Ok remind me..

[912UK]

S2 Cam shaft and timing chains

I remember when I first bought our S2

the cam belts had been changed

so that was a huge tick

then it was mentioned about the tensioner.. Well when I had Chris Turner take a look on the service

he inspected it and it was ok.. I remember now when I went to buy the car I didn't even turn the engine over untill I had removed the rocker cover to inspect it was in good condition under there. no point handing over the money and then it go as you drive home. Seller was some one I knew.

So remind me again

we are keeping the S2 so I want to know it's all sorted under there..

what do I need to change for peice of mind?

chain? tentioner?

it's on 90k

 

[robdimond]

Change the plastic tensioner pads. Takes a couple of hours at most... easy... you need to compress the tensioner and take it out, but don't need to remove the cams. I did the J-tube and crush washers as well because the tubes have been known to fracture.

I did my chain because it was on 180k and had stretched to the limit of the tensioner travel. Not that hard as part of a belt change... just need to (carefully) take the cams out. If it was me I'd probably do the pads now and the chain on the next belt/water pump job.

 

[chrisg]

+1 for Rob - its not the chain that is the issue, but the pads (top and bottom) that wear out and allow the chain to slop around. Once these are replaced you should be OK for plenty of miles !

 

[graham.webb]

As Rob says, chain wear is an issue....any chance of it having stretched (as Rob's) to a point beyond which the tensioner can adjust, then there's a chance that sprocket wear will result.

If you've ever run old bikes you'll know that chain and sprocket wear are linked, and then worn chain=hooked teeth=broken chain. A new chain's a lot cheaper than new cams (or worse).

When I had my belts/rollers/tensioners done, my indy advised changing the chain as a precaution....a "while you're in there" job!

 

[zcacogp]

ORIGINAL: graham.webb

If you've ever run old bikes you'll know that chain and sprocket wear are linked, and then worn chain=hooked teeth=broken chain. A new chain's a lot cheaper than new cams (or worse).

What do worn sprocket teeth look like? Is the wear visible to the naked eye, or is it a case of a few microns off the relevant face of the teeth?

If you take the rocker cover off and eyeball the sprockets, would you see if they were worn?

(The reason I ask is that the sprockets on mine look completely fine, but I am not sure whether this is a reliable test.)


Oli.

 

[912UK]

I have a photo of my car when I took the Rocker off I will dig this out..

I remember Chris saying the pad was not worn out but had some normal wear.

I will have to look though the past history it looks like it's been done at some stage by a Porsche indy..

in the midlands

 

[graham.webb]

Oli....I recall from most of my sadly neglected bikes that when they're really bad, worn sprocket teeth become slightly hooked. Not exactly sure why, but it's likely to be the usual that things that are intended to run with a particular tension or clearance, whatever, will wear more quickly if instead they're running with slop!!

Properly tensioned there should be minimum movement between the two.

Ask me how I now.....nightmare weedy cam chain tensioner on my Honda twin...the adjustment mechanism, not even robust enough for a kid's bike, never mind a high revving 4 stroke, had sheared off with a previous owner. Chain had slackened, wore the sprocket/which wore the chain even more/which then broke. The swarf and muck generated by the flailing chain eventually caused the (v.expensive) roller bearing crank to fail. This is why I always shudder when conversation turns to chain tensioners!

 

[Mike_Pollock]

Graham - that sounds like what had happened to my 400 Dream Honda. The engine was then nicely rebuilt and sold to me, always leaking oil from the camchain tunnel, the sides of which had been ground by the flailing chain. I cracked the cylinder block taking it off, as a previous rebuild had stripped a cylinder bolt and put in a steel insert, which unscrewed out of the cases and into the block!

Upside was driving round Bristol on a very hot and sunny day in my Dads car - the scenery was very pleasant, so much so I nearly crashed it half a dozen times.

 

[Diver944]

If you can see the wear on the sprocket then it's too far gone and the cams need changing £££££££. I've had my chain and slipper pads change three times in my ownership (every 50k miles) and the outgoing chain has always been a few mm longer than the new one going on.

They do stretch, its just a case of spending a little now to make sure they don't stretch enough to damage the much more expensive cams.