350 distributor cam gear pin failed

Discussion in 'Small Block Tech' started by JayZee88, Feb 13, 2020 at 5:44 PM.

  1. JayZee88

    JayZee88 Well-Known Member

    Not long after purchasing the wife’s 69 Skylark I sent a distributor into a local shop to have it rebuilt and converted back to points. Fast forward and the car is over budget and has been plagued with numerous small problems. The pin for the cam gear on the distributor came loose when I was taking it for the first test drive a few days ago. Kinda odd to me as I’ve never had that problem before an any vintage car. The owner of the repair shop is trying to insinuate that the engine locked up (which it did not) and the pin Sheard and fell into the oil pump, however we know what causes those pins to fail and fall in the oil pump. He wants to charge me 80 bucks for a new distributor while keeping in mind he had to take the oil pump apart because it was Slightly damaged. Keep in mind I replaced every item on the front end of that block with brand new components myself and saw the oil pump. The shady individual is trying to pass the cost onto me even though he admitted he himself rebuilt the distributor and knew full well I bought the car not running and the only time it’s ever been ran was at his shop. What do you guys think? I can provide pictures if it would help, but I think we all know what kind of damage would be expected
  2. buick64203

    buick64203 Just plum crazy Staff Member

    Exactly how did the pin damage the pump?
  3. JayZee88

    JayZee88 Well-Known Member

    It fell down in between the gears. They put a new distributor in and it locked up the oil pump when it got between the gears. Thats when they found it. The gear teeth ends were a little banged up, but he has been filing them back. I put a booster plate on it when I started building it and that saved any serious damage I think.
  4. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD"

    I don't see how the distributor gear roll pin could get inside the oil pump. The only way into the oil pump is through the pick up tube in the oil pan and the strainer would have stopped it. I think something else locked up the pump and sheared the pin.
    72gs4spd likes this.
  5. 1987Regal

    1987Regal Well-Known Member

    X2 on what Larry said. or there was debris in the oil galleys before the cover went back on, I don't recall the pickup having a big enough screen to suck in things that big. I think something was in the pump...it ran..the pump locked up...then sheared that pin off. To me that's what makes sense, just thinking how things work in that engine. Josh
  6. Gallagher

    Gallagher Founders Club Member

    Did you install all of the components or did the shop that rebuilt the distributor?
    We’re oil pump clearances checked during assembly?
  7. Bens99gtp

    Bens99gtp Well-Known Member

    I'm not familiar with what the inside of thev350 cover looks like, but I'm assuming somewhat similar to big brothers...........and the drive pin cant get into the pump cavity from inside the cover on the big block.......ifvthe pin cane out it could gear in the dizzy gear . Cam snout gears, timing chain, fuel pump arm area, even fall down into the from of the pan........if the pin was actually inside the oil pump cavity I'd like to be shown how.

    I'm guess improper gear clearances, they got hungry and and ate each other till they stuck but the motor kept going.

    It's crazy how close everything is in there....I took my hv gears apart the finishline had setup to replace a dripping gasket on the bottom side ofvthe booster plate......not a gasket the affected clearance. I was very careful on reassembly,, went slow and even, but by the time it snuggled up there was enough extra drag that it could be turned with a screw drive, but you could tell it wssnt smooth or right. Had it apart 3 or 4 time b4 it would spin smoothly again, so even the process of snuggling the bolts up can play goofy with the insides
  8. Mark Demko

    Mark Demko Well-Known Member

    X2 on what Ben and everyone here has said.
    If and whenever that roll pin breaks, the piece/s would probably stay in the gear and distributor shaft.
    Drop the pan, and look for plastic teeth from the cam gear, that's probably why it wasn't running.
    Oh, and find another mechanic, or ask here and tackle it yourself.
    These cars are old, and just because the mechanic is older doesn't mean they know anything either.
    Many experienced people have passed, and their experience has gone with them.
    ANY vehicle cannot be approached for repair like a bull in a china shop, which is how a lot of people approach repair jobs.
    Last edited: Feb 14, 2020 at 5:11 AM
    MrSony likes this.
  9. JayZee88

