piston opinions wanted

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

  1. cobravii

    cobravii Well-Known Member

    anyone have any input on 425 pistons from EGGE vs. Rebuilders Choice?

    Have you tried either or both?
    what do you recommend?

    Thanks,
    Larry
     
  2. 8ad-f85

    8ad-f85 Well-Known Member

    Search through the site, plenty of opinions and experience on inexpensive, rebuilder type pistons...most of them bad. (sorry)
    I don't remember if they are exactly the same piston or not.
    Personally I'd consider your time as more valuable than the $$ you might save by using a piston like that.
    Piston price is one of the main drawbacks to having a unique and special engine like the Nailhead.
     
  3. Deadsled59

    Deadsled59 Well-Known Member

    Dont use those inferior pistons.
    Contact Tom Telesco here on this site.

    He helped me build/design a set of Custom Forged aluminum alloy pistons with his proprietary design through RaceTec which has rounded edges on the dome to improve "Squish" in the Heads, along with EVERY other parameter i.e. Compression Distance/Pin Height, Fitment for the new pins, ALL built for your desired Compression Ratio, etc...

    Pricey, but WORTH IT, especially if your deck is nice and straight because these can be built/designed to your existing Deck Height/Rod Length (like any other custom set, but Toms' design is superior to what another company can provide) so you'll SAVE $ by not having to cut/deck the block for CRAPPY cast pistons that are .050 "in the hole" to get proper Compression Ratio~ provided the deck is flat/square.
    Tom can help you build them up, I promise.
    Piston to Wall clearance will be around .0030 or slightly more for the nature of the Forged Pistons- more dense, needs more room to expand and close the gap up as they warm up.
    This also opens up the availability of Different Ring Packages, and even up to a .700 Lift Valve Lift, all while maintaining your desired C.R.
    ALL of this was accounted for when I did my set with him.
    His knowledge and help alone was worth the investment on my end.

    Just my 2 Cents.

    Tom can be reached at 203--324-6045
     

    Attached Files:

  4. cobravii

    cobravii Well-Known Member

    I did quick google search on "classic and muscle automotive" and it comes up in Australia! Is that where Tom lives??
     
  5. gs66

    gs66 Well-Known Member

    Ross used to have forged nailhead pistons, not sure if they still do. I would not buy the cheap cast pistons.
     
  6. cobravii

    cobravii Well-Known Member

    technical question: Are 425 pistons cast or forged from the factory?
     
  7. gsgtx

    gsgtx Silver Level contributor

    they are cast. ross pistons are way to heavy. JE makes a good piston. auto tec pistons are good and are the ones Tom T. sells,there cheaper then JE too. DO NOT BUY CAST PISTONS it makes no sense.
     
  8. cobravii

    cobravii Well-Known Member

    I have never heard of JE or auto tech.....

    do you have any more info on them?
     
  9. gsgtx

    gsgtx Silver Level contributor

    rac-tec and auto-tec are the same company. i would go with the rac-tec auto-tec .
     
  10. Deadsled59

    Deadsled59 Well-Known Member

    Tom is out of Connecticut.

    AutoTec/RaceTec are the two adages they use to differentiate the aluminum alloy from one another.
    The box mine came in says RACETEC, but they are in fact AUTOTEC, which is a 4032 ALLOY with will allow a tad tighter clearance if I'm not mistaken.

    Stock Pistons are Cast.
    Most "off the shelf" ones, if not all, are Cast.
    The custom ones Ive mentioned are FORGED.

    Some say the forged option is overkill.
    HOWEVER, with the oddity that is our beloved Nailhead, using FORGED Pistons is not "that much" more expensive than the crappy cast options (300 Cast vs +/- 900 Forged with NEW Pins/Custom Ring options) and having your deck inevitably cut to make them USABLE as they come +/- .050 in the hole!

    Thats why I said if your deck is nice and straight/paralell to the Main Bearing Housings, its a no-brainer to put the saved money from machine work into a QUALITY PISTON that can and I'm sure still is available through Tom with his plethora of knowledge and expertise.
    NOT to mention the valve reliefs are HUGE to allow a .700 lift yet with the larger dome, keeps your C.R. up there AND with good Squish/Quench.

    As Mr. Telesco says- "Its all in the details!"
     
  11. 8ad-f85

    8ad-f85 Well-Known Member

    The reason I suggested doing a search here is that you can read about people's experiences with the egge type pistons for nailheads firsthand.
    Not too much good to read about, but I'd rather that not come from me so much as the rest of the forum.
     
