olie05 Posted August 28, 2006 Share Posted August 28, 2006 I started my car up this morning and there was this noise, almost like a loosely adjusted valve, but much louder. I pulled the valve cover, nothing. I got around to the front of the engine and found that the Harmonic balancer was wobling. Upon further inspection the noise was being made between the back of the balancer and the timing marker. does this mean the rubber in the balancer is breaking apart? Should i put my car out of commission until i get a new balancer, or is it one of those things that as long as i keep it at low rpm's ill be fine? I don't like driving my car when i know something is wrong with it, but it's my only mode of transportation... and i should be in class right now Quote Link to comment Share on other sites More sharing options...
rags Posted August 28, 2006 Share Posted August 28, 2006 If you drive it will cost you a lot more money to fix WHEN it lets go. Joe Quote Link to comment Share on other sites More sharing options...
JMortensen Posted August 28, 2006 Share Posted August 28, 2006 does this mean the rubber in the balancer is breaking apart? Should i put my car out of commission until i get a new balancer' date=' or is it one of those things that as long as i keep it at low rpm's ill be fine?[/quote'] Yes, I think the balancer is breaking apart. I had this same thing happen at a track day. Came in between sessions, heard the noise, searched and found the balancer was wobbling. My balancer was LOOSE. Check your front crank pulley bolt. What I did was to crank it down as tight as I possibly could, then I finished the track day and drove the car home for 4 hours and a couple hundred miles. Then I drove it for another week until I had a chance to take the balancer off. In my case the keyway in the crank was broken off and the snout on the crank was pretty messed up. It probably would have been possible to have it welded, but since I was going to have to remove the crank for that to happen, I just built a new bottom end with flat tops. I hope the damage isn't as serious on yours. BTW, the first engine I pulled to use as a replacement had... you guessed it... the keyway broken off and no woodruff key in the crank. The PO or a mechanic or someone had loaded up the front of the crank with red loctite and it had apparently been run like that for some time. Quote Link to comment Share on other sites More sharing options...
olie05 Posted August 28, 2006 Author Share Posted August 28, 2006 Thanks for the replies. Seems like its time to break out the old 1-1/16" socket edit: 1-1/8" also, just so I don't clutter this thread with extra posts, I just went out to tighten the bolt, only to find it was already tight. The wobling must be completely related to the rubber wearing, and now i'm in the market for a damper. Quote Link to comment Share on other sites More sharing options...
rztmartini Posted August 28, 2006 Share Posted August 28, 2006 me too...are the ATI dampers good for the $$? they have multiple sizes for the L28 and different grooves (different number of belts i assume). if you were to go with a size smaller than the stock pulley it would improve water flow and alt. energy right?? or will that just f**K everything up? Quote Link to comment Share on other sites More sharing options...
Zmanco Posted August 28, 2006 Share Posted August 28, 2006 When I put my L28 in I noticed that the diameter of the pulley was larger than on my L24. I figured that would help with keepiing the lights from dimming at idle, and it did. I think if you went with a smaller pulley you would reduce your water flow, so maybe you meant "larger"? Quote Link to comment Share on other sites More sharing options...
JMortensen Posted August 28, 2006 Share Posted August 28, 2006 also, just so I don't clutter this thread with extra posts, I just went out to tighten the bolt, only to find it was already tight. The wobling must be completely related to the rubber wearing, and now i'm in the market for a damper. Good job catching it early! Quote Link to comment Share on other sites More sharing options...
