Author Topic: Flat twin 60cc (Read 6358 times)

glorfindel · « **on:** March 11, 2021, 02:08:49 PM »

The hirth coupling in the 160cc flat 4 was irritating me, so i decided to do a 'twin'.

60cc, with symetrical cylinders thus the 'fork' configuration of the conrods. Imperial system, 2 rings per piston, 10:1 compression ration (glow)

all allu is 6061t6, crank 1045, push rods, cam shaft and pins are drill rods (w1 tool steel).

here is the 3d model and the crank case i made so far.

Jasonb · « **Reply #1 on:** March 11, 2021, 03:17:41 PM »

Off to a good start.

That looks a bit more than the usual hobby benchtop CNC

have you posted about it elsewhere and I've missed it

Roger B · « **Reply #2 on:** March 11, 2021, 08:20:07 PM »

He is a CNC teacher and does this for a job

It's a 5 axis DMG 1250CTX mill/turn

https://www.modelenginemaker.com/index.php/topic,8770.msg195434.html#msg195434

Jasonb · « **Reply #3 on:** March 11, 2021, 08:29:56 PM »

Thanks Roger, bit of reading for me there (well looking at pictures)

glorfindel · « **Reply #4 on:** March 11, 2021, 09:06:06 PM »

Quote from: Jasonb on March 11, 2021, 03:17:41 PM

Off to a good start.

That looks a bit more than the usual hobby benchtop CNC have you posted about it elsewhere and I've missed it

Quote from: Roger B on March 11, 2021, 08:20:07 PM

He is a CNC teacher and does this for a job It's a 5 axis DMG 1250CTX mill/turn

https://www.modelenginemaker.com/index.php/topic,8770.msg195434.html#msg195434

Im teaching machanical engineering since 1997 ;-)

I'm a CatiaV5 cad/cam/fea teacher that appears to like engines and motor sports. ;-)

The final project i gave this week to one of my class is to design a small 15-30cc single 4 strokes engines.

Kids like that ;-)

So far, i made the edward radial 5, wich is 99% done, only intakes missing.

I also made a derived engine from the Nemett 15, wich is working.

Now i work on the 60cc twin. ;-)

Sorry for my bad english, french is my first language.

Btw, the cnc on the pic is a DMG DMU 50, 5 axis mill.

The DMG CTX 1250 was crashed by a student and is waiting for a new head ;-)

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glorfindel · « **Reply #5 on:** March 16, 2021, 06:10:18 PM »

Since the tcx1250 is off duty, i did the sleeves the old way ;-)

C12L14 Reamed to 1-3/8"

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Roger B · « **Reply #6 on:** March 16, 2021, 08:13:27 PM »

Looking good

Your English is fine

I am well aware what my German sounds like to the locals ( I am English and living in German Switzerland).

glorfindel · « **Reply #7 on:** March 17, 2021, 05:49:23 PM »

Did the first step of the Rocker Support!!

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glorfindel · « **Reply #8 on:** March 19, 2021, 08:17:00 PM »

Did some work today.

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glorfindel · « **Reply #9 on:** March 26, 2021, 01:35:59 PM »

New parts done!! Glow plug hole missing.

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glorfindel · « **Reply #10 on:** April 07, 2021, 02:46:26 AM »

I didnt like the bolt pattern and the threads for the intake/exhaust ports. So i redesigned it with a new bolt pattern and flanged intake/exhaust.

No need to do left/right side anymore.

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glorfindel · « **Reply #11 on:** April 07, 2021, 08:04:01 PM »

Did the nose and the rockers today.

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AVTUR · « **Reply #12 on:** April 08, 2021, 01:01:22 PM »

A nice engine - neither too simple nor too complex.

Is this your own design or are you making it from someone else's drawings?

AVTUR

glorfindel · « **Reply #13 on:** April 08, 2021, 02:51:00 PM »

Quote from: AVTUR on April 08, 2021, 01:01:22 PM

A nice engine - neither too simple nor too complex.

Is this your own design or are you making it from someone else's drawings?

AVTUR

I ordered the Jung flat 4 160cc plans and turned it in a 60cc flat twin , with new rods (fork configuration), heads, pistons, rings, imperial measures (1-3/8" bore) etc...

I got lots of plans, taking idea left and right.

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glorfindel · « **Reply #14 on:** April 08, 2021, 10:29:52 PM »

Cages done!! I used bronzebushing material.

