Author Topic: 45CC Wall Wizard  (Read 8766 times)

Offline Jo

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Re: 45CC Wall Wizard
« Reply #30 on: June 22, 2018, 06:27:36 PM »
The ones on the first pic. look to be aluminium and the earlier cast iron. Or just an artefact of the image ???

Dunno about you, too damned hot here. Well, shove a couple of cans down my neck and doze off in front of the telly

Both are aluminium fins on a cast Iron liner  ;)

That's the advantage of owning your own property/living on your own you don't have your partner/parents telling you off for enjoying a couple of  :wine1: on a Friday evening relaxing after a stressful week at work  :embarassed:

Jo
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Offline Bluechip

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Re: 45CC Wall Wizard
« Reply #31 on: June 22, 2018, 06:33:38 PM »
OR

Friday evening relaxing after a stressless week not at work  in my case ...  :Lol:

Dave

Offline Roger B

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Re: 45CC Wall Wizard
« Reply #32 on: June 23, 2018, 08:11:24 PM »
Wall did a few interesting designs, I look forward to seeing how this one runs  :)  :wine1: Perfect throttle response  ::) ?
Best regards

Roger

Offline Jasonb

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Re: 45CC Wall Wizard
« Reply #33 on: June 24, 2018, 07:04:34 AM »
Did they need much throttle response? Back in the 30s I would not think the means to control them was the same as a modern RC radio and may have just been intended for a tether boat where you just set the throttle and that's it.

Offline Jo

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Re: 45CC Wall Wizard
« Reply #34 on: June 24, 2018, 08:03:41 AM »
Thanks Roger  :)

Perfect throttle response  ::) ?

Back in the early days most model engines were for aircraft and they were either running on full throttle screaming away or not running. So any design that enabled you to have speed control must have been something worth making a fuss about. Being able to have a boat chugging along with a nice four stroke sound must have been something special  :wine1:

Jo
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Offline Gas_mantle

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Re: 45CC Wall Wizard
« Reply #35 on: June 24, 2018, 12:52:42 PM »
I rather like the look of the engine, it strikes me as an odd design if it was meant as a boat engine though. Wouldn't it make more sense to have a tall thin engine in the confines of a hull rather than a low and wide engine ? I guess it will have a low centre of gravity and maybe improve stability though  :headscratch:

Anyway, I'm off to steam up my wobbler on the hot stuff in the Yorkshire sun   :pinkelephant:

Offline Jo

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Re: 45CC Wall Wizard
« Reply #36 on: June 26, 2018, 01:19:22 PM »
I have turned up the cylinder and the fins and fitted to two together only to be told off for making the fins a heat fit on the cylinder  :slap: I have been told this can distort the bore and that it should only be a sliding fit ::)

As I was planning on Smelly's help to hone the bore I had assumed he would true up any discrepancies  :noidea:

Jo
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Offline Dave Otto

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Re: 45CC Wall Wizard
« Reply #37 on: June 26, 2018, 01:40:50 PM »
Seems that if you hone the cylinders after installing the fins, it wouldn't matter. Do they think the cylinder is going to continue to shrink?

You are making good progress.


Dave

Offline Jasonb

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Re: 45CC Wall Wizard
« Reply #38 on: June 26, 2018, 01:53:07 PM »
I suppose if the engine gets hot while running(I'm making an assumption here) the aluminium will become looser and may allow the part of the cylinder that was compressed during honing to expand and you would loose compression right where you need it at the top of the stroke.

Can you not heat them back up and slip the fins off to skim them to the correct fit?

J

Offline Dave Otto

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Re: 45CC Wall Wizard
« Reply #39 on: June 26, 2018, 02:02:14 PM »
There are an awful lot of full sized engines out there running with iron sleeves pressed into aluminum, I'm having a hard time believing that it is going to be a problem.

Dave

Offline Ramon

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Re: 45CC Wall Wizard
« Reply #40 on: June 26, 2018, 02:08:58 PM »
Hi Jo, you may recall that this was exactly the scenario that lead me to lapping/honing when this very situation occurred on the cylinders for the Bentley.

If the liner is longer than the fins and is finished before shrinking the fins on then unless the liner is very thick walled distortion is more than likely to occur. When I did the Eta Elite Mk 2 which required shrunk on fins I machined the liner bore after doing so to alleviate this problem. Honing may not be the initial solution but a lap certainly will, followed by honing for a good finish

May be worth running through the first couple of posts on here again ?
http://www.modelenginemaker.com/index.php/topic,1908.0.html

Tug

Just seen your reply Dave - as you can see this did happen to parts made before but I grant you the liners were thin - just 1mm thick if I remember. I have a feeling but may be completely wrong as have no experience of it that possibly full size the bores would be machined after the shrinking - as per the Eta perhaps?
« Last Edit: June 26, 2018, 02:12:02 PM by Ramon »
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Offline Bluechip

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Re: 45CC Wall Wizard
« Reply #41 on: June 26, 2018, 02:24:20 PM »

Just seen your reply Dave - as you can see this did happen to parts made before but I grant you the liners were thin - just 1mm thick if I remember. I have a feeling but may be completely wrong as have no experience of it that possibly full size the bores would be machined after the shrinking - as per the Eta perhaps?


Vincent bores were 84mm with a shrink fit of 5-6 thou. IIRC. They were then honed to very near size. Then left overnight for all the ( inherent stresses ? ) to subside. Then honed to size.

I have recently seen this referred to somewhere. I'll see if I can find which brain cell has the link ...  :noidea:

Dave

Gorrit .....

http://sumpmagazine.com/classicbikespecialists/vincent-spares-repairs-maughan.htm

Wind down to the bit about cylinders etc.
« Last Edit: June 26, 2018, 02:28:12 PM by Bluechip »

Offline Jo

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Re: 45CC Wall Wizard
« Reply #42 on: June 26, 2018, 03:58:51 PM »
Thanks for looking in guys  :)

Smelly was doing a good job at lunch time sadly some of us still have to work for a living  :facepalm: I hope to get back on to it this evening when it cools down out there.

Jo
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Offline john mills

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Re: 45CC Wall Wizard
« Reply #43 on: June 26, 2018, 04:11:40 PM »
As an apprentice i had to fit cast sleeves to alloy blocks small single cylinder originally running in an alloy bore.
The block bored with not as much as .005" interferance a .020 "step at the bottom 3/8" long.The step turned on the sleeve .The block was heated so the sleeve would drop in to the step.left to cool .then just bored and honed as normal.the cylinder borer left a good finish so only .0005"for honing and it was difficult to hone much more.
I never saw any that i did come back .
STD A SIZE SLEEVE FOR 1/16"WALL THICKNESS  these engines were about 3" bore.
« Last Edit: June 26, 2018, 11:15:33 PM by john mills »

Offline Ramon

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Re: 45CC Wall Wizard
« Reply #44 on: June 26, 2018, 04:23:16 PM »
There you go then - bored then honed after shrinking - confirms my thoughts John  :ThumbsUp:

I have no full size knowledge or experience but do have a fair bit on small I/C engines - I can only speak as I found I guess. Doesn't take much for piston to be tight (or loose) in a bore in those sizes.

Thanks John - Tug
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