Home Construction of Model Diesels

I’ve started this new thread at the suggestion of Ed Holly of Australia, who would like to have the opportunity to discuss the home construction of model diesels with other like-minded individuals. Let’s hear from those of you who are still game to have a go at making your own engines!  [user-submitted-posts]

112 thoughts on “Home Construction of Model Diesels

  1. Ed Holly writes:

    As we all know, Ron Chernich did some wonderful things for the model engine enthusiast, and his website remains a beacon for all of us interested in model engines. What Adrian is doing on this website is terrific, and I think will become the best way that like-minded guys interested in the design of model engines might stay in touch.

    Ron was part of a band of guys who had a unique part to play in the development, design and handling of these engines. Sadly, with Ron’s passing we now don’t get to hear from them. They were of course called the Motor Boys.

    I was very lucky to have known David Owen for a few years, and David encouraged and guided me through the early stage of engine building. If ever I got to know 5% of what David and the other Motor Boys know and knew I would be very happy, such is the esteem in which I hold them all.

    I wonder now if the fun of designing model diesels is being lost. Diesels are no longer in favour in modern aeromodelling – we are now firmly in the electric arrive by post this morning and fly this afternoon era. However, there is an immense amount of fun, enjoyment and satisfaction to be derived from turning some blocks of metal into a living, breathing entity, especially when it’s made to your own design. Of course another scourge of diesels is obtaining ether, but usually where there is a will there is a way.

    Through this blog, I would like to invite any other diesel model engine designers to put up their hands. I think the criteria should be to have designed and built at least one engine and seen it through to completion and running. Of course, comments from others who wish to have a go down the road will also be welcome.

    I have been lucky enough to find the time to build 15 diesels from .5 to 4cc – 5 of which are totally my design and 5 are modified designs of engines from the Motor Boys plans. These include 2 Vee twins and an inline twin.

    So if you fit this criteria, please add to this blog. It would be terrific to share some knowledge and ideas with some like-minded souls.

    Finally, my last design is written up at


    It takes the engine from an idea through to it running with good power and handling, being a 2.5cc single ball race diesel. With this design and write up I’m trying hard to inspire others to have a go … hope to hear from some of you!

    1. Hi Ed (and Adrian)
      Short post to let you know the string is pulled tight.
      Yep, I have designed a running diesel. Its called Sandfly and a photo (low res unfortunately) is on Rons MEN site.
      Have a look and see if I qualify!
      It ran well but was never easy to start without an electric starter. Once running it had far more power than a commercial AE 0.5cc. The extra 0.05cc did not explain the difference!
      Since then I have made a Mills P75 replica (not yet running reliably), three midges (all runners and one a flyaway on its maiden flight, a nearly finished nano, and am now halfway through a Parker V twin Vega…not a diesel.
      Want to do a Tug Wilson inspired Oliver Tiger Mk3 at twice capacity.
      Living north of Auckland and had the pleasure of calling in on Ron in late 2013.
      Doubly sad he has left us for all sorts of reasons, but also because he was hoping to draw up the Sandfly.
      I have sketches but am slow on CAD. Maybe a hybrid? Ink plus PC?

    2. Oh and one more! I knew I had forgotten an engine…this one being a Mills 1.3 replica with an R/C throttle. The engine was built following Ron’s excellent article and was a joy to make, and is a joy to start. It is awaiting a 54″ Southerner to be built for 3 channel.
      Also, one of my Midges powered a Tomboy at the recent NZ Nats Aggregate competition. Phew! That was hard work. Only achieved 5 minutes qualifying flight time in the half hour but managed 12 starts and 10 flights, despite the backplate coming loose during the uproar.
      Finally…for now…I have a cherished AHC 2cc diesel casting from my visit to Ron’s house. He insisted on sorting out a good example from his pile of castings, and sent the plans to follow. So lots to do.

  2. It all started with the Owen Mate, this is the first engine that I built, thanks to David, we will miss him .
    The second engine was no diesel but a petrol engine of 14 cc, inspired by the AlKo Super 14 , for this I made my own drawings in Inventor , this one I want to use on a KK Falcon.
    Right now I’m working on the Nova 1 and the Mills 1.3 , for both of them I have made my own castings .

    PS , Adrian keep up the good work , I am looking forward to your articles every month

    Regards Jef ,

    1. Hi Jef.

      Your building report of the NOVA is superb. I have the plan too,and like to build it also…As I live in Holland! 😀 I am sure,you saw some stuff on my youtube channel.
      I like to ask you,if you can sell me on or two castings or made a set for me. I like to try casting too,one day,but it will speed up the work a lot! The rest its for me possibel to make.
      I hope,you can help me out….Thumbs up for your nice Nova pics!!