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simplyloco · « **Reply #15 on:** April 08, 2021, 11:30:56 PM »

Quel travail excellent!
J'aime la France!
John

MJM460 · « **Reply #16 on:** April 09, 2021, 01:51:04 AM »

Beautiful work, Glorfindel. It is great to see what young engineers of the future are being taught today. I do wish you were close enough to run night classes here though. Though come to think of it, at my age, afternoon might be better.

I am enjoying seeing a quite beautiful engine coming together. Do you have any pictures of the set ups for holding the various pieces or the machining in progress? (If it is possible to see the progress past the coolant spray?)

Thanks for posting

MJM460

glorfindel · « **Reply #17 on:** April 09, 2021, 03:24:35 AM »

Quote from: MJM460 on April 09, 2021, 01:51:04 AM

Beautiful work, Glorfindel. It is great to see what young engineers of the future are being taught today. I do wish you were close enough to run night classes here though. Though come to think of it, at my age, afternoon might be better.

I am enjoying seeing a quite beautiful engine coming together. Do you have any pictures of the set ups for holding the various pieces or the machining in progress? (If it is possible to see the progress past the coolant spray?)

Thanks for posting

MJM460

Thx for the kind words.

I'll put a little bit more details ;-)

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AVTUR · « **Reply #18 on:** April 09, 2021, 02:08:13 PM »

Thanks for the reply.

I will keep on following the postings.

AVTUR

glorfindel · « **Reply #19 on:** April 09, 2021, 03:30:27 PM »

So, back plate done!!

Here is the setup. First i did the CAM part with CatiaV5.

Then in used the 3 axis vise and setted the G54 with the probe.

I use 25mm R390 carbide tool for roughing at 140in/min with a 0.075" depth of cut.

I leave 0.008" for all the finishing passes. I always use a HSS tool for finishing at 15in/min.

Here is 3 shorts videos.

One of roughing with the R390
One of drilling the 8 holes
One of the bearing finishing pass.

Short videos, 'cause i cant let the coolant off for too long, sorry for the quality, the windows are old and dirty.

<a href="https://www.youtube.com/watch?v=5lOfczCyae8" target="_blank">http://www.youtube.com/watch?v=5lOfczCyae8</a>

<a href="https://www.youtube.com/watch?v=zQ6f7rZK1xY" target="_blank">http://www.youtube.com/watch?v=zQ6f7rZK1xY</a>

<a href="https://www.youtube.com/watch?v=4cozDvjeeDU" target="_blank">http://www.youtube.com/watch?v=4cozDvjeeDU</a>

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glorfindel · « **Reply #20 on:** April 10, 2021, 06:00:22 PM »

All the parts, so far, with a 3d printed cam box.

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Admiral_dk · « **Reply #21 on:** April 10, 2021, 07:58:24 PM »

Looks like it will be a very elegant engine when you finish it

I will not envy you your access to such nice tools - but I will admit that I would like have that too ...!

Per

glorfindel · « **Reply #22 on:** April 10, 2021, 08:06:48 PM »

Quote from: Admiral_dk on April 10, 2021, 07:58:24 PM

Looks like it will be a very elegant engine when you finish it

I will not envy you your access to such nice tools - but I will admit that I would like have that too ...!

Per

Thx.

I have decided to start an "engine builder club" at school next year, i need practice ;-)

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AVTUR · « **Reply #23 on:** April 11, 2021, 12:11:20 PM »

Quote from: glorfindel on April 10, 2021, 08:06:48 PM

I have decided to start an "engine builder club" at school next year, i need practice ;-)

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Does that mean you will have many helpers? Or distractions?

AVTUR

MJM460 · « **Reply #24 on:** April 11, 2021, 01:28:47 PM »

Hi Glorfindel, thanks so much for posting those clips. (Short is good!) It is most interesting to see a little of how those complex parts are produced.

I sure wish that a club like that was available when I was studying. I suspect it will be popular.

MJM460

Art K · « **Reply #25 on:** April 11, 2021, 11:49:49 PM »

Glorfindel,
I have been following along not commented till now, I have a lull in the busyness. I like the flat twin, interesting use of scissor rods to do the cylinders in line. Some of the old V12'sused that set up.
Art

glorfindel · « **Reply #26 on:** April 12, 2021, 12:05:58 AM »

Quote from: Art K on April 11, 2021, 11:49:49 PM

Glorfindel,
I have been following along not commented till now, I have a lull in the busyness. I like the flat twin, interesting use of scissor rods to do the cylinders in line. Some of the old V12'sused that set up.
Art

Both rods weight the same, CAD is usefull in those situations.

