oiling timing chain
Ill vote for a tensioner on any build, and pressurized oil jet, very small at that. Yes, the taught side (driver) does the pulling but look at almost any chain after 2000 miles and you'll see new slack. Its just the nature of the beast unless your running a very good chain, and I've even heard Cloyes double rollers looking like noodles after 3 months. If your anal about the double rollers 3 pronounced ridges at the slipper contact, take a file/dremmel/mill and dig your ditches so the slipper is contacting the rounded portion of the links, but its completely not needed as whatever comes off the slipper (wear marks) is not going to make it past the filter, and the stuff is not carbide so its not going to damage anything anyway. I have the original 10" mile full length slipper out of a 247k Mazda OHC MA motor and there is barely a groove in it and that is a factory roller chain. Anyone ever see a high speed shot of a drive chain or belt, it looks like 2 bent belts between the 2 pulleys and this introduces subtle timing variations to the cam and ignition. By keeping the 'slack' side under some controlled tension, this is reduced. It wont fix a worn chain, but it will control the increased timing variations a worn or sloppy chain introduces on and off throttle. If you could watch it under load and go on and off the throttle, you would see the chain slop move from side to side, drive and coast. Control that and your timing will be more stable. "...Another issue with a roller chain setup is the “chordal action,” a whipping motion that happens when the chain turns on the gear teeth. That whipping motion can literally turn the chain into an “S” shape. Chordal action can weaken the chain and also negatively affect valve timing, ignition timing, and mechanical oil and fuel pumps. That’s why it’s important to check the timing chain on regularly. If it’s tired, replace it...."Its an argument that wont convince some but its not hard to see the difference in a tensioned setup compared to a non tensioned setup. And no, your timing chain will not always be as tight as new as even the cogs wear.