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Timing Chain Pictures!?!

From what I'm gathering, it would seem as if the tensioners and the guides were the main issue with this engine, '97-'02. I'm understanding that the post 2002 parts have solved this issue, and once we put those parts in, the issue essentially goes away and this engine is a great engine. From what I understand, that's the case. I don't see anyone in these threads complaining about post 2002 engines/parts; other than the posting immediately before this one...

Am I mistaken, or am I delusional from spending 4 days pulling one of these out in a junkyard? I pulled the new cassettes and tensioners out of an engine that was immaculate inside, and had only 5000 miles on these replaced parts. From my research, the part numbers from any 97-06 4.0 SOHC timing chains, cassettes, gears, etc are all identical. So, theoretically, any post '02 engine will have the new model parts in them and they should hold up, under the assumption that these newly designed parts are "bullet proof".

Am I wrong here? Please knock holes in this conclusion!
 



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I don't call any of the parts bullet proof, and those in question are not as good as you think.

The standard lifespan for any engine is easily 200k miles or more. Timing belts in many engines were discovered early to not be 200k parts, they have shorter maintenance schedules now.

The head tensioner that goes into each SOHC head is not a 200k mile part. Those all have a spring inside which weakens over time. How long it takes for those to weaken enough to allow too much cam chain slack, that's debatable. I would not go over 100k on those, preferably 75k would be better. I've got 56k or so on my replacements right now. When I did the two on my SOHC at 77k, the front had been done before, and the rear was noticeably weak.

The plastic of the chain guides used in 2002+ parts may or may not last 200k. We are just now getting far enough along to begin to see high mileage SOHC engines, those which didn't blow up. Ford is not going to warantee or TSB any of it, so it is all up to us to decide when they need maintenance.

The bottom line is, don't buy one thinking it will never fail on you. Assume that something in the valvetrain will falter, and decide when is the best time to prevent that. If you buy a vehicle and no idea of what has been done, then you should figure that nothing has been done. The new 2002+ parts are not magic parts. Ford didn't use bad parts on purpose, and the 2002+ parts are going to last forever.

Find out how old the parts are, and plan to update them at a certain point.
 






Hey thanks Don, those are all salient points. Of course, nobody should ever think something will last forever, or that it will be without problem even with meticulous maintenance.

Basically you're confirming my assertion, that these parts are far less likely to have issue; essentially problem-free so far. My cousin is a Ford Mechanic at a dealership and he's saying the same thing. Once you replace these things, the engine is great. I think that you're right in warning people to change the tensioners every so often, that seems to be where these chain guide issues all start. Changing those clearly reduces the issues, from what I'm reading.

I'm wondering what the next issue I should look for on these is, and so I'll now dig thru the rest of the threads on this great site. You guys rock on here! Hopefully, I can create some video on my adventure here when I pull the engine and replace the cassettes......anyone out who has the Ford cam tools and is willing to either part with them or rent them to me, please contact me at this name on gmail!
 






Superb write up and pics- thanks, I have done my oom12 kit and replaced the rear tensioner also around a year ago....sadly now the noise has started again and being in the UK the cost plus shipping would make it much more for parts than I have been quoted by an Explorer specialist. So whilst I would love to tear her apart and get oily again..this time I will get it done outside. Then I will have the advantage of a guarantee etc also.
#I know many, many in the UK who have been let down as you have by Ford in the design of this engine......it is very sad that hardly any Ex with the sohc has managed to elude this deadly ailment that has lead to a sad loss of faith in Ford.

They are aware but ignore.....!!!

I think i am VERY lucky
my ex has over 247,000 miles on her all original eng/tran and only just recently its been making a loud ticking when it starts up. I'm on borrowed time now.... when this one gives in i'm parting it out and buying a 4x4 explorer and shaking it with a diesel :D
 






Well, I replaced the rear chain tensioner and didn't pull out the old chain guides. It was excessively easy, just 3-5 screws holding the inner fender liner, and one bolt. From there, pulling the tensioner out is like changing a light bulb. I timed this entire process from the moment I started the jack under the wheel, pulled the wheel off, pulled the liner back, and changed the tensioner, and then replaced it all and put it all back together and dropped it off the jack. It took a grand total of 12 minutes.

The engine runs perfectly now. I just need to take the time to replace the front tensioner; more difficult due to being buried under belted accessories. No rush, since it's not making noise, but why wait--other than the fact that it's January in Denver?

Per my earlier post in August, I picked up all the guides, tensioners, chains, and sprockets at the wrecking yard for a total of $42 (including tax). The tensioners? $2 each. The whole kit new online? $400.

You read that correct: 12 minutes and $2 part. I got the vehicle for $3000 under book since the guy did not know what was wrong and was terrified it was about to blow up on him. Hit youtube and listen to my posts--go to youtube and put in 98 Ford Explorer Denver timing chain tensioner. You'll find them...

Michael
;)
 






Great info! I'm sure Ford lost a lot of customers and families after timing failures only after a few short years of operation.
 






Well, I replaced the rear chain tensioner... 12 minutes and $2 part. ...

