Found the knock - My harmonic Balancer was loose. Tips for repair please??

[Figit090]

Background:
I thought I had rod knock because the rattle became worse the other day. Did some listening here and there with stethoscope but didn't get good results. I pulled the first four plug wires and the noise (coming from the front of the engine) never stopped. Sooo I took off the belts for the PS pump and AC compressor. Still sounded funny, maybe one rattle eliminated (don't know at this point) but I still had a noise I wanted to find.
I got under the car and by chance giggled the harmonic balancer and it moved back and forth on it's axis about 1/4-1/2 inch... in my mind I just thought *....welll SHIT*
So after some pulling and spraying and wiggling, then rigging up a wheel puller with help from my Dad, I got the damn thing off.

Current situation:
The harmonic balancer is out, the key doesn't seem to have damage, but the keyway in the balancer is damaged moderately, and the keyway in the crank has considerable damage, but its not mutilated. I don't have a picture ATM, but it is about half as bad as this picture, found in this thread about the same problem
[thumb]http://www.supramania.com/forums/attachment.php?attachmentid=30615&d=1249436642[/thumb]

Problem with this situation:
I don't have the time or resources to pull the engine and do a proper crank repair & rebalance, or complete replacement; I want to fix this in-car and continue using my car as my daily driver ASAP, and my dad is going to push me to make this happen fairly fast. I'm probably going to think about getting a new car, and until then I ANYTHING is better than a loose pulley. I figure I can do a fix that will be sufficient for this vehicle, especially given the value of a 1986.5 7m-GE and the cost of a perfect repair. I'd rather get this running on the assumption that it will run a few thousand more miles without doing the same thing, or at least until something else expensive breaks, in which case it will be best off with a new motor anyway. It is a hard-top 1986.5, maybe someone will want it for track car base. Hell maybe even I'll do one later on. Doubt it - but I never know.

Inquiry:
Could I get some thoughts on the fix? We were thinking of carefully grinding on the smashed side of the crank keyway to widen it, filing down the keyway in the pulley to match, then putting in a larger key to fit the new clean cuts tightly. Keep in mind it's half as bad as the picture I linked to. Then we'll somehow crank that sucker down to specs (190 something ft/lbs). Tips on HOW to do that are greatly appreciated. I know from torquing head bolts that half that torque is really really tight and I read that the transmission will not keep the thing from turning over...

Another idea I've gathered from the linked thread is to grind a new keyway by hand on the other side, 180 degrees from the damaged one, but it may be harder to make it using a hand grinder without having an old keyway to go by.

Possibly both methods could be used; a slightly larger fixed keyway, and a new one cut 180 degrees opposite from that? I fear that may be too much cutting though? Based on the factory drilled holes in the face of the balancer, I'm guessing all this is very precise. Are those 4 holes drilled to balance for the cut made for the keyway or just factory balancing based on testing the original cast?

Also, I revved the engine a tad when I was moving the car into the garage (it was sticking out), and heard a rattle. I'm hoping I don't have something internal going bad as well...or if that was the crank rattling because it had no balancer - I hope I didn't do damage in those couple seconds of running....
I figure either way I can't afford to tear her down and fix anything internal, but I'm still curious if anyone else has run their motor at all without the balancer and had a little excess noise without realized negative consequences.

P.S. - NO I wasn't the dipshit that torqued this down wrong. Assuming that's the cause of all this?

 

[mdr40z]

I think you know you're screwed, it sounds like you can't do it the right way atm.... in absence of the ability to do it the right way, I suppose you could weld (not jb) the key in, carefully grind to approximately get it right, bang the pulley on and cross your fingers. Of course by the time you did all that you could have yanked the motor, rebuilt the short block and had reliable transportation for many years, g/l

 

[AcIdBuRn02ZTS]

you have a couple of options that I've heard of being done on other engines and im sure it would work here also...

1st... like mentioned above... weld it and grind it down carefully....

2nd... remove the key... they make a tool to drill crankshafts for dowl pins... if the key is a 1/4"... drill a 1/4" hole in the crank and use a 1/4" steel dowl pin instead of the key...

I'm gonna say that it was either over torqued severely or someone beat the piss out of it trying to reinstall it....

As far as other sounds go... without the harmonic balancer... you may hear some prevoiusly unnoticed engine noise... but it wouldnt be much... and running the engine for a short period without the balancer wont cause you any problems... ask the guys that run the cheap UDPs...

good luck either way.
-AcId-

 

[ForcedTorque]

So, you could move it in and out about 1/2 inch, but you still had to use a puller to get it off?

 

[Figit090]

Acid - Thanks. I think welding is out of the question given the shaft has to stay in the engine, and in the engine bay.
A dowel pin is an interesting idea. I'll mention that to my dad, but I have a feeling the smaller surface area of a round pin will eventually get smashed flat against the original keyway in the balancer, or sheared off. Without being able to drill a matching hole in the harmonic balancer, it would probably put too much stress on the pin.
Good suggestion though, I will keep it in mind.
I don't know what a UDP is, but your words ease my mind a bit, thanks.


