Crankshaft Harmonic Balancer

[smclaren]

Yeah, this is not good ... and during the Nationals countdown, of course.

Was tracking down a strange low end vibratory noise at idle, after just reinstalling my newly reconditioned crash box ... wondering if I had missed something in the install .. thought then it may have been a water pump ?
Slop in crankshaft harmonic balancer ... assuming that's the noise ?

https://www.flickr.com/photos/193523216 ... 2y309UC23X

https://www.flickr.com/photos/193523216 ... 6dsir58y4y

Radiator is out, fan is off.

- First Question. Will the generic Repco/Supercheap puller kit fit this balancer ?

- Second question ... whats the dope on replacement balancers, as I see there are a couple of different types (Grey type, red type). Any info here appreciated.

- Third question .... any tips, tricks etc for install appreciated.. Assuming it's grill out and tap it on with a socket, in-line with the key ? Should you replace the key at the same time ?

I'm PREYING that it's just a flogged out balancer or the woodruff key. The last time this motor came out and disassembled was because it had rolled the woodruff key in the crankshaft, damaging the crank beyond reasonable repair.

[Blacky]

Oh dear - last one I saw like that the crank was flogged out - that's a red motor balancer which is the incorrect weight for a grey even though heaps of people use them ............

A generic puller will get it off - depending on type you may be able to get it out with the grille in situ but its a lot easier to reinstall with it out of the way

Good luck and here's hoping its an easy fix seeing as we are 2 weeks out from kickoff !!

[EK283]

Looking at the video it appears very loose, it should just pull off by hand unless it has worn a goove in the crank.

If the crank is worn down you may be able to put a speedy sleeve over it, just maybe, otherwise bad news im afraid.

Greg

[Harv]

Grill out. The balancer will come off with teh generic Supercheap-type puller. Check for burrs on the crank and gently hand-file them off. Check very carefully that the crank woodruff key groove has not been flogged out. If it has, then you will need to either make a specific key to fit (not a great idea), or get the groove machined to a bigger key size (not easy in the car... this would need pretty good hands to do with a Dremel). Oil the shaft and new balancer, allign with the keyway and belt on with a block of wood across the balancer face. Smack it on until the hub is flush with the crank snout.

I don't know that anyone is making the old type balancers with the threaded centre. AFAIK, only the red-motor style (with no threaded centre and three puller holes) are available. You can get a fancier balancer from Ross, but they need modification to the fan to fit (and have an impossibly tight interference fit... enough to detroy a Sidchrome 1/2" socket extension bar if you use that for a drift... don't ask me how I know).

Cheers,
Harv

[Errol62]

Put sealer between the crank and balancer when you put on the new one or it will leak from new.


FB ute fixer upper, EK van on rotisserie

[Craig Allardyce]

Maybe it's just me, but I'd be working out why it's flogging out the keyway (twice), and fixing that issue before replacing the damper.
I know for certain those powerbond balancers will not dampen the crank torsional vibrations in a grey. That's one problem you have............

[smclaren]

Thanks guys .... I whipped the balancer off this arvo. Nothing is obvious in terms of serious damage ... but the key was only just sitting in there. I do have an alternative that I will use.

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Clay ... what type of sealer are you alluding to here, mate ? Whats the application in terms of where ? Up against the inner seal ?

Harv ... thanks for the fitment advice. Looks like I will be reinstalling the same type of balancer as I haven't been able to find an alternative ... apart from the fancy type that you described.

Greg ... balancer didn't fall off mate ... felt perfectly normal in terms of friction whilst removing. Makes me think the key or the balancer was the issue.

Craig ... I agree (kept me up all last night thing "HOW?") but honestly not sure how to diagnose that mate. This is a pretty standard build ... no cam, oversize bore etc ... and it got a new standard crank and key last time ? Insert scratching of head here .......

[Errol62]

On the shaft of the crank Steve, where the balancer slides on, and all over the woodruff key. Otherwise oil leaks out between the balancer and crank.


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[Harv]

The movement between the crank and damper looked like two things:

a) the damper ID was huge compared to the crank snout OD. Even with the key absent, those two parts should be a pretty good interference fit. Yours looked like you could almost rotate the balncer on its own by hand. Check both with a vernier or mike and see how much clearance you have.
b) the key should stop relative movement, even if the balancer and crank are loose fit. The key should not just sit there... you should need to use a SFH to tap the woodruff key out (tap one end, it pivots up, pick it out with a screwdriver). Check the key and groove dimensions, replace key.

