2F rebuild stumbling block: crank/balancer keyway (1 Viewer)

[Chef]

Howdy:
working on re-gakseting a 1978 2F with 106K on it. Backround: had sat dormant for 10 years before I got the truck. After setting valves and timing, it fired right up. Showed 150 compression on all 6 holes after running to operating temp...
Pretty standard teardown til I pulled the balancer. While it did not wobble on the crankshaft, both the crank keyway and balancer slot exhibit some scary looking wear. The key itself looks fine, and still sits tight in the keyway despite the way things look. The motor seems as tho it has not been messed with, but maybe the balancer nut worked loose earlier in it's life, necessitating a new front mainseal? The crank nut was on *tight!*
The question: reassemble and carry on? Reassemble with a spare balancer that seems less worn I might have laying around? Or, am I totally fawked?

 

[Chef]

Additionally:

The rod bearings all loooked fine. The crank bearings showed some waer, thru the coating on the bearings...but no streaking or embedded munge, and you can't feel it with your fingernail.
I'm hoping the consensus is to button it back up and carry on...?

 

[Pinion]

Measure the key. If it is off from a stock key by more than 10% or so I'd be concerned. If not, just put on a new balancer. Maybe one from an FJ60 that has the AC pulley on it for future accessories.

 

[Poser]

You are probably correct that the balancer worked itself loose at one time and was caught before it caused more major damage. If you have another balancer I would install that, with a new key and call it good. Make sure that you install a new star locking washer with the nut. I also use red locktite on the crank nut, but that is just me.

I know of people that have repaired crankshaft keyways with JB weld/epoxy materials, ones that were in far worse shape than this, and have seen them last for many years without issue, but I have not ever done that myself.

 

[FJ40Jim]

If you already have the crank opened up, why not take it to a good machine shop to be repaired?

And install a good used balancer.
And order a new key from Toyota just to be safe.

 

[Chef]

The key itself seems to be fine, and sits tight in the lower portion of the keyway, which also seems to be fine. Just the top half of the keyway seems to be effected.
Steve: it did not have the starwahser there, which also leads me to believe it had been worked on previously. JB weld...really...?
Locktite:yeah, dat's good.
Jim: I don't have the crank out, and would really prefer not to tear down the engine that far, unless I absolutely have to. If I'm going that far, I'd just as soon start throwing rings, and bearings and machine work in while I'm at it. I really just wanted to replace gaskets and seals.
But, I don't want to repeat all this in 500 miles either...

 

[FJ40Jim]

There's also some special Loctite compounds specifically for sticking things on shafts. Might be handy to insure the balancer can't slip.

 

[Chef]

There's also some special Loctite compounds specifically for sticking things on shafts. Might be handy to insure the balancer can't slip.

I'm familiar with red, blue and green (the penetrating locktite), but not this one. Got a specific name for that so I can ask for it at the parts oucnter?


Thanks guys, this has been helpful-alan

 

[Poser]

The key itself seems to be fine, and sits tight in the lower portion of the keyway, which also seems to be fine. Just the top half of the keyway seems to be effected.

In theory, it should be fine as long as everything stays tight and does not move or become loose again. Installing a new key and balancer along with a crank nut lock washer will go a long way to prevent this from becoming an issue later. Red locktite is your friend...

Steve: it did not have the starwahser there, which also leads me to believe it had been worked on previously. JB weld...really...?
Locktite:yeah, dat's good.

JB? yep....and some really great Caterpillar epoxy that they do not make anymore... I know man...if I had not seen it done, and operated the equipment after it had been repaired, I would be calling bull**** all day about this....but when done properly, it is a viable repair option, opposed to a 5K$ crankshaft....that is more rare than a T from the hood of a 25..

Jim: I don't have the crank out, and would really prefer not to tear down the engine that far, unless I absolutely have to. If I'm going that far, I'd just as soon start throwing rings, and bearings and machine work in while I'm at it. I really just wanted to replace gaskets and seals.
But, I don't want to repeat all this in 500 miles either...

Jim does make a very valid point here Alan...and I was going to ask you why you were not going to install new bearings and rings since you have it tore down this far....A decent machine shop could cut a new keyway in the crank 180 degrees out, and since the engine is not timed off the front balancer, it is really a non-factor.


But if you are trying to save some cash, I can understand that....but what you save today may end up causing you to spend more further on down the road...


Good luck!


-Steve

 

[Poser]

I'm familiar with red, blue and green (the penetrating locktite), but not this one. Got a specific name for that so I can ask for it at the parts oucnter?


Thanks guys, this has been helpful-alan

PM me an addy....and you will get some green locktite retaining compound in the mail bud...

Or look around the better stocked parts houses...it may be on the shelf...they are usually pretty proud of it however...

 

[FJ40Jim]

Loctite press fit repair 660.

 

[Mark W]

I've fixed just this problem a couple of times. Addressed it in the Tech X a while back with some (not great) pictures). Braze the keyway into the crank slot, filling the cratered out area. Then use a cutoff wheel on a dremel as a grinder, and some small files to remove all excess material. When you are done it looks like original except that there is a gold/brass colored area on the crank where there used to be a hole. And the key stays in.

If you ever tear the engine down and want to remove the crank gear you will have to remove the key from the crank (the crank gear will not fit over this key even though it appears at first glance that it will). But unless the crank pulley is damaged or you want to replace the crank/cam gear set there is no need to remove the gear. All future machining of the crank can be done with the gear in place.

Put a new balancer on there. That one won't get any better.


Mark...

 

[65swb45]

Alan, I concur with Mark W. I am much more of a fan of a solution that involves good old fashioned metal to miracle-in-a-tube solutions.

I have have done basically the same as Mark W. with the mig at my shop and never had an issue. I bought one extra key to 'sacrifice' during the buildup of the crank, replaced the balancer, and called it good.

Hth

Mark A.

 

[Chef]

Alright, I'll braze the keyway slot back into shape, put a new key and replace the balancer with another one...
What do you guys think of the main bearing pic?

 

[Mark W]

I'm a bit of a splurger when it comes to bearings. I replace them in a heartbeat. If the crank is smooth and the clearances are good (plastigauge it) then I can live with leaving it unmachined.


Mark...

 

[FJ40Jim]

Agreed W/ Mark. Those mains are serviceable, but definitely showing a little wear. I'd throw new stock ones in there, just cause you're in there. Clevite (made in Japan) is less than $70 at advance autoparts.

 

[Chef]

Update

Here's the repaired keyway. About 30 seconds with a tig/high nickel content rod, then a few more minutes with a flat file and a dremel to massage the fill material into shape...

 

[Chef]

Attn Poser

This for your 2F serial number thread. This motor came out of a '78, and appears to have been the orignal motor as far as I can tell. I've never seen a 2F with *no* serial number here...??? WTF?

 

[FJ40Jim]

The engine was rebuilt with a service replacement block. No serial number, because it was not a factory assembled engine.

Show us the casting date. It's 5 small numbers, cast on the driver's side of the block, toward the rear.

 

[Chef]

10-4, thanks Jim...I'll look for that tomorrow, pics then.