Broken Timing Chain

Discussion in 'Small Block Tech' started by Gulfgears, Sep 13, 2018.

  1. Gulfgears

    Gulfgears Gulfgears

    Yesterday my timing chain gave up, with no warning, just quit running. Had car towed to shop I have used before, and while not Buick oriented they do lots of specialty cars. (Chrysler 300 with long rams, 396 Nova on propane, and other stuff) plus the guy says "you get the parts, I'll do the work."
    So from you guys who have either do this or own a shop, how many hours/dollars will it cost to r&r the timing chain?
    Engine is a stock 300 with p/s, a/c and nothing else.
    Any thing I should warn him about before starting?
    Anything I need to buy other than timing chain, front cover gasket, and crankshaft oil seal?
    I am really up against the clock as cruising the coast is the first week of October, money paid and reservations made.

  2. buick64203

    buick64203 Just plum crazy Staff Member

    Should be straightforward baring any broken, rusted bolts. Buy a timing chain set and a timing cover gasket set. While its apart, you can replace the water pump and fuel pump. They'll basically be off the engine with the job, so minimal additional labor. Same for the belts and hoses? Belts will be off and all the coolant will be drained.

    You might want to consider taking the oil pan down and cleaning out all the broken plastic timing chain teeth that likely fell into the pan. For me, its a weekend job. So a repair shop worth their salt should be able to knock it out fairly quickly provided they have all the parts
  3. Gulfgears

    Gulfgears Gulfgears

    Brand new belts, last weekend, fuel pump is maybe five months old, and water pump has been replaced in last three years or so. Removing the oil pan for cleaning have any hidden dangers like seals or anything?
    If this was after the "big dance" next month and time wasn't a factor I'd do it myself, but I' m slow and old!
    Clean out oil pickup screen too?
  4. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD"

    Just ask him to verify oil pump prime before he starts the engine after completing the work. If you run the oil pump with an electric drill, it's easy. Anytime you disturb the timing cover seal, you can lose oil pump prime.
  5. buick64203

    buick64203 Just plum crazy Staff Member

    Ok cool, so your good to go with those items then. If you couldn't remember when they were replaced, then now would of been the time.

    Pretty sure the oil pan has a flat gasket so it should be a relatively simple r&r. So seals involved. Once they drop the pan, they can throw it in the parts cleaner and remove all the timing chain material and any sludge. And the pick up screen will be right there. So Im assuming they're clean that off too. Why wouldn't they right? But better to ask than to assume

    BUICKRAT Torque Rules!

    The only snag I would expect would be the long bolts going through the water pump and timing cover into the block. They may also find the timing cover corroded near these bolts to the point of not sealing properly. Other than that, fairly straightforward for a competent shop. I second pulling the pan to remove the debris.
  7. Gulfgears

    Gulfgears Gulfgears

    Thanks everybody, parts ordered and will be here in 3-6 days hopefully.
    Once I have the parts they will tear into her.
    This car has never failed me in over 6K miles, so I guess I should be a happy camper it happed close to home and not out on the interstate, or at crusing the coast among all those high dollar trailer queens!
  8. Schurkey

    Schurkey Silver Level contributor

    HOW do you know the timing chain broke? Very unusual.

    "I" would have some concerns about the condition of the timing cover, given that the chain BROKE and therefore maybe flailed around in there. A broken chain could cause some carnage.

    I'd also be wondering about piston-to-valve clearance when the cam stopped turning but the crankshaft didn't. There could be bent-valves and/or guides 'n' piston damage.

    As said, if that was a nylon-over-aluminum cam gear, you'll have debris in the pan. MAYBE they can remove the debris with a vacuum cleaner when the timing cover is off...but they'll never get any crap out of the oil pump pickup tube. Ideally the pan comes off, and maybe the pickup tube is cleaned, or maybe replaced.
  9. Mark Demko

    Mark Demko Well-Known Member

    FIRST, diagnose if it IS the chain.
    I'd think youd hear popping thru the exhaust or carb before it quit.
    You said it just quit, with no warning, sounds electrical to me, NOT mechanical.
  10. Gulfgears

    Gulfgears Gulfgears

    They did the twisting the distributor thing until it would run roughly.
    That's usually a good indicator of jumped timing. So I guess a better description of the problem is jumped timing vs broken timing belt.
    End result is pretty much the same.
  11. gsgnnut

    gsgnnut Well-Known Member

    Usually but check the dizzy for a sheared roll pin. I had a 350 do that with exact same symptom.
    BuickV8Mike likes this.
  12. Mart

    Mart '71 350 GS, almost stock

    If it is in fact a broken chain, let us know the brand of chain if it's not stock.
    It should be stamped on side of each link.

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