[UR50SLO]

I'm normaly answering questions on here helping out but i've got a minor annoyance that's come up maby some of you guys have come across.

I put together a 4.3L for my Wife's GMC Typhoon. Used a Nitrated crank,Eagle rods,JE pistons along with a new ballancer SFI (Pro form) I think.

If I remember right when I first timed the engine there was no wobble to the ballancer or pulley. Now I see some slight run-out or wobble. The center bolt in the middle is tight and so are the three holding the pulley.

I didn't beat it on with a hammer... I use a Ballancer installer as I always have.

I was thinking of putting a dial indicator on the frame and turning the engine over by hand and marking the high/low and tapping it with a dead blow till there is no run-out.

Thoughts? Bad ballancer? Looks ok on the outside... Hummm.. ????

Not like we spin this engine... 5000 is max. Don't need it with the boost

Thanks for the suggestions guys..
Scott~

[Henry Highrise]

I would get a new balancer....if that outer ring were to come off not only will it probably tear the radiator up....but I have seen them break the end of the crank.

[seven1nova]

^^ what he said ^^

[UR50SLO]

It is a new SFI solid ballancer...!!!!!!!

That's the part that's bothering me. While running, the bolt in the middle of the crank appears to spin streight.

It's got no vibration issues... even with solid mounts that are on there now.

Hopefully Sunday I'll pull off the pulley and check the run-out. If it varies from inside of ballancer (center) to outside then I'll guess it's a bad ballancer. Never had one before but there's always that "one" ...

~Scott

[seven1nova]

Is the pulley spinning true,

[UR50SLO]

No... both ballancer and pulley do the same thing. (ballancer dictates what the pully will do) As the ballancer is first.

Weird huh...

[seven1nova]

only two things can be wrong

1: Bad balancer

2: Broken crank snout

I choose #1

[DeathRattle]

What about the back of the motor? Is it an automatic? So that way you can see the flexplate to see if it also has a wobble to it. That will tell you if your crank is way out of line if both ends are wigglin.

[seven1nova]

That would cause one hell of a vibration

[DeathRattle]

Originally Posted by seven1nova

That would cause one hell of a vibration

You would think. The motor a just tore down that had about an hour of run time on it. Was wigglin at both ends. No vibration to speak of. You could grab the oil pan or anywhere on it and it was smooth. Except at idle, but that was the lope from the cam, and even then there no wild vibrations.
I would say it was a fair amount too. I would say in the 1/16"-1/8" area at idle speeds, higher speeds I couldn't tell. On an elastomer balancer.

[seven1nova]

Wouldn’t that indicate a bad thrush bearing or the crank was worn out (where the thrush bearing rides?)

[BOBCRMAN@aol.com]

MOST aftermkt balancers (I don't care who's) are made with the ID too small. I get them every week. Usually about .002" small. When you try to install on a new crank. The balancer splits along the keyway groove and wobbles. Then comes off at about 35-6500 rpm. Seen it several times.

I always warn my customers..