      Dank je wel voor elke hulp! 😉

      Grts. peter

      1. Bedankt Peter .
        If you wish I can cast one or more crankcase and cilinderhead for you .
        Yes , I have seen you on youtube , nice work by the way .
        How do we make contact ?
        Groeten / Regards Jef

      2. Hello Peter!
        I saw all your video on you tube and i found them all beautiful .
        I have a question for you : where is the video you made long time ago where you showed a KMD that reached very high rpm ?
        I can not find it anymore on you tube , as well as beautiful it was very interesting for me because if I remember correctly you explained also the changes you made to the engine to make it run so fast.

    2. Attachment

      Hi Jef,

      Just thought you”d like to know that my friend John and I both finished engines to your 14cc JLE design – we built them at the same time, as we had when we previously did a Nova each some time ago.

      Both ran well on home made plugs but mine proved difficult to start – finally pinned down to having the tank too low. We were planning to have a joint running session at a local event last October but a bad weather warning put us off going – maybe this year.

      Hope your Nova ran as well as mine and Johns did – we were well pleased with our first effort at making an engine

      Regards – Tug

  3. Hello,
    I have been a model engine builder for a number of years.
    Some of my engines are shown in the gallery on Ron’s site.
    the diesels that I have made are as follows:
    Owen Mate from the Motor Boys book ( case is EDM )
    Mills 1.3
    Mills .75
    Mills .5 (a reduced scale Mills .75)
    Weaver from the Motor Boys book
    Mini Weaver scaled down to .5 cc

    I have made six engines of my own design that I call the “Davey” .06 (1cc)
    also made in .033 and .026 sizes
    These engines are front rotary valve type with three fluted bypass ports and three exhaust ports, much like the PAW style. Performance is equal to PAW equivalents.

    I am currently designing a side port engine that is a cross between a mills .75 and an MP jet (Letmo).
    The case is like a mills but the front housing screws into the case like the MP jet
    The bypass will be like the MP jet in that it is a hole drilled at an angle in the liner.
    A step in the piston will not therefore be required.

    I very much look forward to this blog and will contribute when appropriate.

    Dave Miner

  4. Hi to the oily folk,
    I have been building diesels for a few years to my own simple designs, much easier than reproducing a commercially made engine.
    My 1.8cc Bollaero is on the Modelenginenews site, along with the 1.4cc BJ Cicada, a joint effort with Rob Jenkins.
    I also made a 4.4cc diesel which was in AMI magazine with plans. I hope Adrian may be able to include some plans on his excellent site??
    Now testing a 7.5cc diesel. And a .49 cu in glow is in a Model Engineer series now.

    1. So this is already developing into quite a prolific line up. Good suggestion and worth seeing where it goes.
      Some thoughts that come to mind for possible outcomes:
      1. Kicking around ideas to improve and extend small engine technology. For example the traditional “push down” contra piston. I have used the Owen method and others as exponded by Ron C, with success. But as Bert Steigler observed in his Bulldog Mills, it all takes up a lot of room! And a push/pull mechanism might be advantageous at reducing hydraulic lock disasters. Then again there is the good fit vs o ring debate. Are we slaves to out-dated convention? Insert your area of innovation here eg Cox TD style carburettors, or using bonded construction eg built up crankshafts etc etc.
      2. Developing more high quality plans for buildable engines. Ron C was extremely modest about his efforts here but his plan sets for the MBs were excellent. I have some ambitions in this area, but hesitate as I am not sure about the appetite. Also its much better to do that sort of thing under group inputs, to keep it sharp and relevant.
      3. Which leads to the potential to form some kind of “son of Motor Boys” alliance. Any takers?
      4. In which case to what end? As far as I know there are several MBS still with us, but the freezing of MEN has rather taken their wisdom away from at least my own access. But one thing I did rather like the sound of was some sort of collaborative build project. Producing several widgets each for a limited production run of something special would appeal. It might, for example, be possible thtat someone out there has cracked the art of crankcase casting, and Imformone would love to have a go at a twice capacity classic diesel as Ramon Wilson has done.
      5. Lastly, for now!, Adrian’s site is a boon in the post-MEN world. I have yet to really explore thencontents but am working at it in fits and starts (life is busy!) but big ups from me for providing the site. I will now need to follow the links in blog replies above to see what you have all been up to in detail. There is a lot of common ground there. I suspect we could usefully swap ideas and how tos for a long time to come given a bit of simple structure to the conversation.

      I will put a sketch and photo package, and story, together about my Sandfly 0.5. If that proves to be of any interest perhaps CAD drawings and a second build to capture setup photos and some sort of article on construction. Then you guys can tell me how it could have been done better!

      regards all
      Dairy Flat, NZ

  5. …back again, having done some following up.

    Great work on Nova castings Jef. Have you needed any heat treatment?
    I have yet to summon the courage to cast my own. Maybe you could do a blow by blow blog class in casting?! Might just get me to have a go.


