Author Topic: Mercedes-Benz W165 Grand Prix engine in 1:3 scale  (Read 71201 times)

Offline bent

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Re: Mercedes-Benz W165 Grand Prix engine in 1:3 scale
« Reply #315 on: April 07, 2021, 04:20:18 PM »
Vixen, thanks for the clarification.

Online Vixen

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Re: Mercedes-Benz W165 Grand Prix engine in 1:3 scale
« Reply #316 on: April 07, 2021, 05:19:42 PM »
Mike:
That's OK, I've kinda lost touch also. But here's the cliff notes summary.

Thanks for the update. I had to look up those place names on the net. Brenda and Quartzsite seem to have a magnetic attraction for RV's, must be the warm winter sunshine and I guess Prescott is cooler in the summer. Good to hear you can do some machining in both places.


Stay safe

Mike
« Last Edit: April 09, 2021, 10:34:19 AM by Vixen »
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Online Vixen

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Re: Mercedes-Benz W165 Grand Prix engine in 1:3 scale
« Reply #317 on: April 27, 2021, 09:30:39 PM »
After a forced absence for a few weeks, today I was  able to get back into the workshop and able to make some progress with line boring the main bearing journals on the first Mercedes W165 crankcase.

I thought again about how I would accurately measure the hole diameter and decided a stepped plug gauge was the best way to go. I have made stepped gauges before and have always found them very satisfactory in achieving a 'fit' to the nearest 'thou'. You can see the stepped gauge I made for the 32mm bearings. There are three initial steps, each of 5 thou. followed by 6 steps, each of 1 thou. Each step is 1/8" (3.2mm) wide. Depending on which step enters the bore, you can easily determine the depth of cut required to achieve the final diameter.




The only downside of the stepped gauge is the need to completely remove the crankcase from the boring bar to make the measurement. I was able to do this by removing only the front bearing block. The front bearing block is deeply spigoted into the front of the crankcase which helps ensure accurate repositioning.

The finishing cut is always the moment of truth, so measure twice, three times, maybe four; then set the final depth on the microbore adjuster. There is something rather satisfying about hitting the required diameter spot on.




Here, you can see the boring operation in progress. The crankcase is supported off the boring bar by the front and rear bearing blocks. The lathe carriage moves the crankcase along the bar via the flexibly mounted torque arm.

I found I could increase the spindle speed to at least 1000 RPM without vibration problems. The journals were bored at a reduced feed rate of 70 mm/min but that feedrate would have taken ages to traverse the full length and back again; so I wrote a short CNC program to add some rapid moves  between each of the five bearing journals. Each cut now took a little over 2 minutes to traverse the length of the crankcase and return to the starting point. I applied copious quantities of light oil to the bar to lubricate the two aluminium bearing blocks. That worked well and there was no detectable wear at the end of the job. The bearing blocks should still be good enough for use on the second engine's crankcase.




Here, you can see the five bearing journals, all to the correct diameter with a fine finish and perfectly in line






Here, you can see the rearmost bearing journal with one of the 32mm ball races in place. The rearmost journal also carries the engine oil pumps, which feeds lube oil to each the main bearings.





A very satisfying first day back in the workshop

Mike

« Last Edit: April 28, 2021, 07:18:47 AM by Vixen »
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Offline cnr6400

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Re: Mercedes-Benz W165 Grand Prix engine in 1:3 scale
« Reply #318 on: April 27, 2021, 09:48:39 PM »
 :ThumbsUp: :ThumbsUp: :ThumbsUp: :popcorn: :popcorn: :popcorn:

Offline Dave Otto

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Re: Mercedes-Benz W165 Grand Prix engine in 1:3 scale
« Reply #319 on: April 27, 2021, 10:04:06 PM »
Hi Mike

Nice work getting that tricky operation completed!
One step closer.

Dave

Offline 90LX_Notch

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Re: Mercedes-Benz W165 Grand Prix engine in 1:3 scale
« Reply #320 on: April 27, 2021, 10:57:02 PM »
Mike-

Spectacular.

-Bob
Proud Member of MEM

My Engine Videos on YouTube-
http://www.youtube.com/user/Notch90usa/videos

Offline steamer

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Re: Mercedes-Benz W165 Grand Prix engine in 1:3 scale
« Reply #321 on: April 27, 2021, 11:58:29 PM »
I really like that boring set up!   When you get a chance could you send a few photos of the bearings and the boring bar adjusting set up?

