Engines

Inline Twin Engine Ep. 13

The flywheel for the engine is next.

It is a straight forward turning job. Here, the first side is done:

Inline Twin 196 (800x450)

The flywheel is turned over and the second side is finished:

Inline Twin 197 (800x450)

The finished flywheel:

Inline Twin 198 (800x450)

As a contrast to the mostly aluminum engine, I decided to cold blue the flywheel. Hopefully this will also help a little with corrosion protection.
I used Brownells Oxpho Blue, and I’m happy how it turned out. It’s not as dark as a commercial black oxide finish, and has more of a blue tint to it.

Inline Twin 199 (800x450)

The flywheel installed on the crankshaft using a taper locking assembly.

Inline Twin 200 (800x450)

While I was bluing the flywheel, I decided to give the rockers the same treatment:

Inline Twin 201 (800x450)

The rockers installed:

Inline Twin 202 (800x450)

I also made the tappets and tappet guides:

Inline Twin 203 (800x450)

Inline Twin 204 (800x450)

Inline Twin 205 (800x450)

Valve springs and spring retainers installed:

Inline Twin 206 (800x450)

Push rods installed:

Inline Twin 207 (800x450)

 

Thank you for visiting my shop.

If you have any questions about the engine or any of the other projects, please leave a comment below, or email at yogisworkshop(at)yahoo.com

For other projects from the shop, please check out the Projects Page in the top menu.

Yogi

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Inline Twin Engine Ep. 11

For the camshaft, I’m staying with the spirit of this engine, as it will be built up of multiple pieces.

I started with the cam blanks, turned and parted off. They are made from 1144 Stressproof Steel.

Inline Twin 165 (800x450)

The second side of the cam blanks are finishe turned:

Inline Twin 166 (800x450)

Drilled and tapped for a set screw:

Inline Twin 167 (800x450)

The two cam blanks, ready for the cam profile:

Inline Twin 168 (800x450)

To set up for the milling of the cam profile, I chucked up a piece of shaft in the collet block, and milled a flat for the set screw.

Inline Twin 169 (800x450)

The collet block is set up vertical in the CNC mill and the cam blank secured.

Inline Twin 170 (800x450)

The profile is milled using a t-slot cutter, to be able to cut both cams in the same program.

Inline Twin 171 (800x450)Inline Twin 172 (800x450)

The process was then repeated for the second cam. The only difference, it is a mirrored version of the first one.

The two cams finished:

Inline Twin 173 (800x450)

The shaft has two flats milled, which need to be indexed 180 degrees. The collet block makes quick works of the indexing.

Inline Twin 174 (800x450)

With the shaft still in the collet block, I engraved a line on the end of the shaft. This will help to time the camshaft.

Inline Twin 175 (800x450)

The assembled camshaft:

Inline Twin 176 (800x450)

To finish up the gear train for the camshaft, I needed the idler gear. When I designed the engine, I utilized stock gears from SDP/SI. SDP has CAD files for all their gears for download on their site, which is a tremendous help in the design process.
For the idler gear, none of the stock gears would fit my application. My solution was to use a stock gear and modify it to my need.

To illustrate the design of the idler, and to adjust the backlash in the gears, I attached a CAD rendering below. The hole in the crankcase cover is drilled oversize, allowing some adjustment.

Inline Twin 185 (800x549)

The stock gear, as received from SDP:

Inline Twin 177 (800x450)

In the lathe, the gear was then bored out to the correct diameter for the miniature ball bearing.

Inline Twin 178 (800x450)Inline Twin 179 (800x450)

Parting off:

Inline Twin 180 (800x450)

A bushing is turned, to hold the bearings, and to mounted it to the crankcase cover.

Inline Twin 181 (800x450)

The gear, bearing, and bushing assembled:

Inline Twin 182 (800x450)

The idler installed on the engine:

Inline Twin 183 (800x450)

The finished gear train, with the camshaft installed.
To note is the line engraved on the end of the camshaft as mentioned in an earlier, for timing of the camshaft.

