Timing Tentioner question.

[zanthus]

So I got my new head for my 280Z removed the head just like my manual said with paying close attention to pushing that wedge into the timing chain so as to not lose the tention. Heres my problem now, I can't get the cam sproket back onto the cam because the chain isn't long enough. I was wondering if there is anyway to adjust the tention without having to rip out the engine and remove a bunch of stuff. I really need to understand how the Tentioner works.

[MikeW]

If the sprocket won't go back on that's a good indication that the wedge didn't work properly. You don't have to pull the engine or remove the head but you will likely need to pull the front cover off to get the chain installed properly.

[Ed]

It sounds like the tensioner popped out, somehow your wedge didn't work properly. The tensioner is basically spring loaded and once it comes out the only way to put it back is to remove the timing cover. You will have to remove the distributor, oil pump, cooling fan and the water pump. Be carful not to break any water pump bolts. There are also some small bolts that hold the oil pan to the timing cover. Remove the ones on the cover and loosen the rest. You don't need to pull the engine. I've done this myself and it only takes about an hour to remove the cover if all goes well. When re-assembling make sure you have the oil pump shaft timing set correctly or it will throw off your distributor timing.

Do a little searching and you will find pictures of the tensioner and several articles on setting the timing.

[Carl Beck]

Even when the tensioner hasn't popped out - it is not easy to get the chain back over the cam gear. Take a lot of force to stretch all the slack of of the metal links... Most mechanics wind up using a screwdriver to get a little extra leverage. Additionally, driving the wedge in to hold the tensioner in place, you wind up shortening up the available slack in the chain. Sometimes, backing off ever so slightly on the wedge - will give you that extra fraction of a mm.. to finally get the chain back in place.

I wouldn't give up too soon... you may just need to use a little more force and take a little more time.

good luck,

Carl B.

[jmortensen]

I agree with Carl. If it's almost there but you just can't quite get the damn gear onto the end of the cam, it's probably not a lost tensioner. You can also use a long 10mm wrench to loosen the top bolt of the curved chain guide, then a prybar to slide it as far back away from the chain as possible. That will give you a little bit more length on the chain. Then when you get the gear on the cam, pry the guide back up against the chain and tighten the bolt. You need a LONG 10mm wrench, and it doesn't give you a whole lot of extra slack, but I've had instances where I absolutely positively could not get the cam gear on without moving the guide.

[MikeW]

While I won't disagree with the experts I do note that a long time ago I had the same problem and had to use a bit of force to get the sprocket back on. A week or so later the tensioner broke and I bent my exhaust valves. It may have been just a coincidence.

[Ed]

I've had my tensioner pop out once too. The sprocket was ever so close. I tried prying it on but there just wasn't enough slack. Not saying that it wouldn't have gone on had I used enough force but how much is too much? Had I gotten it on there with the tensioner out would have caused even more problems. If the wedge was inserted while the sprocket was on the cam then it should have held the bottom of the chain in place. Thus allowing the cam sprocket to go back on by hand.

Nobody is wrong here just don't use too much force to get that sprocket back on.

What kind of wedge was used?

[RogerZ]

When I did mine had to use a long screwdriver to get that last 1 mm so the sprocket would go on. NOt a lot of force but some needed to just get it over the hump.