timing chain

[Mbrooks420]

Those restrictive manifolds will never leave you stranded, lunch your motor, or cause sickening buyers remorse.

 

[MrQ]

I prefer the 4r70w and the lower torque band for my application.

I also bought a 2002 Sport with a SOHC. Traded that in for a 2000 Limited SOHC which I sold to my parents. Speak from experience, not hearsay.

 

[CDW6212R]

It's a learning process, like everything about any car. I own both a SOHC Explorer, and two 302 98's. I'm just into doing the SOHC timing stuff again(did it at 78,450 miles, now it's over 152k). When I get caught up with many things, I'm hopig to swap the SOHC for a built 302 and 4R70W.

The SOHC is a fine engine when running right, good power and fuel mileage. But if the care it receives is poor at any point, expect big issues with the timing etc. The external tensioners have springs inside of them, those will not last 150k, they get weak way sooner than they should(that's the initial start up rattle, that simple spring inside). The other tensioners and guides are not very robust, they are very flimsy thin components, which it's amazing to hear any last 100k miles.

Only by excellent care, plus some praying or good luck, will a SOHC last 200k miles untouched. Without those, that SOHC is going to have problems.

 

[BluIsBlue]

Interesting considering how many high mileage SOHC's are out there. My parents own one with over 220k miles on the clock WITHOUT the guides ever being replaced and that engine is a beast with 4.10's.

I have helped pull and replace timing chain guides on several SOHC's and each one has never failed once the replacement is done. It is NOT a bad engine, just a poor OEM guide design. Just like restrictive exhaust headers on the V8 or temperamental head gaskets on the OHV. Granted it's more of a pain to fix, but not worth chucking the whole engine.

Hate to revive an old thread but, is it super difficult to do the replacement yourself? Any recommended timing chain kit? Read earlier in the thread that the Cloyes kit is alright. I'm creeping up on 133k without any significant noise (except for the odd cold start here and there). I just want to be prepared as I'm aware of the timing guide issues on the motor. Been babying the motor with oil changes around every 3k since I got it but I have zero clue how it was taken car of before I got it. Got the thing at around 125k so there's a chance the chain and tensioner have already been replaced considering many go out pretty close to 90-100k. Otherwise, I really don't know the history of the rig

 

[J_C]

Hate to revive an old thread but, is it super difficult to do the replacement yourself? Any recommended timing chain kit? Read earlier in the thread that the Cloyes kit is alright. I'm creeping up on 133k without any significant noise (except for the odd cold start here and there). I just want to be prepared as I'm aware of the timing guide issues on the motor. Been babying the motor with oil changes around every 3k since I got it but I have zero clue how it was taken car of before I got it. Got the thing at around 125k so there's a chance the chain and tensioner have already been replaced considering many go out pretty close to 90-100k. Otherwise, I really don't know the history of the rig

No, very few go out as early as 100K mi.

Usually, and this is not a guarantee, when you start to hear the timing chain rattle, you have a few thousand miles at least before it becomes catastrophic. That's not consolation to those who didn't have that long but being practical, with no timing chain noise yet, you shouldn't be in a hurry to swap them.

I would NOT assume that the the chain and tensioners have been replace yet at 125K mi. since most of these do not have a failure that early on.

Is it super difficult? That is a subjective question since most people pull the motor and have the specialized tools needed or acquire them to keep timing. If you've never pulled a motor before, then yes it's going to be a lengthy, learning experience. If that is in your wheel house and you're used to keeping track of the order of doing jobs that take several hours, then the learning curve is lower.

It helps if it is not your primary use vehicle, then you can take your time. I would not want to do this job the first time ever, if I relied on the vehicle for critical transportation, and you didn't state that this was the case, just throwing that out there.

 

[C420sailor]

It’ll be obvious when they go.

Do yourself a favor and do the mechanical tensioner mod NOW. Worst case, if the cassettes are already going, you can reuse the tensioners after your rebuild or on a new engine. If the cassettes haven’t begun to break yet, the mechanical tensioners will save them.

That said…I’d sooner replace the engine with a low mileage replacement than rebuild the timing stuff.

And do not use Cloyes. Their components for this engine are trash.

 

[CDW6212R]

I agree on almost every bit of that. The external tensioners are still the weakest links, even the Ford or latest revisions. The internals of those are not capable of controlling oil flow for a normal engine lifetime, or say 150k miles. The fragile rubber check valve inside of them all, are going to become less flexible with age, and then they pass oil, which leaves the chains slack at start up.

I'd do the manual external tensioners, those seem to be very reliable and the chains don't stretch massively after their typical existing age. If you catch it early, then your internal cassettes may be fine to survive another several years.

The component quality from various sources are likely three levels, OEM the best, a rare top brand should be not far behind, and the rest are likely time bomb junk(ala Detroit Axle brand). I have a Cloyes kit to install, I got it before the reports of fast failing tensioners of those came out. I plan to use that kit plus the manual tensioners, or the OEM spares I have if I don't feel like trying the manual type yet.