HizAndHerz Posted October 27, 2006 Share Posted October 27, 2006 A few weeks back we bought a nicely restored 78 280z with a recently rebuilt engine. The previous owner paid out the nose for the rebuild, but I've found major problems that were ignored, including a blown up damper. I think we were lucky that the crank end wasn't mangled. I can't believe anyone would think it is okay to reuse this crank end bolt, key and washer. Most all the force of the washer was on the end of the crank not on the damper. The damper that separated is on the left. It is hard too see in the picture, but there is major separation in the rubber. I'm putting the one on the right on the car until I get the other rebuilt: Look what the front of the washer looks like compared to the nice one pulled from a 280ZX motor: You can see how the washer was bent compared to the nice flat ZX washer. I refused to to pull the radiator again so I made a quick and dirty puller. The threads in the puller were strange (6mm coarse?) and a 1/4" bolt fit almost perfectly except for the dirt in the threads. I chased the threads with a 1/4" tap. I screwed the crank bolt in about 3/4 of the way, then tighened the 1/4" bolts on the puller until the plate pushed the damper away from the crank bolt. Then loosened the puller bolts a few turns, backed out the crank bolt a little, then tighened the puller bolts again. Did this three or four times before the damper could be pulled off by hand. The trick was to make sure I didn't tighten the puller bolts so much that they protuded through the damper enough to dig into the front cover. I'll post when I get my dampers back from rebuilding. Quote Link to comment Share on other sites More sharing options...
Administrators BRAAP Posted October 27, 2006 Administrators Share Posted October 27, 2006 It has been our experience that when the damper fails on an L-6, the L-series crank will “spider crack” at the main and rod journal radiuses. When I mean fail, I mean the inertia ring has physically separated from the hub itself. Your picture is hard to make out so it’s hard to say if the inertia ring has actually “spun” on/around the damper or if the rubber is just starting to separate externally, (hopefully it is just starting to separate so no damage has been done to the crank itself…). If the inertia ring has actually spun, then there is good chance the crankshaft is no longer any good, i.e. junk. I know that is NOT what you want to hear and I can’t think of any other way to sugar coat this, but if the engine was driven for any length of time or under hard loads with a separated damper, chances are the crank is cracked and could fail. If it is indeed cracked, (only a magnaflux will show those hair line spider cracks), the crank could last for quite some time before it actually fails, of course that is dependant on how it is driven… Hopefully you caught this in time…. Paul Quote Link to comment Share on other sites More sharing options...
olie05 Posted October 27, 2006 Share Posted October 27, 2006 in regards to the rubber failing, I'd like to refer you to the case of Me vs. My Harmonic balancer. http://forums.hybridz.org/showthread.php?t=114101 There are pics in that thread somewhere too. Quote Link to comment Share on other sites More sharing options...
Administrators BRAAP Posted October 27, 2006 Administrators Share Posted October 27, 2006 in regards to the rubber failing, I'd like to refer you to the case of Me vs. My Harmonic balancer. http://forums.hybridz.org/showthread.php?t=114101 There are pics in that thread somewhere too. Olie, you've got mail, regarding the intake pipe... Quote Link to comment Share on other sites More sharing options...
HizAndHerz Posted October 27, 2006 Author Share Posted October 27, 2006 Thanks for the input guys. I'm hoping I caught this in time. I was showing the Delco Remy alternator that I recently installed to a buddy when we noticed the crank pulley wobbling with the engine running. When I pulled the damper I noticed that someone put white paint on the timing mark and that the paint went across both pulleys indicating that the the two parts never fully separated. I didn't notice anything unusual except for the slight wobble of the alternator/water pump pulley. After reading the horror stories, I'm going to get the dampers rebuilt for all three of our Z's. Quote Link to comment Share on other sites More sharing options...
Alex_V Posted October 27, 2006 Share Posted October 27, 2006 You can get them rebuilt? I thought it was just replace with a new or used piece. Def something to look into over the winter for my S130... ~Alex Quote Link to comment Share on other sites More sharing options...
Cody 82 ZXT Posted October 27, 2006 Share Posted October 27, 2006 You can get them rebuilt? I thought it was just replace with a new or used piece. Def something to look into over the winter for my S130... ~Alex I thought the same thing. Quote Link to comment Share on other sites More sharing options...
HizAndHerz Posted October 28, 2006 Author Share Posted October 28, 2006 I sent just one of my dampers to Damper Doctor at http://www.damperdoctor.com. $139 plus shipping for a custom rebuild since he doesn't have these already rebuilt. Autozone says they can get new ones for the 280ZX made by Pioneer for $300. BTW, here's something that made it easy remove and to torque the damper bolt. It's a little bracket that bolts to the top starter bolt hole. The bevelled edge meshes with the ring gear on the flywheel. Took 10 minutes to make and saved lots of frustration. Quote Link to comment Share on other sites More sharing options...
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