Jan Ridders Otto Four Stroke

[dbvandy]

I started this thread over on Madmodder.net, and will copy the build posts over to HMEM. This is my second engine in 2 months of building them socomments are welcome...

Now that I have put the Webster to rest, I am starting on the Otto from Jan Ridders plans. What a great guy! I have emailed back and forth with him and he has given me some good insight in his design process and reasoning. The plans arrived in my GMail box a few days ago, so off I go...

http://www.ridders.nu/Webpaginas/pagina_otto_viertactmotor/otto_frametekst_engels.htm

So far I have the cylinder, piston, and head cut and I am beginning to work on the valves... Afterword I will start on the uprights, shafts and 2 base plates. I have not decided on the fuel or ignition at this point, both can be determined after completion of the main engine. I have had very good success with the vapor carb, so I will probably go that route. For the ignition I am looking into the setup on the cheap little Chinese pocket bikes. It is a CDI system that you can get all the parts for for around $20 US.

Here is what I have so far: (I have altered Jans plans a bit by adding some cooling fins to the head and more fins to the cylinder)

The Cylinder is 2 inch x 2 inch 12L14 steel that I bored out (have not honed) and then I cut the fins with a 1/16 inch cut off tool skipping every thread on my lead screw. Worked really good until it snagged one time and stopped dead, thus breaking 3 teeth off the PLASTIC two speed transmission gears in the spindle (cheap Chinese lathe...) I have since replaced the gears with metal ones from LMS and do not plan on having to do that again. (one downside is that they are a bit noisy, but I hope that will wear in after running for a while...)

I tapped the head bolt holes to 6-32 for some stainless socket heads. I think they look better.

The head is 6061 T6 and is close to spec other than the fins and I am using an NGK CM-6 instead of making my own plug. I like to limit the points of failure as much as possible, these plugs should last 1000 times the life of the engine.

The underside of the head. The angle of the plug was changed to 20 degrees and could have been 25 for the shorter CM-6 NGK plug. Without a true mill, I had to use my poor mans mill and then clean it up with my dremel. The seat got a little wide and cut into the valve guide holes, but you will never see it when the guides are pressed in and the plug is capped.

The top of the head. I liked the cooling fins so much I decided to carry them up to the head. It will be functional and look good as well. I will have to cut the side back with my belt sander to clear the uprights.

Head and cylinder assembled.

Head and cylinder assembled.

Piston. I am going to use a viton o-ring to seal the piston. This worked VERY well in the Webster and I have a complete set from Harbor Freight.

more to come......

 

[dbvandy]

I worked a little on the engine on Tuesday and figured out how I am going to do the valves.

I'm using some 12L14 hex turned down to whatever drill I had that was close to 10mm for a press fit into the head.

12L14 has very high lead content and should self lubricate as well as be very strong and wear well. It turns like butter as well...

I have turned one and will work on the second and the two valves tomorrow. The key to getting a good seat is to set your compound up to 45 degrees and do not move it until all 4 parts are turned. You then have to center drill the guide and turn the seat in the same setup, then cut it off.

More to come...

Doug

 

[dbvandy]

Both valves are done now and ready to be pressed into the head... I'm quite pleased with how they turned out, great design, Jan.... (though I did alter them a bit just to make them mine and help it breath easier....)

I turned the valve between centers with a little extra nub on the head side that will be cut off. I have no idea what type of steel it is, it was shiny and came from some old printer. I turned the stem to be .0005 smaller than the bore in the guide. the second guide was a bit tighter after drilling, so I will turn the second valve down to match the second guide.

I precut the nub when it was still between centers, then chucked it up close very lightly and faced the head to size.

Valve parts all turned are ready to be assembled. I used some e-clips I had in a kit. Springs are pre-made. I wound the ones for the Webster... done that... Ford does not wind their springs either... Notice that I cut a little relief into the stem where it will be out of the guide. This will give a little more room for the engine to breath without effecting strength.

Valve and guide assembled. I will seat the valves with valve grinding compound after they are mounted in the head and stable. There just enough play to allow the valve to seat after every cycle and the springs feel about right, not too stiff, not too soft.

 

[dbvandy]

Today was connecting rod and uprights day.... Wish I had a bigger band saw..... and a mill....

I blued up the connecting rod and cut it out with my band saw... the blade was a fine tooth and cut reeeaaalllyyyy slowly.