ForcedTorque - No, I was able to rotate it on it's axis, as if i were turning the crank, but the crank wasn't moving. The pulley would NOT move down the shaft when pulled on to get it off, I'm guessing because of the smashed keyway and any resulting burs of metal on the two pulley and shaft. The keyway is damaged similar to the picture and thread I linked to above, but the damage is about half as deep. My best guess is that the rotational torque here, combined with improper torquing of the crankshaft balancer bolt, allowed the balancer to slightly rotate independent of the shaft, slowly morphing the metal surrounding the keyway with each piston fire, or hard acceleration...



I can slide the pulley on and off fine, I just need to fix the keyway. My dad found some information about a fix another person used (they said it lasted 6 years);

• grind out and file the damaged side of the keyway on both the shaft and balancer, respectively, and get a key to fit the slightly wider keyway in the balancer
• since the damage is a bit greater on the crankshaft, the new key will likely not fit the wider keyway, so we have to fill that gap with something strong (NOT epoxy).
• get a smaller key or piece of hardened steel and machine it down to fit in the gap, then put it in with a dab of JB weld just to hold the piece in place to make instillation eaiser, and smooth any imperfections so the balancer will slide on.
• put in the new key and slide on the balancer, and torque down the bolt, possibly with some Loctite in the threads to help keep the bolt from ever backing out again.

Right now that's our plan. We're going to go see what kinds of keys we can find that might work. I'll get pictures for later too.

 

[IJ.]

I'd be more concerned about the diameter of the shaft as that's what locates the damper it's a light press fit, the key is ONLY for indexing.

 

[AcIdBuRn02ZTS]

The only problem I see is the little piece coming disloged and the balancer spinning on the crank.. I'd be worried about it...

I think your simplest bet woud be to take the balancer off... put a new key in that is the same size as the original and welding it in place filling the added groove that is now beside it... focus the heat on the crank otherwise you'd melt the new keyway... then use a dremel tool to grind the weld down enough to get the balancer back on...

or... drill through the front of the balancer into the crank snout and pin it there... like many cam gears are done on other engines... if there is room to do so.... the pins shouldnt break.. i dont mean those hollow pins... i mean a solid dowl pin...

i'm kinda surprised the bolt itself wont hold it in place... is the balancer and pulley one piece or are they seperate?

-AcId-

 

[IJ.]

:nono:

 

[Suprapowaz!(2)]

When my pulley wobbled off it fucked the key in both pulley and crank. The diameter of the crank snout got smaller from all of the wobbling the pulley was doing. I just sourced another set and bought new keys.

IJ: When you say light press you mean we have to use a press to install the pulley on the crank? Will block of wood and BFH do? The only experience I have with a dampner and crank was my damaged one, and that dampner slid right off because of the damage.

 

[IJ.]

When my pulley wobbled off it fucked the key in both pulley and crank. The diameter of the crank snout got smaller from all of the wobbling the pulley was doing. I just sourced another set and bought new keys.

IJ: When you say light press you mean we have to use a press to install the pulley on the crank? Will block of wood and BFH do? The only experience I have with a dampner and crank was my damaged one, and that dampner slid right off because of the damage.

You can drop the Damper in boiling water and it "should" slip right on but if you hesitate it will clamp down and the wood/bfh needs to come out!

ATI went to an actual press fit and their dampers are a bitch to get on/off so would probably be a "fix" for the OP, he could make a custom key with the curved side thicker to take up the slop and the straight side stock to go into the damper.

The "proper/correct" fix would be to pull the crank make a key from carbon, wled up the crank remove the key and regrind the snout to stock spec but as he doesn't want to pull the crank this isn't an option.

 

[Figit090]

*sigh*

Well the dampener (sorry if balancer was incorrect) DOES slide on easily, in fact it wobbles a bit once it's on. I'm going to check and see if the wobble would be prevented once bolted on, or if the diameter is too large for the entire length of the hole. I'm hoping maybe the wobble only slightly deformed the furthest ends of the inside of the dampener and that the center is still small enough to hold it true.

I can feel where the inside wall of the dampener near the front has been worn down from wobbling, there is a slight ridge onto the front-most portion of the dampener that doesn't touch the crank and is therefore not worn down, and I imagine is close to the original inner diameter.

