Wobbly Crank Pulley Surprise

[kbahus]

Well after driving my new to me 40 home I decided to take care of a couple of the problems I noticed like the crank pulley wobble, thought for sure it would be something simple so I picked up a used pulley and got to work. Once I pulled it off I discovered a bit of a problem, looks like the key destroyed the crank. My question is what do I do about this aside from the standard "rebuild the engine" answer. There has to be some options here

 

[Michael Hanson]

Hi, I think you were right , rebuild time . Mike

 

[DAD2SIX]

Not the best solution. But if the cranks junk anyway you could weld the harmonic balancer/pulley to the crank.

 

[DAD2SIX]

Now you got me thinking outside the box. You could weld a new keyway to the crank. And grind it down flush so you can put the pulley back on.

 

[DAD2SIX]

....or you could use a die grinder and cut a new slot for the keyway 180 deg from the old messed up slot.

Not saying these are the best solutions but you asked for other options.

 

[lostmarbles]

Well after driving my new to me 40 home I decided to take care of a couple of the problems I noticed like the crank pulley wobble, thought for sure it would be something simple so I picked up a used pulley and got to work. Once I pulled it off I discovered a bit of a problem, looks like the key destroyed the crank. My question is what do I do about this aside from the standard "rebuild the engine" answer. There has to be some options here

Put a new woodruff key in there and fill all around it with Loctite 660 Quickmetal.

Use the same paste between the pulley and crank and torque the pulley retaining nut up (making sure it sits/runs true).

Then wait 24 hours before running the engine to give the loctite ample time to set.

If the motor's OK apart from this, then you may get tens of thousands more kilometres out of it before having to do an overhaul.



PS. It may require heat to remove the pulley when you finally need to some time in the future though.

 

[kbahus]

Excellent, I will give the Loctite method a shot. I think someone has been in here before, the woodruff key looks new and the pulley looks out of a junkyard as it has yellow paint marker on the back of it labeling it. Also the lock tab was missing, is this really necessary or would some Loctite on the threads be good enough?

May as well spend the time now to do the timing cover gasket and seal as I don't want to have to go tear back into this again.

edit: Looked up Loctite 660 and it is specifically made for this type of application, pretty cool and thanks for the info!

 

[lostmarbles]

Excellent, I will give the Loctite method a shot. I think someone has been in here before, the woodruff key looks new and the pulley looks out of a junkyard as it has yellow paint marker on the back of it labeling it. Also the lock tab was missing, is this really necessary or would some Loctite on the threads be good enough?

May as well spend the time now to do the timing cover gasket and seal as I don't want to have to go tear back into this again.

edit: Looked up Loctite 660 and it is specifically made for this type of application, pretty cool and thanks for the info!

Personally I'd prefer to have the locking tab. (While I'm not familiar with this particular tab washer, I bet you could easily make one if you had a bit of galvanised sheetmetal lying around and a few tools like .... some tin-snips, a drill, files, and a die grinder.

(But if you were to use loctite, it would pay to use the weaker blue nut-locker version so that it can be undone in the future.)



PS. Back on the subject of the "quickmetal", give it your best shot on your first attempt. By that I mean that I think you should prepare the mating parts carefully first by:

• Removing all traces of oil and grease using Loctitie's spray-on citrus-scented degreaser and clean rags
• Then cleaning the surfaces further with loctite 7649 or 7471 primer (catalyst/activator)

(As you can see, I'm a big fan of Loctite products. But they are expensive.)

 

[TOBASH]

Place new crank pulley and drill either a new dowel as described OR redrill the old dowel with a slightly larger hole and use a tap and then insert a screw with heat resistant Locktite. (DON'T DRILL TOO DEEP or you will kill your seal, so mark drill depth with tape). You can ALSO get machine shoppe to make a new key and you can tack weld BUT you run the risk of burning the oil seal, so you need to make many small short tack welds and wait ten minutes between each one to allow cooling. Your timing mark will be off if you re-use this crankshaft, so when you use a timing light you need to compensate. (Big deal, as I usually time by what sounds best and then confirm with the timing light.)

This problem is a 4 out of ten on the "My Car Is Fu__ed Scale", as the problem is annoying and will require time, but the solution is not hard.

I would avoid Locktite (not the threadlocker but the other stuff being advocated) in an oily area that gets hot and cold frequently as I'm not sure it will hold long term.

