On my 90 Q45 the "plastic" chain guides failed and this was a know issue on those engines so at about 120K miles you had to service them. When mine came apart the before catastrophic failure one of the chains had proceeded to saw through the oil pump. I was thousandths of an inch away from total failure. The very definition of just in time ... I've had a "newish" belt delaminate after an evening of spitited driving and yes it was an interference engine. It seesm like they're always interference engines when they're fun to drive. Two out of three valves bent. Bob S.
I doubt the factory would revert back to the chain technology if there weren't any "belt issues" to speak of. The thought of a better part to make a good car great is always a plus for me hence the inquiry. Another reason is that I'd like to be 101% educated before I make my next F-Car project purchase. I want to be informed of "alternative" options available (technology/parts wise) for the 308's. Thanks for the comments though and please keep them coming.
It looks cool, but I'm surprised not to see any chain guides in the case to stop it from slapping. I also wonder how the tensioner works, if it's a manual adjust it would make the chain more work than the original belts.
I concur. In 7 years Of Lotus ownership, there has not been a single post to our group about breaking a chain. And we really thrash our cars too. Ken
In my many years of fixing cars, I have never come across a broken timing chain. Although I have seen MANY cam belts, with teeth stripped from the belt and some damaged engines. Some people were lucky, most were not. The only work I ever seem to do on timing chains is to replace the worn chain guides. They continually seem wear out and become noisey. It eventually wears the chain out, running steel chain on steel guide. But the guides I have replaced have been saved by quick thinking of the owners, after they can actually hear the "weird" noise coming from the engine. Other than that, I have adjusted and replaced timing chains according to manufacturers specs. I am not saying that chains do not break, but they occur a lot less frequently as to what I have seen over the last 10 years. Someone needs to develop a timing chain kit for the 348 also.
It sounds like there are flat chain guides, maybe left out of the photo, or mounted to the cover: "In order to still increase the quiet running, sliding rails from high-quality plastic in the critical places are used. " Good Q about the tensioner, altho if it's adjustable w/o removing the cover it could be straightforward. Wonder how many Euros they want for the system... I'm glad to see it, now we can point the guys who've been pi$$ing about 308s not having chains to them & they can put their $$ where their keyboard is or shut up!!!
Maybe things are different up here in the cold country than other places around the world, I dont know, but in my 40 years I have seen more broken chains than I can count. Ive seen Alfas, Mercedes, Toyotas, Mitsubishis, even more than a few OHC Jap bikes. Ive never seen one, but Jag six and twelves broke them too. Im not talking one or two, im talking over a hundred over my lifetime. I cant even think back how many. Its a LOT. And the damage is far far beyond anything youll ever see from a belt. The very first chain I ever seen broken was on a Honda Trail 70 when I was around 10 years old. The chain wound around the crank or something down in the block and locked up the engine. The Mercedes 380 V8 originally came with a single row chain. They failed so badly MB almost initiated a recall. As it was they issued a SB and bought a lot of customers new chains and engines in the early days. Virtually any left running today have all been upgraded to the dual row chain. And while its known to go 100K, most suggest 60K because even those have broke. At twice the engine speed the 308 will eat them even faster. I was just reading a thread about a 350 SDL that wound up a chain and it wiped out the entire engine. It broke the cam, the cylinder head, and may have split the block. If you really wanted to make it durable, make a gear drive. It will knock the snot out of engine response and acceleration, but if all were worried about is making the car maintainance free and not having to service it, its the way to go.
Could we please have more info regarding your conversion (i.e. price, manufacturer, availability, reliability, personal experience(s))?
