911hillclimber Posted February 17 Share Posted February 17 Just asking if anyone on here has made a Hemmingway model aero 5cc diesel engine from scratch? 2 Quote Link to comment Share on other sites More sharing options...
Engine Doctor Posted February 18 Share Posted February 18 Good luck I will watch with interest . I have never made a complete engine from scratch but have machined a Bodo Mills crankcase from barstock. Quote Link to comment Share on other sites More sharing options...
911hillclimber Posted February 18 Author Share Posted February 18 The 5cc design is fortunately large enough to keep things away from super precision, I'm not a detailed machinist, just keen knowing just enough to be really dangerous! Doing the first part, the complex cylinder from En8. 1 Quote Link to comment Share on other sites More sharing options...
Martin Harris - Moderator Posted February 18 Share Posted February 18 Watching with interest… Quote Link to comment Share on other sites More sharing options...
911hillclimber Posted February 18 Author Share Posted February 18 Today was starting the cylinder cooling jacket, cutting an internal thread to match the one on the cylinder and to ensure the two screwed tight to seal the cylinder 'head'. All worked out well with a few nervous moments, but what projects are all about! 1 Quote Link to comment Share on other sites More sharing options...
911hillclimber Posted February 19 Author Share Posted February 19 One more part made today, or rather, finished off. The aluminium cooling jacket/cylinder head was machined to have fins and shaped. Talk about tool chatter and swarf! 3 Quote Link to comment Share on other sites More sharing options...
KEITH BEAUMONT 1 Posted February 20 Share Posted February 20 Hi , I made the Sparey from the Hemminway kit,about ten years ago. I found it all straight forward,other than a few points,although from your latest photo you might already have past one of them. The notes suggest using the cylinder to use as the mandrel to hold the fins for machining the head fins. Not a good idea, as the chance of distorting the cylinder with the chuck jaws is high. While you have the gears set up, make a stub mandrel with the thread on to do this job. Also,the notes suggest pre-soldering the inside face of the stub that the venturi screws into, prior to assembling onto the cylinder with the recomended holding fixture. Dont do it,as when things start to melt the fixture comes loose and the stub can the be out of square. Assemble clean and dry and solder as your normal practice. The piston as drawn is far too heavy and can be lightened by taking more metal from the inside. It does not need the close fitting of the con-rod and making the inside thinner takes a few gramms away. It is a powerful engine and mine happily spins a 16" x 6" prop. Keith. 1 Quote Link to comment Share on other sites More sharing options...
911hillclimber Posted February 20 Author Share Posted February 20 (edited) Good to read Keith, thank you. I'm tweaking the design as I go along, bit of metric here and there. I am detailing the project on another non-related forum but here is my latest update of today: Spent all day in front of the lathe today, nice, but sure gets to your knees! Made the contra piston compression screw first, just an M6 set screw, a length of 2mm spring steel and a blob of braze, oh so easy! Next up was the dreaded inlet 'manifold' from the venturi spray bar (needle jet) to the inlet port when I've machined it. This is a small awkward part, drawn 2 x full size on the plan to make it easier. Taper machining on the bell mouth and similar taper internal machining inside to create a thin tapered wall. Easy to type...but got there in the end with a bit of imagination. Finished the bell mouth (shape is more like the mouth of a rainbow trout) with a file, far to intricate to machine. Finished well. So much for those bits, time for the crankcase. Looks complicated but i hope I have started it the right way. You need to machine the inside of the case for the crank shaft and the rod, but the whole lot is trapped in the case by a screw-in back plate and the crank runs onto a bush with a trust face to take the axia 'pull' of the propeller. So, with my nice new 4 jaw chuck, got the casting as true as i thought right and faced the back of the casting, drilled the 7/16" dia hole for the crank shaft bushes and then opened out the inside to 1.250" dia. This left me with just enough cast metal to take the 24 tpi back plate thread. Really could have done with off setting the casting 1/32" more to get more metal but all done now. Threading tomorrow/Thursday and then deciding how to do the crank bushes and keep them in line for the crank. They are a 2 thou press fit. What can go wrong? (watch this space). 73T 911 Coupe, road/hillclimber 3.2L Edited February 20 by 911hillclimber 1 Quote Link to comment Share on other sites More sharing options...
Engine Doctor Posted February 20 Share Posted February 20 I made a mounting block to hold the case on my Bodo Mills c/ case. It was mounted to this using the mounting lugs and the block was then mounted in the chuck. Reason was so as not to damage or mark the case . Cant find pic on my tablet but have it on my pc and will post later. Quote Link to comment Share on other sites More sharing options...
jeff2wings Posted February 21 Share Posted February 21 Just been checking the hemmingway drawings agents the ones originally published in 46-47 and there appears to be a difference in the transfer/exhaust dimensions, what drawings are you using? Quote Link to comment Share on other sites More sharing options...
911hillclimber Posted February 21 Author Share Posted February 21 2010, bought the 'kit' just after Xmas to keep busy! Had my first almost catastrophic set back this afternoon, but have a plan to get out of jail. Quote Link to comment Share on other sites More sharing options...
Engine Doctor Posted February 21 Share Posted February 21 Here are the pics of the mount i madeto machine the crankcase Quote Link to comment Share on other sites More sharing options...
