I have a 1989 (early) base model 2wd, 22R, 4speed. So, i had to pull the timing cover because of coolant leak, fortunately only to the outside. I see grooves in the timing cover on the driver's side but my chain guide is intact. The engine was rebuilt before I got it so it's possible they have been there for a while but they look fresh. I tried measuring the chain for stretch but it's hard to do inside the truck and my numbers do not seem possible. The book says 17 links should be 147 mm (5.787 inches). I'm getting about that number for 16 links, meaured center to center. I reduced the measurement to 10 links and 3.4 inches but get that measurement for 9 links. Am I supposed to measure from the inside faces of the rollers? I don't see how what I'm looking at adds up. Grooves in my cover that look cleaner than the adjacent area, intact guide, impossibly stretched chain, no audible rattle, and smoothly running engine.
Chances are the chain was changed without replacing the timing cover. BUuUt, while you're in there do yourself a favor and replace that piece of crap plastic guilde with a metal one, do both. The grooves in the cover aren't deep enough to warrant a new cover, wouldn't worry about that until it's worn half way through. On replacing the timing chain on a 20/22R/E. The best way to do it is to remove the head and oil pan! Just pulling the timing cover may seem easy enough, but putting the cover back is a pain, AND, it will NEVER seal properly. The head and oil pan are screwed to the cover pressing on the cover mating surfaces. The design mandates the extra work and parts to complete the job properly. So count on a head gasket, Exhaust gaskets, maybe intake gaskets, a tube of silicone and upgrading to metal guides along with the extra time. Do it right the first time and it'll be cheaper in the long run. Metal guides will save you a ton since those plastic pieces WILL break. If you're handy enough it would be a good time to lap the valves and do some minor port work.
Looking closer at the cover pic, might be worn half way through, so replacing the cover might be advisable. Keep in mind, changing the timing cover can open a whole new can of worms. If the block has been machined the timing cover will need to match the block deck or you'll be replacing head gaskets on a monthly basis, the step from the cover to the block will prevent proper sealing on cylinder #1 and it'll just keep blowing gaskets. Could be why the cover wasn't changed when they did the chain.
Let's not forget one main piece that always wares out too, the oil pressure tensioner. Look how deep the chain rides that plastic piece. Change it as well!
If you're going in just replace all the related parts. Not looking forward to doing my wife's Mini. That timing set is the same as the Mazda MZR, pain in the pooter!
