Buick 350 engine build

Discussion in 'Small Block Tech' started by Darron72Skylark, Jul 12, 2019.

  1. Darron72Skylark

    Darron72Skylark Well-Known Member

    Block is looking good, only needed a 0.020 overbore to clean up nicely. Consulted with my machinist and engine builder about the quench question with TA heads and the Autotec pistons. He's very confident that the thickness around the edge of the piston is large enough to provide good quench when matched with the TA heads and a zero deck.
    Initial decking of the block was 40 thousands, and after fitting rods and pistons, will get some final work to bring it to zero.
    The crankshaft had to go back to the outside shop for a second try, which has caused some delay to the project. It just arrived yesterday and all looks good, so balancing the rotating assembly is next. The concept of 1.5 thousands bearing clearance is one that my machinist has embraced, but the crankshaft shop had not fully understood. Now it will be right.
    I had a spare flywheel ready to go, but started on a clutch replacement project for the Skylark over the holidays and needed to use it with the current stock motor. As a result, I'm hoping that the old flywheel can be cleaned up to remove the hot spots and surface cracks. Otherwise, I'm kind of in trouble without a flywheel. I'd prefer not to have to buy a billet one for $325, but we will see if the old one from the stock motor can be saved.
    Camshaft in in the block. Used the coated dual groove cam bearings from TA, and they were a little tight, but a little work on the camshaft solved that.
    By early next week I should know whether the old flywheel is salvageable and can be used to balance the rotating assembly, or whether a shiny new billet flywheel will be added to my extensive bill at TA Performance.
     
  2. Darron72Skylark

    Darron72Skylark Well-Known Member

  3. Jim Nichols

    Jim Nichols Well-Known Member

    Darron, Looks good!
     
  4. sean Buick 76

    sean Buick 76 Buick Nut Staff Member

    I could be looking at those pictures wrong however I think the pistons are upside down. The piston valve reliefs should match the cylinder heads. I’m on my phone so maybe I’m not seeing the photos properly.
     
  5. 300sbb_overkill

    300sbb_overkill WWG1WGA. MAGA

    They're in right, they are just pictured upside down looking the way it is rotated on the engine stand at that angle. Look at the second pic down and you can see the factory index block locator on the top side which is the outside of the block. Also the dowel pins are towards the outside of the block as well.
     
  6. sean Buick 76

    sean Buick 76 Buick Nut Staff Member

    Good stuff, right on thanks.
     
  7. Mart

    Mart Gold level member

    Those pistons probably still need to come out anyway, block doesn't appear to even have been decked or any cleanup cut yet.
     
  8. Darron72Skylark

    Darron72Skylark Well-Known Member

    You are correct, this was just the first mock-up to see how much more needs to be cut.
     
    Mart likes this.
  9. Darron72Skylark

    Darron72Skylark Well-Known Member


    More pictures of the engine build.
    Pistons are fitted, all bearing clearances are at or under 2 thousands. Pistons are within 1 thousands of zero deck.
    Oiling mods done to block, and a stock timing cover that has been ported and rebuilt by TA Performance.
    TA 310-350 camshaft is in and it degreed up perfectly. Using the coated dual groove cam bearings.
    SRE oil pan with mediocre paint job by yours truly (it is so full of brush marks and drips that my machinist made fun of it). It will hold oil, and if it doesn’t leak I’ll be well ahead!
     
    MrSony likes this.
  10. sean Buick 76

    sean Buick 76 Buick Nut Staff Member

    Congrats, this is working out great.
     
  11. Mark Demko

    Mark Demko Well-Known Member

    Looks good!
    LOL about the paint runs on your pan, don't worry 'bout it:D
    Paint doesn't make it run any better or go faster, hell I didn't even repaint my block on my last build;) whatever paint was on there from 20 plus years ago is good enough, LMAO
    NDOF4393.JPG
     
  12. Darron72Skylark

    Darron72Skylark Well-Known Member

    By the way, the old flywheel cleaned up just fine and will be reused for this build. I feel like I got lucky on that detail.
     
    MrSony likes this.
  13. sean Buick 76

    sean Buick 76 Buick Nut Staff Member

    Good news!
     
  14. Darron72Skylark

    Darron72Skylark Well-Known Member

    Small update on compression ratio. Turns out my block was not decked within 1 thousandth as I previously thought, the pistons are actually 5 thousandths in the hole.
    This drops my static compression ratio from 10.5 to 10.4.
    It is a small difference, I’m wondering whether to politely push for a closer zero deck or not worry about it. What do you all think?
    The heads are not yet on, but the rotating assembly is all done. It will be a fair bit of work to disassemble and deck it some more.
    I’m investing a lot of time and money into this build, but I also want to preserve the good, constructive working relationship with my machinist
     
  15. sean Buick 76

    sean Buick 76 Buick Nut Staff Member

    From the research I have done about this topic there are a bunch of factors. The amount of piston rock in the bore, the piston diameter, the RPM, etc. all effect the ideal distance between the piston top and the cylinder head (quench distance). In an ideal world I believe that for a buick 350 with an alum head the ideal quench distance would be 30 thou. Anything less risks an engine failure. Anything over 50 thou looses the gains from quench. But once you are over 70 thou then you are out of the “danger zone” for potential detonation. In short the ideal quench zone is 30-50 thou. 50-70 thou could be likely to have detonation issues in theory.

    With your pistons 5 thou in the hole and a 40 thou gasket that’s a 45 thou quench zone which is fine. And if you used a 20 thou steel shim gasket it would be a bit too tight.

    Plus if it in the compression ratio you are concerned about then simply mill 10 thou off the heads and be up a little higher than you were shooting for. I looked at the specs of that cam and I do not see it being an issue to have 10.4:1 or 10.6:1, your dynamic compression will be fine.
     
    Last edited: Jan 30, 2020
  16. Darron72Skylark

    Darron72Skylark Well-Known Member

    Thank you Sean.
    Sounds like the difference in performance will be minimal at most.
    I think it’s better to save the money and keep a positive relationship with my machinist than to insist on taking those last 5 thousandths off.
    I just needed a little reassurance from the experts here I guess.
     
  17. Darron72Skylark

    Darron72Skylark Well-Known Member

  18. Mart

    Mart Gold level member

    No roller cam?
    Would've been my 1st choice before the alum heads. Flat cam lobes suck. You should break cam in with inner springs removed if you have duals.
     
    Last edited: Feb 12, 2020
    MrSony likes this.
  19. Darron72Skylark

    Darron72Skylark Well-Known Member

    Yes, removing inner springs for the break in.

    In my calculus of cost vs benefit - which may not be perfect, granted - I chose the airflow of the aluminum heads. Having ponied up for that big ticket (including the big valves and level 1 porting) I just couldn’t justify the additional cost of a roller cam or roller rockers.

    When the engine is assembled and dynoed, I’ll post results. And if my results are disappointing, then I and others can learn from it.

    Worst case scenario, I’ll redo things in a few years. I’m ok with learning by doing.
     
    MrSony likes this.
  20. Mart

    Mart Gold level member

    Sounds like you have a plan! You can roller cam it later if you want.
     
    Darron72Skylark likes this.

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