(SBF 302) very BAD vibe around 3500RPM's..

Long story short and im on 3hrs of sleep so please bare with me...This was a MM members car and he fully rebuilt the whole engine..Sold it to another guy and told him about the vibe and the guy never bothered to have it taken care of..Didn't drive it much and pretty much sat in storage...Now that I have it,im trying to fix it with no luck what so ever :( ..Not sure how the engine was put together and im thinking somthing is going on with the crank..Im thinking bent crank or spun bearing but again,thats what im thinking..Never bent a crank or spun a bearing so don't know if either will do this..
When I talked to the MM member that did the build,I think he said the vibe started a little after the rebuild..Not really sure so i'll message him with a link to this thread and hope he will add a little input on this that could help track down the issue..
Anyways,
Anything after 3500RPM will give a BAD vibe through the drive train..When I take off from stop lights or pushing the gas at low RPM to go around someone while driving,I can hear a click,click,click coming from the bell housing area..I thought it was the trans and so did the guy that built it so I replaced EVERYTHING..Flywheel,whole clutch set,throw out bearing,pilot bearing and put another trans in it that is 100% perfect as it was out of my old car..
Got everything done and was happy as hell thinking it was fixed but how wrong was I..When for a test ride and its doing the exact same thing :( ..
Also,
Before changing everything,the rear seal started leaking bad..As soon as I started the engine,it was dripping at idle and the drive was conisitent as in every half sec..Changed the rear seal and it didn't even last a day..Drove around (keeping it under 3000RPM due to the vibe) and after 3 or so hrs,the rear seal is leaking again..Not bad at all and after 3 weeks,oil is still full but I also don't drive it much..Heres a video I took today and just watch how bad my hand vibes on the shifter.... Thanks for any input I can get on this..

https://www.youtube.com/watch?v=JL3goObwb1c

This is how bad the rear seal was leaking before I changed it ... https://www.youtube.com/watch?v=w1own_4EHQ0

Mine had a similar vibration then the crank broke at the second main cap. Trashed everything. If I had it to do over I would pull it down and inspect everything.

if you can feel it with it just sitting there running Id check to see that the balancer is correct and not spun make sure you have the correct flywheel. Possibly something internal in the engine causing the problem wich would require a tear down and everything balanced.

bad u joints click and vibrate also

Quote:

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Originally Posted by fastredgmc

if you can feel it with it just sitting there running Id check to see that the balancer is correct and not spun make sure you have the correct flywheel. Possibly something internal in the engine causing the problem wich would require a tear down and everything balanced.

bad u joints click and vibrate also

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i would pull the drive shaft to rule this out and see if it does it still just dont over rev it since it wont have a load on the engine.

X2.

Sounds like the driveshaft. Mine did the exact same thing after i removed it and didn't mark it.

Sent from my XT907 using Tapatalk 2

Super duper dildo lmao.

Guys if hes getting the vibration with the car revving in neutral while not moving its definately nothing to do with the driveshaft.

I'd say toss a stock 50oz balancer on it thats known to be good, just to eliminate that possibility. Other then that, if it still vibrates I'd be pulling the motor and tearing it down. Do you have any sort of build sheet on the motor? Do you know what parts were used?

I had a buddy that bought a car with a "built" motor and it had a hell of a vibration. He thought maybe it was a bad balncer or flex plate. Turns out the hillbilly that built it had 2 different kinds of pistons in the motor.

Also, are you sure that it was built as a 50oz imbalance and not a 28? It seems retarded that someone would build a motor and keep it at the shitty 50oz OEM Imbalance.

Flex plate / flywheel correct for application? Dyno tech can also balance a motor while it's in the car if needed (Just have your wallet ready lol)

The drive shaft isn't going to do this and flywheel/balancer is 50oz..i'll post more info in a sec,trying to unload the wifes car...

Ok,heres the car I bought and the whole build/info is posted in the ad ..I didn't buy it from him,I bought it from the guy he sold it to but when he sold it,the car had the vibe issue so it had the vibe when he built it or had a shop build it..I sent him a message with link to this thread and hope he replys with info that can help a little..
I did go by his house and got some info but not enough..From what he told me,he did a AOD to T5 swap with a Tremec..Thinking the input shaft that gos into the pilot bearing was bad so I swapped it with a worldclass T5 from my old LX 5.0 ..I also replaced the flywheel with a brand new 50oz flywheel along with brand new pressure plate,clutch disk,throw out bearing and pilot bearing and that didn't change anything..Im 10000000% sure the trans I put in it is perfect because it was in my other Mustang that I sold...I do have another 50oz balancer a buddy give me to try but haven't put it on yet,hoping I can get that done tomorrow but I have a bad feeling i'll be taking the engine out..The car hasn't been tuned but everyone I talked to said a tune won't do this..