piston opinions wanted

Discussion in ''Da Nailhead' started by cobravii, Dec 28, 2016.

  1. cobravii

    cobravii Well-Known Member

    Is race tec and auto tec the same company? I'm wondering because they replied to me and sent me the info request sheet for me to fill out to build the pistons.....
  2. 8ad-f85

    8ad-f85 Well-Known Member

    Comment on knurling pistons,
    It's tough to knurl a couple thou clearance out of a piston without filing them down afterwards.
    Might get away with knurling the non-thrust side or better yet...coating them.
  3. gsgtx

    gsgtx Silver Level contributor

    .0045 is for forged pistons. stock cast pistons need less.
  4. Deadsled59

    Deadsled59 Well-Known Member

    I would appreciate that, Tom!

    Also, thats why I supplied your name/telephone number!
    Credit is due where credit is due, and its most certainly due to the man himself, folks!
    Like I said, give Mr. Telesco a call to get a set of these designed for YOUR build- you'll thank yourself later down the road...

    Let me know what Ractec tells you, and maybe ill have a clue whether or not I'm ordering that Deck/Honing plate in the next couple weeks~ and ill go from there with your continued help.

    Thanks again, Mr. Telesco.
  5. John Codman

    John Codman Platinum Level Contributor

    X2! I bought a set for my .030 over 425 and they are awesome. If the Nailhead has a weak spot it is the pistons. This is not an area to try to save money. After looking at the photos, perhaps you can understand why I have been bugging Tom for a ninth piston just for display.
  6. wkillgs

    wkillgs Gold Level Contributor

    Same company. Race tec is race oriented and uses 2618 aluminum alloy. Auto tec is more street performance oriented and uses 4032 High Silicone Aluminum Alloy.
    Those two materials expand at different rates when heated, among other differences.

    In general, the 'street' piston will need more clearance when exposed to higher loads/higher heat..... towing, supercharging, nitrous, etc. You can run it tighter for normal use.
    The 'race' piston will expand eve more and need more clearance than the street piston.
  7. telriv

    telriv Well-Known Member

    A GREAT suggestion. Check into getting them coated. I know Johnny, Bulldog66GS, had his done. Maybe he can chime in.

    Tom T.
  8. Bigpig455

    Bigpig455 Fastest of the slow....

    Credit is due where credit is due, and its most certainly due to the man himself, folks!
    Like I said, give Mr. Telesco a call to get a set of these designed for YOUR build- you'll thank yourself later down the road...

    Thanks again, Mr. Telesco.[/QUOTE]

    Glad we got that sorted out. Seriously folks, put Tommy's experience to work for you. his price is very competitive with what you'd buy a similar spec'd piston for out the door from any serious manufacturer, and he's done all the hard work and research. Plus, we gotta keep him fed..!

    That said, I'm going to visit my pistons this AM at the machinists. I had been carrying them around, bringing them to work and out to dinner, family holidays, etc..but Tom insisted it was time to gently build a motor around them. I'm still having separation anxiety, they were that pretty.

    Attached Files:

  9. nekkidhillbilly

    nekkidhillbilly post whore

    would coating cast pistons be a good idea? would it live with boost?
  10. 8ad-f85

    8ad-f85 Well-Known Member

    Some cast pistons come with a coating already. Their instructions state to NOT measure with the coating.
    It's more common these days to use them with coated skirts, esp. in situations where some clearance is thought to be reduced.
    There are a few different kinds of coatings available for skirts.
    Consult piston makers and coaters for more info.
  11. 300sbb_overkill

    300sbb_overkill WWG1WGA. MAGA

    What kind of coating are you asking about? A thermo-barrier type coating for the top of the piston to handle more heat, or a skirt type coating to stop piston slap in a loose bore?

  12. wkillgs

    wkillgs Gold Level Contributor

    The problem with cast pistons and boost is that detonation may eventually result in piston breakage. Those domes can crack and collapse in the center. In those situations, coatings don't make much of a difference.
    I know you were planning on efi and maybe a computer controller ignition? If you could add a detonation sensor to reduce boost or timing, that would be ideal. Adding H2O or methanol injection will help prevent detonation too.
    The old turbo Saabs (1980's) had a real nice APC control (Automatic Pressure Control) that would bleed off boost when it sensed detonation. My 79 Turbo Regal had a det sensor that would just reduce timing.... a much inferior method, but it was 10 years earlier than the better Saab APC.

    But We digress..... we have a habit of doing that don't we!

    Johnny went with a thermal coating on the domes to keep the heat in the chamber to maximize power. Maybe he had the skirts coated with something else.... that'll reduce scuffing.
  13. sean Buick 76

    sean Buick 76 Buick Nut Staff Member

    I personally would not use a cast piston for a boosted application over 6 psi but under that they should be fine if the tune is spot on.... Detonation and RPM kills parts not so much max Hp or boost levels. A $1000 piston will hold up a bit better to detonation but not for too long, it will still break. But a $100 cast piston could handle a ton of power if the tune was spot on... Of course if it detonated the cast piston would pretty much fall apart.

    I ran a stock Buick 350 engine with just some home porting on the heads and mild cam to 8000 RPM under 17 PSI and the short block survived just fine. Had some valve float at around 7000 lol!

    Info about coatings:

  14. telriv

    telriv Well-Known Member

    MY PISTONS ARE NOT CAST THEY ARE 4032 FORGINGS. Include Pins, Pin Fitting & Rings.
  15. Mister T

    Mister T Just truckin' around

    Larry, you CANNOT go wrong with Tom Telesco's forged pistons. If you're unsure about him, please understand that he LIVES AND BREATHES nailheads! From one Canuck to another, he will provide the best piston for your engine.

    Many of us on this forum, including me, have had the pleasure of listening to him talk about these engines and love for all things Buick.
  16. nekkidhillbilly

    nekkidhillbilly post whore

    I am aware I was askin in general. can you have a low comp version produced?
  17. gs66

    gs66 Silver Level contributor

    I'll be calling Tom when I need pistons.
  18. telriv

    telriv Well-Known Member

    As low as 8-1 for MAX boost.
  19. Babeola

    Babeola Well-Known Member

    Your forging needs a .300" thick crown and the top ring-land at least .250" down from the top (more is better) for a serious boosted application. You also want to make the best of the available quench and make sure there are no hot spots on the piston or in the chamber. I am sure Tom has already addressed the latter concerning his pistons, but the supercharged crown and top ring-land improvements would add weight and possibly push the oil rings into the pin area in a NA application. I am not sure how his pistons measure with respect to these particular demands of supercharging.

    Cheryl :)
  20. telriv

    telriv Well-Known Member

    The top ring land is .300" as opposed to .200" stock. I could specify MORE dome thickness if it felt is nec. These type pistons are used in boosted apps up to 850 HP with proper tuning. Normally NO PROBLEM with 5-6 pds.

    Quench is not as important on a pressurized situation as on a NA application because your making the nec. additional air needed to offset the problem.

    Tom T.

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