Found in the sump

We also have to remember that a problem with deepdrawn rollers (solid) was identified by the major producers of cam chain some time ago with this very problem. Not necessarily with the chain riding up on the tooth form but usually good old roller battering. Hence the return to a split roller, albeit with a much improved material spec and design. Most automotive chain now has a split roller.
 
The problem is that 150mm rule use to be 300mm when I must have left in in the sump several years ago, always wonder what happen to that rule!!!!
Those circular bits of metal aren't actually from a chain but in fact bits of 300mm rule after being rolled whilst travelling through the mains :o :o
 
I inspected the last cam chain fitted and what did I find?? 1 roller missing a section that one of the pieces I fished out of the sump fits perfectly!
A couple of pins along the whole roller was missing so I guess those other 2 bits came from there.
I've got enough Regina chain for one last cam chain but somehow I don't I'll use it!!!!
My records tell me that chain covered 22000 kays. Not sure what happen there as I usually change them every 15k

PB170719.jpg
 
It strikes me that you should get way over 22K on a cam chain so would expect there to be an issue with tensioning or lack of rider input.

On cam drives tensioning is more critical than just about any other form of drive and if the tensioners are manual then I would suggest regular attention.
 
Andy, the tension is done manually, book says 5mm of movement up and 5 down, 10mm o/a measured between the cam sprockets. I check my valve clearances every 5-8000 kays so the chain gets checked as well. Same proceedure for the last 26 years and first time to encounter this problem. I usually like to change cam chains every 15k,
factory specs say 25k if I'm not mistaken.
 
Over the past 26 years there have been some improvements not only in material but also the actual product.

I do suppose however given the cost of replacement regular changes might be order I would hate to think of the costs on a car engine replacing the came chain after 15 or 25K.

Andy
 
Andy, I treat cam chains the same as oil, change regularly, cheap insurance. It's weird what happenned, something went on there, same as those scuffs on the casing??
 
Rob,

The scuffs were probably caused by the knackered chain, then.

If a series of bushes goes missing, tension will definitely change at some point, allowing the chain to whip around a bit... no big deal.  Be happy that no more damage was caused!  We do believe you change your chains regularly. :D

Andy,

Replacing timing chains on older MB diesels at least is a piece of cake, used to take about 1/2 an hour.  Procedure was regularly required on taxi cabs, every 250000-300000km, or so. :o

piet
 
Replacing the timing belt on my Honda/Acura car is a huge job, you have to essentially remove the engine. About $US1000 in labour. I left it a bit late and it broke, head off, 12 new valves, $US2100 altogether :-X :'(.

Ken
 
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