jstyer

Great feedback.

Probably going to replace... I'd hate to lose one on track.

nine9six

Sometimes, "experience" fails to consider the overall data available and focuses primarily, albeit erroneously, upon only what is known to said "experience".
aka Paradigm paralysis

bcameron59

As you wish... but you still may want to consider that this seems to be a very rare failure. Out of curiosity I did some searching on the forum and I could find no other references than my own (in this and a few other threads) and fineito's post in this thread. Neither resulted in any engine problem.

If one defines risk as the probability of times the impact (cost) of occurrence, then one should consider whether the cost of prevention is worth it, given the level of risk. The cost of prevention is about $500 (assuming DIY ie no installation labour cost). So we would break even if a replacement engine is worth $50,000, and tensioner failure destroyed one in 100 of our engines.

More realistically, a replacement engine can probably be had for about $15K and let's say we want to put $10k into it to make sure everything is up to spec, so call it a total of $25K. One in 50 of our engines would have to be destroyed by tensioner failure to justify the $500 cost of tensioner replacement on a preventive basis.

However, based on the very low reported incidence of tensioner failure (2, of hundreds of forum members over the years, with none resulting in catastrophic engine failure) the odds are probably more like a thousand to one or lower. Logically one should be willing to pay only about $25 or less for preventive maintenance - so $500 looks like pretty expensive insurance.

Sword_of_the_Spirit

Best to do while you're there.....

"Ounce of prevention is worth a euro of care."

geolab

I would 100% change the chains
and then think about the tensioners
I have this obsession to install new chains in an open engine

Churchill

The "overall data available" is two reported 993 chain tensioner failures in the history of Rennlist. If you cared about data, you would therefore recommend against changing the tensioners.

earossi

+1 on chain replacement.

Mike J

I do not like changing the chains if the block is not being split - since that now involved a removable link in the chain. Is probably OK but its my paranoia given a chain failure means engine failure. These chains last a LONG time, and if they are truly worn out (not likely at 104K miles) then they might have also worn the sprockets, both on the cams and the layshaft. As Brian said, its all about risk management. With that sort of what-can-fail thinking, you might as well replace all the moving parts in the engine ...

Cheers,

Mike

george996

if you examine the chain tensioners keep in mind that the driver's side tensioner does not not have as much dampening as the passenger side. if i recall correctly the driver's side has a 3 mm flat surface machined in the piston and the passanger side has a 1mm. you can compress the driver's side by hand but the passenger side feels solid.

joebaehr

I am past this point now, but could not find replaceable link chains for my stock 3.6l engine. Also ruled out new tensioners based on price and no symptoms, but....