Author Topic: Two Cylinder Engine  (Read 26982 times)

Online MJM460

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Re: Two Cylinder Engine
« Reply #210 on: September 23, 2019, 10:07:40 PM »
Hi Roger, an excellent result to have it running so smoothly.

You must be all smiles after all the hard work.

MJM460

The more I learn, the more I find that I still have to learn!

Offline Admiral_dk

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Re: Two Cylinder Engine
« Reply #211 on: September 23, 2019, 10:39:45 PM »
Yeah it is a runner - easy starting and it sounds very even too - what more can you ask for  :ThumbsUp:  :cheers:

Offline Kim

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Re: Two Cylinder Engine
« Reply #212 on: September 24, 2019, 05:00:05 PM »
Runs great Roger!  And it started quite well, too!
Kim

Offline Art K

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Re: Two Cylinder Engine
« Reply #213 on: September 25, 2019, 03:03:29 AM »
Roger,
That's great, it started right up. I suppose next up is a cooling system. :ThumbsUp:
Art
"The beautiful thing about learning is that no one can take it away from you" B.B. King

Offline Roger B

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Re: Two Cylinder Engine
« Reply #214 on: September 26, 2019, 09:57:26 AM »
Thank you for all the support  :ThumbsUp:  :ThumbsUp:

I have given it a few more short runs and took a couple of rpm measurements. The idle is around 2000 rpm (this was just how the carb was set from it's previous duty as a throttle for my fuel injection trials) and the top end is around 9000 rpm.

As Art says the next step is to set up the cooling system. I need to make a couple more flanges and fit the seals in the water pump (once they are in the engine has to run wet or they will burn out). I have a rather large computer cooling radiator to try although I might make a dedicated one for this engine.

I will strip it down at the same time to remove the gunge from the initial runs, cast iron liners and rings are messy at the start, and put some Hymolar on the critical parts.
Best regards

Roger

Offline Roger B

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Re: Two Cylinder Engine
« Reply #215 on: October 04, 2019, 05:22:15 PM »
So I made up the required flanges and then started stripping the engine down for inspection and cleaning. A couple of the rockers were somewhat stiff and there is still not enough clearance in the distributor.
Best regards

Roger

Offline Roger B

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Re: Two Cylinder Engine
« Reply #216 on: October 04, 2019, 05:28:47 PM »
Removing the head everything looks ok. The exhaust valves have been warmed up. Plenty of gunk in the bores from the cast iron. The water pump looked alright so I pressed the seals in place. The camshaft and followers were also ok but as I got deeper in the gunk levels increased. There were some unexpected water droplets in the big ends and crankcase and I found I had forgotten to drill the lubrication holes in the bottom of the big ends  ::)
Overall not too bad. Clean it all up and reassemble.
Best regards

Roger

Offline Zephyrin

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Re: Two Cylinder Engine
« Reply #217 on: October 05, 2019, 08:05:00 AM »
very nice pictures on the innards of your engine, highly informative.

Online Brian Rupnow

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Re: Two Cylinder Engine
« Reply #218 on: October 05, 2019, 01:44:53 PM »
Great results. I'm glad it started right off, because if they don't there is always a bit of heartache trying to figure out whey they didn't. I see from your pictures that it doesn't appear that you used a ring spacer before heat treat.  Is there a name for that method of making  your rings?---Brian
« Last Edit: October 05, 2019, 02:18:38 PM by Brian Rupnow »

Offline Roger B

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Re: Two Cylinder Engine
« Reply #219 on: October 06, 2019, 07:42:44 AM »
Thank you both  :ThumbsUp:  :ThumbsUp:

Brian, I'm not quite sure where my ring making method comes from. The final skimming to size comes from Tubal Cain's 'Model Engineers Handbook' but I think that it is originally from Professor Chaddock. Setting the gap by the diameter of the mandrel of the heat treating fixture may also have been copied or it may have been the easiest way to keep 0.8mm square rings under control  :headscratch: I have added a picture of the rings for a different (16mm bore) engine on the mandrel showing how the gap is formed.

On with rebuilding the engine. I drilled the missing holes in the big end bearing caps although I'm not sure if they are really a benefit. The slots that the rockers fit in were opened out slightly with a fine file to stop the binding. I machined another 0.3mm off the end of the rotor arm before I realised that it was being stopped by the end of the shaft  :facepalm: Deepen the bore by 0.5mm instead. The timing was set before I put the cylinder head back on and then with it all assembled I started looking at the water cooling piping. The pipe between the water pump and the block tended to collapse when I used the clear plastic pipe so a piece of braided neoprene was used instead. The radiator (computer cooler) looks rather large. I will have to find something smaller.
Best regards

Roger

Online Brian Rupnow

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Re: Two Cylinder Engine
« Reply #220 on: October 06, 2019, 01:36:06 PM »
Thank you Roger. I will try and find out more about the Chaddock method of ring making.---Brian

Offline Admiral_dk

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Re: Two Cylinder Engine
« Reply #221 on: October 06, 2019, 08:17:27 PM »
Nice to see continued progress Roger  :ThumbsUp:
I hope that you don't end up with more water in the crankcase after the next runs - though I'm not even sure that you had the cooling system connected last time  :noidea:

I'm sure that the current cooler is a lot bigger than needed - unless you increase the power output and load quite a bit.

Some engines do not like to work under a certain temperature and others are the other way around  :headscratch:  All (I only had 3) Moto-X bikes of my youth, were converted road mopeds and all of them had their max power output exactly when they where started from cold. As they were bump-started, I really could feel the power and acceleration when they fired - and power slowly decreased as the temperature rose. I do not know for sure, if this is the explanation, but my racers and the first road going bikes I had where all two-stroke, air-cooled, and they all shared the max power at cold (maybe the MZ150 where an exception - not much pull anywhere) and all my later four-stroke worked best when heated to at least 60 degree C .... but here the air-cooled lost some above 120 degree C (and the liquid cooled do not go up there).
« Last Edit: October 06, 2019, 08:24:15 PM by Admiral_dk »

Offline Art K

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Re: Two Cylinder Engine
« Reply #222 on: October 07, 2019, 12:47:45 AM »
Roger,
It is good to see progress, even if it's a step back then two forward the R&D department is open for business. It ran very well so I have no doubts about it doing the same soon.
Art
"The beautiful thing about learning is that no one can take it away from you" B.B. King

Offline Roger B

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Re: Two Cylinder Engine
« Reply #223 on: October 07, 2019, 12:36:15 PM »
Thank you  :) :)

Per, As it had no cooling system I only ran the engine for short intervals. I think that this may have resulted in condensation in the crankcase without enough heat to evaporate it away.

I will probably move that cooler over to the horizontal engine ready for some load tests with variants of the petrol injection system.
Best regards

Roger

Offline Admiral_dk

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Re: Two Cylinder Engine
« Reply #224 on: October 07, 2019, 06:23:27 PM »
Condensation sounds like a likely explanation. So it is a question about how long you can run it then - neighbors etc.