ruben
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- Jul 6, 2023
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Hola de qué material es el pistónHola de qué material es el pistónHere is the plan of the piston and combustion chamber. Can you read .DWG files?
Hola de qué material es el pistónHola de qué material es el pistónHere is the plan of the piston and combustion chamber. Can you read .DWG files?
Wat material are made the pistónHola de qué material es el pistónHola de qué material es el pistón
Cast iron in Roger's engine. Mine, aluminium.Wat material are made the pistón
el tuyo de aluminioHierro fundido en el motor de Roger. El mío, aluminio
I have this picture series from a pre war copy of the 'Modern Diesel'. A quick internet search suggests that the first picture is under vacuum, the middle picture is at atmospheric pressure and the final picture is around 200psi (~13 bar).Heh, would have been nice to have more direct evidence on that front. I've seen some papers where they painted the piston with something fuel soluble and after running a few cycles inspect to see where the paint washed off. Might be one way to attack that question.
4000 psi is a fair bit more injection pressure than we are running, I think. At least I'm aiming for 100 bar, about 1500 psi. I'm fairly sure that I've read that the lower pressure reduces 'penetration' of the spray. So presumably our sprays don't go so far. Nevertheless, what we see in that picture makes me think that the spray probably doesn't have much difficulty getting across the small sizes of our combustion chambers and impinging on the piston or (in my case) the swirl chamber wall.I have this picture series from a pre war copy of the 'Modern Diesel'. A quick internet search suggests that the first picture is under vacuum, the middle picture is at atmospheric pressure and the final picture is around 200psi (~13 bar).
IIRC some of the modern diesels are running in the 300 bar range for injection pressures.4000 psi is a fair bit more injection pressure than we are running, I think. At least I'm aiming for 100 bar, about 1500 psi. I'm fairly sure that I've read that the lower pressure reduces 'penetration' of the spray. So presumably our sprays don't go so far. Nevertheless, what we see in that picture makes me think that the spray probably doesn't have much difficulty getting across the small sizes of our combustion chambers and impinging on the piston or (in my case) the swirl chamber wall.
I did consider this, but the head is pretty cramped, the only space available is between the inlet and exhaust ports which is very narrow.Is it possible you had hydraulic lock or near hydraulic lock causing the head gasket to fail that quickly? If your injector got stuck open it would not take long to put too much liquid in the cylinder and get too much pressure. Any room left on the head for an adjustable pressure relief valve? It may be worth doing for a development engine where overpressure is a real possibility. Could save the head gasket, or the crank or con rod if you get the head to hold too much pressure. (Find Hansen did one in one of his videos...)
Thanks, I like this design. I ordered some fiber reinforced graphite material from eBay already, do you think it would need the metal fire rings? I also thought I might try forming fire rings from shim stock and wrapping them around the soft gasket material.Hi @Nerd1000
About the gasket
This is what I did with my 4 cylinder diesel engine, it was perfect
Because my engine's cylinder head and water jacket are aluminum, I had to test the hardness of the aluminum gasket against the aluminum cylinder head, gasket needs to be softer.
If the materials of that part on your engine are different: it depends
If you use teflon instead of paper then all thickness is the same, it will be fine .
View attachment 157721
"do you think it would need the metal fire rings?"do you think it would need the metal fire rings? I also thought I might try forming fire rings from shim stock and wrapping them around the soft gasket material.
Yes, 0.6mm, not without making a dummy injector to adapt my compression tester to the cylinder head (I also need to check if the gauge goes high enough).Did you aneal the copper head gasket? How thick is it? Can you measure the compression pressure?
As flat as I could get them given how well my mill was machined at the factory (the spindle tram cannot be changed without scraping).Ok, I was wondering if the compression might be too high.
Next question how flat are the sealing faces of the head and the block? If they are concave you won't get it to seal.
Hi Roger !Laping or scraping may be a bit extreme, but some fine abrasive paper/cloth fixed to a flat surface may be sufficient. This also has the advantage that if you are not so good with the figure of eight action the surface will tend towards convex which will help the sealing.
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