Vortec 4.3 cracked block ... automotive swap?

Discussion in 'Gas Engines' started by carolinaXJ, Apr 14, 2012.

  1. whitepointer23

    whitepointer23 Previous Member

    you have never heard of a high nickel strong block, it is common knowledge. iron blocks are okay to weld, warm the area and use stainless or cast rods. the volvo blocks i mentioned look the same as the car version but were cast by a foundry in the u.k to marine specs, do you think a company would go to all that trouble for nothing.
  2. Ilan Voyager
    Joined: May 2004
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    Location: Cancun Mexico

    Ilan Voyager Senior Member

    I have heard of, but I do not see truly the technical point, it's like using carbon fiber in a station wagon. Except using already made casting molds and not having to design a new engine for customers accepting to pay a high price for obsolete material. The 4.3L is a very obsolete engine by european standards but it has the merit to exist with all the tooling already done.

    A lot of gas modern engines with 4 valves would be better candidates and for getting 190-240 ponies. Between a 4.3L and a diesel Yanmar 4LH for a similar weight the choice is done...No match in consumption and reliability. Even if it's more expensive.

    Or you use the military system. After 1200 to 2400 hours depending on the work and the type of engine, change it for a complete new one and sell the old. So no problems with the corroded accessories and other miseries. In pro use it's less expensive than all the losses induced by a faulty engine in the middle of the diving high season for example.

    Welding iron blocks is just a bit more delicate than that. The preparation is critical and depend of the type and position of the crack. Also of the age and kind of the iron.
    There are so many techniques that I won't detail. You have the choice between cast rods and oxy acety torch, high nickel alloys, ER312L16, hastelloy (180 if I remember well) and even alu bronze with an AC TIG. Plus some tricks of stress relief after welding.
    You have also special "plugs" when welding is not possible. Long to make the fix but very efficient, and asks for a minimal tooling.

  3. CDK
    Joined: Aug 2007
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    Location: Adriatic sea

    CDK retired engineer

    Like I said Brendon, the Volvo philosophy is quite unusual, it wouldn't surprise me if all their engines are cast from expensive alloys. I recently installed back up sensors in my friend's Volvo V70 and discovered there is no way to drill a hole in the armour plate behind the rear bumper. Even my special drills for stainless could hardly scratch it.
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