Author Topic: Mercedes-Benz W165 Grand Prix engine in 1:3 scale  (Read 64660 times)

Offline Roger B

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Re: Mercedes-Benz W165 Grand Prix engine in 1:3 scale
« Reply #270 on: January 04, 2019, 02:28:29 PM »
Splendid work as ever  :praise2:  :praise2: Thank you for the little bit of design history  :ThumbsUp: I believe that Austin Rover used a cut down Rover V8 as the basis for the V6 engine used in the MG Metro 6R4.
Best regards

Roger

Offline Admiral_dk

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Re: Mercedes-Benz W165 Grand Prix engine in 1:3 scale
« Reply #271 on: January 04, 2019, 06:39:12 PM »
Great to see another update posted about this fantastic project  :praise2:

Quote
If you ask, "Does CNC make engine building easy?     I will reply, " CNC machining doesn't necessarily make it easy, but it does make very complex parts possible"

As someone who so far only has done 2.5D CNC to make dual sided PCB prototypes - I'm rather well aware of some of the many possible ways it still can go wrong - so you have my full "sympathy" (for lack of better word) for why you only did one at a time.
I would also have been worried that I didn't make the mistake of "mixing the files" - milling one side with the file for A and by mistake milling the other side with the file for B, C & D instead of A - been there, done that  :facepalm:  In my case less than £1 in materials + time ....

Offline Art K

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Re: Mercedes-Benz W165 Grand Prix engine in 1:3 scale
« Reply #272 on: January 05, 2019, 05:10:44 PM »
Mike,
I saw this posted yesterday but had spent to much time on the computer already to be able to focus on reading it. This is great work! And yes it is way to easy to confuse and pick a similar program. At least you had two of each cam box.
Art
"The beautiful thing about learning is that no one can take it away from you" B.B. King

Offline Vixen

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Re: Mercedes-Benz W165 Grand Prix engine in 1:3 scale
« Reply #273 on: January 05, 2019, 07:12:55 PM »
Hello everybody, thanks for calling in.

In an industrial setting, one tool path program can be used to make thousands and thousands of identical components. By contrast, in the model engineering world, it can take a thousand different tool path programs to make a single engine. The industrial guys can afford to invest the extra time to fully optimise their tool path code, to minimise production time. Industrial machines are often expected to run unattended, all day and overnight producing  bucket fulls of identical parts. And as they say 'time is money'.

For engine building, I found it safest to create the tool path program(s) for a single component just before it is manufactured. Once the required number of parts have been made I delete that program from memory. That way, I cannot select the wrong one by mistake. If I need to remake a part, then I have to rewrite a new program. The base information for each program is always contained in the master CAD drawing. When the part(s) have been made, I delete that tool path program.

A single component such as a Cam Box for the W165 may need five or six separate programs, one for each cutter, drill size or set-up. I have got into the habit, because it has proved to be the safest approach, of producing the tool path code on the day I machine the part or parts. I don't normally spend a lot of time tuning or optimising the code, It's often quicker to stand by the machine, changing the tools manually and adjusting the feed rate, by ear, for different parts of the program. Sometimes the tool path code, produced by a CAM program, can waste time with unnecessary line of code which only machine thin air. These redundant line of code can of course be edited out,  but that takes time. I often simply increase the feed rate to maximum to quickly work off these unnecessary lines.

There are many roads to a destination, it's all about finding a method, or route, that works for you.

Mike

It is the journey that matters, not the destination

Offline fumopuc

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Re: Mercedes-Benz W165 Grand Prix engine in 1:3 scale
« Reply #274 on: January 05, 2019, 08:08:19 PM »
Hi Mike, your are not alone, I do it the same way.
Kind Regards
Achim

Offline Art K

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Re: Mercedes-Benz W165 Grand Prix engine in 1:3 scale
« Reply #275 on: January 05, 2019, 08:46:55 PM »
I use Sprutcam for a cam program and when it seems to be "machining air" I see if I can tweak it. I don't like the sliding scale on the screen no mechanical one one the Tormach. A little thing about what it's doing and looking at the screen instead. But that's just me.
Art
"The beautiful thing about learning is that no one can take it away from you" B.B. King

Offline Vixen

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Re: Mercedes-Benz W165 Grand Prix engine in 1:3 scale
« Reply #276 on: January 05, 2019, 09:25:26 PM »
Hello Art

My control program is LinuxCNC which is basically the same software behind your Tormach. I always prefer to use the keyboard, short cut button commands to change parameters. Like you, I am not comfortable with using the mouse to move the sliders, key strokes are safer, a physical knob or handwheel would be better still.

