These arent "Good Vibrations"

I recently purchased a Ford Galaxie with a 289 & automatic (no P/S P/B A/C. The car starts/idles perfect, but I have a vibration that resonates the entire car once revved past approx. 1200 rpm and progressively gets worse as the rpm climb. By vibration, I mean the entire front half of the car will vibrate the teeth out of your head and seemingly shake all bolts n screws from the dash. When I look under the hood, there is no noticeable shaking from the engine at idle or revved. First thought was replace the dampener. While I was at it I replaced all the pulleys and the belt with brand new. NO LUCK.

My question is: Could a bad trans mount or flex plate allow these kinds of results? Has anyone had a similar issue with their early 289 and what fixed it?

Thanks for taking the time to read and I look forward to replies, -Kris/Rougebeats

 

Deth Wobbel.

 

is it in gear when this happens or park?

 

While parked or while driving. Its just the increase of rpm that sets it off

 

Probably has the wrong flex plate imbalance (incorrect flex plate for year of engine/crank).

An incorrect imbalance will cause exactly what you describe.



.

 

I was reading up about that, but there are so many variations of flex plates where do I begin to find the correct size/teeth/weight/internal or external balance etc. I have a 28 oz dampener on it now, and that is what was pulled from it when replaced.

 

Have you checked the flexplate you have?

The ballance weight could have come off (as opposed to being the wrong one).

AFAIK the 289 is supposed to have the 28.8 Oz imballance, but that's only from what I read.

Best I understand it they are supposed to match the ballancer, so if you have a 28.8 balancer on there then you should have the same on the flexplate.

Good luck, I can't immagine driving it with that, no fun if you can't drive 'em.

 

nexxussian-you are correct. It is the 28 oz dampener. I suspect I may need to check out the flex plate for cracks or the weight missing? With a new one, do I just match the tooth count/size/weight?

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ALSO-I havent driven the car since I brought it home. Just run it in the garage to see if I had corrected it with new parts. The work:fun ratio is falling off quickly.

 

Check out a mustang forum or a 5.0 forum. They will be able to tell you what flex plate or balancer combo to use. Also your local engine builder/machine shop will know. There are more c-4 fly wheels than Baskin Robbins ice cream flavors.

 

I had a convertor go bad, did the same thing, it still worked, trans shop found it

 

Have you checked Engine mounts or Tranny mounts . Sounds like the engine or tranny is sitting on the crossmember

 

When I first read this I was thinking harmonic balancer, as if the ring slipped and was causing it. But you said you replaced it. First of all, what year car? Are you sure the motor is the original 289? Reason I ask is that in 80 or 81 Ford went to a 50 oz imbalance vs the earlier 28 oz. The wrong damper or flexplate would do what you describe.

You never know what someone did over the life of a car and what parts they might have interchanged. I would verify the engine model and year and go from there. You might also check the convertor to flexplate bolts to make sure they are tight. My Son had a vibration in his Buick and it was loose bolts.

Don

 

thats what i thought^^^^had that happen with a big block.

 

Check the firing order.
SBF's use 2 firing orders.

Early engines us 1-5-4-2-6-3-7-8

Later engines and cams use 1-3-7-2-6-5-4-8

If you mix them up the the engine will still run fair, but shake like crazy.

 

You can eliminate the possibility of a convertor by disconnecting it from the flexplate and running the engine. If it still vibrates then you've at least eliminated that portion. If it doesn't then you've narrowed it down to the convertor or tranny.

 

I had a '63 Galaxie 500 with the same symptoms. Almost drove me crazy checking all the same things mentioned here. The problem turned out to be a broken front stabilizer bar. It was broken in the bend on the driver's side and that allowed the long bar running accross to the other side to magnify vibrations and shook the entire car. Probably not your problem, but easy to look at an check before you start any real work on it. Bill.

 

huh?

 

This is a good place to start from. I once had a car that had the wrong flexplate/balancer combo and I, unknowingly, drove it like that. Eventually I cracked the crankshaft. The car still ran great but had a wicked vibration at 1800 rpm.

 

Are you sure that you don't just have a dead cylinder or cap arcing..........an idle isn't much of a test. A simple crossing of wires (such as 7 & 8) (not unheard of on early SBF) will actually idle pretty good except for increased loading with RPM