Re: Trouble In Paradise
Capt.
I've had a look at Tax's dead engine, and measured up the cam chain tensioner.
I reckon that the spring in the cam chain tensioner is too short. It can't push the plunger to it's full extension - perhaps only 75%. When it stops working, the chain will continue to wear, lengthen, and start to slap around. This will trash the front guide, as it is softer that the rear (moving) guide. It's not the guide that causes the problem, but the tensioner.
The chain, as it continues to wear, will eventually be slack enough to jump teeth on the sprockets. If only 1, only the timing is off. If more, valves are bent.
The more you rev it, the more chance you have of skipping multiple teeth. The chain will rise higher on the teeth because of the higher centrifugal force.
I'm documenting the result on my website, but was going to run them by JohnnyO first, to see what he thought, before making it public. Not sure if he is even available anymore.
(John, if you read this, send me an email, and I'll let you know what I've found)
Mine is due for a replacement cam chain in 1000 kms, and the adjustment left in the spring is 1.3 mm, so mine will be fine. However, I'm no boy racer. I rarely take her above 9 grand, and have never had her on the track. In short, mine has had an easy life.
If yours (& I'm referring to everyone here) has had a harder life, it would be worthwhile checking the spring length. Let me know if you want to do this, and I'll tell you how, once I get a second opinion. (It's easy - only takes 10 minutes)
