[markiemyster]

I recently pulled my engine and tranny out. Had the tranny rebuilt. The engine was fine and had been recently rebuilt by the previous owner about 2K miles ago. After installing the rebuilt tranny with a brand new clutch and pressure plate (Centerforce II) The car ran fine for about 15 miles. Then it developed a vibration. The vibration is not at idle it's only when I give it a little gas. Everyone seemed to think it was the clutch including the tranny guy. I called Centerforce and they ask if I used the proper shoulder bolts when mounting the pressure plate. I miss placed the original bolts over the winter and being a novice I just went out and bought new Grade 8 bolts (without shoulders).
I didn't have the enthusiasm to pull the tranny again so I got the tranny guy to pull it and I sent the clutch back to Centerforce who checked it for balance and said it was fine. So I was sure it was the bolts. I purchased new shoulder bolts made specifically for the pressure plate and figured that would do it.
Well to make a long story longer, the tranny guy put it all back together new bolts and all and it still vibrates.
He pulled the tranny and clutch again and with no tranny or clutch installed he started the engine and it does the same thing. So it has to be in the engine. The flywheel seems fine.
I did very little to the engine when it was out except plugs, wires, cap, and oil. When I get the car back next week I plan on rechecking the wires which I did when I first noticed the vibration.
Any other suggestions???

[gt2betubbed]

Is the vibration at a certain rpm, or is it when ever you give it gas? And, how bad of a vibration is it?

[markiemyster]

Anything more than an idle.
I'm guessing in the 1500rpm + range it starts. The vibration is bad enough to make me think that something is getting ruined if I keep doing it.
I drove it to the tranny shop about 4-5 miles away and I didn't go over 10 mph

[markiemyster]

It idles OK but when you give it the slightest amount of gas it starts and gets worse the more gas you give it. When you shift and the RPM drops the vibration also gets less intense.

[Mikey123]

you neglected to mention the type of enging however some engines are externally ballanced , those engines have weights usually on flywheel or cluch and harmonic ballancer on the front of the engine, they are cruical in there placement in relation to the crank , if the woodruff key on the front of crank sheers the ballencer will move ,sometimes they are rubber mounted and move , also stuff like fan blades bent or missing can cause that also crossed wires but engine will usually miss all the time however have seen stranger also have seen carbs pulling on one bank (pluged main jets) that idel fine but shake under rpm or load due to every other cyl. trying to fire, good luck mikey