First post and weird issue with harmonic ballancer.

[theduster]

Hi, first post in the techincal section. I recently bought a 90TT Z. The car has some minor issues, mostly cosmetic, but I got it for a good price. I ran into a strange issue when doing the 120k maintenance and was hoping someone here would be able to point me in the right direction.

The problem.

Whenever I pulled the harmonic ballance off while disassembling the engine I noticed that it had been rubbing on the lower timing cover. I did the maintenance and kept that in mind while assembling everything. When the harmonic ballancer is installed and the crank bolt is torqued down the ballancer is about an eighth of an inch too far on the crank and does not line up with the accessory pulleys. Everything is back together correctly the best I can tell from looking at the assembly diagrams in the service manual. It seems to me like there should be a spacer between the harmonic ballancer and the timing sprocket (other then the thin gold collored one the holds the timing belt on), but I don't see one on any of the diagrams. Can anyone point me in the right direction? I'm really stumped here and any help would be greatly appreciated.

[nissanfreak12]

You should actually have two spacers goes in this order;
Balancer
Front Crank sprocket spacer
Crankshaft Sprocket
Rear Crank sprocket spacer
Engine

The sprocket spacers actually guide your T-belt so it stays on the sprocket and doesn't rip it apart.

[theduster]

I'll have to check it out later tonight. Thanks for the help.

[GerryO]

http://www.courtesyparts.com/300zx-part ... 4_892.html

[theduster]

Took another look at it last night and figured it out. The outer part of the harmonic ballancer is coming apart from the rubber. Sounds like a good excuse to but an AMS underdrive pulley to me. Thanks for the help.

[ReconZ]

"Took another look at it last night and figured it out. The outer part of the harmonic ballancer is coming apart from the rubber. Sounds like a good excuse to but an AMS underdrive pulley to me. Thanks for the help."

I could be out of line here, but you may want to do a little research before getting that under pulley. Nissan was very meticulous about the engineering of that setup...per their use of a harmonic balancer. Under pulleys have a few benefits, but they can also have drawbacks (including, but not only: under powering accessory drives, etc.) They can also cause significant wear on the engine if the pulley is especially poorly machined. My advice if you want the car to hit 180k....replace the balancer with stock. Just my opinion

[Ace 2.0]

or an ATI race damper,but that is $$$$

[theduster]

I took your advice and went with an OEM pulley. That ATI race damper is too rich for my blood.