Rebuilt motor vibrates too much.

[dsmmotor]

I just put in a rebuilt 7 bolt engine in my 97 gst. It started up and ran ok. Problem is there is the has a shim/vibration to it. Feels kind of like when your front rotors are warpped and you are making a high speed stop. It vibrates at every speed and gets worse when you rev it past 3,000rpm. Kind of like it's out of balance. Checked timming, change plugs and wires. I'm thinking it might be because the new engine has no balance shaft and my old one did. Shouldn't both engines have a balance shaft? Any ideas would help.

 

[ZachM31]

so you wanna know if it should has balance shafts? you might have gotten one that already had the balance shafts eliminated.. or did you not put a balance shaft belt on? i couldnt quite understand what you were saying.. as for the harmonic balancer, i dont know if that would cause a problem.. its just a pulley with a soft middle to dampen vibrations, if its bad, then the outer ring will work it's way in and start rubbing on your lower timing belt cover, unless you have a solid crankshaft pulley.

 

[Defiant]

The 3000rpm tooth-filling-removal is a characteristic of an out-of-phase rear balance shaft.
I don't know what to make of your referring to a balance "shaft". They come in pairs.

But as usual, we'll wait the couple of days it takes for the whole of the truth to surface.

 

[dsmmotor]

Well when the engine came in one of the cam gears had a peice missing. So I had to retime the engine after putting on my old cam gear. I am sure the front balance shaft was not there, because I compared both engines. But I don't know if there was a rear balance shaft or not. That could be my problem, all i did was line up the dot on the oil pump gear to it's timming mark. Would having only one balance shaft be normal though.

 

[ZachM31]

did you make sure that the oil pump sprocket rotated towards the timing mark, what i mean by that is; turn the sprocket and get the mark on it facing up, then let go, if it rotates away from the mark, spin it one complete turn, and do it again, then it should rotate towards the mark, then you know it is in phase (you can also pull the rubber plug on the backside of the block and put a philips screwdriver in there and see how much of it goes in) i like the spinning method better....

 

[MNGSX]

Well when the engine came in one of the cam gears had a peice missing. So I had to retime the engine after putting on my old cam gear. I am sure the front balance shaft was not there, because I compared both engines. But I don't know if there was a rear balance shaft or not. That could be my problem, all i did was line up the dot on the oil pump gear to it's timming mark. Would having only one balance shaft be normal though.

That is it. There is no front balance shaft belt..

The rear shaft is driven off the oil pump...

Do a BS removal and get back to us..

 

[Defiant]

Well when the engine came in one of the cam gears had a peice missing. So I had to retime the engine after putting on my old cam gear. I am sure the front balance shaft was not there, because I compared both engines. But I don't know if there was a rear balance shaft or not. That could be my problem, all i did was line up the dot on the oil pump gear to it's timming mark. Would having only one balance shaft be normal though.

Ah. So, you're running one balance shaft, and it's out of phase.

Well, life is for learning, I guess.