Inline Twin 184 (800x450)

 

Thank you for visiting my shop.

If you have any questions about the engine or any of the other projects, please leave a comment below, or email at yogisworkshop(at)yahoo.com

For other projects from the shop, please check out the Projects Page in the top menu.

Yogi

Inline Twin Engine Ep. 10

The valves are made up of two pieces and silver soldered together. With this method, the long, slender valve stem is already precision ground and doesn’t need to be further machined.

The parts before and after silver soldering:

Inline Twin 154 (800x450)Inline Twin 155 (800x450)

The valve head is finished in the lathe:

Inline Twin 156 (800x450)Inline Twin 157 (800x450)

Last, the valve stem is turned to length and a groove for the spring retainer is cut:

Inline Twin 158 (800x450)

The finished valves:

Inline Twin 159 (800x450)

Another part for the cylinder head is the bracket for the rockers.

First, the stock is clamped vertical in the vise, to machine the contour and drill the hole.

Inline Twin 160 (800x450)

The work piece is laid horizontal to mill the bracket to finish width:

Inline Twin 161 (800x450)

The bracket is cut off the remaining stock with the cold saw:

Inline Twin 162 (800x450)

The last operation is to clean up the saw cut, milling the bracket to final thickness. Drilling the mounting holes, and tapping for a set screw that will hold the rocker shaft in place. The paper in the vise is to protect the finished surfaces from getting marked up.

Inline Twin 163 (800x450)

The finished bracket:

Inline Twin 164 (800x450)

 

 

Thank you for visiting my shop.

If you have any questions about the engine or any of the other projects, please leave a comment below, or email at yogisworkshop(at)yahoo.com

For other projects from the shop, please check out the Projects Page in the top menu.

Yogi

Inline Twin Engine Ep. 9

The cylinder head is one of the more complex parts, requiring a number of different operations. As usual, I’ll let the pictures do most of the talking as I’m going trough each step.

Started with a facing cut:

Inline Twin 124 (800x450)

The outside contour is milled to full depth:

Inline Twin 125 (800x450)

Spotting and drilling:

Inline Twin 126 (800x450)Inline Twin 127 (800x450)

Milling the combustion chamber:

Inline Twin 128 (800x450)

Milling the recess for the O-ring, sealing the coolant passage from the block to the head:

Inline Twin 129 (800x450)

Drilling and reaming for the valve guides:

Inline Twin 130 (800x450)Inline Twin 131 (800x450)

I’ll be using Rimfire spark plugs. Since even the long reach plug is still too short, the combustion chamber is getting an “extension” with a ball end mill:

Inline Twin 132 (800x450)

First side of the cylinder head complete:

Inline Twin 133 (800x450)

The cylinder head is turned over and faced to final thickness:

Inline Twin 134 (800x450)Inline Twin 135 (800x450)

The coolant passage is milled:

Inline Twin 136 (800x450)

The second side complete:

Inline Twin 137 (800x450)

The head is then set up on its side to drill the holes for mounting the exhaust manifold and carburetor mounting. The location for the inlet and exhaust ports are only spot drilled. They are angled and will be drilled later.

Inline Twin 138 (800x450)Inline Twin 139 (800x450)

To finish up the cylinder head, I needed the valve guides as the inlet and exhaust passages are drilled trough the guides. The material I used for the guides is O-1 drill rod.

Inline Twin 140 (800x450)

Valve guides installed in the cylinder head (press fit):

Inline Twin 141 (800x450)Inline Twin 142 (800x450)

The cylinder head is clamped in the vise at the correct angle to drill the exhaust port.

Inline Twin 143 (800x450)

The location of the hole is picked up with a center in the spot drilled location marked earlier.

Inline Twin 144 (800x450)

Using an end mill, a flat is milled to be able to center drill and drill the hole on the angled surface.

