Author Topic: Two Cylinder Engine  (Read 69487 times)

Offline Roger B

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Re: Two Cylinder Engine
« Reply #285 on: January 21, 2021, 05:39:08 PM »
Hi Alex, the most it has run is 10 hrs. I suspect it is more like 5 or 6. The last load trial series was maybe 1/2 hour total.

I checked the crankshaft against the drawing and by a build up of tolerances the outer webs were too thick so I skimmed them back to the correct overall length. Both con rods fitted and turned freely but are a little tighter than on the 180° crankshaft. Next step was to change the camshaft which fitted without problems. The 180° one showed no signs of distress. Now I have to finish rebuilding the engine.
Best regards

Roger

Online Vixen

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Re: Two Cylinder Engine
« Reply #286 on: January 21, 2021, 07:04:05 PM »
Still watching and enjoying what I see. :ThumbsUp: :ThumbsUp: :ThumbsUp:

Mike
It is the journey that matters, not the destination

Sometimes, it can be a long and winding road

Offline Roger B

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Re: Two Cylinder Engine
« Reply #287 on: January 23, 2021, 04:09:16 PM »
Thank you Mike  :)

The block and head were refitted as a unit and everything still seems to go round, although it is a little tighter than before. I got confused on the new ignition cam and drilled the rotor fixing hole 90° out of position  :facepalm: It was easier to re-drill and tap the rotor. I continued refitting the fuel pump and then mounted it back on the base ready for a trial. It started up and ran with the same carb settings as before. The fuel pump output needs reducing as the chamber is tending to flood and I need t  check the valve timings and set the ignition timing (it was just done by eye  ::) )

<a href="https://www.youtube.com/watch?v=IPNMn-ufsRk" target="_blank">http://www.youtube.com/watch?v=IPNMn-ufsRk</a>

Best regards

Roger

Offline Roger B

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Re: Two Cylinder Engine
« Reply #288 on: January 26, 2021, 05:45:26 PM »
The cam timing was correct as I hoped having cut the lobes in relation to the keyway. The ignition timing was also close to 20° BTDC so it makes sense that the engine ran well. It needs it a bit more bedding in and then I can run some quantifiable trials.

As I have reached this point I now need to see about fitting fuel injection for the third phase. There is generally enough space but I will need to modify the back of the timing case to be able to mount the pump on the base of the cylinder block.
Best regards

Roger

Offline Roger B

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Re: Two Cylinder Engine
« Reply #289 on: January 31, 2021, 03:38:49 PM »
I took the engine off to the welding bay for some load tests. Overall I think that it is similar or maybe slightly more powerful than before but there wer two problems:

1) My aging analogue meter seems to have problems and is not reading correctly. As the full load bank is 1 ohm current should equal voltage which it didn't (and I realise that it didn't in the last test with the 180° crank). I borrowed another meter from the workshop and got the expected result  ::) For the last trials I will have to recalculate just using the voltage value.

2) The vibration from the 360° version is causing frothing in the fuel reservoir so fuel is spraying out of the vent and the carb is being starved. If I can get to a non resonant rpm it runs quite well but at critical points it is surging and spraying fuel over the exhaust (yes I know where the fire extinguisher is). A bigger fuel reservoir and possibly a flexible mounting may help  :headscratch:

As I have a set of 180° parts maybe I should make another engine to go around them  ;D

<a href="https://www.youtube.com/watch?v=KaZ4AVgVmps" target="_blank">http://www.youtube.com/watch?v=KaZ4AVgVmps</a>


Best regards

Roger

Offline Admiral_dk

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Re: Two Cylinder Engine
« Reply #290 on: January 31, 2021, 07:45:32 PM »
When I have obviously wrong measurements, I usually end up discovering why - it's a lot worse when you believe the results and much later discover that your wires / probes are faulty and wonder how many wrong values you have used / recorded before you notice.

A common wire to the meter that is starting to deteriorate, might still give the right voltage when used to measure voltage. The same wire will have an increased value when you measure for continuity and be way off the scales when used to measure Ampere ....  :rant:   :zap:   :cussing:

And it's not much better with Scope Probes not up to specs any more  :Mad:

So the fact that you got a problem, means that you can measure the equipment to figure the reason - yes it's annoying that today's results are more or less useless - but at least you know not to trust them for future reference ....

I notice that you use Fluke Meters - are they the True RMS versions ?  If so, it might be interesting to measure AC as well - just to see if there is a lot of fast variation in the DC values you get.
Since you do this at work - any change off 'borrowing'  a good deep memory Scope, with high a quality Voltage and Current Probes ?  If so, try to use the Math Function, as this should give you Voltage, Current and Power. You obviously still need to be sure the measurements represent the true values.

I hope I am giving you useful ideas and doesn't sound like I'm telling you something you know much more about than me ....

Best wishes

Per

Offline Roger B

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Re: Two Cylinder Engine
« Reply #291 on: February 01, 2021, 02:26:19 PM »
Hi Per,

The problem appears to be quite basic, mechanical failure of the movment of my ~40year old analogue meter. I have been using this as it has a 15A range wheras my other meters only go to 10A. A quick check showed that the zero setting is not consistent, sometimes it will return to ~1A sometimes it will be offscale -ve so sometimes it will under read and sometimes over read.