    JayZee88 Well-Known Member

    After I get the car back I am done with this mechanic. He doesn’t know crap about Buick engineering. All work was done by him. I saw the new oil pump gears and yes something was in there. He then showed the distributor (he had to replace the pin last year when rebuilding it). I would have done it myself, but our basement flooded last summer and had to remodel it instead of working on the wife’s Skylark. If the pin didn’t fall in the oil gear shaft something must have been in there. Either way it was their work that caused said failure. Last time I use this mechanic ‍♂️
  10. Mark Demko

    Mark Demko Well-Known Member

    Your mechanic doesn't "get it"
    The cam drives the distributor, the distributor drives the oil pump, the roll pin for the distributor gear breaks, the distributor stops distributing spark, the engine stops, along with the oil pump that's driven off the distributor.
    No way the roll pin jammed the oil pump.
    Is he pulling the oil pan?????
  11. JayZee88

    JayZee88 Well-Known Member

    No. When the distributor failed, He threw a new distributor in the car before looking for the pin. When he noticed a distinct sound (as he told me) that’s when he took the oil pump apart. Not a smart move. I only found out afterward!
  12. Mark Demko

    Mark Demko Well-Known Member

    Have the pan pulled!
    Theres SOMETHING in the pan making its way to the oil pump (probably plastic cam gear teeth)
    The ONLY path INTO the oil pump is thru the pick up tube.
    There is NO WAY that pin can make it into the oil pump from the timing cover.
    And if that pin does break, it more than likely stays in the gear and distributor shaft, remember, its A LIGHT PRESS FIT in there:D
    Have SOMEBODY pull your pan!
    Sorry for the caps, Im not yelling at you, Im just trying to emphasize my point and your "mechanic" is frustrating me:mad::mad:
    Plus I don't want your car to be ruined because of a bonehead:eek:
    MrSony likes this.
  13. JoeBlog

    JoeBlog Platinum Level Contributor

    Your mechanic reminds me of a mechanic back in New England where I grew up. My neighbor brought his 1963 Mercedes 220SE to this guy. It was running funny (I was 15; wasn’t into cars as deeply yet). The mechanic lost the ignition key, so he HAMMERED A SCREWDRIVER into the ignition to start it. He then told my neighbor that the problem was cured by him doing that, and he needed another switch. Run. Don’t walk away. From this guy. Let the car be looked at by someone else, or park it until you’re caught up elsewhere and do it yourself.
  14. BrunoD

    BrunoD Looking for Fast Eddie

    Also,if I'm not mistaken,SBB have 2 different gears,not very common,but one gear has one tooth more then the other.?Possibility?Who know's!.Bruno.
  15. telriv

    telriv Well-Known Member


    The diff. is in the 455/350. The dist. are exactly the same EXCEPT for the gear on the end of the dist. One has one less tooth.
  16. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD"

    The SBB has a 14 tooth gear, the BBB has a 13 tooth gear. The gears can be interchanged to use in each engine. The big cap HEI gears and roll pin are different from the points distributor gears and pins.
  17. JayZee88

    JayZee88 Well-Known Member

    He is pulling the pan on monday (again). I forgot to mention that they DID pull it once before to replace the oil pan gasket. The more I think about it the more frustrated I get at the quality of work they have done. Yeah they painted the intake and valve covers for free, but due to a broken thermo housing bolt they ended up drilling a new hole and tapping it then using silicone to make a gasket:mad:. When they are done with it I am going to have to repair their half assed repairs. Its the first (and last) time I use this shop.
    Mark Demko likes this.
  18. Mark Demko

    Mark Demko Well-Known Member

    Good idea.
    I hope everything ends well for you.
    If yah have anymore issues with the car, let us know;)
  19. jay3000

    jay3000 Well-Known Member

  20. MrSony

    MrSony Well-Known Member

    This a SB style cover with gears installed. The shaft you see engages with the dist. 10000% no way for the pin to go anywhere but the pan.
    unnamed (1).jpg

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