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Vibration issue on new motor tranny install

DirtDonk

Contributor
Bronco Guru
Joined
Nov 3, 2003
Messages
48,743
Oh, and the only engine I've experienced with a mis-matched flywheel imbalance factor vibrated even at idle. Yes, it was very faint at idle, but you knew something was way wrong well before 2000 rpm.
By the time you were at just over 1000 or so you knew there was a distinct balance issue involved.

Does yours just start at 2000? Can you feel it at all at lesser rpms? If it's still an imbalance, maybe it's more likely the damper than the flywheel because it's lighter and smaller diameter?
I'm guessing not in your case, because you've already said it was the damper that came with the engine, correct? But the lighter impact of the damper vs the flywheel would seem to indicate that a mismatched one would have less of a severe impact at lower rpm levels anyway.

So what else was done to the engine? Nothing? Just pull it from the donor and install it?
Does the frequency or amplitude change when you push in on the clutch pedal?

Ooh, ooh! What about something simple like the cylinder head hitting the firewall? Or the shifter hitting the floor?
Seems like just a little shifting of the trans to fit the mount would not be enough to do this, but that cylinder head is pretty darn close to the driver's side firewall to begin with. Maybe yours is hitting some linkage or other, or some bit of the casting is touching the body.
Worth a look anyway.

Good luck.

Paul
 

KyleQ

Bronco Guru
Joined
Apr 24, 2008
Messages
5,480
I got a bad flywheel on my 435 swap - boxed wrong or made wrong. Bought another and compared and warranty'd out the old - runs smooth as butter now.
 

bronconut73

Bronco Guru
Joined
Aug 7, 2012
Messages
9,918
Mine had a 2000 rpm vibration.

I had the 302 firing order when I should have been running the 351 firing order,
Idled fine.
Was running an MSD box back then.
 

Nickm1024cobra

Sr. Member
Joined
Jun 15, 2014
Messages
362
Loc.
Chicago Burbs
Mine had a 2000 rpm vibration.

I had the 302 firing order when I should have been running the 351 firing order,
Idled fine.
Was running an MSD box back then.

Thats a good point. When motor was rebuilt maybe they swapped cams with a different firing order. Could be the 302 non HO order 15426378

or the HO EFI order 13726548
 
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