Michael
;)

Good work, but FYI the parts are not that high. That part from Ford is $25, check it online. Those tensioners have actual springs inside, they weaken over time. Do not buy a used spring and expect long life from it. Spend the $25, about $45 for the front kit.

Use the online Ford parts sources, Tasca Ford is very reasonable, and shipping runs about 10%.
 






Good work, but FYI the parts are not that high. That part from Ford is $25, check it online. Those tensioners have actual springs inside, they weaken over time. Do not buy a used spring and expect long life from it. Spend the $25, about $45 for the front kit.

Use the online Ford parts sources, Tasca Ford is very reasonable, and shipping runs about 10%.

Can you recommend a replacement interval for the two tensioners? The ones in my '97 SOHC were replaced ~9yrs/70k miles ago. I posed the question in a new thread earlier today and ~75k miles was offered, which seems very reasonable.

BK
 






BK, that's about what I'd suggest. Most valve springs are really strong and if possible you should replace at say 100k. Of course nobody does, but it would be best.

I've got almost 60k on all of my replaced parts. The two external tensioners are my biggest worry. Given really hard use I'd say they can go 50-75k easily. With very light use, a person may get lucky and go 150k before the springs get weak enough to let the chains be loose.
 






Well, I replaced the rear chain tensioner and didn't pull out the old chain guides. It was excessively easy, just 3-5 screws holding the inner fender liner, and one bolt. From there, pulling the tensioner out is like changing a light bulb. I timed this entire process from the moment I started the jack under the wheel, pulled the wheel off, pulled the liner back, and changed the tensioner, and then replaced it all and put it all back together and dropped it off the jack. It took a grand total of 12 minutes.

The engine runs perfectly now. I just need to take the time to replace the front tensioner; more difficult due to being buried under belted accessories. No rush, since it's not making noise, but why wait--other than the fact that it's January in Denver?

Per my earlier post in August, I picked up all the guides, tensioners, chains, and sprockets at the wrecking yard for a total of $42 (including tax). The tensioners? $2 each. The whole kit new online? $400.

You read that correct: 12 minutes and $2 part. I got the vehicle for $3000 under book since the guy did not know what was wrong and was terrified it was about to blow up on him. Hit youtube and listen to my posts--go to youtube and put in 98 Ford Explorer Denver timing chain tensioner. You'll find them...

Michael
;)

Wow, I thought the engine has to be pulled for that.
 






its really THAT easy? from the other threads, it seemed like a lot of work, dismantleing

can anyone confirm its THAT easy?
 






rear tensioner

Replacing the rear camshaft chain tensioner is like replacing a large bolt in the side of the passenger side head near the firewall. The difficult part is access and applying the necessary torque. Don't confuse replacing the tensioner with replacing the guides, cassettes or chains.
 






Ditto, I've mentioned it dozens of times, and posted the pictures before. The torque is 42lbs.ft.
 

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Great photos

Excellent photos Don! A picture is worth a thousand words.

By the way, in a past post on the forum a member stated he replaced his rear cassette without pulling the engine or the transmission. He said the heads were off at the time for an unrelated reason. Do you think it is possible? It seems to me the lower bolt would not be accessible.
 






I recall reading that too. I think only if the jackshaft chain had room to be fished off of the jackshaft could that be done. I haven't even seen the backside of these engines. I was planning to swap to a 302 if I had my truck that long. I now don't even need it as a mail vehicle any longer. It's still a great truck, the snow tires let me go anywhere this week.
 






do i need to pull the moter to set the timing after changing the tensioner
 






no timing change

do i need to pull the moter to set the timing after changing the tensioner

Replacing the upper front or rear timing chain tensioner does not affect the camshaft timing. The motor does not have to be pulled or retimed after replacing the tensioner.
 






how about the OHV V-6 IM STARTING HEAR TIMING CHAIN RATTLE WHEN AT HIGH RPM
I SAID Doh!
my girlfriend said how hard can it be i said your funny
this is not a fun job
 






I just finished changing my camshaft cassette and jackshaft tensioner and guide. I followed the instructions on this thread and it worked!! I have average mechanic skills and did a job that would scare many professional mechanics. I never could have done this without this site and most importantly the help Don provided me when I hit a snag. To those considering tackling this job I would say read this thread several times, buy the 6488 timing tool and expect to be working on this job three or four days (if you're an average mechanic like myself). The satisfaction of doing this job is worth all the effort, plus you will save $1500. There are many people on here that are way more qualified to answer questions but I am here for anyone that needs to ask a question too. Good luck.

Did you do just new tensioners and the front cassette or did you pull the motor and do the left cassete as well in the 3-4 days?

Reason I ask is everything I see says to pull the motor and replace the rear set as well as the front set is a 6-8 day job.

Also I have an 03 with 79k on it and my left chain is acting up. I need to pull the cover to see if the guides are still in there but I think based on the crack in my valve cover right at the chain that they are toast. So just because it is post 2002 parts does not mean it is unbreakable.

Does anyone know where I could find a writeup on how to correctly time the cams? I keep seeing refrences to notches in the cams that have to be parrallel to the head, ect. I guess what I am getting at is if one buys the tool is it a no brainer?
 



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