    1. Very nice concept Jef
      How do you solve the crankcase pressure issue? The Taifun Hurrikan boxer was also very lovely maybe,but the problem with that crankcase pressure stays.Poor performer because of that.
      Do you have made the two cankcases sealed from each other? otherwise there will be no carter pressure??
      I think about that many times. Also I saw russian MK 12 b boxers,but it seems in the foto,the cylinders were exact opposite to each other,no off set! Dont know how it was made or look internally …opposite or simultan firing??…and if it runs at all ! Alex Fin makes now also very lovely small boxers..I thing with clack valve intake on top of carter .Looks similar to your concept.
      Please share your ideas ! 🙂
      Any help welcome!

      1. Thanks Peter ,
        At my design the crankshaft pins are on 180 °, so the Pistons come simultaneously to each other and carter pressure is built up , no need to separate the crankcases in two sealed parts .
        I also wonder how some 2 and more cylinders 2 stroke engines are actual working without separate carters ?
        Regards Jef

  6. Hi there – Adrian here. I’m not a home constructor, although I did make a simple Mill’s-style engine years ago as a school metalwork project (it ran well!). These days i’m a restorer and historian.

    I just wanted to remind you all that my main site has a page entitled “Technical Topics”. If one of you wanted to run an article detailing the building of a specific engine, with photos and links to pdf drawings, it’s easy for me to put that up on the main site. All I need is the text, the images and the pdf’s. Such an article can be presented as chapters if that’s more convenient than a continuous narrative.

    Just thought you should know …………

  7. Just finished making my first model Diesel engine a Motor Boys designed AHC: http://www.modelenginemaker.com/index.php/topic,6389.0.html

    We are still to try running it. My pit crew (one Eric Offen) is still wary of helping out test run my engines after last year when he tried enticing my Felgiebel I had built to start running by putting his thumb in front of the prop… 🙁 I don’t like running engines on my own just in case….

    I have enjoyed making my AHC, there was nothing difficult in making it. It has got a nice bounce to it so I am hopeful….

    As I said this was my first Diesel, I have a few more vintage Diesels casting sets that have been extracted from Eric’s collection so hopefully there will be many more. 🙂


    P.S. In amongst some other rather larger aero engines

    1. Hey Jo – good to hear of another AHC being created. Just a few years after the castings started out… 🙂

      Did you keep the standard intake layout or one of Ron C’s variants (rear disc and front induction from below)?

      Meanwhile lots of other interesting posts on this blog so need to come back more frequently!


  8. Hi Richard,

    Its a box standard boring AHC. I am a great fan of making one of each variant of an engine if I can, but I first have to extract enough castings from Eric 🙁 (I believe he has 19 left).

    Talking variants: I have three crankcases for the CM1.4 with plans to make a Diesel, plus two sparkies: front contact breaker and rear.

    I don’t know if anyone knew John Carter? I knew John for over 20 years, sadly we lost him a couple of weeks back. I am pleased to say he gave me what was the last crankcase for his ‘JCEE’ 0.5cc Diesel engine and a copy of his hand drawn up design…… another engine to make in the not too distant future 🙂


    P.S. maybe we need a blog on “making” as well as “General Engine Design” rather than just Diesels..

    1. Yes, I want to second that sentiment that a blog is needed for general engine/machine work. I keep wondering where to get fixed and movable points and casting materials for timer restorations. Is Ebay the best source for screws and taps/dies for a guy in a foreign country? And what about small springs? Anyone help here? Thanks, Paul in Thailand

  9. Thanks Jo. Given Ron’s comments about marginal power I might do mine as a rear induction, just because I have never tried that so far.

    On the subject of boxer twins, my current project is a David Parker Vega twin. That has the cylinders dead in line, achieved by having offset conrods with cantilever a boss for the gudgeon pin and sharing the crank pin with half width big ends.

    Vegas are a successful design so I assume the concept is sound. I guess I will find out when I try to run mine. Crankcase, shaft, conrods, gear case and gears done so far, and just starting on the cylinders. Four strokes ..and twins..have a lot of parts it turns out. 🙂


    1. Thanks everyone who has replied to this blog. It seems there are still a few budding engine builders who enjoy creating an engine that lives which is fantastic. As Adrian says we have here a way of discussing our thoughts with others and that could include a solution to a problem solved by someone “been there done that”.

      I wonder too if there is a way that this blog, or in another format, to include the Motor Boys of which Adrian is one The wealth of knowledge these guys have is incredible and the wealth of information on the MEN website is an indication of Ron’s commitment to the model engine cause over a long time.

      Just wanted to say thanks, Adrian for putting this on here, it sure has started off with quite a flurry …

      Now I have a question and I have put some thought into a solution but yet to find an answer:- Most home-made model engines use a squared off crankcase at some point in their structure, whereas a cast case is more often than not round and round. Thought is you can make it round and round if you can find a way of locking the vertical cylinder part to the crankshaft tunnel part. I thought of threading the two together and am yet to disprove it can be done, another way might be to put the vertical part through the tunnel and the stub then goes through a hole but with a ring internal and bottom of the vertical to stop it going out, locked in place with locktite. Other than that I am at a loss, anyone got any ideas. If achieved I would have a screw on nose and rear plate as I have done before.

