Crankshaft Lock Tab (1 Viewer)

[Honger]

So my crankshaft nut came off awhile back... inexplicably... fortunately it happened while shuffling the truck around in the driveway. The last time I'd driven it had been on the Classic Cruise with the Copper State Cruisers group... a full day off road trip. I'm kind of puzzled on how this could have happened. One obvious problem is that I think it was missing the lock tab. Just weird it would happen 5 years after having been put on there (when I swapped on the 3-pulley harmonic balancer).

Anyway, I ordered up a repro lock tab from @65swb45 along with a new crankshaft nut. I'm getting ready to put the new one on and want to make sure that I get this right.

I had thought the interior tab on the washer was going to bend in to some sort of slot to lock itself in a static orientation behind the nut. That doesn't appear to be the case. It looks like that tab just keeps the washer spaced off the crankshaft at the appropriate height until the nut locks it in.

Once the nut is on and torqued down (to 144 ft-lbs) how will this washer prevent rotation of the nut? If the tabs are bent down around the nut then the whole washer can just turn with the nut.

Any thoughts? Do I leave two tabs flat agains the harmonic balancer so that the rivets will prevent it's rotation?

 

[73FJ40]

@Honger .

The inside tab fits into the broach for the harmonic balancer keyway.

Once the nut is properly tightened, you bend one (or more) of the outer tabs up flush against one of the flats of the nut. Since the washer has 4 points and the nut has six, at least one tab should align with the nut.

 

[Honger]

@Honger .

The inside tab fits into the broach for the harmonic balancer keyway.

Once the nut is properly tightened, you bend one (or more) of the outer tabs up flush against one of the flats of the nut. Since the washer has 4 points and the nut has six, at least one tab should align with the nut.

So somewhere on the threads of the crankshaft there is a spot for that tab?

 

[73FJ40]

@Honger

I assumed you have an F engine that had a crankshaft with a broaching that accommodates the inner tab. If not, it's time for plan b.

 

[Honger]

I have a 2F... and there is a boach for the key for the harmonic balancer. But it doesn't come all the way to the front of the crankshaft.

 

[Honger]

There is a slight slot on the inner face of the harmonic balancer... which is lined up with the key. I’m assuming that’s it.

@73FJ40, you made me take a much closer look which helped me find this.

 

[73FJ40]

@Honger

My mistake. I knew there was a broach somewhere that the inner tab would fit into. It's been a few years since I reinstalled my harmonic balancer, and I've got an F engine.

In any event, it looks like you get the idea now. I recommend that if there are any sharp edges on the nut or the washer, you clean them off before you thread the nut on. You don't want a sharp edge to drag the washer along with the nut when you tighten it, which might drag the inner tab out of the broach.

Good luck.

 

[Honger]

Any reason there'd be oil on the inside face of the harmonic balancer? Not a lot... but could oil be leaking out here?

 

[Steamer]

Any reason there'd be oil on the inside face of the harmonic balancer? Not a lot... but could oil be leaking out here?

Yes, there's a seal pressed into the cover that rides on the balancer. If it needs replacing, now would be the time to do it.
When you switched to the 3 groove balancer did you replace the seal? The seal surface of the balancer could also be worn and may require a speedy sleeve.

 

[Honger]

The balancer was a new OEM part when I put it on 5 years ago so I'd imagine the surface is okay.

Is this seal behind the harmonic balancer pressed into the timing cover?

 

[Steamer]

Is this seal behind the harmonic balancer pressed into the timing cover?

Yes it is. And don't make the same mistake I did. "Did I Ruin My Timing Cover?"

 

[Honger]

Yes it is. And don't make the same mistake I did. "Did I Ruin My Timing Cover?"

So I need to take the timing cover off to replace the seal? It didn’t look like it from the diagram...

 

[Steamer]

So I need to take the timing cover off to replace the seal? It didn’t look like it from the diagram...

I had the cam out so the cover came off anyway. I just can't remember which side the seal was pressed in from. Hopefully someone will pop in with the answer.

 

[Steamer]

Just found a pic of when mine went back together. Sure looks like the seal goes in from the front as you suspected. But I'd get confirmation.

 

[3_puppies]

no need to remove the timing cover, there are a few issues to watch for if you do. just remove old seal and install new one.

 

[65swb45]

no need to remove the timing cover, there are a few issues to watch for if you do. just remove old seal and install new one...VERY CAREFULLY!

FIFY

It only takes slightly less pressure to install the seal than it does to deform the timing cover.

Then they call me for another timing cover.

 

[Honger]

FIFY

It only takes slightly less pressure to install the seal than it does to deform the timing cover.

Then they call me for another timing cover.

@65swb45, do you recommend just removing the cover then to remove/replace the seal?

 

[3_puppies]

@65swb45, do you recommend just removing the cover then to remove/replace the seal?

if you remove the cover, mark where the bolts came from, they are different around the cover.
install you want to leave the cover a little loose so when the crank pulley is installed the cover/seal will "center" itself to the crank pulley then tighten timing cover.

 

[73FJ40]

Also, the two bigger screws at the bottom need thread sealer (blue) or they will leak crankcase oil.

DO NOT ATTEMPT THIS project without consulting a Factory service manual!

 

[65swb45]

@65swb45, do you recommend just removing the cover then to remove/replace the seal?

Yes.