Goooood morning everyone! I'm a new owner of a 97 Ranger with the 4.0 OVH and 187k miles I've been doing a lot of reading and I'm debating about having the timing chain assembly replaced, mainly because of the tensioner. I'm aware that the SOHC tensioners are prone to failure moreso than the tensioner inside the OVH.

At 187k, should I get it replaced? (Money isn't that big of a problem and I want to ensure the engine is maintained).

 

Full inspection necessary? Chains do stretch and the contact skids wear. You've no symptoms, right? See if engine vacuum is within spec.
Bad mpg can be a clue too, but you have no base numbers.
Is replacement of timing components on the maintenance schedule?

Well maintained V-8 engines often go way over 200k. If it runs ok and gets decent mpg, maybe just drive it?
Things will come up with a 30 year old truck and you'll prioritize maintenance tasks.

www.lmctruck.com has an eclectic assortment of parts for older trucks. (800) 222-5664.

Ask on the Drivetrain forum here and on other Ford sites like "Therangerstation.com".