Engine Fresh Rebuild Vibraton/shutter At High Rpm

Discussion in '1994 - 1995 Specific Tech' started by jmil918, May 29, 2014.


  1. jmil918

    jmil918 New Member

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    I just completed my first rebuild on my 95 Mustang 5.0 everything went pretty smooth and the car started right up and idled great. However, when I push the RPMs up I get a very bad vibration. This happens in neutral as well as driving down the road so that should eliminate anything to do with the drive shaft. After doing some research I think I might have made a rookie mistake......

    Almost all of the parts in the engine are new with the exception of the block, the crank, and the connecting rods. The mistake I believe I made was not having everything balanced together. Everything I purchased was balanced at 50oz, but I've been told that even if they are balanced the same, they still need to be balanced together by a machine shop.

    One additional thing to note, I did NOT have the machine shop line hone the mains/crank (Another no no) and when I got it back from the machine shop the crank was pretty tight, but I used thinner bearings and everything checked out with plastigauge. Can anyone weigh in on if I'm on the right track or a possible solution? I have removed, cleaned, and reinstalled the harmonic balancer and there was no change. Thanks!
     
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  2. jmil918

    jmil918 New Member

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  3. toyman

    SN Certified Technician

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    Is the HB new and 50 oz and not 28 oz by mistake?
     
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  4. jmil918

    jmil918 New Member

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    The HB and the flywheel are both new & balanced from 50oz. They were ordered from reputable places (American Muscle & Summit), is there a way to distinguish between 28 & 50oz?
     
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  5. revhead347

    revhead347 I have face herpes.

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    Ugh. Did you have the rods resized?

    Kurt
     
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  6. jmil918

    jmil918 New Member

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    No, I was told since I was re-using the same rods, crank, mains, and bolts that I wouldn't have to do that. Was I told bad information?
     
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  7. toyman

    SN Certified Technician

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    I don't think there is anything that can visually distinguish them. They must also match the flywheel imbalance as well. I would call the source provider and ask if they can confirm the part number for you. All the 302s from the early 80s forward are 50 oz imbalance engines.
     
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  8. revhead347

    revhead347 I have face herpes.

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    Generally whenever you have the bearings changed you do a line hone and a rod resize. I would consult another machinest to see if the first one missed something. It could be something serious or something simple. I have seen engine vibrations that were fixed by swapping around the 6 bolts on the pressure plate.

    Kurt
     
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