I trued it up with my small belt sander and drilled out the holes. The bearing for the crank fits an old RC car drive line that I raced 15 years ago... nice to keep those old parts laying around, you never know.

I needed some cam shaft bearings... found some...

I blued and marked up the first upright. I will match the other two to this one so that they are uniform. I cut the upright out with an angle grinder and the roughed it to pretty damn close with the 4.5 inch hand grinder. The band saw was not up to it with the blade that was in it. Time for a trip to home depot for another...

Then I got it really close with my 1x24 inch belt sander table. It is just cosmetics now, so I will wait until I start cleaning it up to get it perfect and polished.

Two uprights cut...

Starting to look like a motor... yea...

Bearing holes to be drilled tomorrow...

More to come...

Doug

 

[dbvandy]

New band saw blade from Home Depot cuts like a hot knife... should go buy more...

I received my 22mm drill bit in the mail so I was able to drill the bearing holes. I pre-drilled them with my unibit (love that thing) and then opened them up to 22 mm to match my high dollar skate bearings.

The 8mm shaft came from an ink jet old printer that I had laying around just waiting to become part of the Otto.

After getting the bearings in, I pinned the uprights together with a part of the shaft and some tubing. Blacked them up and hit them with my belt sander to even them up to perfection.

Tomorrow (or later tonight maybe), I will start on laying out the base plates. Not quite sure how I am going to countersink the cylinder 5mm into the base plate (I do not have a rotary table... yet...) wish I had seen that earlier, I would have made the cylinder to mount flush and have a 5mm lip that is 2mm bigger than the bore to slide into a hole in the plate...

More to come...

Doug

 

[dbvandy]

I got all three uprights made, bearings in and some 40mm plate spacers roughed out. Now it REALLY looks like and engine...

More to come tonight... took Sunday off to go play...

Doug

 

[dbvandy]

Well, everything is mounted solid now and only a few things left to do. I might be making fumes this weekend...

I made a center line on all the uprights and one down the center line on the base plate, lined them up and transferred the holes in the uprights to the base plate. After the 3 back socket heads were in tight, I did the same for the front.

I had made the spacers for between the uprights last night and you can see them here. Also, the 4 corner post and tapped and mounted.

The crank bearing mounts are marked with center lines as well and the hole locations are transferred from the base plates just like the uprights. I changed the design a bit here: the flywheel side is smaller so that I could mount the uprights from the bottom. This will not effect the operation in the slightest, but if I need to make alignment adjustments I can just oversize the holes in the base plate. The crank side is extra thick because that is what size stock I had in the drawer.

I decided to drill and tap a hole into my drill press table as a pivot for the cylinder hole and a 3/8th 4 flute end mill to plunge the stock out. Worked pretty good. for those that are wondering... the chuck is heated and locktited on to the arbor. (I hope I never need to get it off.)

The 1/4 -20 bolt was threaded through the table and then nylocked tight.

Most of the stock was plunged out and then the base plate was spun to even the sides.

Turned out pretty good... the hole was then drilled out with the unibit (still love that thing...)

Here is where we are tonight.

On the agenda for tomorrow: crank, cams, and intake/exhaust manifold...

more to come...

Doug

 

[dbvandy]

Well, finished the crank bearing blocks, crank, and cam blanks.

I cut the cams from 1 inch 4140. The OD is 24mm with a 17mm hub. I will cut the cam down to 20mm by removing the extra stock with the 4 inch belt sander down to the 20mm ledge I left on the hub side.

Both cams are 11.5mm which is the same distance as the valves are apart.

The crank shaft is 8mm from an old Lexmark ink jet printer. I left it long so that I have options when it comes to the final flywheel design. I put 2 bearings on the crank side and one on the flywheel side with an aluminum spacer in between.

The holes have been drilled into the head for the intake and exhaust. The valve guides were high temp red loctited in (hope I never have to get them out). Tappets and guides to be made after cams are ground.

As she sits tonight...

left to do...
grind cams... Done
tappet holes and press in bronze bushings... Done
tappets... Done
Intake/exhaust manifold
muffler
flywheel (faceplate just arrived from LMS today)... 75% done
wrist pin in piston
mill slot in base plate for belt
design ignition system (got the tazer yesterday... don't think it will work, does not seem to recharge fast enough... bummer...)... 25% Done
design carb (have some really cool ideas....)

