347 vibration need help

Foreverenvyed · Oct 18, 2011

hey guys i was wondering if anyone could help me with a problem im stumped on.
i have a 347 stroker that i bought that was told had a bad clutch.when i started the car it vibrated bad. but thought it was just the clutch or flywheel and went to replace the clutch and noticed one of the bolt hole ears that hold the t5 to the bell housing was broken. so i bought a t5 and a full stage 3 zoom clutch kit. and resurfaced the same flywheel. but when i started the car the vibration through the shifter was still there so i replaced everything i can think of that could make it vibrate. the trans and motor mounts. the old harmonic balancer had a lil rubber coming out so i replaced the harmonic balancer, and it still vibrates just as bad or worst. the old one was a 50oz and the new one is a 50oz but i hear its rare that they balance a 347 to 50oz. the flywheel was a stock ford brand so im guessing its a 50oz too. do you think someone put the wrong balancers on it and thats why the old trans was broken. im not a pro mechanic so im just asking if anyone has ever seen the problem that im having and wat else i could try.
please excuse me for my bad way of explaining things. and ive realized i needed to look at cars closer before i buy them now.
so to the short way the shifter vibrates really bad in and out of gear and low to high rpms.
ive replaced the harmonic balancer. clutch, throw out bearing, pilot bushing, transmission, resurfaced the flywheel, new motor mounts and new trans mount,

mustangspartan · Oct 18, 2011

On most 347 kits ive seen its usually 28oz

teal95vert · Oct 18, 2011

yay, most should be 28oz; balancer & flywheel. if you have been running 50oz, is probably has hosed the bearings.

Musturd · Oct 18, 2011

Yea like said above, most are balanced to 28oz. My stroker has both a 28oz balancer and flywheel on my fox.

5litrarag · Oct 18, 2011

Its kinda rare nowadays, but if its an old kit, it has a good chance of indeed being a 50 oz. The balancer and flywheel being great evidence of that.
Now for the bad news.... I had an engine do exactly what you are describing, I replaced many of the same things and the things that werent replaced was because they were brand new when the motor went together.
What I found and what I think you will find is that motor needs to come apart to be properly diagnosed. Mine ran fine for a couple thousand miles and then one day after being out playing with the boys all day, the motor developed a slight vibration as the rpms went up or down, in or out of gear. I suffered thru this for about a month and then a friend of mine offered to sell me a 347 kit for a good deal if I wanted to pull my current motor and check it out to be sure.
Well when we got it open it was discovered that it had a cheapo chinese crank in it (CAT, dont EVER fvck with that junk) and it was bent. It was measured at like .20 thousandths out if I recall.... I have a couple videos online before and after it was out of the car. I'll see if I can find them again.....
Look under your car and see if you can spot an oil leak at the rear main seal. If so, the crank is probably bent and most likely the block is junk too. Sorry for the bad news, but I'd bet thats why this car was for sale.

5litrarag · Oct 18, 2011

Videos are still there..... if this is what yours resembles, this is most likely the cause since you've replaced all the external items that could cause a vibration.

Good luck man.....

http://www.youtube.com/watch?v=2ZzIMvfDY1Y

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Foreverenvyed · Oct 18, 2011

thanks guys for the help and 5litrarag, mines similar to the vids but worst so im guessing thats my problem. i found out this motor was built in 04 so it was probably needing a rebiuld a long time ago. thanks again everyones help made my day!! in a way.