Timing Chain Tensioner

[warpspeed]

Good afternoon all. Just a quick (but potentially painfull) question, if the timing chain tensioner has "un-wound" it's self can this be rectified without taking the engine out ?

[TT Tim]

Err, shouldn't that we wire-locked?

If it hasn't jumped a tooth on either cam gears or the crank I would think you'd get away with it.

But, just to be sure I'd phone your trusted indi' APM or Austec or similar.

Tim

Edited by TT Tim on Tuesday 4th March 16:43

[warpspeed]

Don't know Tim. Haven't had a look-see yet, I'm just trying to steele my self for the worst case. It's a bit of a strange one as it was running perfectly prior. It just made a bloody rattle when I reved it after re-starting.

[BLUETHUNDER]

Is the rattle there at revs or idle?

[mikesr]

Remove the oil filler neck - 3 capheads - and have a looksee into the cam case before fiddling with the bolt. The tensioner is behind the filler neck.

The tensioner bolt is drilled down its length and should have a steel rod in it.

If the rod is not there it may have fallen out into the cam case. But I don't think there is enough free space for it to do that.

Tensioning the belt is just tightening up the bolt and fitting lock wire

Its at the correct tension if you can just lift the chain from the tensioner blade with a 12 inch screwdriver (I kid you not its in the AJP engine build manual)

Too tight - thicker copper washer under the bolt

Too slack - thinner copper washer under the bolt

Very slack - cam chain probably needs replacing but you can shim out the rod by putting small washers into the hole in the bolt.

Hope there's no damage been done

[longbow]

Mike, you'r right about how to tell if the tension is correct but infact the length of the bolt (shaft running inside drilled out bolt) is adjusted by packing very very small shims inside the bolt itself, as oppose to the copper washer method you mention. The bolt should be fully screwed in and wirelocked either way.

[warpspeed]

Hello again guys. Thanks a lot for your comments I will investigate at the weekend and advise of my findings next week. Thanks again all.