Inline Twin 145 (800x450)

Inline Twin 146 (800x450)

Inline Twin 147 (800x450)

Inline Twin 148 (800x450)

The same process was then repeated three more times for the other ports:

Inline Twin 149 (800x450)

Inline Twin 150 (800x450)

Inline Twin 151 (800x450)

To finish off the cylinder head, it needed a cover to seal the coolant passage.

Inline Twin 152 (800x450)

The finished head assembly:

Inline Twin 153 (800x450)

 

Thank you for visiting my shop.

If you have any questions about the engine or any of the other projects, please leave a comment below, or email at yogisworkshop(at)yahoo.com

For other projects from the shop, please check out the Projects Page in the top menu.

Yogi

Inline Twin Engine Ep. 8

A number of components are finished and I felt it’s time to assemble what I have. I don’t want to get too far ahead of myself, making parts. If there is a problem, it would be easier addressed now rather than later. And it’s always exiting to see an engine taking shape…

A plug is inserted in the camshaft bore to close it off on the back of the engine.

Inline Twin 116 (800x450)

The crankshaft is finished up on the accessory end with a small diameter shaft extension.

Inline Twin 117 (800x450)

The gear installed on the crankshaft:

Inline Twin 118 (800x450)

The connecting rods are assembled with the pistons and needle roller bearings:

Inline Twin 119 (800x450)

The assembled crankshaft is installed and the crankcase closed.

Inline Twin 120 (800x450)

And the assembled engine block:

Inline Twin 121 (800x450)

Inline Twin 122 (800x450)

To give you an idea of the size of the engine, here with yours truly.

Inline Twin 123 (800x584)

I’m very pleased how the engine has turned out so far. Everything is fitting together and works the way I envisioned it when I designed it. I haven’t discovered any mistakes in the design (yet).

It’s very low friction. I hope this will materialize in the running characteristic of the engine. I tried to take a short clip of me turning the engine over to demonstrate.

 

Thank you for visiting my shop.

If you have any questions about the engine or any of the other projects, please leave a comment below, or email at yogisworkshop(at)yahoo.com

For other projects from the shop, please check out the Projects Page in the top menu.

Yogi

Inline Twin Engine Ep. 7

The progress on the engine continues. In this episode I’ll be making the cylinder sleeves and pistons.

The cylinder sleeves are turned from cast iron bar stock. The first side is turned to finish size on the outside and inside diameters. This ensures concentricity.

Inline Twin 101 (800x450)

After parting off, the sleeves are finished on the second side. The small shoulder will create a groove in the cylinder block for an O-ring.

Inline Twin 102 (800x450)

Finish turned sleeves:

Inline Twin 103 (800x450)

…and that’s how they look installed in the cylinder block:

Inline Twin 104 (800x450)

The surface finish in the bore turned out very nice and was cylindrical within less than 0.01 mm. I contemplated to just leave it as is, just turned. But I decided to finish lap the bore. Since the surface finish was already really good, and the bore straight, the lapping took mere minutes to complete (note the cling film on the lathe bed, to protect it from any lapping compound drips).

Inline Twin 105 (800x450)

 

The next parts are the pistons.

I started with turning a boss to hold the blank in a collet for the subsequent operations. The piston diameter is 32mm, too large to go directly into a 5C collet.

Inline Twin 106 (800x450)

Chucked in a collet, the OD is turned to finish size and the grooves for the rings are cut:

Inline Twin 107 (800x450)

Using a collet block, it is over to the mill to cut the recess for the connecting rod:

Inline Twin 108 (800x450)Inline Twin 109 (800x450)Inline Twin 110 (800x450)

Without removing the piston blank from the collet block, the wrist pin bore is drilled and reamed. This ensures the hole is perfectly perpendicular to the milled recess.

Inline Twin 111 (800x450)Inline Twin 112 (800x450)

The last operation is to face off the chucking boss. The piston is clamped very gently in the 3 jaw chuck with some paper to protect the surface from getting marked up.

