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How to replace a crank pulley (harmonic balancer)


nelots86

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Okay, I know it's probably simple as hell. Just keep in mind I'm still learning and I need some advice before I attempt on my 280z. Hope I put this in the right thread :/

 

As the story goes I just finished putting in a new AFM sensor, car was running almost running smooth after first attempt at a valve job, tightened the alternator belt. But as I drove down the road a grinding noise started, the crank pulley part for the alternator seperated from the rest of the pulley. Aarrrggh!

 

First off I know to remove the radiator, and the fan shroud. I'm stuck at removing the bolt. Is there a way to lock the motor up to remove the bolt? And the puller, the bolts from the univeral kit I picked up at autozone are to big, so any idea on the bolt sizes or puller set I should get?

 

Any help would be great. Also I'm planning on getting areplacment from a salvage yard, bad idea? Any ideas for a cheap replacment since all I need is the alternator not the ac since it's dead anyways?

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When I did mine I removed the started motor, used a big flat blade screw driver to 'lock' the engine (the flywheel ring gear teeth), used a five foot pipe on the end of my socket (27mm) to undo mine..

 

if you have a air / electric ratchet, it would be easier.

 

Nigel

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Put the engine in 5th, put the handbrake on and chock the wheels. Now that should lock the engine!

 

For an auto, use your rachet and hit the end of the rachet with a rubber mallet several times until the bolt loosens. My car is an auto and this is how I've done it in the past. Easier still is to run the car on ramps and drop the splash pan and access the balancer from underneath.

 

Good luck.

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  • 2 weeks later...

wooo hoo got it done!

 

Okay so here is what I learned.

 

To replace the crank pulley I had to remove the radiator in order to have plenty of space to work.

 

Get your Z on ramps, pull the hand brake, chuck the rear wheels, put the car into your highest gear 4th or 5th.

 

If you have a skid plate remove it. To me I had an easier time working form under the car. I also had my front bumper cover off ( I have a fiberglass body kit) , for visual purposes.

 

Drain the radiator. There is a drain pug at the bottom. After it drains go ahead and disconnect the rubber tube and let that drain too.

 

Remove the plastic Shroud around the radiator for the fan.

remove all rubber tubing from the radiator and unbolt the radiator itself and pull it out.

 

Then I took I unbolted the fan, 4 small bolts. You can avoid this if you like but that fan will get in your way constantly.

 

Take a 27mm socket wrench with a cheater or pipe to extend it and loosen the bolt about half way.

 

You will then use a pulley puller to pull it off. Get a 3 clawed one, the bolt type universal ones don't come with the tiny bolts needed for these cars. clamp it onto the front of the pulley, place a wrench onto the bolt to prevent it from moving. use another wrench to tighten the crank puller. As it comes off beware that there is a small metal piece that is used to line up the pulley. It will fall out and its a pain to put back in curved side up.

 

Once the crank pulley is ready to reinstall push up that small metal pieace and cram it up with a small screw driver. Slide in the new pulley. Then tap in with a rubber malet. Tighten to 240 lbs of torque. and put it all back together.

 

 

And yay no more grinding noise!!!

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i found when replacing the pulley on my L20et with the L26 pulley the timing marks are about 90 degress out and is enough to bend the valves slightly

 

How on earth did you manage that?? :hs: Did you forget to change over and use the timing marker plate from the L26 on your L20?

 

Weren't you just changing the balancer on a complete and running engine or am I assuming too much?

 

How did cam timing get involved in that exercise?? :icon52:

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You should go ahead and replace the front seal while you have the damper off. It's not critical but it's easy to do at this point.

Ehhh... You have to take the whole front cover off I would think. Its been too long for me to remember but all the other motors I've done the front seal goes in from behind. My motor is fairly young though, not even 5000 miles, and I'm using the same damper so everything SHOULD work out fine.

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  • 3 months later...

I just wanted to add that if you do rent a kit from Autozone or somewhere similar, DO NOT use the 3 prong to remove the pulley. I tried that first with mine and cracked the pulley. After it broke i figured I'd try again since it was already broken but it still would not come off, and cracked again. Get the correct bolts and mount to the inside of the unit to remove it.... no breakage and it is recommended in the Nissan manual. Luckily, I have a 240z parts car and can use the pulley from that...

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I just wanted to add that if you do rent a kit from Autozone or somewhere similar, DO NOT use the 3 prong to remove the pulley. I tried that first with mine and cracked the pulley. After it broke i figured I'd try again since it was already broken but it still would not come off, and cracked again. Get the correct bolts and mount to the inside of the unit to remove it.... no breakage and it is recommended in the Nissan manual. Luckily, I have a 240z parts car and can use the pulley from that...

 

Same thing happened with mine, I had the same pulley breakage as the OP and then when I used a claw style puller it broke the lip of the pulley off instead of actually pulling it off. No problem because I'm getting a new pulley anyway right? Wrong.. got the bolt in style pulley and correct bolts for the L crank (6x50mm worked IIRC) and bent the bolts and ran out of leverage using a pipe to turn it any more. All that pressure and the pulley still didn't budge a bit even after introducing a healthy dose of WD-40 and a bit of heat.

 

Long story short my crank pulley is somehow fused onto the crank and won't come off for anything. Poor car hasn't been driven in almost a month while waiting for it's new engine.

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