S30 Harmonic Balancer Question

[Namerow]

We all know that a lot of the rubber* parts on our 40-year-old cars have hardened with age.  Sometimes this leads to cracking, but it seems to depend on the application.
(* Caveat:  For many of these parts, I'm not really sure that they are made of rubber... as opposed to something man-made).

Then there's the issue of exposure oil.  Also potentially not good for rubber.

Turning to the flexible core of the L-series engine's harmonic balancer, it would certainly be a candidate for age-related problems, and -- for an engine with 'a history' -- it might even have been exposed for years to a caked-on layer of engine oil and dirt.

So here's my question:  Ignoring racing applications, has anyone ever heard of a an L-series harmonic balancer causing problems? Or failing, for that matter? 

Or is that flexible core made from a synthetic material that resists aging and chemicals?

Bottom line:  Is this a part that's a candidate for preventative-maintenance replacement, or can it be safely ignored for street-only duty?

[zKars]

There is documented evidence on hybridz.org, I know it's been discussed, mostly around the issue of time mark wander showing that the two halves had shifted due to that rubber stuff failure or bonding release. Can't remember ever seeing a picture of one that came apart though. True failures are "rare" I believe. 

If you have doubt about yours or want to do something about it, rhere is an outfit in the US (damper doctor I believe) that will replace that elostomer material with new. I had one done years ago. Quite reasonable. 

[Jeff G 78]

Yes, they fail and when they do, bad things happen.  My experience is with racing, but I have also failed one on a street engine.  Luckily, I caught it before crank damage occurred.  The best prevention is to have your damper rebuilt by a quality shop like Dale Mfg. or buy a quality aftermarket damper.

[Kurbycar32]

Mine separated on my street motor just a few weeks ago while warming up in the garage.  Send it to Dale mfg

 

 

Edited March 8, 2016 by Kurbycar32

[gnosez]

Stock unit failed on the dyno. I only use aftermarket ones now regardless of the application

[Namerow]

7 hours ago, gnosez said:

Stock unit failed on the dyno. I only use aftermarket ones now regardless of the application

I'm not aware of any of the usual Z parts vendors (MSA, Rock Auto, etc.) offering an aftermarket harmonic balancer.  Who's your source?

[S30Driver]

DatsunSpirit and Zcardepot both have them.

[Zed Head]

4 hours ago, Namerow said:

I'm not aware of any of the usual Z parts vendors (MSA, Rock Auto, etc.) offering an aftermarket harmonic balancer.  Who's your source?

MSA has several, even the stock type.  Which they call a "pulley" for some reason.  Still comes up when you put "damper" in the search box.

http://www.thezstore.com/page/TZS/PROD/10-2139

http://www.thezstore.com/page/TZS/PROD/10-2138

http://www.thezstore.com/page/TZS/PROD/10-2144

http://www.thezstore.com/page/TZS/PROD/10-2140

[Jeff G 78]

I haven't heard much good about the MSA dampers.  I believe Guy @Diseazd has some info on them.

[madkaw]

My machinist would not balance my assembly with the stock unit in its condition. I sent mine to Damper Doc and had it rebuilt . No problems so far with plenty of 6500+ rpm pulls.

I would rather be running a performance damper though

[Zed Head]

24 minutes ago, Jeff G 78 said:

I haven't heard much good about the MSA dampers.  I believe Guy @Diseazd has some info on them.

The problems seemed to be with fit.  They wouldn't.  MSA tries to address it in the text on the ad page but it's going to take a quite a while.  It's this one, I believe - http://www.thezstore.com/page/TZS/PROD/10-2139

When madkaw says "performance" I don't think he means this one.  That's the brand name.

[gnosez]

BHJ Dynamics and ATI both make them. I have two of the BHJs and one of the ATIs. Finding the right fan belt then becomes a bit of chore.