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Author Topic:   vibrations
Milkman385
Journeyman

Posts: 4
From:
Registered: Feb 2005

posted 02-27-2005 10:56 PM     Click Here to See the Profile for Milkman385     Edit/Delete Message   Reply w/Quote
have been a long time customer of Mustangs Unlimited. My last restoration has been the most painful ever.

some background:

purchased a 1966 coupe originally with a straight six but, as sold with nothing in it no eng/tranny. During the rebuild I discovered that some time in the 1970's the car underwent a major change. A whole host of upgrades including rear axel, all appropriate V8 hardwear, including 70's era disc brakes (which just barely work with some custom adapter hardwear). The fella I bought the car from also sold me a 289 (according to him) and a C4 transmission out of a 78 Ford Fairmont. I rebuilt the engine had the transmission gone through and replaced almost everything on the car.

Here's the deal, the engine was not a 289 it was in fact a 1971 302 orignally out of a Torino, so the harmonic balancer was wrong and I figured that it had been responsible for the wierd vibration i was getting (a pulsing recurring harmonic vibration at speeds in excess of 45 mph and a nasty vibration at idle). Replacing the balancer did not help so believe me we went through everything including buying a new block because the old one we'd rebuilt turned out to be crap it had really worn itself out(nearly eating through the main bearings and nasty scoring in the rods). The new block was a professional rebuild and I put in a 4bbl edelbrock(my holley blew out do to crap getting into it). the new engine was given a stock cam(rule out the RV cam theory) and just yesterday I completely rebuilt the rear end, brand new everything in that rear axel.

The thing is the engine still has the same vibration at speeds in excess of 45 mph. I'm at my wits end here so I took it into a shop and the dude drove it and he tells me that the vibration is in the COMPLETELY BRAND NEW ENGINE. Specifically he said it was a manifold vaccuum leak or a carb leak, all i can say is fat chance, no way in hell. I hope somebody has got some kind of theory on this.


In addition these are the only components used that are not new:

289 HP Heads
4bbl Intake Manifold
Oil pan

Also all components in the rear end were rebuilt and balanced (including the driveline). All components within the engine were balanced by the company that built the engine.

This is not a vaccuum leak in the engine.

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gmliebau
Gearhead

Posts: 279
From: Port St. Lucie, FL
Registered: Jan 2004

posted 02-28-2005 01:30 AM     Click Here to See the Profile for gmliebau   Click Here to Email gmliebau     Edit/Delete Message   Reply w/Quote
What about the flywheel or the tranny? Did you use the same for both motors?

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SteveLaRiviere
Administrator

Posts: 42859
From: Saco, Maine
Registered: May 99

posted 02-28-2005 08:15 AM     Click Here to See the Profile for SteveLaRiviere   Click Here to Email SteveLaRiviere     Edit/Delete Message   Reply w/Quote
quote:
Originally posted by Milkman385:
have been a long time customer of Mustangs Unlimited.

------------------
'70 Mustang Mach 1 351C 4V/FMX/3.25 Open
'70 Mustang Convertible 250 I6/3 speed/2.79 Open
'72 Mustang Sprint Hardtop 351C 4V/FMX/4.30 Trac Loc
'94 F-150 XL 5.8L/E4OD/3.55 Limited Slip

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68 Coop
Gearhead

Posts: 859
From: Mesquite, NV.
Registered: Oct 2004

posted 02-28-2005 08:53 AM     Click Here to See the Profile for 68 Coop   Click Here to Email 68 Coop     Edit/Delete Message   Reply w/Quote
My car was doing that when I first got it, guy tried to tell me 1 of the rims were bent. Turns out to be an old uni joint. Spun out and ate the mufflers.

------------------
William
68 Coupe
"Project Under Construction"

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whiteknight289
Gearhead

Posts: 1273
From: Wheaton, IL, USA
Registered: Mar 2004

posted 02-28-2005 09:45 AM     Click Here to See the Profile for whiteknight289   Click Here to Email whiteknight289     Edit/Delete Message   Reply w/Quote
Welcome to Mustangs And More! There is a wealth of knowledge and experience here, so hopefully with a little patience from you in answering more questions maybe we can all be of help somehow.

Did Mustangs Unlimited restore your car? What is their role in this problem?
Or was that just to provide some background information?

If so much attention has been paid to the engine I would start to look at other components on the car, anything that rotates could cause a vibration.