Belt and pulleys purchased from SDP/SI, should be here next week. I hated to spend the $$$$, but had to be done...

More to come....

 

[dbvandy]

Good day today. Cams, tappets, flywheel, and part of the ignition done.

I blacked up the cam blanks and marked them as per the plans.

Then I used the 36x4 belt sander to sand off the extra stock down to the 20mm lip.

This is the finished intake cam. I will need to fine tune the timing once the belt is installed by grinding off more.

I measured the actual distance from the upright to the valve stem. to my complete amazement, it was dead on... go figure... I then transferred those measurements to the cross brace so I could drill the 3/8 hole for the bushing.

The holes were drilled and then the bushings loctited in. I sanded them flat with the belt sander and counter sunk the bushings. The stock for the tappets is 1/4 inch stainless.

I then measured the distance between the cam and the top of the valve stem. Then made 2 tappets.

Here is the finished cams and tappets.

Cams running:

[ame]http://www.youtube.com/watch?v=Pbt5Wsw93Y8[/ame]

I used the excel pie chart trick to divide the the flywheel into 6 parts for the lightning holes. AND I got to reuse my 1/4 hole in the drill press table as an axle to spin the flywheel on while drilling. I just took a piece of the 8mm shaft and threaded it 1/4-20. Worked well.

Here she sits tonight...

Now off to bed... more to come...

Doug

 

[dbvandy]

Well... its been a few days since I have uploaded some pics, so, here you go...

Let me first start off with a video of how you should listen to that little voice in your head when it says.. "be ready to grab it if something happens"

[ame]http://www.youtube.com/watch?v=GFqtQNU0VmQ[/ame]

All is well... camera fine, engine fine... clamp not fine, extra tight now....

Anyway, I got the piston and connecting rod cut and assembled. I am going to use a Viton o-ring for a good seal, but I might not need it... it seems to have decent compression now... we will see...

I had to make something shiny...

I used a hard brass rod for the wrist pin. Jan suggest steel, but that might grove the side of the cylinder, so brass works good. Not enough compression to worry about sheer... The bushings are brass as well. The oil blow by from the fuel mix will keep them good and lubed.

Piston installed. What a pain... I see now why Jan has only three bolts in the bottom of the cylinder, you can then take the cylinder off to remove the piston. I have four and one is under the main bearing support, so to remove the piston I have to take the engine just about completely apart. I think on next assembly I will forget to put in the hidden bolt... oops...

I added some footsies. The center spacers were removed and drilled and tapped 1/4-20 on the bottom for some threaded rod jam locked into the 1 1/8 38mm long feet. I will get some rubber to glue onto the bottom.

The flywheel supports took forever. If I had it to do over again, I would line drill them out when fully assembled and trued on the lathe. I oversized the hole on the flywheel so that it is only supported by the two aluminum end pieces. It is within .0005 eccentricity and .001 wobble. I could probably get that out with bolt tightening, but its pretty close...

Now for something that I have been dreading... the manifold. I would like to say it came to me in a dream, but really it dawned on me what to do while watching Survivor on Wednesday. The engine usually lives on the coffee table when we are not in the shop, so I have time to stare at it and design.

I decided to have the intake and exhaust come out the top for symmetry and then I don't have to cut into the side of a curved surface for the intake.
The stock was just a piece of 1/2 x 3/4 6061 rough cut on the band saw, drilled for mounting holes (I used two, plan only one) then indicated on the lathe.

Then I turned and grooved. Turned out pretty good... I was worried that it might grab and get thrown because there was VERY little on the inside lip to chuck onto.

I then cut out the extra on the top sides and drilled the holes for the muffler and intake (to be made today)

And now some videos for your viewing pleasure...

Piston and crank. Nothing hits, but it is reeeaaalllyyy close.. about .5mm gap between the connecting rod and the base. Might have to modify if it starts rubbing when at full speed...

[ame]http://www.youtube.com/watch?v=kREFjjO56EE[/ame]

Clamp REAL tight and plug removed so there is no compression.

[ame]http://www.youtube.com/watch?v=6Qt38NhsC5k[/ame]

Exhaust valve held open with cam, plug in.

[ame]http://www.youtube.com/watch?v=4x7Bpu39Kj0[/ame]

More to come... thanks for your constructive comments and suggestions...

Doug

 

[dbvandy]

I'm running out of things to do without belts and ignition parts. Belt and cogs will be here tomorrow... I hope I got the right size...

