the snooper
getting older by the day
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I have a lombardini 6ld diesel it's electric start
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daleyd
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It's going to look like something out of "Wallace and grommet" by the time he's finished!!
C
Chris Stevens
Guest
Radial tension on rings for a compressor pump and an IC engine are completely different, and while reduced radial tension on a IC ring would mean less friction if unit was used as a compressor pump, this would quickly lead to a glazed cylinder, and far less pressure being generated.
Compression ratio on a modern 4 cylinder bike engine is going to be around 11.1 and compressor pump I would guess about 17-18:1, and this linked to far more compression leakage on the IC motor, would mean something far less efficient than a conventional compressor, which would be a lot less reliable and more costly to run.
Bit of basic info on piston rings here: http://korihandbook.federalmogul.com/en/section_6.htm
Compression ratio on a modern 4 cylinder bike engine is going to be around 11.1 and compressor pump I would guess about 17-18:1, and this linked to far more compression leakage on the IC motor, would mean something far less efficient than a conventional compressor, which would be a lot less reliable and more costly to run.
Bit of basic info on piston rings here: http://korihandbook.federalmogul.com/en/section_6.htm
daleyd
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Seeing as there will be no combustion products I don't see how glazing will be a problem, as long as the rings/Pistons are lubricated? No one is saying the design is perfect Chris (these rings are obviously designed for a different application) but the evidence is that although imperfect in theory it will work.
Not quite sure why you think this will be the biggest obstacle, when in reality it's probably the one thing that would work ok!
Not quite sure why you think this will be the biggest obstacle, when in reality it's probably the one thing that would work ok!
C
Chris Stevens
Guest
This whole thread is pretty pointless as what the OP has suggested is certainly possible, but for reasons outlined earlier would probably be at least 30% or more less efficient than a conventional compressor,cost more to run and nowhere near as reliable. Have been involved with designing a few pistons for 2T engines in the past, and getting the right ring for particular application is crucially important, and in the case of the IC compressor project, not only are the rings not suitable, but compression ratio is too low.................
C
Chris Stevens
Guest
IC engine is a suction pump.........and I would be interested to hear whether the outlet would simply be connected to the exhaust manifold?
rtbcomp
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Use a twin and feed the outlet into a small tank feeding the inlet on the other, viola, compression ratio high enough.
That sounds like a twin-stage, as mentioned previously the 2nd cylinder would have to be less than the diameter of the first to achieve a higher pressure.
You might be able to do it with a 4 cylinder engine, pots 1 & 4 feeding 2 (or 3)
C
Chris Stevens
Guest
Be interested to hear where (other than exhaust port) you would get any appreciable pressure output from an IC engine?
mr migwire
It's more fun with metal.
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all of this could have been avoided if you had let me know, i could have shown you the compressor pump that came off of an old vertical setup, it does somewhere in the region of the high 20's cfm wise and is currently languishing in the corner of the storage shed at the railway.
daleyd
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brightspark
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could u really be bothered the amount of second hand ones about or parts
rtbcomp
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Surely you wouldn't get any because the rings wouldn't work??
The rings do work - remember those tyre pumps you screw into the plugholes?
KemppiFrog
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Out the back, I have a Ford 1800TD direct driving, via a rubber coupling, a Renault 1250 cc adapted as a compressor. The spark plugs were adapted as NRVs and it runs at half capacity as only the inlets open every second stroke. I have made up some bridge bits to use the cam to open the inlets at every down stroke, but not fitted them, the exhaust valves stay closed. The modded spark plugs feed into a tube manifold with a big blow off valve at one end and the feed to the blast pot on the other. The regulation is by the blow off valve, so the engine sits at the set speed and it just pumps out air.
Truth being, it was for a big blasting project that didn't come off, so has only run tests. Same reason I have not fitted the mods to double the output. Certainly works.
First ideas were to use a Citröen 2CV motor as the compressor. 600 cc, aircooled, so few probs there. Plus it has a fan and ducts if cooling worries one.
Went with the Renault, as it, like the Ford, were in the shed, along with just about everthing I used in the conversion.
I wrote it up here, might look for the link
KF
I did think about using light springs to use the inlets as poppet valves, but not easy to find ones to try.
Even allowing for waste, it would knock out 50 cu ft min at 2,000rpm with the valve mods, probably much more if goosed a bit.
Truth being, it was for a big blasting project that didn't come off, so has only run tests. Same reason I have not fitted the mods to double the output. Certainly works.
First ideas were to use a Citröen 2CV motor as the compressor. 600 cc, aircooled, so few probs there. Plus it has a fan and ducts if cooling worries one.
Went with the Renault, as it, like the Ford, were in the shed, along with just about everthing I used in the conversion.
I wrote it up here, might look for the link
KF
I did think about using light springs to use the inlets as poppet valves, but not easy to find ones to try.
Even allowing for waste, it would knock out 50 cu ft min at 2,000rpm with the valve mods, probably much more if goosed a bit.
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ROFL that's my luck mate lol!
The idea only sort of formed after I'd seen what power that engine had at home
I'm sure I can arrange another visit - I need to get that drive from you at any rate
Gives you an excuse to buy something from down here as well...
mr migwire
It's more fun with metal.
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a toughbook for the work shop perhaps...
Johnseat
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@KemppiFrog could you please put a link in this thread.
KemppiFrog
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Just had a dig...http://www.mig-welding.co.uk/forum/threads/diy-blasting-compressor.39815/
Crips...three years ago.. Must get on and finish it off
Been lots to do elswhere..
Crips...three years ago.. Must get on and finish it off
Been lots to do elswhere..
chunkolini
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Vaguely related to the original post.
Q; could you use the crank case pressure from either a parallel or boxer twin motor as a kind of pulsed turbocharger?
Ok I know a boxer is effectively a parallel twin. Loads of work and pressure going to waste in my book. or rather my tiny mind. The world is probably lucky that I am not an engineer. This has been stewing for donkeys years.
Q; could you use the crank case pressure from either a parallel or boxer twin motor as a kind of pulsed turbocharger?
Ok I know a boxer is effectively a parallel twin. Loads of work and pressure going to waste in my book. or rather my tiny mind. The world is probably lucky that I am not an engineer. This has been stewing for donkeys years.
