Fresh 350 build front seal leaks Need some advice

Discussion in 'Small Block Tech' started by 70skylarkcusto, Sep 6, 2016.

  1. 70skylarkcusto

    70skylarkcusto God, Country, Cars

    So here's how the story goes

    After about a year of working weekends in the garage I finished phase one of the rebuild on my 70 skylark convertible.
    This consisted of a full front suspension rebuild, conversion to power disk brakes, fresh coat of paint in the engine compartment, a full engine rebuild, and full transmission rebuild.

    Being that this was my first car doing restoration work on you can imagine how ecstatic I was when the I finally heard her come to life for the first time. However, my excitement didn't last long. After I took her out for the first trip out of the safety of the neighborhood I came back to discover a leak coming from the front seal on the timing cover. :( The timing cover was replaced with an aftermarket timing cover through TA performance including new neoprene front seal.

    Here is the question. After talking to the engine builder (very very reputable guy) he told me that I apparently hadnt given him the oil slinger when I dropped off the engine. He failed to mention this to me before I got the engine back fully assembled. However he assured me that because I had replaced the front seal with a new neoprene seal there should be no reason for any leaks regardless if the slinger is installed or not. SO..... should I go through the painstaking process of pulling the timing cover off to install the slinger? or could it be a problem with the seal? or is there something else that could be causing this leak?

    any help would be GREATLY appreciated!


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  2. JoeBlog

    JoeBlog Platinum Level Contributor

    As much as it pains me to tell you this, I must. Yes, the slinger is necessary. Otherwise, all of us here who installed a new timing chain or cover and found it on the bench after completely reassembling the engine would've left it there. It helps oil get to the distributor gear and keep the timing chain lubed rather nicely.
  3. alec296

    alec296 i need another buick

    Sometimes the neoprene seal needs a sleeve to cover the rope knurl on balancer and without the slinger the seal may be farther into the knurl
  4. UNDERDOG350

    UNDERDOG350 350 Buick purestock racer

    The only reason for the slinger is to keep excessive oil off the OE rope seal. I don't use them when a real rubber seal is used and don't have oil leaks.
  5. Schurkey

    Schurkey Silver Level contributor

    Many engine families don't use a slinger. Slingers are something of a crutch for rope seals.

    As said, I'd be concerned about any knurling or groove on the damper hub that goes into the seal.

    If the damper hub is smooth and not grooved, did the assembler center the timing cover on the hub BEFORE tightening the bolts holding the cover to the block? It might be that all you need is to loosen the cover bolts so the cover can center on the damper hub, then re-tighten the bolts. This assumes that the seal hasn't worn excessively already, and that the gasket(s) didn't get adhesive on both sides, so they can slide just a bit without damage.
  6. hugger

    hugger Well-Known Member

    Be kinda hard to align it any different than the way it is now, there is two dowels that align it, you'd have to remove dowels or drill hole larger
  7. 70skylarkcusto

    70skylarkcusto God, Country, Cars

    So would you recommend replacing the seal and trying just that?
  8. 70skylarkcusto

    70skylarkcusto God, Country, Cars

    To be honest I am not sure what exactly he did. But I do have to say this guy has been building engines for 50 + years and used to do all of Paul Newman's engines and was even his crew chief for a while. I kind of find it hard to believe he would have assembled it incorrectly. Because I used an aftermarket timing cover I dont remember there being a groove on the cover itself like there was one the OE timing cover.
  9. 70skylarkcusto

    70skylarkcusto God, Country, Cars

    Does that mean simply reinstalling the slinger would solve my issue or do you think I will still need this sleeve.
  10. Mart

    Mart Gold level member

    Physically look and see how the surface is where the seal is wearing/ riding.
  11. 70skylarkcusto

    70skylarkcusto God, Country, Cars

    Ill start pulling things apart this weekend and take pictures as necessary and most likely will end up putting the slinger back in if for nothing more than piece of mind.

    I'll post my findings
  12. Mark Demko

    Mark Demko Well-Known Member

    Do what Mart said, that will tell you everything yah need to know.
    The chain and fuel pump eccentric are lubed from oil wizzing outta the front cam bearing.
  13. alec296

    alec296 i need another buick

    Yes you need to see the surface seal rides on . Should tell you something about what's happening.
    But as far as if you need the slinger, I have read comments over the years that Jim at trishield uses them and never heard not to use them . And almost any turbo v6 builder . Also the seal needs to face a certain direction. I would put it back in myself.
  14. UNDERDOG350

    UNDERDOG350 350 Buick purestock racer

    Polish the knurling down a little and put in a new seal.
  15. Mart

    Mart Gold level member

    That's a good method. The seals easily have a usable size up to .030 undersize of the journal nominal diameter.
    You may be able to position the seal deeper or shallower in the cover to get the seal lip to ride on a new surface. Or possibly a dbl. lip style seal.
  16. 72gs4spd

    72gs4spd Well-Known Member

    A new seal with a double lip and a speedy sleeve that goes over the hub of the harmonic balancer with give the seal a fresh smooth surface to ride on. While your in there you might as well put the slinger back. Good luck
  17. UNDERDOG350

    UNDERDOG350 350 Buick purestock racer

    Believe the seal goes in from the front on the new covers. No need to remove it.

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