Author Topic: Mercedes-Benz W165 Grand Prix engine in 1:3 scale  (Read 55519 times)

Offline steamer

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Re: Mercedes-Benz W165 Grand Prix engine in 1:3 scale
« Reply #210 on: September 08, 2017, 06:24:49 PM »
Enjoyable and instructive!!! 


Watching along.....

Dave

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Damned ijjit!

Offline Tennessee Whiskey

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Re: Mercedes-Benz W165 Grand Prix engine in 1:3 scale
« Reply #211 on: September 08, 2017, 06:43:39 PM »
This is like looking through the Victoria Secrets catalog: mouth hanging open and dreaming  :cheers: :naughty:. Magnificent machining.

Cletus

Online Vixen

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Re: Mercedes-Benz W165 Grand Prix engine in 1:3 scale
« Reply #212 on: September 08, 2017, 07:12:09 PM »
Hay Cletus

Ha Ha, At least we did not catch you looking through the Ann Summers catalog

Cheers

Mike :LittleDevil:

« Last Edit: September 08, 2017, 07:25:38 PM by Vixen »
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Offline Tennessee Whiskey

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Re: Mercedes-Benz W165 Grand Prix engine in 1:3 scale
« Reply #213 on: September 08, 2017, 08:29:23 PM »
Had to Google it, but, same effect  :lolb: :lolb:

Cletus

Offline Dave Otto

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Re: Mercedes-Benz W165 Grand Prix engine in 1:3 scale
« Reply #214 on: September 09, 2017, 12:51:29 AM »
Impressive work Mike!
I'm really enjoying the whole project.

Dave

Offline Art K

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Re: Mercedes-Benz W165 Grand Prix engine in 1:3 scale
« Reply #215 on: September 10, 2017, 01:21:09 AM »
Mike,
I just caught your latest installment. Looking at the welded cylinder and having a grandfather who was a welder. I can appreciate the skill of the man who welded that MB cylinder and head. I can also see myself in welding step 1. :lolb: Great workaround to an engineering problem.
Art
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Online Vixen

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Re: Mercedes-Benz W165 Grand Prix engine in 1:3 scale
« Reply #216 on: September 16, 2017, 06:01:48 PM »
Part 11B  The Water Jackets

In the previous installment from Vixens Den, we had reached the stage that the water jackets were finish machined on the inside, the base flange was machined and the mounting holes drilled. The outside of the jacket being only roughed to shape.

You will recall that on the full size cylinder blocks, the water jacket consists of thin pressed steel sheets welded in place around the cylider assembly. The lower section of the water jacket had a distinct corrugated shape to allow for expansion. I have attempted  to create this corrugated appearance with a 4.0mm ball mill cutting to a depth of 1.0mm, with a lot of hand filing to complete the shaping. This left a bare 1.0 mm of wall thickness for the water jacket, so the chances of accidentally braking through were quite high.

Each water jacket was carefully positioned in the machine vice so that the individual corrugations could be added. The upper corrugations were reasonably straightforward, running the full length of the water jacket and curving around the the centre line, at each end. The lower two corrugations were much more interesting, as they followed the contour of the individual cylinders thereby forming three large undercuts.





The engine driven water pump delivers fresh coolant the water jackets through an external pipe welded to the water jacket . The fresh coolant is delivered equally to each cylinder via a long tapering pipe through a series of holes cut into one side of the water jacket. The external pipes of the model engine are to be bolted in place rather than welded.



Here we can see two of the water jackets before and after the corrugations were machined. There is not much of the original aluminium billet left by this stage.



The external water pipes were externally taper turned and drilled with different diameter drills to create the taper on the inside. The eight mounting holes in the pipe were drilled and tapped M3.0. One side of the external pipe was then milled away along the joint face with the water jacket. The angle of this cut was carefully calculated so the intersection of the cut resulted in parallel sides which exactly matched the side of the water jacket.





The exterior machining on the water jacket was cleaned up with small files and wet-n-dry abrasive papers to create an acceptable simulation of the steel pressings. The external water pipe will be joined to the water jacket with a row of eight stainless steel button head M3.0 screws. The screws and the joint face are to be sealed with either JB Weld epoxy or a two-pack flexible Polyurethane elastomer, if I can locate some. I would much prefer to use the Polyurethane because of it's inherent flexibility. I also propose to use this material to seal the water jacket to the cylinder heads when the time comes.





In the next installment, a start will be made in the cylinder heads.

So stay tuned.

Mike


« Last Edit: October 23, 2017, 06:09:09 PM by Vixen »
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Offline Nick_G

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Re: Mercedes-Benz W165 Grand Prix engine in 1:3 scale
« Reply #217 on: September 16, 2017, 06:33:34 PM »
.
Wowzers.!  :ThumbsUp: :)


Nick

Offline Admiral_dk

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Re: Mercedes-Benz W165 Grand Prix engine in 1:3 scale
« Reply #218 on: September 16, 2017, 08:52:14 PM »
Very impressive  :praise2:

Quote
This left a bare 1.0 mm of wall thickness for the water jacket, so the chances of accidentally braking through were quite high.

