give some gas and all is good again. Runs great in any gear. Stop at a light and you get the shakes again. Any ideas?:roll:
 
Sounds like something has come apart in the converter.
 
check your harmonic balancer ,maybe coming apart,or if you installed the motor from another car ,it maybe the wrong one,it could cause problems in transmission.I accidentally made that mistake,forgot to switch them,you know how hard it is to find someone to rebuild a pushbutton transmission for a 64 Barracuda? Any ways you should check that out first and then go from there.
 
This is an all origional 40k car. I already installed new motor mounts. The converter/ balancer/ trans. mount I'll need to check!! thanks for the ideas!!
 
Mine used to do that, oddly only around 700 RPM, any lower or higher and it was fine. Drive train mounts and a valve adjustment fixed it for me. I did both at the same time so not sure what it was.
 
Don't mean to push the thread up but I am having a similar issue.

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I just acquired a '74 Dart Custom 4-door with a 225 (160K miles) and it starts and runs in P/N just fine (it's blowing some oil into the air cleaner, but that appears to be an unrelated issue) Plugs are all a nice brown, and dry compression came in at 155-165 on all 6. Not sucking air through the tail and no vacuum leaks on the 1-lunger.

However, once in gear is vibrates...the antenna & anything of any length starts wobbling.

When I start off from a dead stop and accelerate hard, I get a good shuddering that disappears when the torque comes off or when it shifts into 2nd, whichever comes first. I had them replace the left motor mount insulator when new exhaust was installed, the tranny mount seemed solid (if I grab the driveshaft with 2-hands and shake it, I can get a little movement); likewise the right mount appeared blameless...

If I rev the motor fairly hard in Park, I hear a train of light knocking, can't tell if it's top end, cam, or crank. I just adjusted the valves today, no change. In gear with the parking brake hard set, there is some lifting of the block at the (new) mount on acceleration, maybe 1/4", which seems normal.

If the car is driven gently, there's no issue except when standing at a light...my son has taking to throwing it in Park because it is so annoying.

I'm guessing that the engine is fairly worn and I'm getting some blowback but that won't cause this...I have a trans mount and can get a right motor mount...reading around about harmonic balancer issues, but it doesn't show up at speed. I've had U-joint issues with previous Mopars ('65 Fury/383, 83 Ram conversion van, 318, both 727s) and this does not feel like that did (which was more of a fine vibration when accelerating at speed).

Thanks
 
could it be its idling to low? that will cause it to shake the crap out of the car and make everything rattle...

explain the sound more... get out of the car and look for it... location?
 
805moparkid said:
could it be its idling to low? that will cause it to shake the crap out of the car and make everything rattle...

explain the sound more... get out of the car and look for it... location?
Click to expand...

I have to put it on a tach tomorrow, & check the timing...be surprised if I find anything.

It sounds like a mellow valve knock when I blip the throttle hard. I hear it coming from the motor, from under the hood when I'm hand-throttling it. Car does NOT knock under load...or at least, it can't be heard from the passenger compartment. It made the same noise after I adjusted the valves (they were quite loose). I've never had a slant 6, so I don't know if it's normal (I doubt it :/ )

Flex plate? I can check that by pulling the dust cover & rotating the assembly, correct?
 
Three-nuts said:
I have to put it on a tach tomorrow, & check the timing...be surprised if I find anything.

It sounds like a mellow valve knock when I blip the throttle hard. I hear it coming from the motor, from under the hood when I'm hand-throttling it. Car does NOT knock under load...or at least, it can't be heard from the passenger compartment. It made the same noise after I adjusted the valves (they were quite loose). I've never had a slant 6, so I don't know if it's normal (I doubt it :/ )

Flex plate? I can check that by pulling the dust cover & rotating the assembly, correct?
Click to expand...

Yes.
 
check for a disconnected or rotted through vacuum hose, PVC valve. sounds like an air leak to me at low idle.
 
if they are loose, even one... one at a time take it out, brake clean out the hole and bolt, dry them and then blue locktite the bolt... reinstall and tighten, do all 4 that way...
 
1965_belvedere said:
check for a disconnected or rotted through vacuum hose, PVC valve. sounds like an air leak to me at low idle.
Click to expand...

Been through all of the hoses & replaced the PCV valve. Pulled each hose one at a time & capped the barb at the carb. Closed the choke slowly, no increase in idle until it died. Finally, emptied a can of carb cleaner all over everything; no change. Motor actually idles well and even, as noted there's no sucking from the tailpipe (well, once in a blue moon...might be a slack timing chain). Checking the plate in a bit.

Thanks for the suggestions!
 
My 69 Dart slant used to do that, for ~15 years. Slowed way down and idled rough in D. Would stumble when leaving a stop light. Had to rev the engine a bit to avoid stalling. Once going, it ran fine. My wife feared driving it. Even changing the whole engine didn't help, plus many other things before that - intake manifold, head rebuild, hoses, electronic ignition, etc. Finally my ~4th carb (Holley 1920) made it run perfect. All the other carbs (rebuilt from Auto Parts) must have idled lean (could never adjust well). I understand the internal metering block of those are sealed, so they can't be rebuilt fully.
 
I wonder how many of these are an engine miss as opposed to balance and mounting issues.
I hear a lot of engines missing that the owners don't know it.
 
TrailBeast said:
I wonder how many of these are an engine miss as opposed to balance and mounting issues.
I hear a lot of engines missing that the owners don't know it.
Click to expand...

well there internal balance and with the 120* even throws most people dont even re-balance them... they self cancel most everything...
 
Today's work produced zero results

-- set timing (found a problem*)
-- re-gapped valves (did them hot this time)
--set idle to 750-RPM
-- checked vacuum (forget the number, but it was steady, with a very slight flutter)
-- replaced the tranny tail mount (note: test the crossbolt in the mounts from Anchor before installing. The bushing I.D. was too small...I had to drill it out. It was all fun & joy trying to hammer that b**ch home before realizing there was a problem...then hammer it back out again)
-- checked mixture. Found the rearmost exhaust manifold bolt was partially missing, depth test revealed the rest of it was still in the head. Great.

* problem: the timing showed as at least 10-degrees advanced. I bottomed out the distributor in an attempt to hit the TDC mark, and couldn't make it. Static check revealed the flywheel is off by 5-10-degrees . from the marking plate...which is angled over the flywheel as though it were bent,, but the timing chain cover is perfectly flat...Could be a harmonic balancer issue.

Based on all this, I'm wondering if it isn't some kind of torque converter problem. Hard shudder in 1 on hard acceleration. Low-frequency wobble at idle in gear. Then again: harmonic balancer...

In general, this car was unmolested. It still had the vacuum amplifier hooked up. Somebody had monkeyed around with the choke - there was a zip-tie holding it open, and the fast-idle cam is missing, Other than that. it's sorta lke a time machine.
 
Arg. Sounds like a rod knock. :(

Took it out on 295 & opened it up to about 70. Sounded like someone was jackhammering under the hood. When I parked it in the driveway, heard a nice knock at idle. Sounds like a rod knock...although there's no vibration at speed, and the knock quieted down after a bit.

Does sound like something's not right in the bottom end.

Great. :sigh:

(edit): confirmed. #5 has bitten the dust. Hasn't windowed the block yet, but it's just a matter of time...
 
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