Piston pin height

Discussion in 'Street/strip 400/430/455' started by 1969RIVI, May 24, 2020.

  1. LARRY70GS

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

    My advice is to build a ZERO deck motor now with the right pistons. That way, you bolt on the aluminum heads and go. That means spending a little more now for the better custom pistons. You want lump, turn the idle down. It will sound like it is about to stall.:D
     
  2. 1969RIVI

    1969RIVI Well-Known Member

    Ugh Larry you're so good at changing people's mind:p. I was set on autotecs for a while then started looking at the TA pistons and thought I could "get by" with them and save a few bucks but deep down with all the reading I've done on this site I know I shouldn't be a cheapazz on the pistons and just go with the autotecs. That being said I should probably still do valve reliefs along with all my other mentioned plans above^^ and could still use the .20 gaskets?
     
  3. telriv

    telriv Founders Club Member

    You can't go wrong with the AutoTecs. They will ask you ALL kinds of questions you'll need to give answers to. Like finished deck height, head gasket compressed thickness & bore , finished con rod length, combustion chamber CC's after the heads are done, flat tops or with valve reliefs, ( I would get valve reliefs especially IF you think you will go with a bigger cam in the future) desired compression ratio, where you want the piston below deck, 0 deck, etc. keeping your squish area around .025"-.050" for best combustion & detonation resistance & some other things I may be forgetting at this moment.

    Tom T.
     
  4. LARRY70GS

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

    Yes, if your motor was 0 deck instead of .015, the SCR would be 10.56:1, and your DCR would be 7.84. That is with your .020 steel gaskets, and 25cc valve reliefs. With the customized pistons, you can change the valve relief ccs to adjust compression too. Give JW a call. He has built enough of these motors, he can steer you in the right direction. You need a good machinist also who will do what you want.

    It be nice if you could use the calculator. You can change things around and see the effect.
     
  5. Bigpig455

    Bigpig455 Fastest of the slow....

    The CD on the 1621A's I just got from TA was 1.985, measured and verified. I had seen the part number in the sealed power catalog as 1.980 too, so I waited till I had them in hand to spec deck height. Maybe TA had a run made that way?
     
  6. 1969RIVI

    1969RIVI Well-Known Member

    Yeh I'm thinking valve reliefs are a good idea no matter what piston I choose as it leaves room to grow with the cam if I so desire.
    Good idea Larry I'll probably call Jim once all my machine work is done and go over the specs with him to get a better idea on parts selection. The machinist I'll be using has done lots of buick 455's and has all the tooling to do everything properly. I have my eyes set on getting a new computer for my business so hopefully I'll be able to download the calculator and play with it at me leisure instead of bugging you all the time lol:p.

    Just out of curiosity why didn't you go the autotec route? I know you've been working on a nice engine or are those TA pistons for another build?
     
  7. 70 GMuscle

    70 GMuscle Plan B

    I guess no e85 near you.
    It’s real popular here on Long Island.
    $1.49 a gallon race gas.
     
  8. 1969RIVI

    1969RIVI Well-Known Member

    No we don't have e85 here.
     
  9. 70 GMuscle

    70 GMuscle Plan B

    Sorry man.
    My friends have been pushing me to get a e85 carb for my Chevelle. C12 is 70 a pail at Cecil county for 5 gallons. 100 on Long Island.
    I’m thinking of pistons n rods for Buick.
    Up compression.
     
  10. Bens99gtp

    Bens99gtp Well-Known Member

    Around here e85 is more than regular gas at most places
     
  11. 70 GMuscle

    70 GMuscle Plan B

    But a real good investment power wise. We are talking cents.
    It’s 105 octane. My friends run over 13 to 1 cruising around and racing.best bang for the buck fuel.
    It wasn’t around when I built my Buick. But might get a dominator for it for other car.
     
  12. Bens99gtp

    Bens99gtp Well-Known Member

    If you drive your car often yes it can be nice, if it sits you can have many of the same issues as pure methanol. For driving it makes sense if your combo is on the edge.......for pure out racing I would go to methanol, its basically the same expensive to swap over to and your get 100% the benefits not just some.

    E85 ratios move around alot.. so your tune can move around some from tank to tank
     
  13. Bigpig455

    Bigpig455 Fastest of the slow....

    "Just out of curiosity why didn't you go the autotec route? I know you've been working on a nice engine or are those TA pistons for another build?"

    Funny, because I do have a set of Autotecs in my Nailhead, and I like them fine, ..it was only for the reason that the Sealed Power had everything I was looking for in an off the shelf piston for a very attractive price: Pin height, dish CC, alloy spec and abredable skirts. Given that this will always be a iron head, stock class motor I didnt need 0 deck or huge valve reliefs, and it still gave me the 10:1 and DCR I was looking for without crazy machining costs. I just never shopped them around once I got the specs from TA..
     
  14. 70 GMuscle

    70 GMuscle Plan B

    You buy a test kit. Check right at the pump.
    Tune stays good. Get fuel at same place and stock up.
    Place near my house is excellent for it he says. Most consistent.
    But letting it sit, like the e15 we use For daily driving is no good for any carb. And I’m sure very inconsistent. I won’t test as the fuel sucks and we know it.
    For $1.49 a gallon vs. $12.00+. Difference adds up fast.
    When my friend brings 15 gallons to track for long weekend it cost him about $32. My 15 gallons of C12 was $195.
    His car is faster than mine, lol.
     
  15. Bens99gtp

    Bens99gtp Well-Known Member

    I get that it cheaper for sure but c12 is a serious fuel.

    I run 12:1 on ll100 av fuel and have no issues. It's only 4.50 a gal

    As with any fuel there are draw back and pros. Just have to weigh them out, the only reason I'm not using meth is how little I get to runs dont want the extra work
     
  16. 1969RIVI

    1969RIVI Well-Known Member

    IMG_117979625859823.jpeg Here ya go Ben :D:p
     
  17. Bens99gtp

    Bens99gtp Well-Known Member

    ;)

    I wish I got to use my car enough to do that, right now life just isn't there.

    Good new is my car is together and if I can squeeze the time I will try to go to Quaker, judt need to go get new belts and helmet
     

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