      Finally, Richard, have you thought of a blade and fork for the big-ends of the rods. This creates no side-loads and it works terrific, I did it in my 60 degree Vee twin … inspired by Mark Lubbock’s ML Midge, you see it running at https://www.youtube.com/watch?v=D8FZ26UPFr4

      1. Ed, after Ron passed away I made a very serious effort to keep the Motor Boys alive as a group. I’m afraid that they really didn’t want to know – with Ron’s passing, soon followed by the departure of David Owen, there simply wasn’t the interest and the critical mass required to sustain the group as a viable entity.

        Of course, if any individual Motor Boy wants to join the discussions here, they’re free to do so. If that should happen, no-one would be better pleased than I!

  10. Guys, I have an inquiry about the Motor Boys plan for the Nalon Viper. A friend of mine would like to have a go at building one. Does anyone have access to that plan or know how access might be gained?

    1. Hi
      Mike Crisp, who ran a very successful repair and restoration business here in the UK made a few vey good repros of the Nalon Viper. it might be worth contacting him to ask about plans……

          1. Hello Ken !

            Thanks for our quick reply i have no problem at all to give you my mail

            I can show you my poor engines built in the past !
            Now i am working on a DYNO replica …

  11. G’day Adrian
    I am currently building a pair of Naylon Vipers from a set of plans I purchased from Ron Churnich I can send you a copy.
    Rob Jenkins.

  12. Not strictly on topic because we’re not talking diesels, but a good friend of mine is making a few replicas of the pre-WW2 Atwood Crown engines. They have a neat little circular stamped emblem in .015 in. thick sheet bronze riveted to the bypass. It was coin-stamped from a die – about the size of a US dime. Does anyone out there know of someone who might be able to tackle such a production? My buddy would be prepared to order a handful of these if available, or to buy the die and stamp them himself.


  13. Like to introduce myself as Bernic de waal from Perth Western Australia. I have been an rc enthusiast most of my life and for the past 3 years collecting diesel engines. The past 2,5 years I’ve been building diesel engines, 3 cyl radial(1.6cc), boxer twin(1.1cc), v-twin(1.1cc) and single(0.67cc).Also, my own version of the 0.15cc Albion Bambi and a Lobo Pup Twin(from drawings). All are running engines.
    I have to make it very clear that I’m not an expert at design or building and all my creations are trial and error. My radial engines are based on Wolfgang’s Hoepfner 15cc radials of which I have the plans(given to me by him, we are very good friends). Although based on his design they are very different in design and manufacturing. Scaling it down to a running 1.6cc engine brought its own challenges ie casting vs cnc crankcase and many other design changes. However, I can confirm that all my engines start by hand.
    I would like to join this discussion to learn more about design and manufacturing so I can broaden my skills. I don’t have a website, but I do have a YouTube channels with most of my creations. Look for Bernic de Waal
    Thank you

  14. Hi all, I have been a hobby builder of model engines for many years. I have recently built and run a Holly Buddy . Thanks Ed. I am now building the BJ Cicada from the plans on MEN.
    I live in White Rock BC.
    This is the first time I have seen Adrian’s site. thanks

    1. Pat, nice to hear from a fellow BC Lower Mainland resident! I live in Coquitlam. Perhaps we could meet some time to run a few engines together!



      1. Would like that Adrian. I spend a lot of time on building RC planes too. I don’t do a lot of flying, but I build a lot.

  15. Adrian, re your suggestion for a construction article on an engine, I am building a BJ Cicada. Can photos be uploaded here?

  16. I have been a modeler and engine collector for many years and would now like to try building small IC model airplane engines. I have a limited background in machine shop tools having taken one machine shop course many years ago in college. My shop area is small so I am considering a Sherline lathe and mill as a start. Comments and suggestions would be welcomed.

    Also, I don’t know of any sources for plans and castings for the engines. Does anyone make small engine kits like those Roger Schroeder used to furnish? Also sources of raw material that I can buy in small quantities?

    I would like the opportunity to correspond with any hobbyists regarding making small IC model airplane engines utilizing tabletop machines such as the Sherline lathe and mill.
    Thank you.

    1. I’m facing the same problem, as I have purchased a number of unfinished ignition engine builds such as Drome Demon, Bat, Westbury Kestrel and New York Miniature as well as some other engines, diesel and glow that need work. What is the minimum tooling for this kind of problem? I only know of the Unimat line of hobby lathes and attachments from model railroading experience. Can you use one to make a needle valve for example? Some of those threads are so fine. Thanks, Paul

      1. Hi Paul and Michael,

        The first post in this thread is an engine you might consider building. It is 2.5cc and is probably as easy an engine to build as any. There is a link there to how the design was arrived at and plans to make it.

