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Author Topic:   Engine vibration
Robert K
Gearhead

Posts: 706
From: Nashville, TN
Registered: Apr 2000

posted 10-22-2001 07:51 AM     Click Here to See the Profile for Robert K   Click Here to Email Robert K     Edit/Delete Message   Reply w/Quote
I've got a driveline vibration in the fastback at about 3500+ RPM's. The vibration gets worse as you go faster. Now under normal speeds you don't notice it but from say 75-90 it's very noticeable. I'm thinking flywheel, driveshaft, maybe a wheel ? What else could be causing this ?

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67convertible 289/auto
65fastback 302/4sp

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69maverick
Moderator

Posts: 1506
From: Thomaston,CT.
Registered: Jan 2001

posted 10-22-2001 09:54 AM     Click Here to See the Profile for 69maverick   Click Here to Email 69maverick     Edit/Delete Message   Reply w/Quote
I would look at the drive shaft first. When was the last time the U-joints were serviced or changed? The other thing to look at is the tires Did you brake a belt? or did a balance weight come off?

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franklin
Gearhead

Posts: 131
From: VA
Registered: Nov 2000

posted 10-22-2001 10:13 AM     Click Here to See the Profile for franklin     Edit/Delete Message   Reply w/Quote
You could eliminate the flywheel/engine/torque convertor by revving it up in the driveway and see if it vibrates.

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Robert K
Gearhead

Posts: 706
From: Nashville, TN
Registered: Apr 2000

posted 10-22-2001 10:14 AM     Click Here to See the Profile for Robert K   Click Here to Email Robert K     Edit/Delete Message   Reply w/Quote
The U-joints are brand new. Although the tires don't have that many miles on them (I'll say 6000) they are about 7 years old. I guess it's possible a weight could have come off. I probably need to have the tires balanced just to be sure.

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67convertible 289/auto
65fastback 302/4sp

[This message has been edited by Robert K (edited 10-22-2001).]

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Robert K
Gearhead

Posts: 706
From: Nashville, TN
Registered: Apr 2000

posted 10-31-2004 01:08 PM     Click Here to See the Profile for Robert K   Click Here to Email Robert K     Edit/Delete Message   Reply w/Quote
Wow I can't believe it's already been 3 years since I posted last on the engine vibration ! I still have the vibration but since I seldom drive the car over 70 mph, it hasn't really been an issue until recently. I just put a set of TCP motor mounts on the car and now the vibration is worse than ever before. Is it a safe bet that the vibration is in the driveline then ? After doing some research here on M&M, I've discovered the common culprits of vibration seem to be tranny mounts, u-joints, driveshafts, clutchplate/discs and flywheel.

Revving the engine while parked, it doesn't seem to have the vibration. I can feel it really start at 60 and then as you past 70 you don't want to go any faster because of it. What's the general concensus as to which part to swap first. I have an extra drive shaft from another 65 mustang that I could swap in. It came out of an automatic car so I don't know if the driveshafts are the same length or not.

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67convertible 289/auto
65fastback 302/4sp

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Moneymaker
Administrator

Posts: 27870
From: Lyons, IL, USA
Registered: May 99

posted 10-31-2004 02:03 PM     Click Here to See the Profile for Moneymaker   Click Here to Email Moneymaker     Edit/Delete Message   Reply w/Quote
I owuld swap out the drive shaft since you have one.
If the vibration persists, then at the offending speed, put the car in neutral or depress the clutch to see if it goes away.

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Alex Denysenko
Co-Administrator and Moderator

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BornInAFord
Gearhead

Posts: 561
From: Bend, OR, USA
Registered: Dec 2002

posted 10-31-2004 03:52 PM     Click Here to See the Profile for BornInAFord     Edit/Delete Message   Reply w/Quote
Is there a way you can put the rear end up on jackstands or a lift and sort out the vibration that way?
Daniel

