Continue Running w/ broken REAR timing chain guide? (4.0 SOHC)

[JKolbfleisch]

I've seen all the nightmare stories online about the 4.0 SOHC timing system. The engine wasn't making any significant noise but when I pulled the valve covers off for some other maintenance I noticed the REAR (passenger side) chain guides are broken.

I hardly feel like yanking the engine just to replace the dang things. Will the chain just make noise or how likely is it to jump a sprocket tooth?

 

[drdoom]

How many miles on that engine?

 

[JKolbfleisch]

120,000 miles. Seem to be running fine ... but bothe the traction and other side guides are clearly broken. 90% in-tact .. but snapped off from the bottom pivot point.

 

[colintrax]

Replace them asap, but I guess as long as you're not WFO it'll be ok for a little while.

 

[Powerslave]

well i had a tensioner break and the chain jumped, all 3 pistons on the right side kissed valves.

 

[Maverick13]

well i had a tensioner break and the chain jumped, all 3 pistons on the right side kissed valves.

The Ford 4.0 SOHC is a non-interference engine. Meaning it won't kiss valves if the chain jumps.

 

[joney]

The Ford 4.0 SOHC is a non-interference engine. Meaning it won't kiss valves if the chain jumps.

Sorry, it IS an interference engine!

 

[floridacatfan]

I’ve been running mine for some 20 k miles with broken rear and forward broken guide (visually verified) but I put a pre-oiler in to prevent the rattle - I would not guarantee it won’t break but that’s my experience - I never run it very hard for fear of a slip

 

[drdoom]

At 258,000 miles my front guides gave out, jumped one tooth (this I verified during disassembly) busting a nice hole in the valve cover. I made the repair using the $8.00 USD imported guide assembly, improvised timing tools, JB Weld, and some leftover RTV. I've put about 30,000 hard miles on it since, and the engine runs perfectly.

 

[donalds]

I installed a preoiler as well!

 

[JustAnotherMember7]

The Ford 4.0 SOHC is a non-interference engine. Meaning it won't kiss valves if the chain jumps.

I have a pulled 4.0SOHC engine that says otherwise.

 

[swshawaii]

Here's the main source of that "non interference" BS on the internet. Messaged Underhood Service YEARS AGO with no response or correction.
Also read comments after the article.

Exploring the Service Needs of the Ford 4.0L V6 Engine

At a rather anemic 210 horsepower, the 4.0L SOHC V6 is not exactly a high output engine. It also has an unusual overhead cam drive setup.

www.underhoodservice.com

"Fortunately, the 4.0L SOHC is not an interference engine so a timing chain failure won’t bend the valves. But it does create an expensive repair for the vehicle owner."