Crankshaft pulley out of alignment

[Guest rationull]

Please forgive the long story...

 

I just got an '83 280zx N/A. The seller told me that after adjusting the timing to pass a smog check his mechanic came to the conclusion that "the timing mark was in the wrong place." He said he had adjusted it to spec to pass smog, but it wasn't running right so afterwards he adjusted it back.

 

After doing some research I determined that it was probably the case that the harmonic balancer/crankshaft pulley had come out of alignment. I hear it's fairly common on the L28.

 

I'm not that skilled with cars at this point, but I'm learning. Since I'm pretty busy with school right now I didn't want to get into replacing it on my own, so I took it to the nissan dealer shop in my area (please don't make fun of me too much.. I don't know any mechanics in the area yet and I wanted to make sure the place I went would at least have the proper documentation) They said that they had checked the timing, and it was only 2 degrees advanced. So they put it back to spec (8 deg) and didn't notice any problems.

 

The car drives fine.. there may be a bit of hesitation at low RPMs that could be attributed to retarded timing but I'm not 100% positive that I'm not just making it up. At any rate it was only changed 2 degrees.

 

To the point.. When school calms down I plan on finding TDC and seeing if indeed the pulley is incorrect. But I'd like to put it off for a while if possible.. how urgent is this? Is there any risk of damage if the pulley is a little bit off, if I put off checking for a month or so? How long would it take for the pulley to actually come apart and wreck stuff at the front of the engine?

 

Thanks, again, sorry for the long post.

[NISMO619]

Im finding out on my 1983 280zxt thats timing on the harmonic balancer isnt really that hard. set timimg to 0 deg. thats TDC now hears the trickey part i found out seting the top of the timing chain to number 1 timing sprocket while the top cam is dead on with the right valves opening and closeing. lets not to metion the way the oil pumps need to go on .

Hears what ive learned " zero Degrees on the harmonic balancer pull number one mark on the top chain sproket and number 1 spark plug timing ton your distributor " baicly making sure your rotor is hiting number one sparl plug wire.

If im wrong some one correct me ... as im doing my first 280zx turbo rebuild on a 1983 280zxt 2+2 digital dash " tuxedo " paint

[Dragonfly]

To the point.. When school calms down I plan on finding TDC and seeing if indeed the pulley is incorrect. But I'd like to put it off for a while if possible.. how urgent is this? Is there any risk of damage if the pulley is a little bit off, if I put off checking for a month or so? How long would it take for the pulley to actually come apart and wreck stuff at the front of the engine?

 

Thanks, again, sorry for the long post.

 

A lot of this depends on what the problem realy is. If for example the first mechanic to work on this had an adjustable timing light that was not working properly he could have easily thought that your timing marks were off, he then would have adjusted everything untill it passed. Now you have taken it to a different mechanic and he says it was off by 2* and made a 2* adjustment. IF that scenario is true then you have nothing to worry about, 2* is pretty minor in a stock street driven engine.

 

Now if the outer ring or the balancer is rotating on the inner hub of the balancer that means that the elastomer (rubber in your balancer) has seperated from the metal, if this is the case you will initailly notice that your timing marks will always be different each time it is checked. You may also notice a squeeling noise that sounds like a belt squeel even if your belts are tight, you may notice other auxilaries not working like they should (the balancer is not pulling the belts correctly). IF you find any of this to be the case you should park the car immidately and have it repaired where it is at or towed to a shop and repaired, by the time you see the above signs your are verrrrry close to doing fairly expensive damage. It would be your radiator that would recieve most of this damage as the balancer will most likely choose your radiator as its exit point.

 

Either way I would have a mechanic check it out looking specificaly to see if the elastomer has seperated, also ask to watch what he is doing so you can learn in the process.

 

Dragonfly

[Guest rationull]

Wow, it's been a while since I posted this.

 

DragonFly: Thanks for the clear description of the symptoms of a failing balancer. After checking the timing several times after a variety of different driving conditions and never seeing the timing deviate from spec, I ended up concluding that either as you say the first mechanic's timing light was malfunctioning, or that he didn't unplug the vacuum line from the distributor like you're supposed to. I recall messing around with it and seeing symptoms similar to what was described to me if I didn't unplug that line during the timing test.

 

I certainly didn't see the timing reading wildly varying every time I checked it. This one I chalk up to a mechanic's mistake.

 

Thanks for the replies!

[Dragonfly]

Wow, it's been a while since I posted this.

 

I have to try to remember to look at the date on the post... duh

 

Dragonfly