Harmonic Damper problem

[TomoHawk]

Vintage snowmobiles?

[chris b]

I also had a very unfortunate engine rebuild that used one of those MSA dampers. It had horrible vibrations from day one.

On my recent rebuild I was persuaded to go for what I think is a BMW style damper. Tony Flood from Flood Motorsport who put my motor together was quite insistent that it be installed. His experience goes back to working on the factory Datsun rally Z that was used by Ross Dunkerton to win the Australian Rally Champinship in the early 70s.

The damperis quite large (see attached photos). I got mine through Start Wilkins Motorsport.

[Zed Head]

Here's a "while you're at it" maybe - if you have had any thoughts about going to an alternate ignition or engine management system, like Megajolt or Megasquirt, add a 36-1 wheel to the damper and pulley before installing.

[steve91tt]

That's one of the things I like about the bhj damper. It has an optional bolt on electronic ignition ring and sensor mount for the datsun motor. I'm sticking to my Mikuni's and distributor for now but it's nice to have an easy upgrade path for the future.

[240260280z]

vintage snowmobiles?

[steve91tt]

I ended up going with the BHJ damper (Part #: NIS-REB-6-SP). It appears to be a very well made part and installed without any fuss. However, I did widen the mouth of the inner end of the keyway slightly as per Dave Rebello's suggestion. This allows for easier alignment while installing. I raced the car this past weekend and the damper seems to be doing its job. I wish I could say the same for my ignition coil...but that's another story.

[Diseazd]

The later Nissan stock dampers (280's) have about a quarter inch radius (inside diameter) larger than the rest of the bore. This is very important as far as alligning the woodruff key. You have 1/4 inch to feel the key engage the groove in the damper. If not aligned perfect, it will drive the woodruff key through your oil slinger. Ask me how I know this?

[steve91tt]

The BHJ part also has a stepped ID. This makes installation much easier on a press fit part such as this.

[Kennymonster]

Bump revival on this thread;

I've had a nagging oil leak (a big one) that's been pouring over my front sway bar as well as pooling over the alternator bracket and passenger side cross member, just did a timing cover job with all the proper gaskets/permatex seal, oil pump gaskets, etc., and it's definitely coming from above the oil pan somewhere, so I figured it's got to be the front main seal. I pull the crank pulley and find this, very close to Arne's post: This might not be good...

As much as I'd like to blame the PO, it didn't look like that during the timing cover job, so I can only assume I didn't install the pulley properly upon reassembly of the front cover. I have an AutoX this Saturday that I've been putting off for 3 months in this car, so made a whole bunch of calls trying to see what's feasible on time.

Despite the bad reviews, I had actually ordered the $89 MSA damper last night and said what the hell, I just need it for this weekend.

Well they canceled my order and gave me a call today, apparently the quality control feedbacks really got to them (whether it was due to you guys, or may be whole lot more people who complained), apparently the fitment issue was bad enough they returned all their inventory to the supplier, and had them re fab the parts properly.

From what I was told, ~5 weeks ago from today (August/2013) they received the improved prototype with better fitment/install specs. Although they were promised another batch, I guess it's still on 'back order' status until they actually come in, whenever that might be. This applies to both the 'Race' version that imploded in Steve's case, and the budget sub $100 damper as well. I'm not sure if they just addressed the fitment issue alone, or the build quality.

I called BHJ but their pulleys were little bit out of my price range, and I really didn't want to junkyard this part since that'd be a bigger gamble pulling an unknown condition pulley. Oreilly's whom I usually get most of generic seals / parts for the Z, actually had this in stock for next day: Precision Parts Powerbond OEM PB1212N - Harmonic Balancer | O'Reilly Auto Parts

Looks to be just a rebuilt or factory replacement unit at $224.. if it lasts even half the lifecycle of the stock one I'll be happy. Picking this up tomorrow and hopefully be running on Saturday, I'll definitely report back if there's an issue with any wobble or install.

[Jeff G 78]

$224 sounds like a lot for an auto parts store damper. I would suggest finding a good used one for the weekend and then have one rebuilt by Dale Mfg. For $110, you won't have to worry again (from what I hear). I have no first hand knowledge of Dale dampers, but they are very highly recommended by Tony D. He has been using them forever with zero failures and I trust Tony's endorsement.

[Kennymonster]

Thanks for source Jeff, I'll keep that in mind for the future, would be a good idea to have spare. My predicament was needing the part by tomorrow evening, and it was either ~$400 for BHJ part or $224 for this, both new in box parts, doesn't seem too bad (as long as it ends up working properly) since the blown up SFI pulley is also around $220.

[Lazeum]

Your damper is damaged because:

- Either the key & damper haven't been installed properly (key not fully in position). Crankshaft bolt has been used to force the damper to get into position. The key put some loads (high stress) on the damper which is bad. There should be no load at all between the key and the damper. The key is just an index to install the damper with proper orientation.

- Or, crankshaft bolt hasn't been torqued properly. If it gets loose, all torque from the -now- loose damper is taken by the key & the damper resulting in the failure mode you've experienced.

Ckeck also you crankshaft to make sure it is not damaged. I do not see anything critical here but timing might be off a little if index key is offset.

Edited August 10, 2013 by Lazeum