When to run a stall converter?

Discussion in 'Small Block Tech' started by Reidk, Nov 16, 2020.

  1. alec296

    alec296 i need another buick

    I don’t know how this cam is, it’s not the same specs. Lift isn’t a huge issue, more duration is. valve train should be ok. As they are not on tighter lobe centers. I guess you will find out soon enough.
     
  2. alec296

    alec296 i need another buick

    As far as screen , inspect it good. Make sure it’s ok. I would get the melling 20-is5 screen .
     
  3. Reidk

    Reidk Well-Known Member

    I'm gonna be running big tube hooker headers too. My bro said that will help with the big cam...something about overlap...? Hope this all works great. My head porting bits will be here Wednesday. Excited but nervous.
     
  4. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD" Staff Member

    When I put those advertised numbers into my DCR calculator, at 9:1 SCR, I get 6.62 DCR.
     
  5. Reidk

    Reidk Well-Known Member

    What does that mean?
     
  6. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD" Staff Member

  7. Reidk

    Reidk Well-Known Member

  8. alec296

    alec296 i need another buick

    Less low end torque. Higher Reving engine. More upper rpm power.
    When I did the same for you originally, the 284 duration spec and cam advanced 4 degrees,024 gasket, .030 off head for estimated 50cc head, I got 9.03 compression, and 7.04 dynamic compression. Which would have made a fairly strong lower and mid range. And would still be fair on 87 gas. But at the limit. And Larry put cam advanced 4 degrees, trying to bring up the dynamic. If set at zero advance, it’s 6.37 dynamic. When you want to be closer to 7.5 to 8.0 range (that max performance range very strong power and torque).
    But if you like the really choppy idle well it would probably be like that.
     
  9. Reidk

    Reidk Well-Known Member

    Idle isn't as important to me as good burnout power. I have access to 89 octane and 91 octane at many stations around here. walmart has 93 octane right at the pump. I'm okay with more expensive gas. I'll call Ta about the cam today.
     
  10. johnriv67

    johnriv67 Well-Known Member

    If you don't raise your compression or drop the size of your cam, that 6.62 DCR is going to make your 350 depressingly gutless. I'd highly advise switching cams or raising compression, or you're gonna have a bad time.
     
  11. alec296

    alec296 i need another buick

    Yes. Double check that cam specs. More lower torque will be better for you. Not that you can’t get there with those specs, you would need more convertor and 3.73 or 3.90 gears or possibly 4.10 gears.
    As far as the gas rating, you need higher octane the closer you get to 8.0 dynamic compression.
     
  12. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD" Staff Member

    My grandmother likes hotrods too:D Seems to me you just want to drive them, but you have NO Interests in trying to understand, but I'll try anyway.

    Our engines are 4 stroke engines. The 4 strokes are Intake, Compression, Power, and Exhaust.

    1) Intake Stroke- The piston moves down in the cylinder. The intake valve is open. Air/fuel mix is drawn into the cylinder.

    2) Compression- The piston moves up, both valves are closed. The air fuel mix is compressed.

    3) Power- The spark at the plug ignites the air fuel mix, and drives the piston down.

    4) Exhaust- The piston moves up. Exhaust valve is open. The burned gases are pushed out.

    The cycle repeats.

    Static Compression Ratio (SCR). The ratio of the volume above the piston at the BOTTOM of the stroke to the volume above the piston at the TOP of the stroke. The Static compression is fixed once the engine is built, it does not change.

    The Dynamic Compression Ratio (DCR) has to do with camshaft valve timing. It is the running compression AFTER the intake valve closes.

    Focus on the intake and compression strokes. Since no compression can occur with an open valve, both valves must be closed. The intake valve valve is open on the intake stroke as air fuel is drawn into the cylinder. If the intake valve closed at the bottom of the stroke, then DCR would equal SCR, BUT IT DOESN'T. The intake valve closes AS THE PISTON IS ON IT"S WAY UP ON THE COMPRESSION STROKE.

    Different cams close the intake valve relatively earlier or later. Bigger cams close it later. This means that part of the stroke is used up until the intake valve closes, and actual compression begins. DCR is calculated by using the stroke left AFTER the intake valves closes. DCR IS ALWAYS LOWER THAN SCR. How much lower DEPENDS on the cam. This is the reason a cam description specifies a required SCR, what you refer to as "my cam was spec'd for 9.0:1 compression.

    Now read that linked article and see if it is still Spanish to you.:)
     
    70skylark350 likes this.
  13. Reidk

    Reidk Well-Known Member

    I'm still learning. I've done plenty of engine swaps and bolt on parts...this is my first build though. I understand how the engine works. Just alot of info being thrown at me.
    I called TA they said the info just got wrote down incorrectly on the card but they'd look into it. I asked them about the composite gaskets. I'll be ordering them. But he also suggested just having the shop mill the intake side of the head.
     
  14. Reidk

    Reidk Well-Known Member

    What are these 228 and 220 numbers? 20201124_091952.jpg
     
  15. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD" Staff Member

  16. Reidk

    Reidk Well-Known Member

    These numbers are alot lower than the 297 and 298. Ta said I have the right cam. stuff was just wrote down incorrectly on the left side of the cam card.
     
  17. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD" Staff Member

    There is A LOT OF CONFUSION HERE. Your cam card says, TA 284-88H. The TA catalog says,

    Advertised duration numbers of 284* Intake, 288* Exhaust. Lobe separation angle of 110*

    Duration @ .050 is 223* Intake, 230* exhaust. .460"/.460" lift with stock 1.55 ratio rocker arms.

    The only thing accurate on that cam card is the Camshaft part number?
     
  18. Reidk

    Reidk Well-Known Member

    I'm assuming the. 228 and .220 numbers are the actual numbers that we need to pay attention to. Based off of these numbers my build should be fine...should expect good low end torque? While on the phone with TA I ordered oil pan gasket, bigger oil pickup tube , new dip stick, and the thick composite intake gaskets.
     
  19. alec296

    alec296 i need another buick

    So your cam is good. lift at .050 is the other numbers. You can tell how radical cam is, but I believe it has something to do with degreeing cam.
    time to start working.
     
    Reidk likes this.
  20. Reidk

    Reidk Well-Known Member

    Currently I've been drilling and tapping 6 busted exhaust manifold bolts. Bought sharp drill bits and a sharp tap. Is going well. 5 minutes per hole.
     
    alec296 likes this.

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