My 0.02

Best,

T

 

[kbahus]

After a bit more research I decided that I better contact Loctite as the spec sheets show that the max gap is .020 and that it won't cure any thicker. The gouge is deeper than the .020 spec so I was concerned that it might not work. I emailed Loctite this morning and received a quick reply with a couple options. Option one is to use 660 for the key then apply Fixmaster Steel Putty to the gouge and assemble or try the Fixmaster Steel Putty for everything and not use the 660. I did not get a straight answer if I will be able to remove the crank pulley down the road if use the putty.

What do you guys think? Lostmarbles, have you used the 660 to fix this problem with success?

 

[Trollhole]

New crank or weld the nut to the shaft and then to the pulley. Slowly! Cool it with air after every tack. Expect it to still wobble and be in the back of your mind waiting to fail at any time. Live with that for a year and see how you feel about taking it on a long journey.

Put a new seal in before doing this cause it ain't ever going to come off again. Don't expect it to seal the oil in fully.

That or do it right and just buy a used motor.

 

[kbahus]

Welding the pulley is definitely going to be plan "b" if this Loctite fix doesn't work out. My luck with the 2F is pretty bad it seems. I have a second 2f that was torn down, not sure if the crank is good but it might be, regardless doing a rebuild is not in my budget for the next three years or so until I am done with my masters.

 

[Ctenosaurian]

I had the same problem with my 1976 when I first got it. I got a lot of the same recommendations that others have given you as well as one other one. Someone suggested to me to try to braze the worn portion to allow you to place another woodruff key in the slot. I was really tempted to just weld the pulley on there, but in the end, I pulled the motor and installed a new crank. To me it was worth the extra time and money to have it done right. If you go this route, make sure to torque the crank pulley nut to factory specs.

 

[lostmarbles]

......I would avoid Locktite (not the threadlocker but the other stuff being advocated) in an oily area that gets hot and cold frequently as I'm not sure it will hold long term.....
T

Loctite is manufactured with engineers (automotive, marine, etc) in mind rather than home handypersons. So the manufacturers expect their products to meet oil during service.

Neither the presence of oil nor normal engine temperature variations will harm most cured Loctite products (including 660 Quickmetal).

After a bit more research I decided that I better contact Loctite as the spec sheets show that the max gap is .020 and that it won't cure any thicker. The gouge is deeper than the .020 spec so I was concerned that it might not work. I emailed Loctite this morning and received a quick reply with a couple options. Option one is to use 660 for the key then apply Fixmaster Steel Putty to the gouge and assemble or try the Fixmaster Steel Putty for everything and not use the 660. I did not get a straight answer if I will be able to remove the crank pulley down the road if use the putty.

What do you guys think? Lostmarbles, have you used the 660 to fix this problem with success?

I can remember using Quickmetal on similar damage to an industrial refrigeration compressor where coupling-meets-crankshaft damage had occured. (Refrigeration/airconditioning was my trade in a past life.) But I admit, the damage (in particular - the gap to fill around the key) was not as bad as what I see on your F-series engine.

And I still have Quickmetal in my garage and still use it from time to time where I need locking but the gap exceeds what will work with my green loctite. (BTW - I've found the manufacturers tend to be conservative with their shelf-life information and that most Loctite products last almost indefinitely if the bottle/tube is kept sealed. Which is another reason why I like them so much.)

I know the gap around your key is outside the working specs of Quickmetal. This is why I used phrases like "give it your best shot first". However having said that, I'm pretty confident it would work well if you only were to take the care I suggested with:

• cleanliness during application/curing
• use of an activator/catalyst (which will promote stronger/deeper curing), and
• ensuring the pulley will be set in place TRUE (which may require a dummy/dry-assembly and a bit of brief engine running .... and this may of course make the cleanliness aim harder to achieve because oil will be thrown around and that will need to be given time to drain away and then you may need to use special tricks to get back in there to re-clean!)

The principle locking force will be accomplished by the loctite that sits between the pulley and crankshaft rather than what's in/around the keyway. So I doubt it matters if that thick part doesn't reach full strength.

And equally importantly .,... Unlike my refrigeration-compressor application, here you have bugger-all load being transmitted via the Loctite (so it actually needs far less strength than I needed in my compressor application where it carried the FULL motor load.

I have no experience of the steel putty.

But I think you're better off with it all curing at the same time using the same Loctite product ... so my recommendation is still Quickmetal.

And while "loctiting it all togething" (as I'm recommending) isn't best engineering practice, it's still more gentle (and therefore better engineering practice in my view) than any welding or brazing fix.

And the purpose here is to "lock-in-place" so removal could well involve heat application. And if that coupling incorporates a harmonic balancer (or otherwise contains rubber) the heat will of course destroy it.