Can this be shimmed with some thin copper wrapped around the shaft? :icon_mad:

I might be able to source another dampener locally...I'm going to see about getting a used one from a turbo engine. (assuming they are the same part)

 

[AcIdBuRn02ZTS]

its really starting to sound like your going to need to pull the crank.... if it has worn the balancer... im sure it has done some damage to the snout of the crank also....

my suggestion at this point would be to to get the car in the air... drop the pan (which is a pita) and pull the crank... either have the crank fixed by a local machine shop or do it yourself...

making a bushing for the balancer could work... but you would still have to find a way to hold everything in place... the ati dampener may work as suggested above but they arnt the cheapest in the world...

if I where in such a bind... i'd almost consider welding it solid.. balancer to crank and driving it... the crank will have to come out for repair anyways so if you ever would have an internal problem... pick up a used crank and dont worry about re-using your current stuff... I've personally seen it done before... and no... its not right at all... but will it function... yes.

Now... before I get severely flamed for saying that... I will say that it isnt a good idea by any means... and will basically require that you replace the crank if any internal problems arrise down the road... however if time/money are a current problem... and I was in the situation... i'd think about it anyways....

The BEST solution at this point is to pull the crank and fix it properly otherwise you are very likely to cause more damage then good as it stands.

GOOD LUCK!!
-AcId-

 

[IJ.]

 

[AcIdBuRn02ZTS]

... I did say it was the WRONG thing to do... and that pulling the crank was the best option...

figured I'd put some emphasis on that...

-AcId-

 

[Figit090]

Thanks for the info thusfar Acid, it's helping.

Ian - is that picture referring to his suggestions? My ideas? Both? Who has No Fucking Idea? I'm asking because I don't like the message I received from that image, and I would like clarification to avoid miscommunication.

I'm doing my best with what I have ...and if 10k miles later the bearings can't handle anymore, fine.:icon_frow I think they will be ok. I figured I'd have Rod Knock a good 5k miles ago anyway. I'd imagine the valvetrain would need attention by then, or the bearings would have succumbed to BHG water damage, or both, and with all those expensive repairs I may as well get a whole new turbo engine and do everything right, while it's on a stand...
I can't justify sinking more and more money into this engine. I can't rebuild everything at once because of time and cost, and I can't replace things as they go bad for similar reasons.

I know full well what SHOULD be done but frankly I don't think it's possible given my circumstances. This engine has seen at least two BHG's, and based on little clues here and there the P.O. or mechanic cared much less than I do...otherwise I wouldn't have this problem. There are little dents on the balancer from a hammer and the BHG i fixed was clogged with head gasket stop-leak crap...if that gives you any idea.

I'll do my best to make the balancer run smooth and fit tightly, with a properly sized key (the one it had was TOO SMALL) and shimming..or a new balancer. I'm still waiting to hear back on a balancer here, but I might buy one on eBay.

I will probably try something like your suggestion IJ, and take a key that is larger and grind it down to take up the space in the crankshaft.

 

[IJ.]

Fig: Don't get your panties in a bunch it was for Acid's idiotic suggestion...

If you were trying to offload the car you "might" use something like DevconA but welding a bonded Dampener on come on it's ridiculous in the extreme...

 

[Figit090]

Fig: Don't get your panties in a bunch it was for Acid's idiotic suggestion...

If you were trying to offload the car you "might" use something like DevconA but welding a bonded Dampener on come on it's ridiculous in the extreme...

Not bunched Ian, just preventing that. :biglaugh:

Welding it on is a little bit much. Like I said, just clarifying.

If it weren't for the fact you cannot remove the front plate with the dapener on...it wouldn't be so silly....because if you planned to get rid of the crank in the near future anyway, you could be sure it wouldn't come loose in the meantime! hahahaha.:naughty:

 

[IJ.]

I bought a halfcut engine many years ago that had been repaired with DevconA.....

The Damper WASN'T coming off...

 

[AcIdBuRn02ZTS]

...putting what I'd like to say aside... Your right... its not a good suggestion which I believe I made fairly clear.. however... in an emergency situation... you do what you have to do... some people dont have the time or money to "just pull the crank and have it fixed properly" which is what I suggested.... dowling the crank is a common practice however for several different applications... so I dont quite get how that is "half assing" anything....

Anyways... good luck to the op with what ever they choose to do...

-AcId-

 

[IJ.]

...putting what I'd like to say aside... Your right... its not a good suggestion which I believe I made fairly clear.. however... in an emergency situation... you do what you have to do... some people dont have the time or money to "just pull the crank and have it fixed properly" which is what I suggested.... dowling the crank is a common practice however for several different applications... so I dont quite get how that is "half assing" anything....

Anyways... good luck to the op with what ever they choose to do...

-AcId-

I don't give a rats arse what you'd like to say....

The Snout is damaged and undersize the bore in the damper is oversize no amount of dowling it is going to hold it WILL come loose again..... :nono:

It needs to have parallel surfaces so there is no rocking, think of what the damper actually does and you'll get why the fit is so important.

If this thread had been in Tech you'd have been infracted for your post.

You're new so get a little slack but don't make a habit of idiotic cletus suggestions.