Glad to see your posts Mike...

Dave
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Online crueby

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Re: Mercedes-Benz W165 Grand Prix engine in 1:3 scale
« Reply #322 on: April 28, 2021, 12:02:09 AM »
Stunning work, very inspiring!

Offline Art K

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Re: Mercedes-Benz W165 Grand Prix engine in 1:3 scale
« Reply #323 on: April 28, 2021, 03:18:42 AM »
Mike,
Seems that I've missed a lot and had to play catch up. I must say I like the micro bore set up. At work I bore the parts out but noting so elegant as your W165. I have to set up a scrap part and tap the cutter back and forth to adjust the diameter. I do trust my lathe to cut properly. I wouldn't trust my ability to center it properly on the crosslide, which has no ability to bolt anything on it, except for the round T slot. Great work as usual.
Art
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Offline Jo

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Re: Mercedes-Benz W165 Grand Prix engine in 1:3 scale
« Reply #324 on: April 28, 2021, 08:05:42 AM »
Well done Mike, another tricky challenge solved with a bit of ingenuity  8)

Jo 
Enjoyment is more important than achievement.

Online Vixen

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Re: Mercedes-Benz W165 Grand Prix engine in 1:3 scale
« Reply #325 on: April 28, 2021, 11:45:55 AM »
Thanks Jo and everyone for calling in, that's especially welcome in these times of forced isolation. The MEM forum is one of the few places to show and talk engines with fellow,  friendly model engine makers.

Jo, necessity is the mother of invention and ingenuity. Not all of us are blessed with machinary as accurate as your Mr Silky (Hardinge). Actually, I think the 'bearing on the crankcase' method may actually be simpler and achieve better concentricity, than the uncertainty of packing, shimming and aligning the crankshaft onto the carriage/cross slide. Many lathes (such as my old Chipmaster) are devoid of Tee slots on the cross slide.

Dave, if you refer back to reply #294, 5th April, you will find some photos of the bearings and the boring bar adjusting set up. The bearing blocks are simply 10 mm thick aluminium plate with an accurately bored holes for the bar.

I bored milled the holes using a G03 (circular interpolation) command. You can play around with the declared diameter of the cutter to fine tune the finished bore diameter. The bearing surfaces are supplied with generous qualities of lube oil and did not appear to wear.

Incidentally, the larger 8.0 mm Mirobore insert (the one on the right in reply #294) with the triangular insert is now surplus to my requirements. Anyone interested?

Mike
« Last Edit: April 28, 2021, 08:26:38 PM by Vixen »
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Offline Laurentic

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Re: Mercedes-Benz W165 Grand Prix engine in 1:3 scale
« Reply #326 on: April 28, 2021, 08:16:51 PM »
  :ThumbsUp: Nice one Mike, loved the method, not seen that before, am impressed by its logic and simplicity

Chris

Offline Roger B

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Re: Mercedes-Benz W165 Grand Prix engine in 1:3 scale
« Reply #327 on: April 29, 2021, 11:19:53 AM »
Nicely done  :praise2:  :praise2:  :wine1:
Best regards

Roger

Online Craig DeShong

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Re: Mercedes-Benz W165 Grand Prix engine in 1:3 scale
« Reply #328 on: April 30, 2021, 02:34:53 AM »
Mike, your work is a constant source of inspiration.  I love following along.

 :popcorn: :popcorn: :popcorn:
Craig
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but rather it's the interesting folks you meet along the way.

Online Vixen

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Re: Mercedes-Benz W165 Grand Prix engine in 1:3 scale
« Reply #329 on: April 30, 2021, 01:11:27 PM »
Thank you all for calling in  :ThumbsUp: :ThumbsUp: :ThumbsUp:

Craig, I am fascinated by your crazy poppy-uppy thingies, Never seen the like before. :popcorn: :popcorn: :popcorn:


Just completed the line boring of the second crankcase. It went much quicker than the first as I knew the required setting to achieve the 32 mm bore.




I am very impressed with the ease of use and accuracy of these Microbore inserts. It takes all the drama and guess work out of the task. I do not expect to ever need to bore a series of 32mm holes in the future, so I will probably relegate the bar to the stock shelf and use it to make other engine parts. The Microbore insert will be carefully saved for another day and another diameter.

Mike
« Last Edit: April 30, 2021, 04:53:42 PM by Vixen »
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