        Another engine that is worth considering is the BollAero 18 — this was my first engine and lots of other guys made it their first also. Not as powerful as the 2.5 being a sideport but nevertheless another easy to build design. Free plans are on the MEN website http://www.modelenginenews.org/ go to engines then go to plans and you will find it there. Let us all know if you do proceed with one So there are a couple of options to consider … Ed

        1. Interesting suggestions and thanks, but my main concern is what minimum machinery do I need for basic builds and restorations. Will a small Unimat suffice if I am patient with the harder cuts? I’m semi retired so time is not a problem but money is. Is there a book out on basic machining skills? I think all threads would have to be cut with tap and die. I’m OK with that as I did some of it to restore an Excelsior motorcycle a few years back. Do most guys use Metric or English or US thread systems? Big problem there I think. Thanks, Paul

        2. Ed, My interests currently run thus and so: finish rebuild of Technopower 5 #A5-030 first series and test, get and run M5 Morton, make piston, rod and run Condor Midget, assemble and run first model Madewell .14, build New York Miniature from partially done kit, finish a Bat project, same same for Drome Demon-possible repro kit because it’s too shiny, run OS type 10 and others, check out and run Ouragan (3cc?), run other French diesels, and my ME Snipe RC with mufflers. Finish and fly my diesel or electric Super Privateer long wing special. Maybe other stuff too. Who knows? Thanks for now from Thailand.

  17. Hello Everyone,
    I am looking for the plans for the Fig Tree Pocket Twin. The plans are in the Motor Boys Model Engine Plan Book, but I have been unable to find a copy.

    I have been a hobby machinist since 1984 and an aero engine builder since 1999. All my engine builds have been spark or glow-plug to date, so a compression-ignition twin would be a nice finish to my bucket list. I am 73, long retired, and have done most of what I wanted to do when I started this hobby.

    I will gladly pay for copying and postage or the privilege of a download. I would prefer PDF format. Thanks for any help.

      1. Hello Ed,
        Thank you for your offer, but I have already received a copy of the plan from a member over on the HMEM forum.

  18. Hi I’m new to this site but have been tinkering all my life and now 74. Who can tell me if the induction stub on an Amco.87cc diesel is soft soldered onto the cylinder side or silver soldered ? Also what shape the end of the tube should be .What diameter inside and O.D.? what length > What material I don’t have any of the original carb but I’m thinking of modifying one for an E.D. Bee .Any suggestions chaps and chapesses?

  19. Hello All,

    I was successful in getting the Fig Tree Pocket plan and am well along in building it. How about a recommendation for a break-in propeller? It is a 4cc( .25cu. in.) twin.
    Thanks for any help.


    1. That engine is a David-Andersen diesel made in Norway. There’s a detailed article about those engines on my web site. You should be able to find your engine there. Otherwise, without seeing it or knowing its displacement, identification really isn’t possible.



  20. If anyone is interested I did a short article on casting and making some replica engines. The article is in Zoe Quilters website (which is now static)
    Look for http://www.fuelsoaked.me.uk Part 71 for info.
    I have since done several more engines and a couple of model cannons .
    Presently doing a Frog 100 bicycle spoke engine.

  21. My pal John Maddaford (alas now departed), made some of the best repro engines around and I have quite a few of them – Stentor, R&G Hornet, Super Atom, Westbury Zephyr, Bantam 0.16, Junior Brown Junior 0.19, and Excelsior 0.19. They are all superbly made and run very well. I know the background on all of them, except the last where I am unable to find anything at all other than I believe the original was Dutch and made in 1939. Can anyone shed any light please?
    Remember the Owen Mate? Well many years ago I bough the kit from David Owen, and somewhere it still resides in my workshop untouched, despite the best of intentions. Probably the last in captivity.

    1. Hello David, long time no see!
      John Maddaford got the Excelsior drawings from me and as you rightly say it is a Dutch design from around the time of the Nova and perhaps by the same person. It was, like the Nova, a design for home construction and I have no knowledge of it ever being produced commercially. When I sold-off my workshop and dispersed all my anciliary stuff, all my drawings went to Eric Offen so he will have the Excelsior drawings. Sad to say, although I did scan and digitize some drawings, the excelsior was not one of them.
      Hope this helps. If I find any more info in my files, I will email to you directly.

      1. David
        I have now found that I have a general arrangement drawing of the Excelsior and part of the words that went with it.
        Briefly the Dutch engine design was published on 20/12/1942 and was designed by Leeuwen, the Nova designer. It was 3.22 cc with bore and stroke each 16mm.
        I will email what I have to you directly since this blog does not appear to allow for posting of images.
        take care
        Ken Croft

  22. Message for Adrian from Ken Croft.
    Good morning/evening [your choice].
    I believe that Maris Distlers is looking into the possibility of the engine drawings produced by the Motor Boys, some of which were available freely to the public, but others only to the MB’s themselves, might be made more accessible to the public. There may be copyright issues to be addressed, though I doubt that, but as one of the MB’s I have all the drawings both public and for members, and of course I also have the book of engine plans that we produced. I am very happy to participate in the venture and will happily make all the information that I have, available to his project should it materialise. One minor problem is that we established TurboCad as a standard for all our drawings and although Ron generally published drawings for the group in jpg form, I have only the TCad versions since I found them much more useful to work from. I can if necessary convert TCad to jpg. Any way, this is enough verbocity for now, I just want to make it known to you that the recources I have are available.
    take care
    Ken Croft

  23. Thanks very much for this, Ken! I’ll raise the matter with Maris and get back to you. Making that resource available to the home construction community would be a great thing indeed!