Driveshaft (again)
Flywheel missing a weight or the wrong flywheel
brake drum or brake rotor
wheel or tire
bent axle

Scott

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senzstang
Gearhead

Posts: 248
From: perry, oh, usa
Registered: May 2002

posted 02-28-2005 12:11 PM     Click Here to See the Profile for senzstang   Click Here to Email senzstang     Edit/Delete Message   Reply w/Quote
My guess would be your flywheel or tranny.
If the flywheel is supposed to be 28oz balanced and you have a 50 oz you will feel a vibration.

Not all C4's are the same. You may have a C4 that is supposed to be used with the 50 oz late model balancing.
I am no expert (understatement) but I had the same issue. I had a C4 that was supposed to have been from a early 70's 302. I put in a new engine, rebuilt 289, and had all kinds of vibration. I tried everything and finally out of desperation bought a C4 from a 66 from one of the members on this site. Put it in and vibration went away.

Don't run it long with this vibration or you will burn up the bearings on the new motor.

Phil

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Milkman385
Journeyman

Posts: 4
From:
Registered: Feb 2005

posted 02-28-2005 08:30 PM     Click Here to See the Profile for Milkman385     Edit/Delete Message   Reply w/Quote
Okay, thanks for the replies.

Firstly, the comment regarding mustangs unlimited was for background purposes and this post was originally on mustangsunlimited forum.

Now then, the fly wheel was sent in to the shop with the engine it is supposed to be properly balance and has a weight welded on it. This was brand new. The transmission as i have said is out of a 1978 ford Fairmont and is a C4 it was gone over but never with the engine. There is a chance that this could be the problem. However I am using the 70's style balancer and pulley on my 1972 engine(the new one).

I did the rebuild on the rear axel myself they did not appear bent at that time. Still it could be that the rims are bent, though I cannot tell, there is no noticable "wobble" in them while on the road. The rotor and drums were turned before being put on the car.

The U joints are brand new and lubed.
Thanks again for your posts.

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hardhat
Journeyman

Posts: 47
From: summerland, ca
Registered: Feb 2004

posted 03-01-2005 01:46 AM     Click Here to See the Profile for hardhat     Edit/Delete Message   Reply w/Quote
I had the same problems about a year ago. It turned out to be a bad wheel. I had the wheels balanced twice so I figured it could not be the wheels. Many hours (and posts) went into everything listed above. Finally I took a few more hours and replaced every one of my wheels with the spare and would take it on the freeway a couple miles to see if the vibration would dissapear. Finally on the last wheel, it went away. I took the tire off the wheel and found a balled up can of fix a flat. I actually paid somebody to balance the wheels, twice! I would recomend checking the wheels again.

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

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74merc
Gearhead

Posts: 956
From: Demopolis AL
Registered: Jun 99

posted 03-01-2005 02:34 AM     Click Here to See the Profile for 74merc   Click Here to Email 74merc     Edit/Delete Message   Reply w/Quote
I don't think the tranny cares what balance you have, I think the situation above (senzstang) was a fluke.
I ran a 1974 C4 28oz and swapped to a 1985 AOD that was on a 50oz imbalance engine, got the correct 164 tooth 28oz imbalance flywheel and all is well.

If you have a 50oz flywheel on a 28oz motor, you would NOT drive it, trust me on this, we're talking full on shaking, vibration isn't the word.

Could be the flywheel (custom balance, right?) may not be exact, could be the rims, tires, brake discs/drums, driveshaft, torque converter if it sat too long, etc...

I'm betting on wheels/tires/brakes, something in that area... could be front end parts that don't have slack in them until under severe strain (over 45+ mph) and heated, to give slack.

When your engine is running, sitting in the car, in neutral or park, held at 3000rpms, do you feel any vibration above normal?

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Milkman385
Journeyman

Posts: 4
From:
Registered: Feb 2005

posted 03-01-2005 02:35 PM     Click Here to See the Profile for Milkman385     Edit/Delete Message   Reply w/Quote
I think I'll try that. Though, I don't have a tachometer in this vehicle. However, I suppose that I can guess about how much 3000 rpms is. The car vibrates, you can feel the engine running. Do you know what I mean? It does shake, and at idle quite noticably. I will however check the wheels again.

Thanks for your suggestions.

No, it has a bad recurring harmonic vibration at speeds in excess of 45 mph.

[This message has been edited by Milkman385 (edited 03-01-2005).]