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Robert K
Gearhead

Posts: 706
From: Nashville, TN
Registered: Apr 2000

posted 11-05-2004 02:50 PM     Click Here to See the Profile for Robert K   Click Here to Email Robert K     Edit/Delete Message   Reply w/Quote
The extra driveshaft I have is 52 1/2" long without the yoke and the driveshaft that's currently on the car now is 51" and it doesn't look like I have a whole lot of extra room to put the longer one in. The extra d/s I have came out of a 65 mustang with a 289 and a C-4. I currently have a 1978 302 with a toploader and a 9" rear which seems to be taking up the extra room. I jacked the car up and ran it with it in gear to 100mph and then out of gear to the same RPM range (a little over 4K) The worst vibration seems to be right at 75 mph. There seems to be some vibration both in and out of gear so it's really difficult for me to pinpoint what the cause to be. I guess a sledge hammer approach would be to replace the pressure plate and clutch disc, have the flywheel balanced and replace the driveshaft and maybe the trans mount. Of course, I've also been contemplating the T-5 swap but for some twisted reason I really like the 4-speed.
If it's not one thing, it's another.Sometimes these old cars just wear me out.....And while I'm complaining, I'm also getting tired of listening to the whine of the Flex-a-Fan. It cools better than stock but the NOISE !! aaaaRRRGH !!!!

I'm done complaining now......

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67convertible 289/auto
65fastback 302/4sp

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FoMoGo
Gearhead

Posts: 149
From: Motor City USA
Registered: Feb 2003

posted 11-05-2004 03:27 PM     Click Here to See the Profile for FoMoGo   Click Here to Email FoMoGo     Edit/Delete Message   Reply w/Quote
Check your transmission mount.

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Robert K
Gearhead

Posts: 706
From: Nashville, TN
Registered: Apr 2000

posted 11-05-2004 04:05 PM     Click Here to See the Profile for Robert K   Click Here to Email Robert K     Edit/Delete Message   Reply w/Quote
Do trans. mounts go bad ? I'm sure the one I have now is a 40 year old original. Other than making sure the bolts are tight is there anything else to check ?

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67convertible 289/auto
65fastback 302/4sp

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FoMoGo
Gearhead

Posts: 149
From: Motor City USA
Registered: Feb 2003

posted 11-05-2004 06:41 PM     Click Here to See the Profile for FoMoGo   Click Here to Email FoMoGo     Edit/Delete Message   Reply w/Quote
The transmission mount is an combination of stamped steel & rubber with (2)studs. Similar to an engine mount. The rubber acts as an insulator to dampen vibration.

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n2oMike
Gearhead

Posts: 2864
From: Spencer, WV
Registered: Jan 2001

posted 11-08-2004 02:20 PM     Click Here to See the Profile for n2oMike   Click Here to Email n2oMike     Edit/Delete Message   Reply w/Quote
Most likely culprit is the driveshaft, since it doesn't vibrate in neutral with the car sitting still.

You can even take it loose, and turn it around a half turn to see if that changes anything. Sometimes it will.

Good Luck!

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Mike Burch
66 mustang real street
302 4-speed 289 heads
10.63 @ 129.3
http://www.geocities.com/carbedstangs/cmml_mburch.html
http://www.fortunecity.com/silverstone/healey/367
http://www.mustangworks.com/cgi-bin/moi-display.cgi?220

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Robert K
Gearhead

Posts: 706
From: Nashville, TN
Registered: Apr 2000

posted 11-08-2004 04:56 PM     Click Here to See the Profile for Robert K   Click Here to Email Robert K     Edit/Delete Message   Reply w/Quote
I checked the trans. mount bolts and they are tight. I removed the drive-shaft and turned it 180 degrees. The problem may only be just slightly better. I noticed when I had the d/s off that the rear u-joint was binding when I tried to move it by hand. I don't think that's normal but I'll have to replace that maybe next week. One thing that I did notice is that the vibration sounds harmonic in nature. By that I mean it sounds rhythmic or cyclic. It sounds like "waa-waa". I was wondering if it could be exhaust related. I have dual exhaust on the car but no cross-over pipe. What are everyone's thoughts on this ?

