Main Bearings or Other Problem?

[Sig191144]

So,

I noticed my fan blade hitting my crank pulley on my '75 cruiser with a 2F motor. There is some play in the space between what appears to be the drive shaft and the crank pulley. When I tap the front of the crank pulley with a hammer, it slides back to what seems to be its intended location and the fan, temporarily, ceases to make contact with the crank pulley. What is my problem here? Is this a big ($) deal? What are my options?

Thanks,

C.

 

[JohnnyC]

Do you have the nut on the crank?

 

[Sig191144]

Do you mean the nut in the center of the crank pulley? If so, I have not touched this nut, and it appears to be tight. What size socket fits it? I have had this cruiser for a few years and it has always run well. Would I be able to properly access and/or tighten this nut with the radiator in place?

Thank for your help,

Charles

 

[JohnnyC]

You should do a quick mud search on this ... I think 46mm .... it needs to be a deep well socket

 

[Tysano]

Don't think it's the crank moving, if it was you would have bigger problems than the fan rubbing. I would be willing to bet, the harmonic balancer is the issue. Either the nut has come loose or the balancer is coming apart, as they are two pieces.

 

[Sig191144]

Johnny and Ty,

Thanks for your responses! After a better inspection, it appears that......there is NO NUT AT ALL! How long have I been running without this? Only God knows. I am ordering a new nut from SOR. What a relief. Do these things sling off sometimes?
C.

 

[honk]

It could be a crankshaft end play problem caused by worn or incorrect crank thrust bearing. The way to look is by dropping the pan, so you can easily lever the crank and use a gauge setup at the crank nose to measure the end play or feelers to measure the bearing clearance.

Figure out a way to watch for crankshaft fore and aft movement when the clutch is applied and released with your engine running. All you need is someone pushing and releasing the clutch while you watch. This is only a quick check though, and you might not be able to tell if the crank moves or not.

If the end play is excessive (go to FSM) I THINK that the thrust bearing could be changed by removing it's bearing cap, loosening the others, and pushing the new bearing top half in around the crank. The other half just goes in the bearing cap so is easy to do. (I've done this on AMC 258 sixes but never on 2F. Should be about the same).

edit: this before the news about the missing nut...posted while I typed.

 

[JohnnyC]

Just slide off ... No

But... If your cruiser at some time has had a PO

IMHO it was probably never tightened down all the way when the front seal was replaced... I don't know the torque ... Maybe somebody else does

 

[skully3]

There is a tab/washer that locks the nut on, slides into the keyway slot and bends over the nut. 46 mm deep socket like Johnny said..

think its 130 ft lbs or zap it on with an air impact gun like you would a lug nut and use your head. Hard to keep the motor from turning and get an accurate reading on the torque wrench.

 

[JohnnyC]

@skully3

good call on the lock tab... forgot about that

 

[rkymtnflyfisher]

What is this tab you speak of? My 2F didn't have a tab on it when I tore it down, it was salvaged from an 83 FJ60, did they do away with it after a certain year?

 

[skully3]

What is this tab you speak of? My 2F didn't have a tab on it when I tore it down, it was salvaged from an 83 FJ60, did they do away with it after a certain year?

not sure when they changed but the 60 series 2F had a different pulley and nut.

40 series

later 2F

 

[73FJ40]

Lock for all F, 2F engines 6909 - 8007.

No lock for 2F engines 8008 - 8510.

 

[JohnnyC]

this will have to go into the memory bank

stupid modern TLC engines lol

 

[rkymtnflyfisher]

interesting, thanks guys!

@JohnnyC don't go too far back in that memory bank, it might hurt!

 

[78fj40mg]

There is a tab/washer that locks the nut on, slides into the keyway slot and bends over the nut. 46 mm deep socket like Johnny said..

think its 130 ft lbs or zap it on with an air impact gun like you would a lug nut and use your head. Hard to keep the motor from turning and get an accurate reading on the torque wrench.

You are correct the torque setting is 130 ft. lbs. As far as using an air impact gun that's good for the initial torque, however, you still need to use a torque wrench in the end by engaging the transmission and parking brake which will prevent the engine from turning so you could properly torque the nut.

 

[skully3]

@78fj40mg think that pic I posted of the 2F was from your build. Good idea on the parking brake.

 

[78fj40mg]

@78fj40mg think that pic I posted of the 2F was from your build. Good idea on the parking brake.

Thanks Skully I appreciate the mention!

 

[Weber Sarge]

If the nut was missing , I'd pull that assembly off and inspect the end of the crankshaft - it's likely damaged .
Sarge

 

[Sig191144]

All,

Thanks for the feedback. I ordered the nut and lock washer and they arrived today. The end of my crankshaft is undamaged, and everything fits perfectly. What a relief.

C.