Guys

I am trying to re install my harmonic balancer hub on the my crank and did not mark the postion of the hub on the crank when I removed it. Rookie mistake.

On my LT4 crank I have a machined slot. On the inside of the hub there is no slot so th ehub is not keyed to the crank. On the outside of the crank hub there is an arrow that based on my search thru the threads should be at TDC. So now I need to get my crank at TDC on the compression stroke. I think I have my crank at or very near TDC. The cam stud is at abt 9 o'clock. The crank slot is about 12 o'clock.

I have my oil pan off so can have my helper turn the crank so I can see where the piston gets the TDC.

Does is make sense that the arrow on the hub should be lined up with the slot on the crank?

I got most of my info from the link below.

Thx for your help.

http://www.lt1engine.com/tech/remove...lt1-crank-hub/

 

from what i under stand ,it does not matter where the hub is put back on,its neutral balanced,that arrow lines up with the one on the balancer(bolts only line up that way).
also you should be able to look inside the hub and see where the crank slot was sitting .

 

that link describes pulling a hub really well.

put #1 cylinder at TDC, install hub with mark (mine had a small triangle) at 12 o'clock

 

a word of caution; with a 96 ob2 engine BEFORE you squeeze that hub down, make sure the reluctor wheel has not fallen off or moved from its (precarious) perch on the front of the lower timimng sprocket key (96 keys are ever so slightly longer with an extention designed to engage the reluctor wheel; do not use a "regular" key which sets flush with the sprocket)

and its not a rookie mistake; regardless of whether the hub and balancer are "neutral balanced", setting the #1 piston at TDC and installing the hub as described above, is the fsm procedure.

 

As mmracecars suggested, I could see where the crank slot had left a mark on the inside of the hub so I put the hub back in the exact same position on the end of the crank. I put lithim grease on the hub and the end of the crank and drew it down with a 3 inch long 7/16 x 20 SS bolt. Then finished the pull down with the hub center bolt. I am hoping this is the right way to do it.

I do not think there was any sort of key in the slot. I think the slot may be used by the crank shaft sensor for timing purposes. Maybe you guys know for sure. No parts were loose or had been moved inside the timing chain cover that I could tell.


I had pulled the timing cover to replace the gasket and 3 seals. I could not tell for sure, but it appeared to me the crank shaft seal was leaking. The water pump bolts were also not very tight. The entire front of my engine was so caked with dirt and oil and perhaps even some coolant it is hard to tell the source of the leak. I did find a wire sticking out of the crank seal, but the spring was still in the seal. I also pulled the oil pan.

I do have another problem with the driver's side cat. I broke all the bolts trying to rermove it from the exhaust manifold. I put penetrating oil on the bolts, but they were badly rusted. I am wondering if anyone has ever tried to drill out the broken bolts laying on there back on the garage floor. Or is the best way to fix this problem remove the manifold? I am worried the studs going into the block may also break


Thx for all you help. It is greatly appreciated.

 

As mentioned above by mtwoolford, there is absolutely a key in the slot and it is used to locate the reluctor wheel. The reluctor wheel works in conjunction with the Crankshaft Position Sensor (CPS) to determine if the engine is misfiring which is then reported as part of the OBD II diagnostics. On these engines, it is not used for timing. In fact you can unplug the CPS and other than the SES light the engine runs fine. People with large cams often program it out or raise the rpm threshold in order to avoid setting codes.

Regarding the manifold, it can be done laying on the floor or with the car on a lift. Use a punch on the center of the old bolt. Start with a small bit and start drilling.