Mike
It is the journey that matters, not the destination

Offline Art K

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Re: Mercedes-Benz W165 Grand Prix engine in 1:3 scale
« Reply #277 on: January 05, 2019, 11:41:11 PM »
The short cut commands are great but I don't tend to remember them, use them. Ditto on the non-existent knob.
Art
"The beautiful thing about learning is that no one can take it away from you" B.B. King

Offline Vixen

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Re: Mercedes-Benz W165 Grand Prix engine in 1:3 scale
« Reply #278 on: March 29, 2020, 12:33:48 PM »
Hello There,

It's been a long time since I updated this Mercedes W165 build. Instead, I have been concentrating on the 1/3 scale Bristol Jupiter and more recently on finishing my two 1/4 scale Bristol Mercury radial engines. The work on the Mercurys is nearing completion, so I thought to review where I had reached with the other big project, the Mercedes W165's. We all have a lot of time on our hands, so I thought a longer update would give you something to read and give me something to do while locked down inside the house.

The build log shows I had got as far as finishing all four cam boxes and the installation of the camshafts (less cams). Since then, I have made a start on the complex geared drive train which drives them. Each of the four cams is driven by a 64tooth 0.8 Module straight cut spur gear. I made a start on these gears by preparing the gear blanks from EN8 steel discs. The discs came from a water jetting company, they were the offcuts (outcuts??) from a larger job.




The discs, enough for the two engines, were bored and turned to size. Both outside faces were turned to the correct profile before being transferred to the mill for drilling out






Here is one of the cam gear blanks on the rotary table, the magic roundabout, having the hub mounting holes and the outer lightening holes milled and drilled.




Eight cam gear blanks await there turn to visit the tooth doctor




But before I can cut the teeth I need something to mount the gear blanks on. I decided I would get greater accuracy if I cut the gears on the actual shafts on which they will eventually run.
A set of keyed hubs for the camshafts were turned, key broached and drilled







Here you can see completed set of keyed camshafts (less cams), hubs and gear blanks. A visit to the tooth doctor is imminent, you cannot put it off forever.




I am going to cut the 64 teeth using the 4th axis unit I made by converting an old EMCO Compact 5 lathe bed. First I needed to confirm the holding torque to be sure the gear blanks would not rotate the spindle due to the cutting forces.




Then the assembled camshafts and gear blanks were mounted in the collet chuck, the tailstock support was brought up and the gear cutting was underway. I prepared a looped tooth cutting Macro program for my LinuxCNC controller. All I needed to enter was the number of teeth, depth of tooth and distances for the involute cutter to travel and of course the all important feed rate. The feed rate was monitored by ear and adjusted accordingly.  Zick zick zick, zich dont you love the sound of the gear cutter at work




Actually, gear cutting this number of teeth was very straight forward using the CNC control. At least I did not have that worry associated with manually indexing a rotary table of "do you want one extra wide tooth at the end or two narrow ones?"




Here you see a pair of camshaft gears in place on one of the cylinder heads. The gears mesh beautifully.





And here you can see both cylinder heads in place with a perspex mock up of the whole cam shaft gear train.




I will talk more about the gear train in the next installment. Hope it will not be too long in coming.

Until then; stay indoors, lock down and remain safe.

Good luck

Mike
« Last Edit: March 29, 2020, 10:45:11 PM by Vixen »
It is the journey that matters, not the destination

Offline cnr6400

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Re: Mercedes-Benz W165 Grand Prix engine in 1:3 scale
« Reply #279 on: March 29, 2020, 01:54:07 PM »
Great work Mike! an impressive engine. Glad to see you went to the bar early in gear cutting work. (the torque bar, that is)   :Lol:

Offline awake

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Re: Mercedes-Benz W165 Grand Prix engine in 1:3 scale
« Reply #280 on: March 29, 2020, 09:07:30 PM »
All I can say is, wow!
Andy

Offline Admiral_dk

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Re: Mercedes-Benz W165 Grand Prix engine in 1:3 scale
« Reply #281 on: March 29, 2020, 09:16:17 PM »
Great to see this build is still on  :cheers: - I had been wondering if it was my memory (again) and that you had completed it without me remembering so ....  :old:

Don't get me wrong as I also enjoy your other builds enormously too  :praise2:

Offline Vixen

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Re: Mercedes-Benz W165 Grand Prix engine in 1:3 scale
« Reply #282 on: March 29, 2020, 09:27:11 PM »
Thanks for calling in.

The problem is too many big projects and too little time. They each have to wait to take their turn.

Mike
It is the journey that matters, not the destination

Offline Art K

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Re: Mercedes-Benz W165 Grand Prix engine in 1:3 scale
« Reply #283 on: March 30, 2020, 02:41:07 AM »
Mike I see what you mean about to many projects. It is good to see you back to work on the W165 that gear train mock up reminds me of the Offy gear train. And, those are some realy nice looking gears.
Art
"The beautiful thing about learning is that no one can take it away from you" B.B. King

Online sco

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Re: Mercedes-Benz W165 Grand Prix engine in 1:3 scale
« Reply #284 on: March 30, 2020, 09:25:24 AM »
Can't wait to see that completed gear train!

Simon.
Ars longa, vita brevis.