BMW Harmonic Balancer / Equivalent / Better

[Whittie]

Hey all,

 

I currently have what I am told is a BMW harmonic balancer on the car. I've heard it's solid gold. Either it has gold in it, or it's just the price, I'm not quite sure. Both??

 

I had in mind about a grand, but less than that would be a bonus.

 

Either way, it's done the keyway on the crank and it's starting to wobble, so while the engine is out of the car it's time to get a replacement. This one has been good, so I'm happy to buy another the same, but is there anything out there as good/better, for the same/better money?

 

Here is a pic of the balancer. Like I said, I believe it's a 200mm BMW balancer

 

 

The motor has a 60thou bore, flat tops, high compression (being rebuilt to more, currently 240psi compression test) and rev cut is set at 7500rpm, so a replacement has to be able to do 8000rpm no probs (just in case!) and looking for 200rwhp, if that makes any difference, but just in case the details change the requirements.

 

I've been told in the past that for what I do in the car (essentially a track car) that a plain, simple, solid harmonic balancer would be best as comfort and roughness is not really an issue (depending on bearing life of course!).

 

I'm not sure what they cost, or where to buy them, so if anyone has some insight they could share, that would be great! My mantra for this build has always been 'Do it right, do it once' so I'd like to stick to that and not need to buy another any time soon.

 

Cheers

[NZeder]

This setup is common on L6 race engines here in NZ. The balancer should still be good it just that the adaptor that bolts to it (the custom bit) might have it keyway damaged. I am sure a good engineering company can remake you the adaptor to match a good crank - they have a sample to work with - the one on the car in the pic

[Whittie]

Indeed there is keyway damaged. We had to get the car going for an event and used some type of super putty, that is holding perfectly adequatly, however, The machine shop will be fixing the job while the motor was out. I didn't realise there was a custom bit holding the balancer in tho!

 

The balancer itself, however, is stuffed. When you look at the engine from above as it's running the balancer has a wobble in it. It's not a flat face anymore, so I am looking to get a new one.

 

If in fact, it's not busted, then yes I'll just make a new plug for the balancer and get it back on the motor.

[peter mc]

Hi i like the ati super balancer it is pretty dear but it is a quality item you can get them from sw motorsport or look them up on the net

[DatPilot]

I have read a plug for a place Precision Balancers ( think>?) in Wagga Wagga

 

will find the post and link it here

[NZeder]

Hi i like the ati super balancer it is pretty dear but it is a quality item you can get them from sw motorsport or look them up on the net

They are very nice units, are smaller in diameter than the dinner plate BMW units, and it is good there is now L6 versions - 15 years ago those of us in NZ that were looking for improvements the BMW was the best solution at the time. I like the ATI Super balancer

[peter mc]

yer they are a nice unit . they are a 3 peace design which makes them easy to fit and work around

[dazzed]

Hi Whittie, this fault is very common, cause a mass of  weight  locked in by a tiny little woodruff key, need to single keyway the crank snout, and there is a chance you may not even be able to get it of and if you do the damage to the crank wont enable you to get the new one on, the harmonic ballancer will be ok , the drive pulley that it bolts too will be damage, this happened to me i couldnt get the pulley off i bent a pro lisle ballancer pulley and 6 high tensile cap bolts trying, so i figure it aint coming off in a hurry so i pumped some loc tite in the front of the snout and tightened the bolt with impact gun , and has been the same for years , if you need a new drive pulley give Rob at robco a call  03  97751413 . Daniel.

[dazzed]

Hi Whittie, this fault is very common, cause a mass of  weight  locked in by a tiny little woodruff key, need to single keyway the crank snout, and there is a chance you may not even be able to get it of and if you do the damage to the crank wont enable you to get the new one on, the harmonic ballancer will be ok , the drive pulley that it bolts too will be damage, this happened to me i couldnt get the pulley off i bent a pro lisle ballancer pulley and 6 high tensile cap bolts trying, so i figure it aint coming off in a hurry so i pumped some loc tite in the front of the snout and tightened the bolt with impact gun , and has been the same for years , if you need a new drive pulley give Rob at robco a call  03  97751413 . Daniel.

cause of all of this is pre ignition, bad fuel worn distributor wrong ignition timing curve, and is quite possible the crank shaft has been fractured

[RayRay]

Heres the link to the ATI Balancers.

http://www.atiracing.com/products/dampers/charts/damnissan.htm

[silverz]

The balancer I had reconditioned at Precision Parts is still going strong. they did a good job.

