When to change timing chain?
 

I recently purchased a used 2003 Ford F150 4.6L V8 SOHC with 120k miles on it. I'm not sure what maintenance has been done it but it seems to run pretty smoothly.

I did all the normal maintenance to catch it up (oil/oil filter change, fuel filter, air filter, flushed/refilled radiator, checked all other fluids).

I did not see a recommended mileage/time interval to change out the timing chain in the Ford maintenance booklet or in the owner's manual. My father-in-law has a 94 F150 with over 300k miles and has never changed out the timing chain.

Is there a time/mileage when I should look into replacing the timin chain on my F150? I plan on keeping it for the long haul so it needs to last.

we dont have a timing belt, but a timing chain which are suppose to last two or three times that... so... 200,000 or 300,000 miles lets hope... hopefully the lifetime of the engine

With CLAssic Oldsmobiles/Ponitacs it around 80,000.
Is you father-in-law's 94 F-150 a 300 six? Or a 5.0/5.8 job?
About 10 years ago I was hearing with the 9th generation trucks it was aobut 90,000 miles for a timing gear change.
My suggestion is to replace the unit with a steel !

My father-in-law's F150 is a straight V6 and he has really worked it hard over the past decade. He's never replaced the timing chain on his and it has 300k+ miles on it.

.4.9 300 straight 6 is gear to gear no chain to worry about.also that engine has 7 bolt main on crankshaft.those engines are built to run forever.

they sure are. the timing on those are very simple

How about a timing chain on a 1994 f150 with a 5.0L V8? Anybody have an idea on how long it might last?
Mine is at 105k miles and I'd like to make it last a great many more.

Keep your oil changed. Those pushrod engine chains are a lot shorter and stouter than these newer chains on the OHC engines. Nowhere near as much stretch to be had as long as you’ve got oil lubing and cooling them off. Ford wasn’t prescribing water (5w-20) back then.

Same answer as before: if it's not on the maintenance schedule, it's NOT a maintenance part. It's good until you observe some symptom that suggests a problem with it. Then you CHECK it. If it's worn out, you change it like any other part. If it's OK, you leave it alone, and keep looking for the source of the symptom.

Tires aren't on the maintenance schedule either - you don't toss them until you have a specific reason to.That depends on how the engine is maintained. If you don't change the cheap oil, then the chain (along with the rest of the engine) will wear out rapidly.If it's good right now, there's no reason it can't be good for another 500Kmi.

Click these & read the captions:

(phone app link)
https://www.supermotors.net/getfile/...chainslack.jpg

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https://www.supermotors.net/getfile/...123_173533.jpg

(phone app link)
https://www.supermotors.net/getfile/...229_111753.jpg

BTW
Comparing a smallblock (5.0L, 5.8L) to a modular (4.6L, 5.4L, new5.0L, 6.2L) is irrelevant because smallblocks are non-interference engines. If a smallblock's timing chain slips (they never break), you replace the chain, and go back to driving. If a modular chain slips or breaks, you replace the engine or total the truck.

I have changed my chain, cam and crank sprockets (3 pcs) when there are five or more degrees of play when indexing the crank pulley on zero degrees taking up the play, and reversing the crank direction while observing when the distributor begins to move, stopping and noting the position of the timing marks on the crank pulley.I don't regularily check timing components until they either fail or I am tearing apart the front of the engine such as a hard to get at water pump or timing cover. There is no set in stone mileage when they wear out. Maintenance and driving habits are key factors on how long timing components last. Most of the time when the chain/sprockets are badly worn, the chain will jump on the sprocket when you turn off the ignition and the engine stops.
Most cases the timing components on the old non overhead cam engines because they are so short and last the life of the engine even as they get sloppy.