Single Row 3.8L M116, what's so bad about them?
 

:confused:

My BMWs have single row chains and they aren't prone to breaking... is it just the fact the guides are weak? Such that the chain/guides need to be done more often?

The double row conversion seems to be too much of a chore, I could slap in a Euro 500 for the cost/time involved...

This is a really, really long chain. I'm sure that there are pushrod V8's with 300K miles on the 12" chain, no problem, with nylon toothed gears, yet (keeps it quieter, I understand). I have always felt that the guides and tensioner are more to blame in these failures than the chain. But also, consider that there really is a lot of force on those guides - and the PSI on these plastic parts with a double chain is less than with a single (certainly, the 116 doesn't take all that much more or less force to operate the valvetrain than does a 117). The analogy would be that a 90 pound woman on stiletto's can put more force on a spot on a floor than a 300+ pound football player with size 14 shoes.

Either convert to duplex chain or change it often. It will bend valves on the left bank, guaranteed.

For the $72 and change it costs, and the hour it takes to roll in, I'd change it every 15k miles or so. If I had an engine lift to do it myself, I'd convert it.

How involved are we talking to convert? Front cover has to come off correct? As I have been told, I run a big risk of hurting the headgaskets if I do that...

First you pull the engine. Then remove TC cover, remove TC and gears, replace TC and gears, install TC cover and install engine. Sounds so easy stated that way!
This is why they sell the single row chains for DIYers.

If the motor comes out, something larger will go in its place. ;)

Like an M120?

every 15K?! :confused:

I agree that 15k is too often, but 50k might be right. Also oil changes are critical. I'd say 5k for highway vehicles and 3k for those that just putz around town. You can also check chain stretch. If it gets to 8 degrees or better, it's time.

Well, with the way I drive my Benz engine, I would do 15k on a single-row chain. It's something I can easily do myself. If you pay someone to do it for you and don't drive with your foot to the floor constantly, often at the redline, then I'd say 50k would probably be fine. I wouldnt go further.

I believe the suggested changing interval for the simplex chain is approximately 30K miles while the duplex is 100K+.