Administrators BRAAP Posted August 28, 2006 Administrators Share Posted August 28, 2006 I hate being the bearer of bad news but there is a chance that your crank is now junk if indeed the inertia ring did separate from the hub of the damper. This is NOT good. When the rubber goes away, the damper is NOT doing its job, i.e. the inertia ring is not “damping” the twisting forces that are taking place within the crank shaft. Depending on how long the engine has been ran like this or how “hard” it has been ran, the crank could be junk. I’ve seen this MANY times with the L-28. If you caught it early enough, there is a chance the crank is just fine, but… One example is a fairly new mild race engine to be used primarily for open track days. The crank magged good when the engine was originally assembled, owner wanted to use his used damper. The damper was witness marked and he was instructed to monitor that witness mark after each event and if the marks were no longer aligned, the engine was NOT to be started again until a new damper was installed. Typical end user, he didn’t check the witness marks even once. The inertia ring separated from the hub, who knows how many laps he ran with it like that at Thunder hill, it wasn’t many. The crank was removed and magged out of concern and sure enough, over half the rod journals were spider cracked at the radius as well as a few of the main journals. Another crank was then installed with a NEW damper, that engine is doing very well today. Quote Link to comment Share on other sites More sharing options...
olie05 Posted August 29, 2006 Author Share Posted August 29, 2006 uh oh.... That would really stink. Ok, I might pull the pan tomorrow as well, is there anything I can look for, or are these cracks extremely invisible to the naked eye? btw I picked up a 280z damper after looking through some really crappy ones, I found a decent condition one, with the timing mark where it's supposed to be. Quote Link to comment Share on other sites More sharing options...
naviathan Posted August 29, 2006 Share Posted August 29, 2006 Just for FYI if anyone is interested. This site has some nice pulleys and such. It's a serpentine belt setup and I know I've seen people request info on such a setup. Just figured it went with the original topic. Quote Link to comment Share on other sites More sharing options...
olie05 Posted August 29, 2006 Author Share Posted August 29, 2006 Those are some pretty pulleys... they are pricey though. I spent a few good hours on the car today, and got a few things accomplished. Namely, installed the other harmonic balancer, installed the ac compressor and flushed the coolant system... here are the pics of the carnage: Pictures of the rubber... notice the "bad" side and the "good" side: The other balancer... lets see how long this one will last. The proper way to remove a balancer: BTW, I was able to move the outer ring of the old balancer by hand, but I had to use the "claw" to remove it. The new balancer does not wobble Quote Link to comment Share on other sites More sharing options...
Zmanco Posted August 29, 2006 Share Posted August 29, 2006 http://www.damperdoctor.com Here's a site I remember reading others speak highly about. I have not used them. Quote Link to comment Share on other sites More sharing options...
Administrators BRAAP Posted August 29, 2006 Administrators Share Posted August 29, 2006 Oliver, In regards to “looking” for cracks the crank would need to come out any way, so in that case, just have a machine shop magnaflux it as the mag will detect cracks that we can’t see. Looking at your pics of the damper, there is a good chance that your crank is ok. It looks as though the rubber is just “starting” to fail, so the inertia ring should still be damping at least a little bit. Definitely swap it out for a known good one and if you install a used one, witness mark it. I just use a chisel to witness mark as it wont rub off. Good luck, Quote Link to comment Share on other sites More sharing options...
JMortensen Posted August 29, 2006 Share Posted August 29, 2006 Heh, heh. Maybe you might want to mark the other side... Quote Link to comment Share on other sites More sharing options...
olie05 Posted August 30, 2006 Author Share Posted August 30, 2006 Braap, that is very good news! I'm very glad I caught this problem early. Jon, you tlakin to me? ok well yes I will probably put a mark on the a/c pulley and a corresponding one on the alt/WP pulley. Quote Link to comment Share on other sites More sharing options...
JMortensen Posted August 30, 2006 Share Posted August 30, 2006 Both of you guys marked the pulley on the backside. Kinda hard to read the marks back there. Looking at the pics, I think my Euro damper is a little simpler though and can be more easily marked on the front side. Quote Link to comment Share on other sites More sharing options...
Administrators BRAAP Posted August 30, 2006 Administrators Share Posted August 30, 2006 Yeah, that is the back side. The back side is a little easier to mark yet harder to read once installed, i.e. be a contortionist bent around the front of the engine with the little mechanics mirror or from underneath the car using a little mechanics mirror. The front side would be easier to read, but is a little tougher to get the marks lined up and as close to each other as possible. I think Mortensen is alluding to the fact that marking the front would be a more ideal approach and I’d have to agree. Quote Link to comment Share on other sites More sharing options...
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