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Whats the limit of a wet shortblock?

Posted by perrytheplatypus157, Oct 21, 2020

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  1. perrytheplatypus157

    perrytheplatypus157 Proven Member

    Joined Jun 18, 2017
    Fall River, Wisconsin
    Just curious, who here has a high horsepower fully wet block? and what do you make (hp and dyno type) or trap? Looking for personal experiences please. And for those who have half fills and street drive their vehicles, how do you like it? Do you notice any overly excessive heat anywhere? I've seen posts like this that are older but I'd like to revisit the topic to see if the advancements in technology have allowed us to stretch the capabilities of our beloved cast blocks

    3K  16

    1990 Eagle Talon TSi AWD
    11.49 @ 127.56 · 1G DSM
  2. motomattx

    motomattx Proven Member

    Joined Dec 9, 2010
    wampum, Pennsylvania
    I make close to 1000hp on my wet block.

    Drag Race Build 4K  10  24

    1995 Mitsubishi Eclipse GST
    fwd · manual · 2G DSM
    awdmonster1904 likes this.
  3. bastarddsm

    bastarddsm Proven Member

    Joined Aug 26, 2003
    Mendota, Illinois
    It literally depends on a million things. I think somewhere around 800whp you can have problems. Certain piston designs seem to always appear in engines that split cylinder walls. Half fills don't seem to help anything, and they just crack above the fill. Think about where a flag pole breaks off at.......

    I had a motor not only crack a cylinder wall, but break a business card size piece out at 700-750whp. It was a fresh motor with like 10 passes on it. It was 0.040" over though, and it was making some steam, 144mph traps at almost 3300lbs back then. I was also using some oddball pistons - Probe. They have offset pins, and small skirts, just like the pistons that I see in broken blocks all the time.

    I'm slightly worried I'm getting into the danger zone on my current setup - 145 traps at 3000lbs. It's only 0.020" over and I have good pistons, so I'm not especially worried. But I'm pretty short on time and money these days so I'm kind of avoiding turning mine up any further.

    If I was trying to go as far as possible powerwise on a wet block, I would not do any kind of fill. I would find a block that can be used at standard bore or close to it, and then get custom pistons - shooting for as little of overbore as possible. like 0.002" or so, max of 0.010 over. Cylinder walls are around 0.180" thick, so 0.010" is more than 5% of the wall thickness gone. I'd also search out a good virgin non performance used head. 1 light decking and use a felpro composite gasket, and standard ARP's at like 105 ft*lbs. Work my tune to keep that gasket happy. I strongly believe if you can't keep that gasket happy you are making dangerous levels of cylinder pressure. This is pretty much the current path i'm on (at 0.020" over though) and the car runs 9's and isn't broke all the time.
    Last edited: Oct 22, 2020

    Showcar Build 6K  1

    1991 Eagle Talon N/T
    9.805 @ 144.00 · 1G DSM

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