Best practice is to discard the crankshaft and rebuild the engine. This whole thread is about dealing with the situation once someone has decided NOT to go down this full-rebuild route. Well ... that's my take on it anyway.......




Edit... I believe this loctite fix (if properly done) is a more reliable fix than welding the nut to both the pulley and crankshaft and as such, I'm pretty sure that if I did it I would never be worried about it loosening up of it's own accord and leaving me in trouble out in the bush somewhere..

 

[kbahus]

Thank you for the detailed reply. So I am going to go through with the Loctite 660 and I plan on using the activator too. Looks like I will need to buy a 50ml tube as the smaller tube is only 6ml, I don't think 6ml would be enough. Hopefully this will fix her up so I can focus on getting her tuned up and running well.

This forum has been so helpful I decided tonight to finally buy a silver star. Thanks again!

 

[Nothinghead]

Now you got me thinking outside the box. You could weld a new keyway to the crank. And grind it down flush so you can put the pulley back on.

I did (or rather my mechanic friend) exactly this today to the same problem I had in mine. Mine wasn't as bad but still, my fingers are crossed that I'll get a few more miles out of this to save up for a drive train swap. We were hoping to put P/S on but this bandaid means it probably wouldn't take the strain of the P/S pump for too long.

 

[lostmarbles]

I've just remembered another trick I've used in the past that you may like to copy if that gap around the key really worries you Kbahus.

If you have the patience you can make your own special key with a big cancerous growth on its side that's been filed/ground to fill the hole left by your absconding crankshaft fragments.

That way you restrict the amount of Loctite needed and can achieve full cure throughout its depth.

The main trap to avoid in this is from becoming lazy (and wanting to shortcut the large amount of time required to do it properly) and thereby refitting the pulley before you've filed/matched your cancerous key sufficiently to what's required. Such an error would likely leave your pulley running out-of-true (ie. off-centre towards the keyway) which will harm the effectiveness of your front covers oil seal.

And I should probably explain more about why I regard the welding/brazing options so negatively.

Putting extreme heat into the end of a shaft can make it do odd things ... like simply shearing near the weld point at a later date for instance.

And if you were to weld the nut to the pulley, you'd be welding cast iron to steel which is not good/reliable.

But more importantly, without any loctite between your pulley and shaft, your pulley will still want to wobble due to the wear (missing metal) the mating surfaces will have incurred from running so long with the pulley loose. And this insecurity is likely to break your welds somewhere down the track in my opinion.

And apart from the above, I could never ever force myself to weld anything onto a crankshaft, camshaft, or suchlike...



PS. Sorry to rattle on further on this topic.. But I woke in the night fired up about something that's made me write to the editor of the main local paper here (which is something I normally strongly resist doing) and your pulley problem somehow poked it's nose into my brain at the same time.... And since I'm up so early and writing stuff ... why not go onto ih8mud and waffle a bit on more interesting/satisfying hobby interests eh?

 

[kbahus]

If I had some fragments to work with I might give that a shot but it sounds to me like it would be quite difficult to do, and my patience is pretty thin these days.....

The Loctite 660 showed up today as well as a timing cover gasket set, still waiting on the activator. I discovered the pulley nut has a big gouge so I am trying to find a replacement for that and the locking tab washer too. The bore on the pulley I removed looks really out of round so I am going to go with the replacement pulley I sourced too. Fingers crossed that this works.

I was pondering today that I wonder if Fluidamper or ATI would be interested in making a custom pulley sans keyway. I was a BMW/Mini/Audi tech for 5 years and none of those cranks used woodruff keys. Even the supercharged Cooper S had a press fit crank pulley. If the tolerance is correct for the fit I don't see why it wouldn't work, maybe I will send them an email to inquire.

 

[kbahus]

Finally got around to resealing the timing cover and installing the pulley. It turned into a bit of a mess as getting the pulley on was much more difficult than I imagined and it took a ton of torque to pull it on. Next time I will heat up the pulley but didn't have my torch handy today, I also recommend removing the front bib so you can get a square hit on the pulley to get it started. Sadly I missed with one of my swings and got the outer lip of the pulley. I didn't want to push it any further than I did but I am 98% sure it's fully seated. The replacement pulley was much harder to install than removing the old pulley and with as tight as it went on I decided to let it sit till Friday so the Loctite fully cures before turning it over and seeing how true it runs and if it's going to work. Fingers crossed.

 

[Nothinghead]

Where'd you find a replacement pulley?