Engine vibration

I have a 1992 Mustang GT that has a bad vibration in the motor.  It only vibrates under throttle which leads me to believe that the flywheel is wrong. The motor is internally balanced so does anyone have any suggestions?

The car has a 5 speed Tremec in it that I am going to drop so I can take a look at the flywheel,clutch etc. and replace the flywheel with a zero balance one. I have a sneaking suspicion that when my brothers and father put the motor in they used the stock 50 oz. flywheel and stock dampner with an internally balanced motor.

Any help would be great. Thanks  

It sounds like you're on the right path. If the engine is truly internally balanced (aftermarket crank/stroker kit, etc.) then you need a zero balance damper and flywheel. The stock '92 engine is 50 oz. imbalance and requires the proper 50 oz. damper and flywheel. If any parts are mismatched you will have a fairly severe vibration that worsens with rpm.

HTH...
Mark  
Mark Houlahan
Technical Editor for:
-Modified Mustangs & Fords Magazine
-Mustang Monthly Magazine

1965 FFR Roadster 427W/TKO-600 5-speed
1966 Mustang 289-4V/C4 Auto
1968 Mustang 4.6L Three-Valve/5R55S Auto
1990 Mustang 306/AOD
2001 Ranger SuperCab 4x4 3.0L V-6/5R44E Auto
2002 Explorer Sport Trac 4.0L V-6/5R55 Auto

when you got the engine built.. it was balanced..  there should be a balance card with it...  that will list the Imbalance needed for the flywheel...

before tearing the transmission out..

there are TWO possible firing orders for that year car..  the 5.0EFI and the 5.0HO motors not only have the firing order different.. but the way the injectors are hooked up is different..   both engines are sequential fuel injection... so the injectors have to fire in the same order as the spark plugs..   having the firing order for either wrong .. will cause issues..

it depends upon which cam you used...  what the firing order will be..

follow the last 2 spark plug wires from the drivers side of the engine.. to the distributer cap.. are they routed NEXT to each other all the way... separate them like this..



 

Thanks guys. Checked the wires and moved them but the vibration is still present. Do I have to replace both the flywheel and balancer with 0 balance versions of both or only the flywheel?  

Quick story on the car. It belonged to my brother Mike, who bought it in S.C. in 1997. In July of 1999 he passed in an accident at 20 yrs. old. (Not a car accident) At that point my Dad, youngest brother and I decided to make the car the way Mike wanted to and give it to Steve. Body off paint job to Wild Strawberry, motor work, interior etc.  The car never really ran right and was never really finished.  This passed February my youngest brother Steve fell asleep driving home, drove off the road and was killed at age 33.  Now the car is mine to finish.

I took it to a dyno shop where they tuned the car and got it running really well, except the vibration.  They didn't do the original work so they know nothing about the motor and we have no paperwork from the original machine shop but we do know that the motor is internally balanced.

Any more information that anyone can provide would be greatly appreciated.  The car has a lot of sentimental value and I just want to drive it.

Thanks,  

Sorry for you losses Stone, but I can only imagine what the car must mean to you and your dad...

An internally balanced engine must have a zero balance flywheel/flexplate and damper. If the damper is an aftermarket part it MIGHT have a removable counter weight. I've seen lots of dampers that come zero balance and have both the 28 and 50 oz. imbalance weights in the box.

Before pulling the trans check the damper, as it is external and easy to look at. Rotate the engine by hand and check for any sort of sticker or part number on the damper around the timing marks and report back what you find. Lets start there...

Mark
.  
Mark Houlahan
Technical Editor for:
-Modified Mustangs & Fords Magazine
-Mustang Monthly Magazine

1965 FFR Roadster 427W/TKO-600 5-speed
1966 Mustang 289-4V/C4 Auto
1968 Mustang 4.6L Three-Valve/5R55S Auto
1990 Mustang 306/AOD
2001 Ranger SuperCab 4x4 3.0L V-6/5R44E Auto
2002 Explorer Sport Trac 4.0L V-6/5R55 Auto

MustangMan,

The car means more than anyone could ever imagine.  When I drove it home from the dyno shop, it was the first time I had driven the car without Steve. It was bittersweet at best but I knew I had two passengers with me on that drive home.

This is what I found. Damper is stamped E4TE A3A. I can tell its weighted by the cutouts and holes drilled. Next step?

Thanks,
Jeff  

The E4TE-A3A is indeed the late-model Mustang 50 oz balancer. Of course we still don't know what you have for a flexplate either. If your engine is indeed internally balanced (all stock Ford 302s are externally balanced via the weight system on the flexplate/flywheel and the balancer) you'll need to at the least change out the balancer but you won't know for sure until you know what the flexplate is. Put a zero balance balancer on it first, as that's easy to swap out and then see what, if any, vibration is still there.

Mark
.  
Mark Houlahan
Technical Editor for:
-Modified Mustangs & Fords Magazine
-Mustang Monthly Magazine

1965 FFR Roadster 427W/TKO-600 5-speed
1966 Mustang 289-4V/C4 Auto
1968 Mustang 4.6L Three-Valve/5R55S Auto
1990 Mustang 306/AOD
2001 Ranger SuperCab 4x4 3.0L V-6/5R44E Auto
2002 Explorer Sport Trac 4.0L V-6/5R55 Auto

Great. Thanks Mark. I'll get one ordered tonight and keep you posted.

Jeff  

I had two choices for the 0 balance damper. 1.) 28 oz. with removable weight and 50 oz. with removable weight. I decided to buy the 28 oz. seeing as how I know the 50 oz. is wrong.

I installed the damper at 0 balance and the car shook so bad that I immediately shut it down. At this point I reinstalled the 28 oz. weight more or less for troubleshooting and started the car. It ran extremely smooth.

The only conclusion I came up with is that it's not the original 92' motor and it was never internally balanced. Either way the vibration is gone and now I can finish working on the interior and cleaning things up.

Thank you for all of the help Mark. We greatly appreciate it. as soon as the car is complete I'll post some pictures