 

Regards

Peter

[Aaron Neubauer]

That looks like a SWM unit on the engine.  I originally bought a Ross balancer (solid) but it requires some machining for the bolt and washer to fit so I got the SWM unit to fit instead.  I didn't particularly want to machine a factroy balanced unit.  Though after hearing about this, I'm not sure which unit to use....

[Whittie]

Unfortunately, I can't comment accurately on the source of this unit. The previous owner had it fitted and the car was being serviced and maintained by a local shop, so who knows where they got it. I have spoken to them and they know a lot about zed's, have a great history and are very reputable (much like a western equivalent of SW, just focused on english motors and cars) but I just have a feeling it's not a Stuart Wilkins part. Nothing to say either way with evidence, I just don't think so.

 

This balancer has been on the car and outlasted 2 motor's and around 10 years of racing and abuse, so longevity is not an issue really, Just that I've heard there is better so I wanted to ask the guys that know (you guys!).

 

I will email ATI and see what they have to say once I get pic's of the balancer that comes off the car and the keyway damage, just to make sure the crank is not busted and then purchase direct through them. Light weight rotating components are far better mods than light weight sprung components and I'm chasing cheap performance, so I'll probably go with their product even tho a replacement/rebuilt BMW unit would work.

 

I think hard use and about 40,000+ km of racing revs is what has caused the failure of this unit. The motor does not ping even on full advance on the dizzy and MSD and a static compression test of 240psi, so more compression is the aim of the latest rebuild. The motor has had a hard life, it gets worked hard and components fail, that is just par for the course, I just can't justify replacing it with a rebuilt unit or a secondary product when something as good (seemingly) as the ATI product is the same price!!

 

Thanks all for input!

[Riceburner]

Hey whittie, that looks exactly the same as the balancer I have on my l28, it is a BMW 8" unit that Len Brennan makes up over here in Victoria. Was around $300 if I remember correctly.

[Z]

Just an update on Gareth. J's post, I just picked up a Len Brennan 8" BMW unit for $380 (plus $47 postage to Brissy) if you end up going that way.

[mossy]

Heres the link to the ATI Balancers.

http://www.atiracing.com/products/dampers/charts/damnissan.htm

 

Anyone know the right part number for the ATI L28 balancer, there seem to be a lot of different part numbers on that link for the L28

[Whittie]

It depends what model you want. They all fit, but are 2 or 3 ring (strength perhaps?) and steel or aluminium (weight).

 

I'd advise giving them a call and working out what you need direct with them.

[Whittie]

Well, this arrived the other week and MY GOD is it an amazing piece of kit!

 

It is suprisingly heavy at around 7 pounds, but extreamely well made. I got part #918040 which is actually a kit with a generic damper #917070, the three ringed aluminium piece and an adapter for the L series crank, #916020,  so that the damper can be mounted to the crank and locate on the keyway.

 

I don't have the exact number on hand, but it was about $650-$670 AU delivered. The BMW part, which finally died on my car, is around $480 delivered, so the difference is not huge.

 

The ATI damper comes with a warranty of up to 1200HP drag motors, in fact the lowest power figure mentioned on the warranty card is 800hp I think this damper will suffice for a piddly 200rwhp L series motor

[peter mc]

the rings as in 2 or 3 are o rings that do the job on the harmonics they work at different rpm. they work a treat and  are very well made

[mossy]

Looks like another option here from Kameari, just over $400, couldn't find any reviews on it though.

http://www.rhdjapan.com/kameari-l-type-racing-damper-pulley-57719