Inline Twin 113 (800x450)Inline Twin 114 (800x450)

The finished Pistons:

Inline Twin 115 (800x450)

 

Thank you for visiting my shop.

If you have any questions about the engine or any of the other projects, please leave a comment below, or email at yogisworkshop(at)yahoo.com

For other projects from the shop, please check out the Projects Page in the top menu.

Yogi

Inline Twin Engine Ep. 6

The last part of the crankcase assembly is the cover on the back, or the flywheel end of the engine.

First, I turned the inside of the cover where it will seat an additional ball bearing. I’ll be using a sealed ball bearing (2RS style) to serve double duty as an output shaft seal. Sealed bearings are grease filled and lubricated for the life of the bearing, but I’ll remove the inner seal and use the engine oil for lubrication, leaving the outer seal in place to prevent oil from leaking out of the engine.

Inline Twin 091 (800x450)

The part is turned over, and finished on the outside:

Inline Twin 092 (800x450)

The last operation is on the mill to drill the mounting holes:

Inline Twin 093 (800x450)

The finished part:

Inline Twin 094 (800x450)Inline Twin 095 (800x450)

 

The next parts for the engine are the connecting rods. The big end will house a needle roller bearing, and the small end a bronze bushing.

The first side is machined to the full depth plus a little extra to allow for the second side machining.

Inline Twin 096 (800x450)Inline Twin 097 (800x450)

A set of machinable soft jaws was milled out, to hold the rods for the second operation:

Inline Twin 098 (800x450)

The extra stock is milled off and the rods machined to final thickness.

Inline Twin 099 (800x450)

The finished connecting rods:

Inline Twin 100 (800x450)

 

Thank you for visiting my shop.

If you have any questions about the engine or any of the other projects, please leave a comment below, or email at yogisworkshop(at)yahoo.com

For other projects from the shop, please check out the Projects Page in the top menu.

Yogi

Inline Twin Engine Ep. 5

In this episode, I’ll be continuing the work on the crankcase by making the cover for the accessory end of the engine.

First operation, face milling the top:

inline-twin-065-800x450

Spotting and drilling the hole pattern:

inline-twin-066-800x450

inline-twin-067-800x450

Roughing the contour:

inline-twin-068-800x450

Milling the counter bores:

inline-twin-069-800x450

Finishing pass:

inline-twin-070-800x450

And an edge break around the contour with the spot drill:

inline-twin-071-800x450

First side finished:

inline-twin-072-800x450

I decided to make the gear cover as well, as I can use the same tools and similar set ups.
Again, first step was a face cut:

inline-twin-073-800x450

Spotting and drilling:

inline-twin-074-800x450

inline-twin-075-800x450

Roughing:

inline-twin-076-800x450

Milling the relief for the screw heads:

inline-twin-077-800x450

Finishing pass:

inline-twin-078-800x450

Edge break:

inline-twin-079-800x450

First side of the gear cover done:

inline-twin-080-800x450

A set of machinable soft jaws were installed in the vise and milled out for the second side operation.

inline-twin-081-800x450

Second side of the cover finished, still in the vise:

inline-twin-082-800x450

Another pocket was milled out in the soft jaws to finish the second side of the gear cover.

inline-twin-086-800x450inline-twin-087-800x450

The finished parts:

inline-twin-083-800x450inline-twin-084-800x450inline-twin-088-800x450inline-twin-089-800x450inline-twin-090-800x450inline-twin-085-800x450

 

Thank you for visiting my shop.

If you have any questions about the engine or any of the other projects, please leave a comment below, or email at yogisworkshop(at)yahoo.com

For other projects from the shop, please check out the Projects Page in the top menu.

