Old diesels

[PatMc]

I did something similar to Tim as part of an article that appeared in the now defunct AMI magazine. I'd acquired couple of mangled ED 2cc diesels that I wanted to be able to use in vintage models & happened to have a carb from a worn out Enya 09 III. 

 

  

 

I think the one on the right is a Comp Spl & the other is a "Penny Slot" with a replacement home made head.

 

 

This shows my version of a radial mount to replace the damaged originals.

 

 

 

Going from memory the extension is a scrap of brass tube soldered to the existing inlet spigot with the carb epoxied in place very similar to Tim's arrangement. The Enya carb worked very well without any need to reduce the bore.

 

I used a slightly enlarged APS Frankenstein as test bed for both of these engines (& a few others). The carb was more effective than I'd expected.

 

 

[Mike T]

Hmmm.  Food for thought. What's it going to go in though?  I've got laser-cut ribs for an Outlaw, but I also fancy a cheeky Bugaboo...

[GaryW]

I've just joined the Diesel Clan for the 2nd time in my life with my PAW 19 RC powered Ben Buckle Scorpion 

& very much looking forward to the smell of diesel in the air again

[Mike T]

Ha! 😁  Looking good, Gary!  Fingers crossed for the weekend weather and the re-maiden!

 

Meanwhile, in other news, having drawn a blank on ebay and the BMFA for small glow engines, I rummaged through my own stash and found a near new ASP12.  The bore of its carb is just under 1/4" and the carb spigot on the ED Comp special is 1/4" BSF, so I've ordered some taps from Chronos.  The good thing is that this will have no impact on the Comp and if it doesn't work well enough, the carb can go back on the ASP (albeit with a few threads in the bore!)

 

 

It's a bit of overkill, but it's what I've got 🙂

Edited July 27, 2023 by Mike T
PS

[brokenenglish]

Normally, I think your Comp Special should have sub-piston induction.

[Engine Doctor]

Some ED mk2's certainly had sub piston induction (SPI) . I believe all the Comp Specials ,easily identified by thier scalloped engine bearershad SPI. Many of these early engines differed slightly as experiments were made dyring production run so it might not have SPI not noticable in your pic. A carb  might not slow it effectively if it has SPI  . Any "O" rings in the carb will swell  up and eventually disintegrate as they dont like diesel fue or petrol. If the carb works then you will need to replace any rings with Nitrile " O" rings.

Le5 us know how it runs. The nice thing about those mk 2s and Comp specials was that they would start with a hard stare if they catch just  a whiff of diesel !

I see your engine has a prefix "M" on the number . Possibly converted from a marine unit ?

Edited July 28, 2023 by Engine Doctor

[MikeQ]

Hi

 

just saw this thread.  Tom Oliver, a well known local model engineer around my parts, knocked up a couple of RC carbs for me.  For an Irvine Mills 75.  As you might expect with small diesels they dont give the same smooth response of a 60 glow but good enough for a bit of guided free flight.  Putting one in a ‘much updated’ Mercury Tiger Moth that I’m in the middle of knocking out.  I’m sure TomO has some kind of tie in with SteveWebb models, for making such bits and bobs, although its pre pandemic last tome I talked to him.  Really interesting guy!  Motor sound over compressed in video but just the recording.

 

 

 

 

love messing with diesels.  Have the scars to prove it.  Was once asked by a co-worker if the little slash scars up my wrist were self harm injuries.  Nope, just sticking your hand through a running propeller to adjust the comp ... dooaahhhh.

 

 

 

 

Edited July 28, 2023 by MikeQ

[brokenenglish]

5 hours ago, Engine Doctor said:

Some ED mk2's certainly had sub piston induction (SPI) . I believe all the Comp Specials ,easily identified by thier scalloped engine bearershad SPI. Many of these early engines differed slightly as experiments were made dyring production run so it might not have SPI not noticable in your pic. A carb  might not slow it effectively if it has SPI  . Any "O" rings in the carb will swell  up and eventually disintegrate as they dont like diesel fue or petrol. If the carb works then you will need to replace any rings with Nitrile " O" rings.

Le5 us know how it runs. The nice thing about those mk 2s and Comp specials was that they would start with a hard stare if they catch just  a whiff of diesel !

I see your engine has a prefix "M" on the number . Possibly converted from a marine unit ?

ED, just a bit of info.
Not all Comp Specials have scalloped lugs. It was done to differentiate in relation to the Penny Slot (the Mk II). When ED stopped making the Penny Slot, they stopped scalloping Comp Special lugs, so "later" Comp Specials have normal straight lugs, probably around 50% of total production.
The serial number on the OP engine is a normal Comp Special serial number (Dec. '47). So it's very early production (looks like the 64th Comp Special made).
Finally, I tried an RC carb on a Comp Special, around 40 years ago and IIRC, it wasn't very successful. 

Edited July 28, 2023 by brokenenglish

[Mike T]

Mine has SPI, so expectations have been lowered accordingly.  I've no idea if it was originally a marinised version either.  When I bought it, it had no spinner nut or washer, nor tank and the comp screw was 'lent' to another engine. The one on it now I got from PAW.  If I put it in an airframe, then all period features will be restored.

Can anyone confirm if the crank thread is 2BA?

[brokenenglish]

There's no reason to think that it might have been "marine", the M prefix on the serial number is just the production month (December).

Mike, this photo shows the way your engine should be. It's the first production configuration.

[Mike T]

I think the M actually means November (both I and L being omitted from the series, leaving M as the 11th number).  On this basis I think mine is the 64th engine made in Nov 1947 (it could be 57, I suppose - the article explaining the numbering doesn't address how successive decades were recorded...).  As you can see from my pics, mine also has the (very effective) fuel cut-off.  Some savage* has previously butchered the alloy fuel pick-up and tank mount in order to plumb a 'normal' tank.

 

 

 

*me

[brokenenglish]

Yes, you're right about the serial number. I forgot about the "L" and I'd run out of fingers.
The S/N couldn't be '57. By 1957 the serial numbers were on the side of the case and I think the lugs were no longer scalloped. I'm not sure of the exact year they stopped scalloping the lugs, but it was before 1957.

[Mike T]

Just a footnote:  The carb conversion went fine - run taper and 2nd 1/4 BSF taps down the carb spigot and job done:

 

No pics of it running, sorry, but as predicted it ran as normal at full throttle.  Lowering the throttle knocked a few '00 rpm off and that was it.  Sub-piston induction (over)rules OK!

 

Oh well!  Whatever I build will end up 2-channel...

Edited August 24, 2023 by Mike T
only way to add text after an uploaded picture :(