  24. Hello to all.
    I am Ken Croft, one of the few surviving original Motor Boys. Now aged 77, for about 65 years I have been an active aeromodeller, and for around 20 of those years I was also a self-taught home engine builder. Since my permanent move from the North of England to live in SW France 8 years ago, and the dispersal of all my engineering equipment, I have not been involved in model engine building. Primarily my interest and that of the MB’s, was to re-create engines from the past, though a few own-designed engines did appear from time to time. My work on engines involved pattern making, permold die making, melting aluminium and pouring my own castings, and all the usual machining operations. The only equipment I did not have was a cylindrical grinder, but I had the usual lathe, mill, drill press, Delapena [Sunnen] honing machine, and a furnace for melting metal.
    If you have a few minutes to spare you can see most of my home made engines, totalling 40 different designs, on my Flickr web site here :-
    All of those engines were built with the purpose of powering my model aircraft, though not all actually got into the air! All bar three of the engines ran well. Two were absolute little sods, the 3rd was a 4-cycle engine that I built but never finished because I simply lost interest in it. I will happily answer any questions about my engines. I hope you enjoy the engine pictures and any others you may find on my Flickr site.

  25. Attachment  Pistons-and-Cylinders-for-beginners.doc

    I have a very long winded thing I wrote a long time ago that maybe is already published somehwere, that may be of interest. It attempts to undo the mystery about piston and cylinder finishing for beginner diesel builders. It may not be in the form that is of use to you, but here it is. You can do what ever you like with it. I do have the original images if you want them separately. Sorry about the length of it all.
    The piece is attached.
    Seasons greetings.
    Ken Croft

  26. Thanks for this, Ken. For some reason, the attachment doesn’t open from the regular blog site, but it did come though – in my Administrator role, I was able to download and save it. I’ll see about setting it up in my “Technical Topics” section on the main website (with full accreditation to yourself) and will let you know if I need original images. I’ve tested the new image upload facility on the blog site, and it seems to work perfectly for jpg images. Just a bit of a hiccup on the .doc files, which we’re looking at just now.

    Thanks again, and Season’s Greetings!!

    1. Cor blimey, I do use a lot of words in that article. I think I give you a close run Adrian !!! But I hope some folk find it readable and of some help.
      Happy Christmas.
      Ken Croft

  27. No-one gets on top of me when it comes to word counts, mate!! However, you did give it a good shot! Many thanks for the contribution! If you think of anything else that others might find useful, the site is at your servicel!

    Cheers, and Happy Christmas to you too!!


  28. Sorry, it took me a while to figure out the code thing at the bottom. I want to answer my own question about getting started building and repairing engines. Hemingwaykits.com has a very nice list of materials needed to get started. About how to use them? That’s another problem but I think it’s shouldn’t be too hard to figure out once you get the machines in front of you. Thanks again and Happy Holidays, Paul

  29. For cheap diamond lapping paste go to banggood.com, works perfectly and post free
    Look for diamond lapping syringes only. $8 to $10 for 12 5gram syringes of various micron sizes

  30. Adrian.
    Seasons greetings.
    I am trying to reply to an email just received from Maris Dislers re Pepperell engines. I have had no trouble in the past, but 3 attempts today 5 Jan have bounced back with “undeliverable” messages. Could you email me with some other way of contacting Maris. Even a phone number would be ok.

  31. Hi Adrian,
    As you may remember, I have made quite a few model diesel engines.
    Most work well, but I am having trouble with my latest one.
    Its a mills replica but only .4 cc.
    The engine starts easily and runs strong for about a min. but then sags and will stop.
    It does not feel hot or gives any indication that it is over compressed.
    changing prop. sizes does not seem to make a difference.
    After it stops, it will restart easily and then, after a min. will sag again.
    The engine will turn an APC 6×4 at 9000 rpm.
    Any ideas?


  32. I have an Owen Mate 2cc diesel kit that I bough back in 1998. It is complete with instructions, drawings, etc., and is in the original box as supplied to me by David Owen. Probably the last one left unmade or untouched. Everything is there include the unique alloy extrusion made for the crankcase. Total weight of everything is approx 1500g. I am not going to make it now, so the best offer takes it. Postage will be at cost. If anyone is interested and would like a photo of kit contents, please let me know.

      1. The complete kit contains all the metals required, plus screws and a big roll of papers, including plans, instructions, etc.
        Dave H

  33. Greetings to one and all! Just a short note to advise that thanks to the generosity of Ken Croft I hope soon to be able to make the entire Motor Boys model engine plan book freely available through my website. We have already added a link to my site to provide access to the formerly exclusive “Members Only” plan book which was provided to new subscribers to Ron Chernich’s wonderful ” Model Engine News” (MEN) website. Check it out at:


    We hope soon to be able to provide a link to the far larger main plan book in the same way. Stay tuned!!



