Forged vs Hypereutectic piston in daily driver

Discussion in 'Street/strip 400/430/455' started by hunter7389, Sep 18, 2017.

  1. Bluzilla

    Bluzilla a.k.a. "THE DOCTOR"

    Interesting opinions, ...... While I haven't built hundreds of engines with Hypereutectic Pistons, the dozen or so I have built I am happy to report are still rolling around the streets, .... not in my control, .... with no failures to report. I am not in any way defending or advocating the use or misuse of Hypertectic Pistons. If folks have the misfortune of detonating a Hypereutectic Piston into little pieces then that same detonation will more than likely have pounded the life out of the rod bearings too boot. I agree with others that the Hypereutectic Piston tolerances are key, but when dealing with setting pistons, ..... when aren't they?
    I make sure the piston to wall clearance is to manufacturer's spec, I file fit the piston rings to their spec, and all is good.
    I do recommend a forged piston for more serious street/strip or race use for the obvious reasons mentioned throughout this thread (as I recently purchased a new set of Very Nice Diamond Forged Pistons from JW for my next BBB street/strip build.... Thanks Again Jim!). That's all the personal info I have for the OP of this thread.

    Larry
     
    Last edited: Sep 21, 2017
    Gary Farmer likes this.
  2. hunter7389

    hunter7389 Well-Known Member

    The $90 is a negligible cost really. I cant find the speed pro hypers in stock in any case.

    Leaning towards the forged Speed pro's from TA, are there any drawbacks? The machine shop is willing to install anything I provide, but he is worried about forged pistons rattling when cold
     
  3. MD_76_LIMITED

    MD_76_LIMITED Trust the process...

    I went with the Speed Pro forged pistons for the "its only $90 more" line of thinking as well. I haven't experienced any rattling when cold. They've served me well thus far...no complaints here.

    The only drawback is the weight when you start comparing them to other more expensive forged pistons (which is not the focus of this thread)
     
  4. john.schaefer77

    john.schaefer77 Well-Known Member

    I run the speed pros on an engine I run even in the winter. Never heard a rattle. I agree with the weight, but it hasn't affected the car as far as I can tell
     
  5. Mark Demko

    Mark Demko Well-Known Member

    I have the Speed Pro forged in my 87 GN, totally quiet when cold.
     
  6. LARRY70GS

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

  7. Jim Weise

    Jim Weise EFI/DIS 482

    It was a huge problem with the LS motors, but was really not the piston's fault.. the issue was instead of individually matching each piston to a bore, they did some crazy calculation about overall fits, and slapped it together. It was called "net clearance" but it caused many LS motors, especially in trucks, to have piston slap from nearly day one. This was a huge scandal for GM, they finally pronounced piston slap as "normal" and moved on..

    I did not follow this too close, as nothing with the new SBC interests me much, although I did laugh the other day when I was reading thru one the the lastest product catalogs mailed to me by one of my suppliers. Typically not much of interest for a Buick guy, but there are odds and ends... I came across a big full page spread on the new Generation 1 SBC blocks, designed for LS heads...

    Ya, Corporate motor, you just keep telling yourself that.... :confused:

    The 5.3 in my Suburban rattles like a flower girl on the Marcas at a Mommas and Pappas concert, and uses about a quart of oil per 2500 miles, it finally now has plugged up one of the catalytic converters, but I can't complain, it does have 340K on it.

    As far as the OP's question, the real issue with that piston is it's compression distance. Have them shave the block .020 and it will only be down in the hole .020 to .030... Instead of .050.. Not ideal, but better..

    The math figures to a 10.525 stack up height, and your block is 10.570 or taller now... so a nice .020 cut will not only clean up the decks, it will limit the compression killing, detonation inducing deck clearance.

    That speed pro piston has an offset pin, and coated skirt, along with updated clearance recommendations, It should not be noisy. The only negative I have heard about the speed pro piston lately is that they are now made in India, and the quality, based on the variation in actual sizing, has gone to hell..

    The next step up is the new Autotec piston that is out now for my 470/482 combos... advantages are they have valve reliefs designed into them, a bigger dish to better keep the CR down on iron head stuff, and are a whole lot lighter than the speed pro's. For about an additional $100... over the speed pros with valve reliefs. USA made too.. cost is reasonable (compared to what we used to deal with for a custom piston which was about 1k for a set) ...and they do allow me to change the CD of the piston, to match whatever deck height and clearance your builder wants to spec. 4032 material goes in at .003 for a nice quiet piston.. Custom piston, so there is about a month lead time..

    If I can help you with pistons, let me know, otherwise good luck with your build.

    JW
     
    Gary Farmer likes this.
  8. 87GN_70GS

    87GN_70GS Well-Known Member

    What alloy was the old SP 2362P piston made of?
     
  9. 8ad-f85

    8ad-f85 Well-Known Member

    I might be mistaken but those were likely VMS-75, which was their variant of 4032
     
    87GN_70GS and john.schaefer77 like this.
  10. Eric

    Eric Founders Club Member

    Go forged...an ounce of prevention is worth a pound of cure!

    Buick Eric / Oregon :cool:
     
  11. hunter7389

    hunter7389 Well-Known Member

    I went with the forged speed pro's. The cost/benefit was right for my mild build that will still get driven hard at times. Thanks for everyones input!
     
    Gary Farmer likes this.
  12. john.schaefer77

    john.schaefer77 Well-Known Member

    I think they are a good choice. I was able to pick up a set a few months ago for $430 including a set of rings. I am very happy with them, running 12:00's and 6000 RPM for the occasional track visit. My buddy went with the speed pro hypers. He is very happy also running about the same as me.
     
  13. 87GN_70GS

    87GN_70GS Well-Known Member

    I checked my old 80's 90's S/P, Fed Mog catalogs (lazy me) and you are correct.
     
  14. BadBrad

    BadBrad Got 4-speed?

    A $90 insurance policy on a multi-thousand dollars engine you hope to amortize over 20 or more years? Why is this even a question?
     
    john.schaefer77, 8ad-f85 and rmstg2 like this.
  15. D.S.R.E.455

    D.S.R.E.455 Active Member

    I also recommend using a 4032 forging in street performance applications.
    They are a bit lighter,especially with ta lightweight pins,they run a tight piston to wall clearance and can handle abuse much better!
    You really cant compare LS hyper pistons to that of buicks, gm has those pistons really scienced out well and they dont use ancient dish designs, they use coatings and even then they still break under hard use!
    That said i agree with Jim that cast pistons are fine in mild engines, i never use KB hyper pistons but i have had good luck with speedpro hyperutectic pistons.
    In a buick 455 anything over stock i would just go with the speedpros from TA but thats my opinion
     

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