sbjaj

I have a 1988 Nissan 300zx that keeps jumping time. It will run fine for a couple of months and then it will not start. Since February I have put two belts in it. The first time it shucked a belt, I started it , it ran for just a second and then choked out. I tried to start it again but it just turned over like all the spark plugs were out. I just replaced the belt and it ran better than it had before –for a month and a half. The second time my wife shut the car off at the gas station and when she tried to start it wouldn’t even fire. I brought it home and replaced the tensioner pulley and the belt. Both times I made sure I was able to move the belt vertically between the cam gears 14-15 mm. The other day the car started rough while my wife was out and she brought it directly home and parked it in the drive. Once again, I think it has jumped time; sounding like there are no sparkplugs in it when you turn it over. Is it possible that a cam gear is bent, and how would you check to see if it was? Is a bearing causing this grief? Can I fix it with dynamite?! All help is appreciated, --oh, my wife said “NO jokes about it being her fault!”
Thanks

Zen31ZR

Not her fault, might be yours though.

Actually, I'd suspect the tensioner pulley, or rather, it's mounting stud. It might be bent. Don't forget that you also have to tighten the pully to an acceptable level and torque it down. Some people forget that.......The spring is simply there to keep it sorta in place if the bolt loosens, not to act as the main tension holder.

I'm assuming you are replacing the belt as per the manual suggestions, IE: the rocker arms must be removed from at least one cam otherwise it will not tension up properly. I'm also assuming the pulleys are facing the right way. Dunno if you can turn them around backwards, but I never tried.
Also, don't forget these belts stretch, so tension must be rechecked after the first few hundred miles. Also, don't use a cheap imitation belt, try to get a factory belt. The cheap ones are known for stretching quickly and causing problems.

If you have an FSM, fine, but if you need one, it's in amongst the stickies at the top of this page.

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1992 Yamaha FZR 1000. 145 Hp, all stock..