OK - now you are into nail biting territory  :insane:

Online Vixen

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Re: Mercedes-Benz W165 Grand Prix engine in 1:3 scale
« Reply #219 on: September 17, 2017, 09:18:40 AM »
OK - now you are into nail biting territory  :insane:

Hi Admiral,  Most parts of this project take me into that territory

Mike
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Online Vixen

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Re: Mercedes-Benz W165 Grand Prix engine in 1:3 scale
« Reply #220 on: October 23, 2017, 05:40:40 PM »
Part 11C  Cylinder Heads

There has recently been lots of steam engine stuff posted on the forum. I thought it was about time to post another 'fix' for the petrol head junkies out there.

The next items to be created were the four cylinder heads. Each head contained four cylinders, each of which were fitted with 4 valves inclined at an included angle of 56 degrees to form a penthouse combustion chamber. Each combustion chamber being surrounded by a water jacket. Apparently the 56 degree valve angle was the maximum which would allow the individual valves to removed and replaced from the combined welded cylinder/ combustion chamber.

Four 8" x 4" x 3" aluminium billets were faced off and the central cleft between the inlet and exhaust valves machined. On each head, two 3mm diameter holes were drilled the full length of each embryo cylinder head. The holes were drilled 4" deep from either end of the billet using the method described in earlier installments. Again, luck was with me and all the holes lined up perfectly. These long holes interconnect the various parts of the cylinder heads water pockets. I decided to make these drillings at an early stage before much work was undertaken. It would be easier to redo the drillings at this stage if there had been a problem.




The interface with the previously made water jacket was machined next and trial fitted



This is a preview of how the cylinder blocks will eventually look.


The next stage of machining the cylinder interface is a most important stage to get right. In the  full size Mercedes engine the individual cylinders are welded to the individual cylinder heads. The model engine will have the individual cylinders screwed into the combined cylinder head. The accuracy of the cylinder screw threads was of the utmost importance so I decided to try a technique which was completely new to me. I would try thread milling with a single point tool on my LinuxCNC controlled mill.

The four thread pockets were machined with an undercut to accommodate the end turns of the thread.


Here is the toolpath for the cutter. The cutter was made from a 3/8" x 32 TPI tap. All the teeth except one were ground off. The remaining cutting tooth looked quite pathetic but it cut all the threads perfectly, if fact some of the nicest threads I have seen. The single point cutter spins like a normal mill cutter and will cut a V grove of the correct angle for the thread. The cutter is then moved in a circular motion at the correct diameter while simultaneously being withdrawn by a distance equivalent to the required thread pitch. The item being machined remains clamped to the mill table, while the cutting tip moves in a continuous helix.


It all sounds very hairy, but in fact these was probably the easiest threads I have ever cut, much easier and cleaner than on a lathe. The cylinder threads were 1" x 32 TPI


Here we see all four cylinder heads plus the two test pieces I experimented with before committing to the model parts. So far , so good


Next, I pocked out the water spaces around each combustion chamber. If you look closely you can see where I intersected the 3mm diameter holes I drilled earlier.




The next stage was to machine the interior of the combustion chamber pent house shape. The V of the pent house accomodates four valves with a 56 degree included angle. I made up precision angle plates for the fixture plate at 28 degrees half angle.


The cylinder heads were attached to the fixture plate with clamps and bolts passing through two spark plug holes. A ball mill was used to form one side of the combustion chambers.


Each cylinder head was then flipped over to complete the second side of the combustion chambers pent house roof



The next stage was to machine the inlet and exhaust valve pockets. With four valves per cylinder and four cylinders per head, there were a lot of holes to mill. I chose to thread mill the 1/2" x 32 TPI threads using the same single point thread mill is used earlier on the cylinder threads.


Here we can see the four embryo cylinder head blocks with all the internal machining completed.


The next installment from Vixen's Den will describe the fun and games of machining the outside of the cylinder heads.

Stay tuned

Mike

« Last Edit: October 23, 2017, 05:47:11 PM by Vixen »
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Online Jo

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Re: Mercedes-Benz W165 Grand Prix engine in 1:3 scale
« Reply #221 on: October 23, 2017, 06:33:39 PM »
The next installment from Vixen's Den will describe the fun and games of machining the outside of the cylinder heads.

I thought the next instalment might include a bit of Jupiter stroking  :mischief:

Jo
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Online Vixen

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Re: Mercedes-Benz W165 Grand Prix engine in 1:3 scale
« Reply #222 on: October 23, 2017, 06:44:27 PM »
Hello Jo

Just about to jump on the overnight ferry to St Malo to collect said Bristol Jupiter. The 12 hour winter ferry deals are cheaper than a DHL delivery

Getting excited :cartwheel: :cartwheel: :cartwheel: :cartwheel: :cartwheel: :cartwheel: :wine1: :wine1:

Mike
It is the journey that matters, not the destination

Online Jo

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Re: Mercedes-Benz W165 Grand Prix engine in 1:3 scale
« Reply #223 on: October 23, 2017, 06:58:13 PM »
Getting excited :cartwheel: :cartwheel: :cartwheel: :cartwheel: :cartwheel: :cartwheel: :wine1: :wine1:

I would never have guessed  :lolb:

I am sure you will look after Danny's engine for him  ;)

Jo
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Online Vixen

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Re: Mercedes-Benz W165 Grand Prix engine in 1:3 scale
« Reply #224 on: October 23, 2017, 07:06:25 PM »
Hello Jo

At least I have made sure it does not fall into the hands of some auction treasure hunter.

Mike
It is the journey that matters, not the destination