Yogi

Inline Twin Engine Ep. 4

The next part I’ll be making for the engine is what I call the cylinder block. The challenge on this part will be the O-Ring groove deep down in the bore and the space for the liquid cooling. The first picture is a sectioned rendering to illustrate how the finished part should look.

inline-twin-045-800x563

I started with squaring the block on 5 sides on the Bridgeport.

inline-twin-046-800x450

I then moved the work over to the CNC mill where the top side was faced over and two holes for the bores were pre-drilled. To rough out the two bores I used a long end mill and a helical interpolation. This is by no means the most efficient way when it comes to metal removal rate but it works very well with the long end mill. Another benefit is that it will produce the right size bore so it’s not going to take many passes with the boring head to get it to size.

inline-twin-047-800x450

And bored out to finish size using a boring head.

inline-twin-048-800x450

For the O-Ring groove I used a small slitting saw. The saw is 1 x 0.043”
The groove is quite deep down in the bore making it a bit nerve wracking as it’s impossible to see the cut. It’s one of those “let’s hope the code is right” moments…

inline-twin-049-800x450inline-twin-050-800x450

To relief the block for the coolant I used a T-slot cutter.

inline-twin-051-800x450inline-twin-052-800x450inline-twin-053-800x450

The next operation was to mill a step to seat the sleeve.

inline-twin-054-800x450

The last operation on the top of the block was to drill the holes for the cylinder head and coolant passages.

inline-twin-055-800x450

To top side finished:

inline-twin-056-800x450

The block is then turned over to drill the mounting holes on the bottom.

inline-twin-057-800x450

The bottom “flange” is milled.

inline-twin-058-800x450inline-twin-059-800x450

And the passage for the coolant inlet is drilled.

inline-twin-060-800x450inline-twin-061-800x450

Last, the step on the sides were milled. This is a cosmetic feature as I needed a bit more length on the cylinder head but didn’t want to lengthen the crankcase.

inline-twin-062-800x450

The finished cylinder block.

inline-twin-063-800x450

The engine is slowly taking shape:

inline-twin-064-800x450

 

Thank you for visiting my shop.

If you have any questions about the engine or any of the other projects, please leave a comment below, or email at yogisworkshop(at)yahoo.com

For other projects from the shop, please check out the Projects Page in the top menu.

Yogi

Inline Twin Engine Ep. 3

In today’s episode, I’ll be making the crankshaft.

This whole engine is built around the crankshaft, and it’s design. It will be a test bed for future use of this idea.

Please refer to Inline Twin Engine Ep. 1 for a CAD rendering of the crankshaft.

The individual parts are turned on the lathe first. This will be the rear, the flywheel end of the engine.

inline-twin-030-800x450inline-twin-031-800x450

Second side finished turned.

inline-twin-032-800x450

The crank discs were turned next:

inline-twin-034-800x450inline-twin-035-800x450

What will be the front end of the engine (the accessory end):

inline-twin-036-800x450

After all the parts are finished turned, it was over to the mill. I machined a set of soft jaws, to be able to hold the part accurately on the bearing seat. It is very important the hole for the crank pin is not only accurate in diameter, but also exactly perpendicular for everything to line up when assembling the crankshaft. Any misalignment would result in binding of the bearing.

inline-twin-037-800x450

Two of the discs were drilled to be tapped, and two countersunk.

inline-twin-038-800x450

The front and rear parts being finished as well:

inline-twin-039-800x450inline-twin-040-800x450

The different parts, ready for assembly:

inline-twin-041-800x450

…and the assembled crankshaft:

inline-twin-042-800x450

The crankshaft installed in the crankcase:

inline-twin-043-800x450inline-twin-044-800x450

To demonstrate how well it turned out, a short video:

I’m very pleased how free the crank is running. This part of the build has exceeded my expectations, and I can already envision this type of crankshaft in future engine builds.

Thank you for visiting my shop.

If you have any questions about the engine or any of the other projects, please leave a comment below, or email at yogisworkshop(at)yahoo.com

For other projects from the shop, please check out the projects page in the top menu.

Yogi