There is one bush mechanics solution, but it is pretty drastic. With the balancer in place, drill a hole horizontally in the seam between the crank and balancer (just like cutting a round woodruff key slot). Tap in a hardened pin. Rough, but might get you out of trouble if things get dicey.

Cheers,
Harv

[Craig Allardyce]

"Craig ... I agree (kept me up all last night thing "HOW?") but honestly not sure how to diagnose that mate. This is a pretty standard build ... no cam, oversize bore etc ... and it got a new standard crank and key last time ? Insert scratching of head here ......."

My bet is there is excessive torsional vibration causing it to come loose on the woodruff key, and or wear the key way, key, shaft, etc.
I went through this drama with this type of balancer. The lack of vibration dampening caused the steel cam gear to be flogged out in about 200 kms.
I'm guessing this was the same type of damper that was on the previous failure?
You may have to look further afield as well. Stuff like poorly weight balanced rods, pistons, crank, and flywheel, can have a dramatic affect on vibrations in the engine.
Either way, the outer oscillating ring on the those dampers are 700 grams lighter than the standard damper, so they are less affective than the standard damper. The grey crank by design needs a vastly different damper to a red motor crank. In engine balancing terms 700 grams is massive. The excessive vibration is just finding the weakest point. In this case it maybe a worn crank snout and or key way. Worst case is snapping the front throw on the crank.
The standard cranks have a frequency based vibration point at 6200 Rpm. Frequency intervals of crank vibration nodes is even so at half the revs (3100 rpm) you will have another vibration point, and then at 1550 rpm. This equates to about 60 mph, 30 mph, and 15 mph, in top gear. My most noticeable vibration was at 30 and 60 mph and felt like really rough combustion and or timing issues. It was of course peak combustion pressures and their resultant torsional vibration effects on the crank. I don't know what your experiencing, but if you think it is vibrating at any specific rpm and load point, try reducing your timing and see if it changes. This would confirm cylinder combustion pressure and crank twisting is an issue. If its vibrating consistently at any point that doesn't change with load I would look at something being out of balance.

[Brett027]

Fantastic advice there. Thanks Craig.

[EK283]

All great advice although for harmonic issues, which the grey is renowned for it points to one thing, balance.
I noticed in the earlier posts that this vibration started after you changed the clutch, this does point to the possibility that the clutch, which should be balanced neutral, has thrown this out.
If for some unknown reason your balance has been done with the red harmonic it may have been done wrong.
Clutching at straws here but you never know what has been done before.
There will be no short answer here.
Greg

[smclaren]

Thanks guys ... I appreciate all the input.

[ardiesse]

Steve,

I haven't read all the thread, but my experience with the aftermarket "grey" harmonic balancers isn't good. The only one that's been on a motor of mine fractured the hub and was quite loose as a result.

"Officially" I recondition original equipment grey harmonic balancers. But car-related stuff has been a low priority of late, I only have reco'd wide-pulley balancers (you're welcome to one if you want to do the world's only EK six-volt conversion). Doing another production run has been a constant "gunna" for a while now . . .

. . . perhaps you'll push me over the line. If a narrow-pulley grey harmonic balancer were available, would you take one? And I'm not going to sugar-coat it either, most people do a double-take when I tell them how much I charge for a reco grey-style balancer.

Rob

[Craig Allardyce]

Steve,

I haven't read all the thread, but my experience with the aftermarket "grey" harmonic balancers isn't good. The only one that's been on a motor of mine fractured the hub and was quite loose as a result.

"Officially" I recondition original equipment grey harmonic balancers. But car-related stuff has been a low priority of late, I only have reco'd wide-pulley balancers (you're welcome to one if you want to do the world's only EK six-volt conversion). Doing another production run has been a constant "gunna" for a while now . . .

. . . perhaps you'll push me over the line. If a narrow-pulley grey harmonic balancer were available, would you take one? And I'm not going to sugar-coat it either, most people do a double-take when I tell them how much I charge for a reco grey-style balancer.

Rob

Knowing what it takes to do one, it would be well worth it. The consequences of running the wrong damper could cost way way more.