911hillclimber Posted February 22 Author Share Posted February 22 (edited) Nice solution! I don't have a miller but do have a compound slide for the lathe. Will have to use that (vise attached to it) to mill the mounting lugs on the case and could make a similar 'chuck-block'. Good food for thought. Pic below is a quick set-up to see what versatility I can get off the slide. Here to machine the ports in the cylinder. The case is much harder as it is a rough casting and tricky to get hold of. Need to fix the cock-up I've made of the block's 24 tpi thread and back plate first or it's start again on the block. The castings are available easy at lest and Hemmingway's are just 20 mins away from me. Edited February 22 by 911hillclimber 1 Quote Link to comment Share on other sites More sharing options...
jeff2wings Posted February 22 Share Posted February 22 Nice old pre-war Drummond, you have a face plate for it? Quote Link to comment Share on other sites More sharing options...
Andy Stephenson Posted February 22 Share Posted February 22 (edited) 2 hours ago, 911hillclimber said: What a fascinating piece of kit, One thing that intrigues me is how does the main slide move as it seems to be clamped to the bed. Edited February 22 by Andy Stephenson Quote Link to comment Share on other sites More sharing options...
911hillclimber Posted February 22 Author Share Posted February 22 (edited) No, don't have a face plate (yet)! The Drummond is a beauty, absolutely love it to bits. From it's serial number i think it is 1922 or 23, a hundred years old. The Drummond was sold to Myford during the WW2 and lots of Myford parts fit it. The round bed is really a very pronounced C shape, the round tube has a slot all the way along the bottom and the slide is locked onto a centrally running screw hence getting the axial travel. Here is a bit of an update: Got out of thread trouble this morning with a Sh!t-or-Bust approach that saved the day, or rather the cylinder block and rear cover machined parts. Got it all to screw together and tight. Did my first Lathe/Miller cuts using the Myford cross/vertical slide which was satisfying and decided to call it a day until tomorrow when the rain will keep us indoors. Need to borrow a 17mm reamer now and the block can be milled for deck height, rod clearance and induction porting. Will cut the cylinder ports first thing. A few pics: Here, the block and the rear cover are in their chucks, hence the strange picture. The flat face next to the thread is too large, it needs to be machined when the crank and crank pin are in place to set the float of the crank, so some more fitting needed later. 73T 911 Coupe, road/hillclimber 3.2L Edited February 22 by 911hillclimber Quote Link to comment Share on other sites More sharing options...
jeff2wings Posted February 22 Share Posted February 22 (edited) A face plate can be very good for odd shapes Edited February 22 by jeff2wings 1 Quote Link to comment Share on other sites More sharing options...
911hillclimber Posted February 23 Author Share Posted February 23 Cricky! 1/2 a workshop on there, but does look very very stable and dead true. Quote Link to comment Share on other sites More sharing options...
911hillclimber Posted February 23 Author Share Posted February 23 Managed a few hours in the garage today. The cylinder ports are all cut using a 1/8" slot drill which is the smallest I have, but new so keen. Slightly juddery cutting due to the excessive back lash in the lathe's cross slide, but with a little help of a Swiss file, all done. Borrowing 3 reamers off my mate on Monday to ream the crank shaft bushes out and also be ready for making the con rod which must be the most awkward part to make in the whole engine. Bits of this engine slowly gathering. A few pics as ever say more than my words: 73T 3 Quote Link to comment Share on other sites More sharing options...
jeff2wings Posted February 23 Share Posted February 23 Well you're making good progress particularly as the lathe is both basic and vintage (but perfectly adequate )you might find it useful to have a look at modelenginenews.altervista.org there is a full build thread for the Speary that I'm sure you will find useful . In the meantime, I've a bit of catching up to do 😄😄 Quote Link to comment Share on other sites More sharing options...
911hillclimber Posted February 23 Author Share Posted February 23 Thank you, I found that link a week ago and it is full of tips. Part of that write-up is supplied with the plans for the engine by Hemmingways. I have not yet thought of a way to machine the mounting ears and the cylinder/block deck height, going to be a challenge... Back and knees aching after standing at the lathe for hours and days, so taking a few days break to walk the pains away! Did you soft solder the transfer box and the inlet stub to the cylinder? Quote Link to comment Share on other sites More sharing options...
KEITH BEAUMONT 1 Posted February 25 Share Posted February 25 In the notes by Ron Chernich, he recomends silver solder for the venturi stub and soft solder for the inlet cowl. I did that, but on the follow up 0.63cc Sparey ,I soft sodered both with no problems. Keith Quote Link to comment Share on other sites More sharing options...
911hillclimber Posted February 25 Author Share Posted February 25 Thanks for the advice. I have both but will prefer the soft solder route too. Borrowing the reamers tomorrow but awaiting the right dia drills for the reaming (all 1/64th under size). Spent ages sorting out how to hold the case for the milling and boring of the deck height etc, but all sorted now i think. No idea how I'm going to turn the crank pin on the crank, that will need some inspiration! Quote Link to comment Share on other sites More sharing options...
911hillclimber Posted February 26 Author Share Posted February 26 I now have the reamers and awaiting the drills all under size by 1/64" which might be here tomorrow. Had a few hours today making the crank bushes. The material supplied had a remarkably reluctant skin on the surface, but eventually the parts were made with about 2 thou interference fit (I guess) and were knocked in place with red loctite helping along the way. The bushes can now be drilled and reamed to 5/16" dia and removed from the 4 jaw ready for machining the case mounting lugs , deck face and cylinder bore followed by the transfer port. All tricky on the compound slide and the cutters in the lathe chuck. It is doing this that you realise how flexible even these old cast steel machines are even with light cuts. I have no idea how to machine the crank yet, but that is for another day. There are hours to be put into the crank case yet. The crank bush is much smaller, the part you see is the crank thust bearing face that is part of the main bush: 73T 911 1 Quote Link to comment Share on other sites More sharing options...
Jason Channing Posted February 27 Share Posted February 27 Very nice build. Quote Link to comment Share on other sites More sharing options...
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