I redesigned the muffler. It looked like it might be a bit fragile and exposed and easily damaged or knocked off. Not that I am going to be tossing the motor around, but things happen, so I made it with a mount that bolts to the tappet cross member.

It is high temp loctited together.

The intake was the same idea. I will connect the nipple to the vapor tank with some silicone hose or some aluminum tubing.

And a view of it on the motor. Starting to look pretty complete now.

More to come... not much more, but more just the same...

 

[dbvandy]

cogs and belt arrived today... yea... the belt calculator online was dead on! I bought one smaller and one bigger just in case. Tomorrow I strip the engine and cut some slots...

Here is a link to the calculator: http://www.sdp-si.com/Cd/default.htm

Vapor tank will be a glass tube with socket heads to adjust the mixture and throttle... we will see how well it works...

More to come...

Doug

 

[dbvandy]

I cut the slot today and mounted the 192 tooth belt, though I think a 191 would have been PREFECT, it was not offered. I had to bore the holes larger in the cogs to 8mm drill, still do not have an 8mm drill. I drove all over today looking for one. I used a 5/16th and then made a reamer with my chop saw and some 8mm rod. It worked ok. Might make one perfect then harden it for future use.

To cut the slot, I had to mount the plate square to a piece of 3/8 x 2 inch aluminum bar so I had something the clamp to with the vise.

I plunged the holes to start with, then ran the XY compound vise along the sides to clean them up. Not a perfect setup, but it is what I have and works good for cuts that do not have to be super precise.

The finished slot. A bit wider than I wanted to clean it up good, the table moved just a bit between the first and second plunge, but unless you have the plans in front of you and a caliper, you would never know.

This is a wide shot of my "mill" setup. I purchased the $89 XY compound vise from Harbor Freight for $13 (had a good coupon) and I have had the 8 in drill press for 15 years. Bounces around a bit, but plunges well, and then side cuts to clean up the edges. I made a locking bolt for the spindle so that I could set depth and lock it in place.

The small cog with the spacers to keep the bearings apart.

The top cog and belt. I will make the tension idler pulley, top spacers, and cut a slot in the middle support tomorrow.

Ordered some lighters last night... we will see...

A little video of the progress... still have to set timing, I think I will have the motor run toward me, front of cam going down... I think it looks better.

[ame]http://www.youtube.com/watch?v=5YLhv0h_NQM[/ame]

More to come...

Doug

 

[dbvandy]

Well, I am officially out of things to do until the lighters arrive. I will probably work on the vapor tank tomorrow, but I plan to use the one off the webster in the beginning.

I plan to put a belt powered fan on the engine after she starts running. Might not do much, but will look cool. The round groove will have an o-ring the will be connected to a small shaft, thus giving about a 1 to 10 ratio, driving the fan fast.

The pulley is adjustable along a slot to tighten the belt. You can see the o-ring waiting to drive the fan....

Engine as she sits tonight...

And a little video showing the compression and valve action. I have just eyeballed the timing for now, will get it right later...

[ame]http://www.youtube.com/watch?v=GEp0UEkB89E[/ame]

More to come...

Doug

 

[dbvandy]

Got Gas...

Got Spark...

Got To Go!!!!!!!!!!!!!!!!!!!!!!!!!!!!

THE OTTO LIVES!!!!

I had another coil from junk weed eater and I got tired of waiting for the lighters to get here, so I epoxied some neo magnets to the flywheel and used one of the original coil mounting brackets from the Webster to mount the coil to the Otto. I also used the working vapor carb from the Webster, but will make one just for this engine soon. Not looking for pretty right now, just want to hear some pop...

After some eyeball timing, I pulled the cord and it popped popped... but, it kept jumping ignition time, retarding about 45 degrees, I would reset, it would fire 4-5 times, then jump time 45 degrees again.

[ame]http://www.youtube.com/watch?v=XL4mJ4AcePw[/ame]

Turns out the three tiny 8-32 set screws did not have enough bite to hold the flywheel on the 8mm shaft, so I tapped them out for 1/4-20 set screws and all is well. will probably thread the end of the crank shaft and put on a locking nut and star washer.

Then she came to life after some fine tuning of the intake and exhaust timing. But, the camera battery died so this is all for now...