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glorfindel · « **Reply #27 on:** April 13, 2021, 03:26:01 PM »

Cutted the cams this morning. I cnc a bar and slice it with the wire edm.

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glorfindel · « **Reply #28 on:** April 14, 2021, 05:29:30 PM »

I did the rear crank today, 2 setups. The last one ( chuck in a vise) is not "standard"... ;-)

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glorfindel · « **Reply #29 on:** April 24, 2021, 05:21:04 PM »

Hi guys.

Did the "front crank" the oldchool way but did the web on the cnc ;-)

Then came the moment of truth, when you put ewrything together, crank wise and make it turn for the first time by hand...It turned pretty smoothly!! So everything is aligned!!

Did the cambox too, i let the "floor" a little bit thicker that what i calculate to be sure to match the lenght of the timing belt without using a bender.

Finaly, i did the pistons. My bore is 1.3767" and my pistons are at 1.374"

Tried to do the master rod...did go well, finish was horrible and i had an offset in my bushings.

Will work on that Monday.

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glorfindel · « **Reply #30 on:** April 30, 2021, 07:30:20 PM »

Cam shaft and linkrod are done.

I have to make a fixture to finish the MasterRod.

Rings are cut to size and waiting for heat threatment.

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glorfindel · « **Reply #31 on:** July 30, 2021, 05:04:36 PM »

Hi there!!!

Here is where i am.

Almost finished the Flat twin, minus the valves. The cnc that i use to make them was crashed(students can be hard on machines lol!!) so, i'll have to wait t'ill september.

I'm working on the "Boxer" configuration of my flat engine.

I never made a one piece crank and i never made a 2 pieces conrods. So that will be fun!!

Any tricks about one piece crank??

Finally, im slowly gathering infos about Wankel engine, wich probably will be my next project after the Boxer.

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Roger B · « **Reply #32 on:** July 30, 2021, 07:07:43 PM »

I am strictly hand machines and tend to use a Keats angle plate for making one piece crankshafts. One build is here:

https://www.modelenginemaker.com/index.php/topic,7883.240.html

Roger B · « **Reply #33 on:** July 30, 2021, 07:12:23 PM »

The 180° version is here:

https://www.modelenginemaker.com/index.php/topic,7883.0.html

I'm enjoying all the CNC work, it's something I need to look into one day

glorfindel · « **Reply #34 on:** July 31, 2021, 01:01:33 AM »

Quote from: Roger B on July 30, 2021, 07:07:43 PM

I am strictly hand machines and tend to use a Keats angle plate for making one piece crankshafts. One build is here:

https://www.modelenginemaker.com/index.php/topic,7883.240.html

Quote from: Roger B on July 30, 2021, 07:12:23 PM

The 180° version is here:

https://www.modelenginemaker.com/index.php/topic,7883.0.html

I'm enjoying all the CNC work, it's something I need to look into one day

Thx for the links!!!

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glorfindel · « **Reply #35 on:** November 10, 2021, 04:07:52 PM »

It should fire tomorrow!!!!

Putted a small prop for cooling and the support system is ready!!

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Admiral_dk · « **Reply #36 on:** November 10, 2021, 07:27:09 PM »

Looks great - so we hope that you will have success starting and running it

Per

Roger B · « **Reply #37 on:** November 10, 2021, 07:34:59 PM »

I eagerly await the video

eccentric · « **Reply #38 on:** November 10, 2021, 11:12:23 PM »

Wow, she is a beauty! Great job.

Art K · « **Reply #39 on:** November 12, 2021, 02:31:07 AM »

Looks very good! I have been contemplating a flat twin version of my Val engine. The benefit of the two throw crank on it is balance, less vibration. Up to this point I've only made single cylinder engines. I have tried to avoid built up cranks. I couldn't do that with Val but minimized the amount of pieces. It does have an overhung crank like your flat twin. I look forward to hearing it run!
Art

glorfindel · « **Reply #40 on:** November 12, 2021, 04:47:33 PM »

Update!!

It didnt start! Lol!!!

I have compression (a lot), fuel and fire....

So i think my timing is off or something like that, or carburator setup....

I "unplugged" one cylinder 'cause the drill was barely able to swing both cylinders lol!!

It suck, my other engines fired up first time, this one will need some work!!

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Author Topic: Flat twin 60cc (Read 6358 times)