harmonic balancer

E

e9allan

Well-Known Member
Messages
93
Reaction score
3
Location
Virginia
Hi,

My harmonic balancer and main pulley assembly decided to fly off as I was driving the other day. I guess now is a good time to replace the old leaky front seal!

Anyway, the balancer got a little beat up and I was wondering if it is still better to just swap the pulley parts out and use the balancer that came with my crank or does it make a difference? In other words, is the balancer balanced specifically to my crank or is it balanced it its own right and all the balancers are interchangeable?

Thanks,

Allan
 
balancer

Alan,
must have been quite a shock when that happened. The front damper is balanced and it should also have been checked/adjusted when assembled with the crank, flywheel, clutch. There is also a specific orientation relative to the crank, but I don't know if it's to minimize vibration or not (which could cause the bolts to losen). If the bolts were installed with the correct torque and all the mating surfaces and threads/holes were clean and new lock washers were used it shouldn't have loosened up. Some folks use blue locktite to be safe. Brit engines often use locking plates here as a backup. Was your engine an original factory build or has it been rebuilt by some hack?

I had the same failure in a 3.0Si 3 decades ago on Memorial Sunday in the boondocks somewhere in Illinois. Took a while to find all the bolts and washers scattered across the road. Found a gas station guy prepping his 1/4 mile dirt car for the evening's races who let me use his shop to reassemble (he thought BMW stood for British MotorWorks car). I was lucky that he had an old metric socket set (he'd seen VW bugs before). That Sunday afternoon repair with a bit of blue loctite for luck lasted many years and several trips across the country!
 
The nuts holding the pulley on the balancer didn't loosen - the giant 36mm nut holding the balancer/pulley assembly on did. Hard to say how long I was driving around until the balancer worked its way off the crank. Yes, it made a hell of a noise beating around until it fell out. I looked in the rearview and there it was laying on the street. Luckily, I didn't see where it damaged anything else on the way out other than a few scratches on the oil pan. Unfortunately, the pulley isn't useable and will have to be removed from the balancer and replaced. I also need to source a woodruff key. I have the nut.

This engine has never been apart that I can tell. I have been meaning to replace the engine mounts - wonder if the extra vibration helped coax it off.
 
The big nut

Those suckers don't come off easily, and I can't see how it would if the engine had never been apart. It would take a lot of vibe to loosen a properly installed nut (it's around 300ftlbs or more, right Don?). Maybe it was replaced at one point with a fatigued wave washer or someone guesstimated the torque rather than doing it right with a 3/4" drive torque wrench.

I think you need SFDon's advice here....
 
Some comments for you ....
Do not reuse the nut.
Get a thread file and chase the crank threads.
Gun the bolts off first and then assemble flange
and nut first.
You must clock/index the flange to dampener holes
and mark them- they are asymmetric.
 
Thanks SFDon,

How much do you think it would cost to ship that tool to VA?

Okay, so I need a new nut, washer, woodruff key and pulley. I will reuse my balancer. Any idea where I might source any of these parts?
 
I'll throw a nut and washer in the box.
Get the key from the dealer.
I'll look for a pulley- usually throw them away.
20 bucks to ship?
 
AFAIK reuse of nuts and bolts

Luis A. said:
Don, do you mean the nut should never be reused or just in his case since it's suspect, having come off like that?
Click to expand...

There are some applications that require sufficient stretch and distortion of the fastener that your best off not reusing. Example, on my wife's DD, the manual explicitly says no-reuse of brake caliper frame bolts. Some people treat flywheel bolts and big end nuts/bolts as 1-time use fasteners (even ARP hardware is cheap relative to cost of a failure).

Don,
I'm also curious if the recommendation to use a new nut and washer is SOP (standard operating procedure) or specific to the case where a failure has occured.
 
Using a thrashed nut on a beat on threaded shaft is a mistake.
My guess is that he is in for a serious amount of filing to get things
cleaned back up.
 
Sent you the tool, flange, nut, washer, and correct length
bolts for the tool. You need a pulley, key and 8 bolts.
Don't forget to index the pulley to the flange and make sure
your threads are clean!
 
Thanks so much. I will get the other parts and follow your advice. Right now, I only have an R100GS as transportation and it has been raining a lot lately.:shock:
 
Doesn't get any better than this

sfdon said:
Sent you the tool, flange, nut, washer, and correct length
bolts for the tool. You need a pulley, key and 8 bolts.
Don't forget to index the pulley to the flange and make sure
your threads are clean!
Click to expand...
 
I got the parts and the tool you sent today. Thanks again. Now, I am just waiting on new bolts and washers from the dealership and a pulley is on its way from California. Everything should be here by the end of the week.

Ohmess - I am near Charlottesville in a little town called Gordonsville. SteveHose followed me and had his wife flag me down one day. Haha. I sold my coupe. It now lives in Australia, but I still have the Bavaria that needs the above mentioned repair.
 
My wife still tells that story to anyone who will listen! Beautiful part of VA.

e9allan said:
I got the parts and the tool you sent today. Thanks again. Now, I am just waiting on new bolts and washers from the dealership and a pulley is on its way from California. Everything should be here by the end of the week.

Ohmess - I am near Charlottesville in a little town called Gordonsville. SteveHose followed me and had his wife flag me down one day. Haha. I sold my coupe. It now lives in Australia, but I still have the Bavaria that needs the above mentioned repair.
Click to expand...
 
You must log in or register to reply here.
Back
Top