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67convertible 289/auto
65fastback 302/4sp

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RonnieT
Gearhead

Posts: 895
From: Port Allen, La. 70767
Registered: Jun 99

posted 11-08-2004 08:27 PM     Click Here to See the Profile for RonnieT   Click Here to Email RonnieT     Edit/Delete Message   Reply w/Quote
My wifes car had a similar problem about after an accident. It almost drove the shop crazy trying to figure out the problem. They just started replacing parts (under warranty so I didn't care)until they finally replace the right part. It turned out to be a bad wheel bearing. The car would be fine until about 65 mph and then you would start hearing a rythmic noise, at 75 mph the whole car would vibrate and it would get worst the faster you went.

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Ronnie
69 mach1 351W-4V engineless at the time!
70 Torino GT 351C-4v with a "shaker"
Mustangs and More Member #23

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senzstang
Gearhead

Posts: 355
From: perry, oh, usa
Registered: May 2002

posted 11-09-2004 08:03 AM     Click Here to See the Profile for senzstang   Click Here to Email senzstang     Edit/Delete Message   Reply w/Quote
Are you sure your drive shaft is the correct length? I had the exact same problem until I put your old C4 in mine. When I place the 2 trannies next to each other, the tailshaft of yours was 2 1/2 inches longer than the one that was in my car. Soon as I put the new c4 in vibration went away.

(FYI to readers - I bought Robert's old C4 he took out for his 4 speed)

Phil

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Ryan Wilke
Gearhead

Posts: 2588
From: Stanton, Michigan, zip 48888
Registered: Oct 2000

posted 11-09-2004 10:41 AM     Click Here to See the Profile for Ryan Wilke   Click Here to Email Ryan Wilke     Edit/Delete Message   Reply w/Quote
quote:
Originally posted by senzstang:
Are you sure your drive shaft is the correct length?

I always thought you should have 1" to 1.5" of movement of your front yoke into your trans tailhousing. An easy way to check your driveshaft "freeplay" is to smear some grease on the front yoke shaft, between the tailhousing seal and the U-joint. Then take it for a short drive, making the suspension work....Drive up into steep driveways, do a spirited launch or two, brake hard, etc. then come back & jack it up and see where the seal pushed the grease to...it should indicate that that the shaft yoke moved in & out about 1.5" If it didn't, it maybe is too long and binding a bit.

With that information in hand, the next thing I'd do is to locate/call a driveshaft service place and ask them to check / re-balance your shaft. Once you've confirmed it's balanced, re-install it with your new rear U-joint and lube it well. Do another test drive & report back!

GOOD LUCK!
Ryan

P.S.
Has the shaft ever had a yoke welded on? If so, it may not have been located inline with the other end yoke. Remember the yoke ends need to be in the same plane....

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hardhat
Journeyman

Posts: 68
From: summerland, ca
Registered: Feb 2004

posted 11-09-2004 10:43 PM     Click Here to See the Profile for hardhat     Edit/Delete Message   Reply w/Quote
Robert, I just went through exactly what you are now. I checked everything twice. Ultimatly, it was a can of fix a flat gone bad in a wheel. I had the wheels balanced twice before this. Nobody caught it at the tire store (if they really did balance them). I swapped out each wheel one at a time with my spare tire until I narrowed it down to the culprit. Good luck & shake the shakes!

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73' conv. 351C 2v mild cam, exhaust, fmx

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Robert K
Gearhead

Posts: 706
From: Nashville, TN
Registered: Apr 2000

posted 11-11-2004 09:17 AM     Click Here to See the Profile for Robert K   Click Here to Email Robert K     Edit/Delete Message   Reply w/Quote
Ok, senzstang, I want my tranny back!

No, I'm not sure I have the correct drive shaft length but it does seem to fit. If anything it could be maybe an inch shorter. It came out of an 85 cougar and was the only driveshaft at the time that fit when I swapped in the Granada 9" rear and the toploader. The original driveshaft is too long. I'm sure the front wheel bearings are original and I'll take a look at those as well. I bought the tires and wheels brand new so hopefully there's no fix-a-flat problems with them.

I did notice a very very shallow dent towards the rear of the drive-shaft. I wouldn't think that would be enough to cause a vibration but you never know. I guess the next thing to check are the front wheel bearings and have the driveshaft balanced.

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67convertible 289/auto
65fastback 302/4sp

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