Cam drive gear issues

[Bolt_Crank]

Hello all, I just recently aquired a project 1st Gen Z34, and until I can afford the project bits I was looking at getting the ol' LQ1 running again... Did all the diagnosing I could so far, and found that the pulley that drives the cams wobbles and slides in and out (with the bolt removed, it stays when the bolt is in) ... My Google Fu is weak and I haven't found anything so far.

Is there just a bearing at the end of the shaft that could account for the wobble? I know the belt tensioner is seized, as I couldn't budge it at all, but the wobble has me concerned the most.

[Dave96z34]

Take a pic. Are you saying the timing belt drive has movement? That's not normal. The tensioner isn't spring loaded in the typical sense. It has a rubber plug on the back side that you remove and insert a jewlers flat head and turn and it will contract. Then you insert a paper clip in the other hole and it will stay pre-loaded. Then pull the pin when your all done putting it together.

[Bolt_Crank]

Correct, it'll move side to side and up and down... It binds enough that the motor can't start. With the bolt out, it'll smoothly slide outwards about 3/4 inch then stop.

[Dave96z34]

That means that the balancing shaft bearings and retainer have failed. Iv never herd of that happening. I would tare it apart and look at it closer but it sounds like game over for the engine.

[Schurkey]

That means that the balancing shaft bearings and retainer have failed. Iv never herd of that happening. I would tare it apart and look at it closer but it sounds like game over for the engine.

WHAT "balancing shaft"? Far as I know, the "shaft" is more of a dummy or jack-shaft, providing only oil pump drive at the rear, and providing a location for a belt-drive pulley at the front. If it does any "balancing", I don't know about it...yet.

[Bolt_Crank]

I'm holding out hope that it might be just the retainer, lol... Everything spins freely, and smoothly, when it's disconnected, with no odd noises from the engine while cranking over, and zero binding or gritty feeling while spinning the intermediate shaft by hand...

[Schurkey]

You need the REAL GM-authorized service manual for your vehicle. They're often available on eBay, for reasonable money.

[Bolt_Crank]

In the meantime, I'll try and get a VCR running and see if this helps...

No book, though lol

[Dave96z34]

The shaft the runs the oil pump and the timing belt is called the internal blaning shaft. Thats why it dosnt have one on the outside other then the tiny dampener. It looks like a normal pushrod v6 cam shaft blank but the lobbs were never ground in to it.

[Bolt_Crank]

I just hope the bearings are good... I'd like to run the 3.4 for awhile after I get the chassis grafting done, lol.