  12. wkillgs

    wkillgs Gold Level Contributor

    I'm late to the discussion, but I'll sum it up:
    Originals were cast, which are fine for daily drivers, but won't hold up for high performance use on crappy fuels.
    The replacement cast pistons from Egge, Rebuilders Choice, Sealed Power, and Silvolite will have a lower compression height which will increase the quench distance (bad), and lower compression (bad). Also won't give much clearance for hi-performance cams since the valve pockets aren't very deep.
    The old Badger and Zoillner cast pistons were a close reproduction of the originals.

    Forgings include Ross, TRW, and Jahns. They're pretty much unavailable these days. The Ross pistons are about the same weight as the originals. I have some NOS TRW's and some Ross's here and have previously posted the weights, compression heights, and dome volumes. They do have some shortcomings with respect to CR, quench distance, and valve pockets.

    Best bet is to get the Racetec/Autotec forgings that Tom developed. They will produce the proper compression, give the optimum quench distance for combustion efficiency and power, and can used thinner rings for lower drag.
    You do need to have your block measured to ensure the pistons fit properly. Full details are in this thread:
    http://www.v8buick.com/showthread.php?275648-Tom-Telesco-working-on-GOOD-pistons-for-the-Nailhead!

    If your goal is better-than-stock performance, these pistons are the best choice.
     
  13. gsgtx

    gsgtx Silver Level contributor

    I used JE in my 425 and 446 they are well made and are about 150 grams lighter then stock pistons. Dave Nelson built the 300 buick stroke and used autotec, thats when i first heard about autotec and put them in my 340 buick built with no problems. also used them in my 440 dodge built again nice no problems and lighter weight. after the 340 built I told Tom about autotec and how reasonable the price was for a well made made light piston. Tom worked with Randy at autotec and designed a nailhead piston for us. which am going use again in my 401 built. Randy was the owner of JE pistons at one time i believe.
     
  14. nekkidhillbilly

    nekkidhillbilly post whore

    some of the companies will build one off forged units. I have been thinking of having that done and going with a pro charger but idk yet.
     
  15. Deadsled59

    Deadsled59 Well-Known Member

    gsgtx,

    what clearance are you running with your AutoTec Pistons?
     
  16. cobravii

    cobravii Well-Known Member

    Ok, I sent info requests off to JE and autotec.

    Thanks everyone for your info, much appreciated.

    BTW if anyone has a set of .060 over 425 pistons for sale I'd be interested.
     
  17. gsgtx

    gsgtx Silver Level contributor

    i think 4.5 thousands.
     
  18. Gary Bohannon

    Gary Bohannon Well-Known Member

    Volumetric efficiency vs thermal efficiency .
    On a nailhead, volumetric efficiency is expensive to improve and very limited due to valve and port limitations.
    But, the old nailhead can gain some performance by using a very thermal efficient piston design. Design all you can get out of this piston (quench, etc.), then grind a cam that will take a 10.0 to 1 static compression ratio (SCR) and provide about 7.8 to 1 dynamic compression ratio (DCR) for good power on pump gas.
    Polish the piston tops, combustion chambers and valve heads to a glass finish for more thermal efficiency and detonation free combustion.
    Make sure your cooling system is capable of maintaining a maximum of 180 degrees tops on a hot july day.
    A Pertronix 3 in your distributor with multi fire (and rev limiter) will protect and maintain your clean and shiney cumbustion chamber and pistons.
    Use full 12 volts from key to coil, a Pertronix 3 coil and pertronix plug wires (that won't disrupt the module).
    I love nailheads and often thought what I would do on a limited budget. Switched to 455 after wife totaled my 65 GS 401.
     
  19. Deadsled59

    Deadsled59 Well-Known Member

    Not to hi-jack the thread, but was curious as I'm sure if you've read my later posts in my thread "59 Nailhead Rebuild Saga" that using my block with "up to" .0045 clearance MAY be in my scope- trying to clean up that Out of Round condition still and have +/- .004 clearance in some spots...

    At .0045, was that more "race" oriented?
     
  20. telriv

    telriv Well-Known Member

    .0045" will cause light piston slap at cold start but should quiet down when fully warmed. Also, another option would be to have the pistons "Knurled" to make the clearances a smudge tighter. I don't know if this can be done with these pistons. I will call & ask if you'd like Will.

    Auto Tec will tell you you will have to go through myself to get these pistons that we spent over 1 1/2 yrs. working on. If you had spent the amount of time & $$$$ nec. to do this that I/we have spent you wouldn't be too happy being cut out would you???




    Tom T.
     

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