Nemett Jaguar--Canadian Style

[Roger B]

Use a blunt tool and cold weld the laminations together 

[Brian Rupnow]

Thank you for all the helpful suggestions guys. Now its time for an even more technical question. The original Bobcat engine which was the basis for my design, turns counterclockwise when viewed from the flywheel end. I want this engine to turn clockwise (I don't plan on a propeller.) The cams are made as individual pieces and Loctited to the camshaft. On the original engine, the instructions on cam positioning were to set the cam lobes 102.5 degrees apart with the cam closest to the flywheel (exhaust cam) "leading" when the engine was set up for counterclockwise rotation. I think that if I set it up with the intake valve leading,then that will let the engine run in a clockwise rotation when viewed from the flywheel end. Trouble is, I'm having a brain fart right now---If I reverse the cams as previously stated, should the intake and exhaust assemblies switch to opposite ports on the cylinder head? I'm sure if I chew on this long enough I will arrive at some conclusion---I'm just not sure what conclusion.

[Maryak]

Hi Brian,

IIRC the only difference between a right and a left hand engine is the cam shaft and the firing order, certainly true for the good old Perkins diesel.

Perhaps draw up one of these



Best Regards
Bob

[Brian Rupnow]

Today we made a small (very small) start. The crankshaft gear and the idler gear are both going to be 15 tooth 24DP gears. They will be 0.25" wide. The steel crankshaft gear will have two set-screws in the hub to hold it in position on the crankshaft end. The idler gear will be made from cast iron---It has no hub and will spin freely on a steel shaft. I chose cast iron for its self lubricating properties--it won't require a bushing. I had a left over piece of cast iron from another job that was 1.5" dia. and 5/16" thick. The o.d. of the gears is 0.708" I used a piece of 3/4" cold rolled steel for the crankshaft gear. I turned it to the correct diameter on the end and in what will become the hub area, then put in a 3/16" reamed bore. I set the cast iron up in my 3 jaw chuck and put a 3/16" reamed bore in it. then I used a short piece of 3/16" cold rolled steel and some Loctite to put the cast iron blank and the cold rolled steel blank together. I then drilled both pieces 1/16" for a couple of pieces of 1/16" cold rolled which will act as "drive keys'. Tomorrow I will set the cold rolled up in my 3 jaw chuck and turn the cast iron down to the same 0.708" diameter as the steel x 1/4" thick. Then I will set it up in my rotary table and cut both gears at once. Then a bit of heat to separate the pieces, and open the bore in the crankshaft gear out to 9/32", which will be the finished bore. The finished bore of the cast iron idler will be 3/16" so no farther changes will be required to it. Then cut off the cold rolled to the desired hub length and drill/tap it for two set screws.

[Brian Rupnow]

Thanks Maryak---It's good to hear from you. I have built so many hit and miss engines with only one cam that two cams confuse me.

[Brian Rupnow]

This is the second step in this (two for one) gear cutting trick. the cast iron blank is now reduced to the same diameter as the cold rolled steel. Now---Off to the rotary table.

[Brian Rupnow]

TA-DA!!!~--Now, on to the camshaft gear. I think since I have room for a big hub on it, I will make it from cast iron too.--Cast iron leftovers are free. Brass I have to pay for!!!

[Niels Abildgaard]

There was a gentleman recently here who wanted guidance on how to make 200 watts continuosly .
Having a pushrod version of  a 15 ccm engine and Gus and Swifty  making OHC versions will lift this site from being lonely old men ,how do I know,to respectable members of society.
How do we measure fuel efficiency?

[Brian Rupnow]

Niels--I haven't got the faintest idea what you just said there, but I hope it was something nice!!!---Brian

[cfellows]

Your gear turned out nice, Brian.  Think you've got this gear cutting thing down to a science.

Chuck

[Brian Rupnow]

Thanks Chuck--if the Lord smiles on me this afternoon I'll have the last one done.

[Brian Rupnow]

It is absolutely amazing what a large portion of the day gets eaten up by 3 little parts!!!--Don't get me wrong---it didn't take the whole day. Just most of it. The rest of the day was spent building a built in cabinet in my garage for my new generator (The one I bought for the spring flood that never happened):eek:to live in.--If the teeth on that largest gear look a little blunt on the ends, its because they are. I had the gear blank Loctited onto a shaft to turn it to finished o.d., and right on the last "truing up" cut the damn Loctite broke loose. By the time I got it re-Loctited it had gone out of center enough to demand another truing up cut, so its about 0.010" undersize on the outer diameter. That won't effect the mesh, and its hidden inside a gearcase so I'm not too worried about it.

[Brian Rupnow]

I learned long ago to never trust the centers that my computer or I calculate for meshing spur gears.--(Yes, there was life before computers---I used to do it all with trigonometry.) Now each time I make a gear train, even a simple one with only two gears, I use the measurements that will be used in machining the final part in which the gears will be fitted, to drill and ream holes in a scrap and then mount the gears and see how well they mesh. I must have lived right this week, because they mesh just fine!!! I also discovered a bonus today.(sitting at the left hand side of the picture.) While rooting around in my cast iron short ends looking for something to carve a gear from, I spied one piece that looked a bit larger than all the rest. I don't know what project it is left over from, but it is 1.6" diameter x 2" long. The cylinder for the Canadian Cub is 1.575" maximum diameter at the flange, x 1.705" long. If I can get lucky enough to have this piece clean up and leave me 1.575" at either end, I will have a free cylinder. Dang, I love it when that happens!!!

[AussieJimG]

Get in quick Brian, while Murphy is up at Philjoe's place. He will be back any time soon.

Jim

[sbwhart]

Hi Brian

Only just picked this thread up, looks a fascinating project I've got Malcolm Stride's book on miniature combustion engines ISBN 9781861269218 a must have for any one with an interest in this subject. I'll be quietly following your progress.

Stew