'94 TBI 350 Timing Chain

[Kirth Gersen]

Engine (RPO L05) has 250K miles and it's had a gentle life, no towing, runs well & reasonably quiet.

Is there any reason to be worried about timing chain & gears?

I'm not eager to do it, but is there any value in pre-emptively replacing the parts? I'd hate to have the engine catastrophically fail one day (valves hit pistons, etc).

 

[94OldRed]

IIRC, when I rebuilt my engine at 205k miles (same year as you), the timing chain and sprocket still looked good. Thankfully you don't have to worry about a chain and sprocket as much as you do a timing belt. I'd say if your truck is running fine with no stumbling, misfires etc. you should be alright.

That being said, if you want to do it, the job isn't too difficult.

 

[CrustyJunker]

A couple TBI trucks I've owned had sloppy timing chains at about 140,000 miles (at the mercy of previous owners' maintenance).

Easy old trick to check is with a timing light. Disconnect your ESC wire, and if your timing is bouncing around dramatically (should be at or around 0° on a stock truck), you may want to consider a new timing set.

As 94OldRed said, less likelihood of catastrophic failure vs. a timing belt, but still is worth a check!