View Poll Results: Your experience with a cast crank

Voters
16. You may not vote on this poll
  • Cast crank, stock engine, no problems

    8 50.00%
  • Cast crank, stock engine, crank failure

    1 6.25%
  • Cast crank, mild upgrades, no problems

    6 37.50%
  • Cast crank, mild upgrades, crank failure

    1 6.25%
  • Cast crank, heavily modified, no problems

    1 6.25%
  • Cast crank, heavily modified, crank failure

    1 6.25%
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Thread: Cranks, Cast vs Forged

  1. #1
    What it is? Not Verified Feedback Score 0 ViperZ's Avatar
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    Cranks, Cast vs Forged

    I've read alot of threads on cast vs forged cranks. Obviously the forged cranks are much stronger and are the better choice. Right now I'm running a 92' engine with the cast crank that came with it. My mods are listed in my sig and I plan on reaching around the 400-450 whp range. After doing research, I've read completely mixed reviews on whether or not it would be safe to run the cast crank, some saying it would be fine, others saying it will snap like a twig. I'm creating this thread to get more input from engine builders/machinists and to see who has really had problems with cast cranks. Any input would be greatly appreciated. Thanks!


    -Aaron

    In the poll, please don't vote if external factors were the cause of the failed crankshaft and not the crankshaft itself.

  2. #2
    Now with more poop-smear Not Verified Feedback Score 8 (100%) IPD's Avatar
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    what sig?

    and imho, 400whp is probably fine, but i wouldn't go much higher. i've heard of at least one guy whose cast crank gave out who happened to be running 16g's at the time.

  3. #3
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    As long as you don't detonate, you will be fine with a cast crank. Just set the tune a little rich to make sure that doesn't happen. Also, make sure your oil pressure is good and the bearings for the rods and mains are in good shape.

  4. #4
    I AM IMPORT POWER Feedback Score 1 (100%)
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    As i stated in the 3si thread, I have seen stock TT ande NAs with snapped cast cranks.

    -Chris

  5. #5
    I'm Kind Of A Big Deal Feedback Score 8 (100%) Emilie@GZP's Avatar
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    Quote Originally Posted by Import Power View Post
    As i stated in the 3si thread, I have seen stock TT ande NAs with snapped cast cranks.

    -Chris


    WTF do you have to be doing to snap a crank!?! yeesh!
    Circa 2005... Oh my, how far I've come
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  6. #6
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    i have never seen a snapped crank, not even when the cylinder wall in my flathead ford colapsed .broke rods and pistons but not the old cast crank

  7. #7
    What it is? Not Verified Feedback Score 0 ViperZ's Avatar
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    Quote Originally Posted by Import Power View Post
    As i stated in the 3si thread, I have seen stock TT ande NAs with snapped cast cranks.

    -Chris
    I've seen them snap before too, never on one of my cars though. I'm on the fence about using the cast crank. What causes the cast cranks to fail? I'll have brand new bearings, new oil pump, the car will be tuned and monitored right away, and I will be running a knock warning light set low. The most knock I've read is 2 counts when I was NA. Ever since I went TT and threw in the 8.0:1 pistons I haven't seen any signs of knock at all. I was running 5psi on DR650s on stock injectors. If I have a healthy running engine that is balanced, would I still be running the risk of snapping the cast crank? Are they just that sensitive?

  8. #8
    Forum User Feedback Score 2 (100%) fullracegt's Avatar
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    yo i had a 94 vr4 which had a 4-bolt with a cast crank i didnt know they ever came like that, i thought 2-bolt's were cast and 4-bolts were forged? and i thought they were all forged after 1994

  9. #9
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    Quote Originally Posted by inperfectdarkness View Post
    what sig?

    and imho, 400whp is probably fine, but i wouldn't go much higher. i've heard of at least one guy whose cast crank gave out who happened to be running 16g's at the time.
    Sorry, I copied my post from "the other site" and I don't have a sig here yet. I've got a TT converted 92' with DR650's, 8.0:1 pistons, running 5psi on stock injectors for now, I'll be going with 720's and a fuel controller (undecided), lightweight crank pulley and flywheel, solid motor mounts, full exhaust, bov, etc... I've already overhauled the heads and when I threw in the pistons, I got new rod bearings and rings. I'd really like to overhaul the whole bottom end this winter and before I go out and spend $300+ on a forged crank, I want to know the reasoning for cast crank failures whether it be due to imbalance, knock/detonation, vibration, improper lubrication, or if they are just that sensitive. One thing that has me worried is the solid lightweight crank pulley causing uneven vibrations through the crank and causing it to fail. That's a whole other discussion in itself.

  10. #10
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    Quote Originally Posted by fullracegt View Post
    yo i had a 94 vr4 which had a 4-bolt with a cast crank i didnt know they ever came like that, i thought 2-bolt's were cast and 4-bolts were forged? and i thought they were all forged after 1994
    Half way through 92', when they switched to the crank sensors, all DOHC 3S's came with forged cranks from there on. If you have a 4-bolt with a cast crank, someone swapped it out for the factory forged crank

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