All of the engines from the mid eighties on have ratcheting tensioners, but that's not the only reason that your 103 engine is pretty trouble free in the timing chain area. As was said earlier the 103 has a short chain and is a single cam engine. That in addition to the ratcheting tensioner allows you to just keep your oil changed and not worry about it.

The 104 engine has a ratcheting tensioner, but it is a two cam engine so there are more gears and MANY more chain guides to give trouble.

The 400E your friend has does not have a 104 engine, it has a V8. The V8's need particular attention paid to their chains and associated parts. The V8 chain is at least twice as long as the 103 chain and has a zillion guides and gears. These guides are plastic and will get brittle with age and mileage. If one breaks it will typically jam in the chain, breaking the chain.

The key is not simply periodically replacing the chain. The chain would probably never break on its own. The key is inspecting periodically to see that the guides and everything are in good shape. Since everything comes apart to do this, a new chain is usually rolled in at the same time.

Hope this helps,