With this engine and generator set up I am only reaching around 9A so no problem. The horizontal engine gets up to around 12V at 12A so I will need another meter for this.
Best regards

Roger

Offline AlexS

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Re: Two Cylinder Engine
« Reply #292 on: February 01, 2021, 08:29:39 PM »
Hi Roger,

Maybe this could help you out for quick measurement of volt, current and power?

https://nl.aliexpress.com/item/4000206861390.html?spm=a2g0o.productlist.0.0.42bf38ceOkYZ5Q&algo_pvid=105b1b23-c4b3-4559-b265-9b396e85663a&algo_expid=105b1b23-c4b3-4559-b265-9b396e85663a-0&btsid=2100bde316122106286337560e53d8&ws_ab_test=searchweb0_0,searchweb201602_,searchweb201603_

I think it does not have the accuracy level and quality of Fluxe meters. But maybe I tell old things and have you already consider of this meter.

And for the vibrations of the 360 deg, how is the engine running on lower rpm's? Good progress! ( for my self I started on working on a ac -> dc dyno)

Offline Roger B

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Re: Two Cylinder Engine
« Reply #293 on: February 02, 2021, 07:08:53 PM »
Hi Alex,

Measurement systems are not a problem if I look at my work resources, I just have to look deeper if I need more that 10A DC ( AC clamp meters take me to a few thousand amps). For the 180° series I just didn't see the obvious problem at the time, I was concentrated on how the engine was running.

As expected the 360° version is not so well balanced as the 180° version. This is a short clip of it wandering around the bench at lower speed. I am not sure how to reduce the vibration in the fuel reservoir  :headscratch: The next step is fuel injection which won't be affected.

<a href="https://www.youtube.com/watch?v=SLvOzfd8gpY" target="_blank">http://www.youtube.com/watch?v=SLvOzfd8gpY</a>
Best regards

Roger

Offline Admiral_dk

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Re: Two Cylinder Engine
« Reply #294 on: February 02, 2021, 07:51:51 PM »
Place the fuel tank at some distance (or in that nice heavy Vice) and run a thin rubber hose (made for the right fuel) to the engine.

On a full size engine you usually use a balance axle nowadays .... and rubber mounting of the engine is nothing new either (just look inside the engine bay of your car).

Offline Roger B

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Re: Two Cylinder Engine
« Reply #295 on: February 03, 2021, 07:18:11 PM »
Hi Per,

This engine is intended to be used in a model tractor so it has to survive on it's own. The 180° crank version with the CD carb worked and maybe a fuel injected 360° crank version will be better  :headscratch: A few more months work may tell  ::)
Best regards

Roger

Offline Admiral_dk

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Re: Two Cylinder Engine
« Reply #296 on: February 04, 2021, 11:08:20 AM »
OK - how about rubber suspension of the tank then - normal on motorcycles (though that is normally not because of fuel, but comfort and longevity).

I don't know about two cylinder European tractors, but the John Deere of Old had a 180 degree crank ....

Offline Roger B

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Re: Two Cylinder Engine
« Reply #297 on: February 23, 2021, 07:43:37 PM »
Due to the vibration problems with the 360° crankshaft and the CD carb I have started on the fuel injection system. The pump module and the injector will be based on the diesel ones. The pump will be mounted above the timing case and will be driven with an excentric from the crankshaft to give an injection per revolution. The pump will be fixed using the fixings for the timing case backplate.

A bit of milling has produced the support bracket and then I will go back to lathe mode to produce the pump element and the body.
Best regards

Roger

Offline Roger B

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Re: Two Cylinder Engine
« Reply #298 on: February 27, 2021, 07:36:07 AM »
The bulk of the adjustment slots was removed with a 2.5mm drill ready to be cleaned up later with a 3mm end mill. The M3 fixings to join the body to the bracket were drilled and tapped and then the body was set up in the 4 jaw independent chuck to bore out for the pump element.
Best regards

Roger

Offline Roger B

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Re: Two Cylinder Engine
« Reply #299 on: March 03, 2021, 07:56:24 PM »
The bore for the pump element was started with a 7.5mm drill and finished with an 8mm end mill. The clearance for the spring was then opened out with a 10mm end mill. This showed a problem  ::) I hadn't moved the fixing holes over when I moved the pump centre over so it broke through into the fixing holes  :facepalm: As this would still work I opted to continue. I will have to remake the bracket and the pump body, but maybe I will need to do that anyway later due to some other unknown problem. Finally the delivery valve end was reamed out to 6mm and a lead in for the pump element O rings was cut using a large centre drill.

The pump element is made from 8mm silver steel as for the diesel. The spring end and the O ring groves were machined and the blank was parted off. The bore was then drilled 1.85 mm and reamed 1.95mm. Finally the delivery valve seat was cut with a 4mm end mill and the thread for the delivery valve was cut M5 x 0.5.
Best regards

Roger

 

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