Good Vibrations? - Alfa Romeo Bulletin Board & Forums
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post #1 of 4 (permalink) Old 07-11-2019, 04:43 PM Thread Starter
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Good Vibrations?

Having recently changed out clutch ,flywheel,PP etc I tackled a mild vibration In the wifes 64 GT Sprint.. which was tolerable...No problem "sweetie" ... I'll fix it..NOS U-J, CSB ...sent Drive shaft out to check balance...all good...reassemble should be smooth as a babies butt. So confident sent her out on the test drive... WHOA!!! what a grievous error in judgement. She started yelling coming in the driveway... shook like a magnitude 7.0 ... what did I do!!!!! ruin 43 years of bliss in less than 3 hours?
My mechanical impetus , challenged...what to do!! Self doubt...the only thing it could be is a bent DS (I said to myself!!!) But it checked out...Maybe I F--ed up ...(I don't think so?)

Went through ABB threads Giubo, peanuts, bearings, dust cover!!!... you get the point .. none of the above....Sent the Prop shaft out to another shop and my suspicion confirmed... turns out the shop I sent the DS to be balanced F--ed up.. the DS was out by .0325MM the wear in the original drivetrain absorbed it. However.. when all was inspec.... well it exacerbated into a very bad vibration , Moral of the story your first impressions are usually correct.. or I should have let it be...? In any case all the universe is back in alignment.
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The older I get.. the faster I was....
Tom

Last edited by Tom Frasca; 07-12-2019 at 03:56 AM.
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post #2 of 4 (permalink) Old 07-12-2019, 04:24 AM
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How do you measure 1/1000 of an inch in drive shaft alignment? That is 1/4 the thickness of a dollar bill. It might have effects on a jet engine but can't see it on a drive shaft. just wondering? What caused the groove?

Last edited by divotandtralee; 07-12-2019 at 04:30 AM.
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post #3 of 4 (permalink) Old 07-12-2019, 06:58 AM Thread Starter
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Quote:
Originally Posted by divotandtralee View Post
How do you measure 1/1000 of an inch in drive shaft alignment? That is 1/4 the thickness of a dollar bill. It might have effects on a jet engine but can't see it on a drive shaft. just wondering? What caused the groove?
Oops wrong decimal place.. 3.25mm about 1/8 inch deflection...

Set up on a high end balancer bolted in, the scratch mark is the area of distortion ...... no physical damage to explain deflection. My better half bought the car 4 years ago... this was the last little bit to be done. I do not know what the PO may have done there is zero accident damage, running over something would leave some sort of evidence. This is a real head scratcher.. Thankfully Keith Goring at Alfa Unlimited had a DS popped it in..smooth as silk. (for an Alfa) Now I think I will try and find a shop that can fix it. OEM parts are getting tougher to find, I feel obliged to keep it in circulation.

The older I get.. the faster I was....
Tom

Last edited by Tom Frasca; 07-12-2019 at 07:10 AM.
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post #4 of 4 (permalink) Old 07-12-2019, 07:12 AM
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Decimals can be a problem
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