gas block diesel head?

Discussion in 'DIY Marinizing' started by adamanderr, Dec 13, 2007.

  1. adamanderr
    Joined: Mar 2006
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    adamanderr Junior Member

    Where should i look for info or possibility of converting a gas block to run on diesel? is it as simple as bolting on compatible diesel heads, since fueling and valve etc are in head? what about having a head machined?

  2. Kay9
    Joined: Oct 2006
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    Kay9 1600T Master

    Pertty sure this wont work. I would think the air ports would be all wrong for a compression engine. I would also think that the wall thickness of a gas engine would not be big enough (read strong enough) to withstand the forces generated in the combustion chamber of a diesel engine. Also what would you do with the holes for the distributor and timming chain? I think you are wasting your time. Find an old diesel and rebuild it. If you cant find one let me know and I can direct you to several.
  3. old750
    Joined: Sep 2007
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    old750 Junior Member

    Just my 2 cents...

    It can be done! But it wont last you very long.

    GM did it back it the 80s with a v8 - i think the 350. It was a big flop. They converted to diesel. Biggest problem was the block not being stout enough, walls were too thin.

    I'm thinking if the worlds largest auto company can't do it right, I won't even try it at home.
  4. guy plain
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    guy plain Junior Member

    not a good idea to do.....the VW 1.6 idi has a comp of 23-1 thats 525 psi of compression..the 1.8 gas is 9-1 i think thats about 165 psi....i think the bottom end would meet the pan in short order.....not saying im right.but from gas to diesel theres a whole world of differense......biggest thing is ..would it be worth doing when there are so many diesels to choose from?
  5. gonzo
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    gonzo Senior Member

    The 350 Oldsmobile is the only engine I know of that converted a gas block to diesel. However, the main bearings were larger and the pistons where different to get more compression and thicker at the top too.
  6. parkland
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    parkland Senior Member

    How big of an engine is needed?
  7. slow fred
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    slow fred Junior Member

    You can convert a Perkins.
  8. parkland
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    parkland Senior Member

    Convert a perkins TO gas FROM diesel?

    Internationals DT 466 7.6 liter truck engine can be converted to run on gas, and propane.

    I'm not aware of any gas engine that you can just throw injectors in the spark plug holes and change the crank for a longer stroke.
  9. jonr
    Joined: Sep 2008
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    jonr Senior Member

    I wouldn't bother, but you could insert a thick piston sleeve to substantially reduce the displacement to a point where the block and crank would hold up.
  10. parkland
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    parkland Senior Member

    Likely the piston arm would hit the cylinder bore before that happened.

    And what about the head?

    If your heads are designed for a 4" piston, and now you have a 3" piston, theres still going to be 4" of pressure on the head.
  11. parkland
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    parkland Senior Member

    For conversation sakes....

    There is a way to get a gas engine to run off diesel or any oil. Gasification.
    I spend almost 3 months playing around with it about 3 winters ago.

    What I did, was used a wood stove to generate a bunch of heat.
    I installed a steel tubing coil in the stove, and part of the chimney.
    The oil would travel into the red hot coil, and turn into a vapour or gas.
    Depending on the exact temperature seemed to depict if it was an actual gas, or oily vapour.
    The coil exited the stove, ran through a coil in a barrel of water, then into a large bag.

    At this point, it's ready to burn.
    It burns much like propane. Several times I lit the end of the hose, and it burns clean as you can imagine.
    It is also heavy, I flowed some out onto the grass, and the white fog stays close to the ground. I lit it and it was like a natural gas fire haha.

    Anyways, I got my chev 5.7 v8 engine to run on it, a little, but it was hard to throttle anything. I didn't want to destroy the engine.

    I did a more elaborate setup with a briggs lawnmower engine, and after a bit of practice, got it running really great. It did fire up the first pull, this stuff burns really well.
    I see no reason why it wouldn't work well if a little effort and time was spent on it.

    I have always been meaning to devote some more time to playing around. I want to do a truck. But I'd use the exhaust to gasify the oil. Sounds easy, but it will actually require an onboard computer to run a custom air intake valve and fuel intake valve. The computer would be essential to keeping the EGT's at a perfect spot to generate the fuel gas.

    It would also need a secondary fuel and starting system.... similar to how you wait for glow plugs, you'd have to wait for the propane burner to heat up the exhaust enough to start producing gas from the oil.
  12. WestVanHan
    Joined: Aug 2009
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    WestVanHan Not a Senior Member

    Was this guy Boston on here was into that stuff. he used his exhaust to heat up and burn free waste motor oil in his diesel pickup
  13. parkland
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    parkland Senior Member

    I did that on an old beater once, long ago.

    Above, what I described is totally different.
    It was a gas engine, the oil was heated enough that it turned into a gaseous vapor, and yes it ran lol.
  14. Petros
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    Petros Senior Member

    I have owned a worked on a number of diesels as well as gasoline engines. The pressures in the combustion chamber after combustion are not necessarily any higher, despite the compression ratio difference. Peak combustion pressures after combustion in both gasoline and diesel engines are about 2,000-3000 psi. the real problem is the knock and average combustion temps are much higher is a diesel. To convert a gasoline engine would take a lot of work, and still not be very reliable. You not only would have to change the pistons, head, cooling system, etc. but you have to created an accessory drive for the injector pump, plus a completely different fuel system from tank to engine. You would also need a much larger starter to turn over the high compression engine. I owned one of the early GMC trucks that had the auto engine converted to diesel, the engine itself did not give me any major problems, but the starter was too weak and I would replace them about as fast I would replace the airfilter (I carried a spare under the seat). the other problem was the idiotic automatic glow plug that never worked correctly and would burn up costly glow plugs. Most people converted it to manual glow plug.

    to convert the engine you would need a complete overhaul and replaced a lot of internal parts. By the time you did the overhaul, scavenged/bought all the necessary parts and bits, debug the system so it would run reliably, you still would have an engine that has a rather limited life. It would not be worth it.

    It would just be cheaper to buy a complete diesel engine and install it, and more reliable as well.

    If you want an alternative fuel you might look at a propane conversion, it is a fairly easy do-it-yourself project (with a conversion kit), and propane you can get for less than $2 a gallon right now. It would cost less and be easier to convert a gasoline engine to propane rather than attempt a diesel conversion.

  15. Frosty

    Frosty Previous Member

    What Petros said its a silly Idea realy and and will need a new crank to get up to 22.5 compression ration . The liners are fine but again as petros mentions mean effective pressure on the piston is HP there is no more HP from a diesel than gas infact probably less.

    Interesting on the, where do you drive the pump question . It might be possible to common rail the engine with the engine management control. But again its a theoretical problem and it is the Oldsmobile 350 that I only know of that did it meaning that the gas version was a strong motor.

    As said a new crank would be needed and Im still not sure if the throw would go into the gas block. and as they dont make them its none starter.
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