[ame]http://www.youtube.com/watch?v=QXejfWRZ-q8[/ame]

Got too late to run it more because everyone was in bed, so I will fine tune it more tomorrow...

More to come...

Yeah.....

Doug

 

[dbvandy]

Well, I spent a few minutes tweaking the motor today. No new parts, just a timing wheel made from a 360 deg protractor.

Here are some videos:

The Engine running about 2500 RPM. Being as there is no real throttle to control RPM, you control it through mixture. Richer runs cooler and slower, lean runs hotter and faster. One issue with the vapor carb is that this is a moving target as the powerful hydrocarbons vaporize first and so you have to add a ton of air, then what is left is less volatile and you have to adjust it with less air bypass to enrich the mixture.

[ame]http://www.youtube.com/watch?v=ZxxWcMz2oMk[/ame]

I used a smaller and lighter flywheel (5 inches) than the plans called for because this is about all my 7x12 can turn. Maybe when the cam timing is better and the ignition more reliable, I can get it slower, but this is about it for now.

[ame]http://www.youtube.com/watch?v=Aitbz_I655s[/ame]

The old timing light I have pops ghost images, but the timing is pretty close to 10 degrees BTDC. I did not have the timing wheel when I shot this, so I will use it when I fine tune the ignition timing.

[ame]http://www.youtube.com/watch?v=6eHFW680rbw[/ame]

After 20 minutes and 2 tanks of Coleman fuel with a few drops of Marvel Mystery Oil, the cylinder only got up to 190 degrees and the head only up to 145. I do not see it being run much harder than this, so that is about my benchmark for temp. Then she ran out of gas....

[ame]http://www.youtube.com/watch?v=YmQ13qe9lQY[/ame]

The coil was mounted with the old bracket from when I had the coil mounted fixed to the Webster base. If it becomes a permanent part, I will make a more elegant mounting system. Timing is changed by rotating the position of the flywheel and the new 1/4-20 setscrews hold it very well. Right now it HAS to be clamped tight to the table because the flywheel is way out of balance from the addition of the magnets. I might epoxy some washers 180 degrees to balance it.

The Vapor tank is a transplant from the Webster. It ran good, so I just wanted as few variables as possible to get it running smooth. The tank for this engine will be made when my rotary table arrives.

The intake valve seem to be floating a bit causing it to stay open and blow fuel out of the tank. I later deduced was exhaust timing closing too early and creating pressure in the cylinder, then the intake opened and the pressure went into the tank, spewing fuel. But, I had some stronger springs, so I put them on just to make sure. The other ones seemed a bit week.

The Marvel mystery oil does not burn so it just collects in the cylinder. This is a good thing. Once it is broken in I will reduce the mixture as even now it does not smoke when running. The smoke you see in the videos is from 3and1 oil used to lube the valves and cams.

There is a little burnt oil and carbon on the exhaust side as to be expected when it is so oil rich. This is after about an hour of running and 10 tanks.

Still on the fence when it comes to the piezo ignition. I might see if I can tuck this coil in under the cam in a tasteful way. I do not know if it will deliver a reliable spark at cam RPM, so it might have to stay on the flywheel. Maybe if I paint the lamination silver or something...

More to come...

Doug

 

[ozzie46]

Great runner. I really like the sound.

Ron

 

[RManley]

Nice looking engine and well photographed

I like 'quick' writeups as I always get impatient for them to be finished and run

Rob.

 

[dbvandy]

The build started on February 8th and there was a week without building because the plastic gears in the head popped some teeth (now have metal ones). The build log started on February 16th on Madmodder.net and was copied over here.

I am really amazed at the sound that comes from this engine! it has quite a crack and is very loud. I love it!!!!

after I get the ignition final designed, I will start making it pretty....

Thanks for the comments...

Doug

 

[dbvandy]

Well... I had her up to 5600 RPM today running really smooth... Idles about 800...

I tried to use a carb off an RC car with about the same results as the webster... bad...

I whipped up a quick adapter for the 10mm carb

The carb installed... it ran, but either idled or sputtered to 2000 RPM then died. after about throwing it across the room in frustration, I put the vapor carb back on. I love that thing...

I did play around a bit and ran the engine on propane and some other stuff... maybe I will make a demand valve and run it off a bottle...

[ame]http://www.youtube.com/watch?v=ibARki78E-U[/ame]

This week I plan to finalize some things... glass vapor tank, and ignition (coil or piezo)

More to come...

Doug