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SteveLaRiviere
Administrator

Posts: 42859
From: Saco, Maine
Registered: May 99

posted 03-01-2005 02:46 PM     Click Here to See the Profile for SteveLaRiviere   Click Here to Email SteveLaRiviere     Edit/Delete Message   Reply w/Quote
One quick way to see if the vibration is in your engine or the car itself is to find a deserted highway, bring the car to the speed that the vibration occurs and shut off the engine. Be sure to turn the key only enough to shut the engine and not lock the steering wheel if the car is '70 or newer. Also, only do this on a straightaway if the car is powered steering equipped.

If the vibration goes away, it's in the engine. If it's still there, it's not.

------------------
'70 Mustang Mach 1 351C 4V/FMX/3.25 Open
'70 Mustang Convertible 250 I6/3 speed/2.79 Open
'72 Mustang Sprint Hardtop 351C 4V/FMX/4.30 Trac Loc
'94 F-150 XL 5.8L/E4OD/3.55 Limited Slip

[This message has been edited by SteveLaRiviere (edited 03-01-2005).]

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grego37
Journeyman

Posts: 92
From: los angeles,CA,USA
Registered: May 2004

posted 03-01-2005 02:52 PM     Click Here to See the Profile for grego37     Edit/Delete Message   Reply w/Quote
Did you say it starts to happen at around 3000 rpm? Can you test in your garage or driveway?
Slowly bring up from idle to 3000 or ?rpm
see if you notice the vibration.

If the vibration is still present you can rule out the wheels/tires,brake assy, drive shaft,trans? etc.. then you can focus on the engine.
And vise/versa if the vibration is gone , then i'd look into the rotating parts.
good luck.

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Milkman385
Journeyman

Posts: 4
From:
Registered: Feb 2005

posted 03-05-2005 03:12 AM     Click Here to See the Profile for Milkman385     Edit/Delete Message   Reply w/Quote
So, my mustang has now been in the shop for three days. The folks over there apparently can't tell a 500 cfm edelbrocke from a 650, they tell me I have inadequate carburetor (and running lean no less) for my engine. they also tell me that there is probably a crack on the intake because there's a half degree of jump in a vaccuum gauge from 16-17 when connected.

To me these are unrelated to the vibrations. The vacuum gauge reading sounds a little low to me should be about 20 if memory serves. This could be due to late timing, carb vacuum leak things like that right? I know my brand new carb is a 650 performer series. Also both manifolds I've had occurred simulatenously with the vibrations. The dumb dudes working on my car also now want to remove the transmission and torque converter and just hook the starter up and start the engine to see if the vibration is still in the engine.

Any ideas?

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68 Coop
Gearhead

Posts: 859
From: Mesquite, NV.
Registered: Oct 2004

posted 03-05-2005 09:01 AM     Click Here to See the Profile for 68 Coop   Click Here to Email 68 Coop     Edit/Delete Message   Reply w/Quote
Yeah, take it to another shop . Sorry, I know what it's like, shops tring to get Xtra monies off ya, because they THINK they can do/say anything, and you are supposed to believe it. Try what Steve L mentioned, and see if it vibrates while the motor is off.

------------------
William
68 Coupe
"Restomod in Progress"

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adragon8u
Gearhead

Posts: 4857
From: Oceano, Ca. member# 2895
Registered: Mar 2003

posted 03-05-2005 09:26 AM     Click Here to See the Profile for adragon8u   Click Here to Email adragon8u     Edit/Delete Message   Reply w/Quote
I'm still having the exact vibrations you decribe on my 66 coupe with a 289.(except for the vibration at idle. please post what you find, if you find.

------------------
"I started with nothing, and I still have most of it left"
I'm an optimist, but I don't think it helps much
"It's better to have loved a short girl,
Then never to have loved a tall"
http://webpages.charter.net/adragon8u/mystang

[This message has been edited by adragon8u (edited 03-05-2005).]

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fred
Journeyman

Posts: 57
From: berea ky
Registered: Oct 2004

posted 03-05-2005 09:28 AM     Click Here to See the Profile for fred   Click Here to Email fred     Edit/Delete Message   Reply w/Quote
Have you tried to simulate the vibration on jack stands, put the car on stands see if the vib is still there, them remove both rear wheels if it goes away the prob is in the rear tires or rims, if not try putting hose clamps on the drivshaft is it better or worse, if it changes have the shaft balanced,if not try taking of belts if you have p/s or a/c take off the belt and try could be as simple as a cracked bracket or a bad pump, you must use process of elimanation to isolate where it is comming from, any other way, changing parts etc. gets expensive real quick, small note if you take off the rear wheels be sure to put some lug nuts on or remove the brake drums as they can fly off when testing.

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