  34. Adrian, hello from Trinidad, CO. I’m looking to participate in the blog…looking for a new connecting rod for a FROG 500 diesel blue head. This one suffered the twist off the head while the piston is stuck torture test. As an alternative, center to center length would be great…allowing me the opportunity to try to make one that might suffice first time around. Would you provide an email address reply? I would like to lend a hand with support for your growing information site. Best regards, Steve

  35. G’day Dave Miner
    When your engine stops have you felt the crankcase adjacent to the crankshaft bearing to see if it is hot . I have had this problem a number of times.Maybe your crankshaft crankcase fit is a little too tight and this can cause your engine to sag and stop. If so just polish a bit more off the bearing diameter of the crankshaft. leaving a small ring at either end for a seal. Failing that your piston cylinder fit may just be a little tight and need some more running in. Also have you checked that your backplate is tight and has a good seal.
    Just some thoughts.

  36. Good news for all you home constructors! I’ve now added links on my main website to both the Motor Boys International Plan Book and the formerly-exclusive Members Only Plan Book. These may be accessed respectively at:




    Hope this helps some of you! Big thanks are due to Ken Croft for his generosity in making this material freely available.

  37. Attachment

    Hi Adrian, thanks you so much for loading the Motor Boys plans in the two instalments that were available for free and the ones that Ron supplied when you joined the MEN site.

    The Mills 1.3 plans were available through Ron, I enjoyed the build a few years ago and I still have my copy but I cannot see it in the 2 sets of plans you have loaded. Maybe because it wasn’t a Motor Boys design that Ron supplied it separately.

    This then raises another question, is there a case for engines that weren’t designed by the Motor Boys to be made available in a 3rd set. The Mills 1.3 would certainly fit this category and in recent times my Holly Buddy might be worthy of inclusion?

    Happy to supply both plans if you deem it worthwhile – and maybe this might shake a few more out of the ether that others have designed and built. It would be great to have engines plans all available in the one place.

    1. Great idea, Ed! I can easily create a page for “Miscellaneous model engine plans”. Please by all means send them along. I think I have a few Chris Boll plans around that I never got to scan and put up – this would be a fine opportunity to set that right.



  38. I not able to build model engines, but I have been looking for 2 diesel engines for my model that I am building, Been trying to find 3 cylinder straight less than 3.5cc, some thing like a replica of the stationary kubota 1lt. Do any one know of any

    1. Pete, I’ve never encountered any diesel engines matching that rather ambitious specification! I think you might have a long search …………..

  39. I have found numerous articles referencing the Sugden special, but nowhere can I find a plan! I have the Aeromodeller articles – including plan – but this is a low res scanned version and the numbers are often illegible. Any one know if I can get a legible version anywhere?

    1. Beginning with the upcoming January 2019 issue, I’ve started a new thread on the Technical Topics page dealing with plans for model engines suitable for home construction. The Sugden Special plan is among the first designs to be featured. Enjoy!!

  40. Adrian. Although I disposed of my big collection of engine drawings about 10 years ago I still have a fair collection scanned onto my computer. Rather than just randomly submitting plans to you, maybe a better idea might be for folk to request what plans they would like to see on this site. You could otherwise end up with plans of little interest to the bulk of your followers.

    1. Great idea, Ken! OK, you guys, speak up!! What plans would you like to see that aren’t already available on the main website? Please post your suggestions on this thread and Ken and I will work together to get them up on my new Plans for Home Construction page.

  41. Wow, just came across this great discussion…
    Adrian – great work on your site and collecting & making available these plans.
    I’d love to see the plans for the Nalon Viper 2.5cc come up… a very handsome engine with a great pedigree. I believe Eric Offen may have the plans. Unfortunately, I don’t have a contact for Eric but he was a “Motorboy” too; perhaps Ken would know.
    Thanks again!

    1. Thanks for the comment, VijaY! Good suggestion – I’ll put that plan up with the others. It’s a great engine altogether – too bad that it never saw production.



    2. Vijay, I’ve added the Nalon Viper plan to the main website (adriansmodelaeroengines.com). You can find it either by going to the Gallery entry for the Nalon Viper or to the thread in Technical Topics on Model Engine Plans for Home Construction – there are links on both pages.



    1. I can probably find out, Paul, but you need to be more specific. Are you talking about the reed valve model?? Dan Calkin changed the design at least 4 times! A photo might help.

      Let me know, and I’ll see what I can do.



