Harsh Vibrations!

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phazersonstun

New Member

Feb 28, 2007

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Nov 17, 2007

#1

• Nov 17, 2007

• #1

So I dropped in an 1988 roller-cam 5.0 into a 67 coupe. The car is pretty much together but I get a NASTY vibration when I rev it. I Know that the original 289 was internally balanced while the late-model engine is externally balanced. I had to use the old flywheel from the 289 because the 51oz for the 5.0 was too large for the C4 transmission's bellhousing. Is this my problem or is it something else? Any help would be greatly appreciated.

 

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bnickel

Founding Member

Aug 21, 2002

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lubbock, texas

Nov 17, 2007

#2

• Nov 17, 2007

• #2

phazersonstun said:

So I dropped in an 1988 roller-cam 5.0 into a 67 coupe. The car is pretty much together but I get a NASTY vibration when I rev it. I Know that the original 289 was internally balanced while the late-model engine is externally balanced. I had to use the old flywheel from the 289 because the 51oz for the 5.0 was too large for the C4 transmission's bellhousing. Is this my problem or is it something else? Any help would be greatly appreciated.

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that is most definitely your problem. the balance factor for the 2 engines is so much different that it is causing the engine to basically fight itself on every turn of the crank. you need a flexplate for an 81 or 82 302 with the small bell c4.

 

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C0V3R

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Feb 14, 2003

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Australia

Nov 17, 2007

#3

• Nov 17, 2007

• #3

btw its 50oz not 51oz

 

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bnickel

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Aug 21, 2002

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lubbock, texas

Nov 17, 2007

#4

• Nov 17, 2007

• #4

C0V3R said:

btw its 50oz not 51oz

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true, i didn't really feel like pointing that out though.

 

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phazersonstun

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Feb 28, 2007

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Nov 18, 2007

#5

• Nov 18, 2007

• #5

Really? Great! So where can I find one? I haven't seen an such an early V8 at the junkyard in a long time. Could I find a flywheel from a similar platform?

50oz. Got it.

 

rbohm

Founding Member

Apr 12, 2002

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tucson,az

Nov 18, 2007

#6

• Nov 18, 2007

• #6

here are 4 such flexplates from summit racing;

http://store.summitracing.com/egnse...94905612+4294863728+4294840126+115+4294871826

 

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BornInAFord

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Apr 22, 2005

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Bend, OR 97701

Nov 18, 2007

#7

• Nov 18, 2007

• #7

You can also have a machine shop rebalance your current flexplate to 50oz, too, although this may be as expensive as just getting a new correct one or finding one on ebay. You definitely DO NOT want to run the car as you currently have it as it will tear itself apart in quick order.

BTW, all factory 260, 289, 302, 5.0L and 351W engines were externally balanced. The difference is in the balance weight on the flywheel/flexplate and front harmonic balancer.

 

CraigMBA

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Mar 24, 2007

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Nov 18, 2007

#8

• Nov 18, 2007

• #8

And while you're at it, what damper did you use?

 

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phazersonstun

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Nov 19, 2007

#9

• Nov 19, 2007

• #9

I am using the stock 5.0 dampner. Why do you ask?

 

Pbum5

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Oct 27, 2004

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Minneapolis, MN

Nov 19, 2007

#10

• Nov 19, 2007

• #10

Because - You need the correct balance dampener and flywheel/flex plate for your application.

 

CraigMBA

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Mar 24, 2007

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Orange, CA

Nov 19, 2007

#11

• Nov 19, 2007

• #11

phazersonstun said:

I am using the stock 5.0 dampner. Why do you ask?

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Because that one's 50 oz and OK and the other one is 28 oz and isn't OK.

 

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bnickel

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lubbock, texas

Nov 19, 2007

#12

• Nov 19, 2007

• #12

the 5.0 balancer is also balanced for the 50oz imbalance of the 5.0 motor as well as the flexplate. same goes for the early 28oz motors, the balancers and flexplates must match there as well.

 

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phazersonstun

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Nov 19, 2007

#13

• Nov 19, 2007

• #13

Right.