Author Topic: Two little CHUK's  (Read 4048 times)

Offline b.lindsey

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Re: Two little CHUK's
« Reply #30 on: September 01, 2019, 03:43:39 PM »
With some, there is a tendency for moisture to condense on the inside of a cold cylinder which adds drag. Getting the cylinder up to  some lower starting temp negates that. That is my explanation but they do have very close tolerances .

Bill

Online Jasonb

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Re: Two little CHUK's
« Reply #31 on: September 01, 2019, 04:14:54 PM »
I don't think the piston comes out of the cylinder on the Alyn version, does not on my smaller one so would it be possible to leave the ring of the bearing support the 40mm and bore out the cylinder allowing the bracket to overhang?

You would have to assemble the piston and rod and put in the bore before fixing the bracket but can't see that being an issue
« Last Edit: September 01, 2019, 04:21:21 PM by Jasonb »

Online Jo

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Re: Two little CHUK's
« Reply #32 on: September 01, 2019, 04:44:14 PM »
The piston TDC is 6.5mm below the top surface of the cylinder.

Jo
Enjoyment is more important than achievement.

Online Jasonb

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Re: Two little CHUK's
« Reply #33 on: September 01, 2019, 05:06:52 PM »
Could be a goer then unless Graham knows something we don't.

What do the drawing show the bracket being fixed to the cylinder with, I can't see any fixings on Grahams original maybe just the magic coating was enough? Does have a special bolt hole pattern for the base to cylinder joint though :o

Offline Alyn Foundry

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Re: Two little CHUK's
« Reply #34 on: September 01, 2019, 07:03:26 PM »
The bearing yoke was a slight heat and press fit onto the cylinder.

I'll leave it to you regarding bore size but being able to remove the piston from the cylinder easily, does have its merits.

A cold start!

 

Cheers Graham.

Online Jasonb

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Re: Two little CHUK's
« Reply #35 on: September 01, 2019, 07:06:26 PM »
Can't ask for it to start much better than that.

Do you think that placing the exhaust holes radially around the opposite side to the inlet would have any benefit as regards to it not disturbing the flame?

Offline Alyn Foundry

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Re: Two little CHUK's
« Reply #36 on: September 01, 2019, 07:18:13 PM »
Can't ask for it to start much better than that.

Do you think that placing the exhaust holes radially around the opposite side to the inlet would have any benefit as regards to it not disturbing the flame?

I'm not sure what you're referring to Jason?

As you're aware the exhaust is through the diaphragm at the bottom, in this case. Are you referring to the string of small holes that can be seen?

If so that was an idea for gas firing that didn't work.

Cheers Graham.

Online Jasonb

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Re: Two little CHUK's
« Reply #37 on: September 01, 2019, 07:26:36 PM »
Ah, I thought that once the exhaust has passes the valve you may have had it coming out there rather than the big hole in the base. None of the photos of yours that I have show whether they are through or blind holes.

I can now see why there is a hole at the side which I assume was where the gas went in and the holes acted as a row of burners

Online Jo

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Re: Two little CHUK's
« Reply #38 on: September 01, 2019, 08:17:21 PM »
Runs nicely Graham but what do I need to do to get my engine to go "Quack"  :)

I noticed that your inlet shutter goes below the port rather than above does that make any difference  :noidea:

Jo
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Offline Alyn Foundry

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Re: Two little CHUK's
« Reply #39 on: September 01, 2019, 08:26:31 PM »
Runs nicely Graham but what do I need to do to get my engine to go "Quack"  :)

I noticed that your inlet shutter goes below the port rather than above does that make any difference  :noidea:

Jo

Ah.... That'll be the " Peeking Duck " I guess.... :)

It's down to the diaphragm Jo, a thin metal one rings. I recently changed mine for a cast Iron one.

Regarding the shutter I discovered that opening that way disturbs the flame much less as any exhaust left in the cylinder goes up rather than down.

Cheers Graham.

Offline Alyn Foundry

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Re: Two little CHUK's
« Reply #40 on: September 03, 2019, 03:37:57 PM »
Hmmmmmm.

I must stop with the " corny " jokes, put the thread on hold!   ;)

The last pass at nearly 41 mm.

Very handy, if you have one!!

Had to fight for metal here to get the lip for the diaphragm. Now ready for the Delapena.

Cheers Graham.


Offline Alyn Foundry

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Re: Two little CHUK's
« Reply #41 on: September 03, 2019, 03:39:48 PM »
LOL

 :lolb:

Online Jo

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Re: Two little CHUK's
« Reply #42 on: September 03, 2019, 04:10:51 PM »
I decided I didn't like using that titchy little boring bar for such a long bore so as soon as I could upgraded to Big Bertha  :) For the last cuts I bored once at 39.5mm, then twice at 39.8mm, which even with a 30mm diameter boring bar after the final cut I found the bore had creeped up to 39.92mm - it is now ready for honing. Sadly unlike Graham I don't have all the parts for my Delepena hone at that bore  :wallbang: so I will be honing another way  :-\ While the cylinder was still supported by the fixed steady I faced to top to the correct height.

Two suitable washers were made to fit one of my 25mm arbors and the cylinder was set up for turning the outside of the fins, the outside at the top of the cylinder and the lip for the diaphragm. I chose to give the cylinder two lips one fits the base casting and the other is the correct height for the diaphragm lip but importantly I have increased the diameter of that lip to 45mm to take account the larger diameter cylinder bore. (The base casting has had its pocket made slightly deeper to allow for this  ::)

Time to take it in to the inspection department to see what Surus thinks of it  :pinkelephant:

Jo
Enjoyment is more important than achievement.

Offline Alyn Foundry

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Re: Two little CHUK's
« Reply #43 on: September 03, 2019, 07:18:19 PM »
Special jobs....

Call for special tools....

Last used, quite probably, to do the last CHUK 2!! 20 years ago.

It's coming together nicely now.

Cheers Graham.

Online Jo

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Re: Two little CHUK's
« Reply #44 on: September 03, 2019, 08:06:07 PM »
Graham, I can tell someone has done this before  :thinking:

Jo
Enjoyment is more important than achievement.