      1. My Elf twin is #1496. I’ll have to work on a photo, but it appears to be #18 in the model engine encyclopedia.. ie 1950 with reed valve intake in rear case casting and new cylinder with no provision for intake. I think it’s the only model glow twin he made and 182 were produced. No throttle or exhaust tubes and I’m un aware of the who the first purchaser was. Thanks again, Paul

  42. I have built 18 or 20 diesel replicas, some Motor Boys, at least one from Ron’s fantastic web sight, 3 MPC IMPs. A number of my builds are on Ron’s old sight. I build purely for the enjoyment and use most of what I build to fly models. What a great joy to see a scratch built model with an engine as well fly.

    I have a alternate firing twin in the design stages, looking at some simple ways to couple the crank so that the con rods don’t need bolted on caps. It will be a while before I can get back to it, my shop has been decimated by a move and I am very busy with other things right now.

  43. Attachment

    Hi – I confess I have not looked in to Adrian’s site since about it’s fourth issue. That’s not because there was anything wrong just that my interest was primarily the making of engines which at that time was not covered. As other modelling interests also took precedence so its presence went off the radar – something that as age creeps up is ever more noticeable.

    A chance encounter with Hugh and Lynn Blowers in the local supermarket last weekend where the subject of ‘engines’ rapidly trumped that of shopping led to the realisation I was obviously missing something good – my thanks to Hugh for the recomendation.

    Some may be aware that my interest lays mainly in making 5cc replicas of smaller commercial engines and build logs of these have been featured elsewhere. The latest engine was the Mk3 Oliver, all machined from solid with a cast iron piston in leaded steel liner. They have proved excellent runners in fact the first tried started instantly with that Oliver characteristic – backwards!

    Currently nothing is being made but drawings for a twin shaft 5ccc tethered car engine have just been finished. This is based on a scaled version of the Nalon Viper and hopefully machining will get underway in early spring. Also have thoughts on a 5cc version of the Jena 2cc, drawings for them also finsihed and waiting for some action.

    Really great to find somewhere to share directly with those with the same interest

    Regards – Ramon Wilson aka ‘Tug’

    1. Thanks, Tug! Nice to have you aboard!! By all means keep me informed of anything which may be of mutual interest!



  44. Thanks for the acceptance Adrian, pleased to be here. It will be a few weeks as yet before a start is made but I certainly will

    Best – Tug

    1. Hello Tug. I followed the construction of your big Oliver’s on some forum or other. Anyone can acquire machining skills, but carving cases from solid the way that you do is beyond mere skill, it is almost art. I am sure that you are welcome here but I doubt you will learn anything, your work is way beyond most model engine meddlers.
      Ken Croft

  45. Hello Ken,
    Thanks for the endorsement, much appreciated of course but I really don’t see what I do beyond a model engineering project. Pace yourself, one bit at a time and let each piece lead to another is all I apply. Desire to acheive ones goal must be forefront though, I perhaps should add.

    Happy to share with anyone if they are interested and vice versa – theres always something to be learnt from someone.

    Regards – Tug

  46. Greetings to one and all! I just wanted to let you all know that my valued mate Ken Croft has provided some invaluable comments relating to his recent construction of a fine example of the Clanford Clan 0.24 cc diesel from the Motor Boys plan. I’ve added these comments to my pages on the main website relating to Plans for Home Construction. They can be found at:


    I’m sure that any prospective builder will find Ken’s insights extremely valuable. As a bonus, Dave Jones of Queensland, Australia has added a number of comments of his own to what Ken has so kindly written. Having just completed a run of five superb examples of the Clan (of which I own engine no. 4), Dave has a wealth of recent experience upon which to draw.

    I hope that some of you find this useful. Sincere thanks to both Ken and Dave!

  47. Hi!
    My english isn’t that good so i have question abouth the cylinder lapping. It’s written “look for perhaps a thou difference between the bottom of the cylinder and the exhaust port area”.That i undestand, since i am using mm it wood bee 0.025mm. Then it’s written “then a couple of tenths”. What does that meen? I’m guessing it’s not a tenth of an inch. So can anyone explain the this for me.
    I have already made an Mills 1.3 and it run’s perfect but i guess tha’s juat luck when it comes to the lapping.


  48. Attachment

    Hi Adrian,
    These parts for a JB Atom/Bomb (?) have just come into my possession. No cylinder liner or piston so I’d like to to rebuild it. I’m not sure the prop driver is original as the fit on the taper is very poor but reclaimable.

    I’ve read through everything I can find (both engine reviews, info on MEM and your own detailed info) I haven’t found a decent picture of a liner so wonder if you can answer a couple of questions for me.

    I can draw out a liner to give the timing as given but I would like to know the size of opening (height wise) of the exhaust port itself and also the total width of the exhaust port flange( again heightwise) Can you help me here?

    Also I read it has Oliver type porting with holes drilled at an angle. Do these holes interupt the lower threaded area or is the threaded portion set above the entry point of the transfer ports ?

    I intend to use what material I would normally use for these parts – CI piston/CP in En1a leaded steel liner. Piston will be conventional as opposed to the insert original and a new pin and con rod made.

    Any assistance on getting this little engine running again would be much appreciated

    Regards – Tug

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