Willans Blast Injection engine

[gunna]

I apologise to wheelwright for not acknowledging his post before, but I just had another look at the video, and you can plainly see the movement of the eccentrics for a similar fuel pump just above the governor housing.

Ian.

 

[MuellerNick]

but I can tell you now that that is the fuel pump for this engine.

So I don't need it. I know where my fuel pump is.


Thanks,
Nick

 

[Mark Rand]

Sorry if this is a thread diversion, I got here via Nick's thread.

I have worked at what was Willans Victoria Works in Rugby for the last 30 years. Unfortunately, I believe that all of the early oil engine documentation went to Lincoln when that work moved away from Rugby and it may well have been lost. I'll ask my historian colleague if he knows of anything relating to the early Willans oil engines if it's of any interest, though.

It just so happens that the end of the evolution for your engine finally left the works on its last trip (to the wreckers) earlier on this year.

She was 12 cylinders 17 1/4" bore by 21" stroke, 428rpm and rated at 6500hp. She provided electrical power for the site up until the late '70s and then performed peak-lopping activity until the late '90s. The picture shows her in April this year, in her berth at what was the engine test house, that later became the development laboratories for the site.

The only good thing that came out of this is that I got permission to keep all of the drawings and records we had for this engine and aim to make either a 1:12 or 1:10 model of her before I die.

Regards
Mark Rand

 

[gunna]

Hello Mark,
Oh if your friend can find any info we would be very glad to see it. Our engine is No D219 probably made in 1928 if he finds anything in that area. It was one of a pair D218/D219. I'm glad we are not working on your V12, it looks a bit big.
Thanks,
Ian.

 

[gunna]

Since I have already shown a couple of views of the cylinder heads, I might as well finish the set.
This is the No. 2 head which has the air start valve fitted. Both the other heads are drilled for air start and have blanking plugs fitted to the holes. That is a 300mm/12 inch ruler laying across in front. The red tape covers the inlet holes for blast air and fuel. Big holes down the front are inlet and exhaust ports.

Same head, from above. I like an engine you can walk around on!

And, while we are at it, the third cylinder on the "operating table".

Ian.

 

[kvom]

Seems Ian has an advantage over Nick as he can take anything apart to see what's inside. Hope to see a video of it running one of these days.

Nick, is the MAN engine painted like that to preserve it in the outdoors, or was that the original paint job?

 

[MuellerNick]

or was that the original paint job?

I think that were at least 5 "original paint jobs". That lady is 105 years old.
But at that time, all engines were black. I don't have to find out this.


Nick

 

[gunna]

....... Hope to see a video of it running one of these days.
.

Don't hold your breath if you mean the big engine. Yes it will run one day but that could be quite a few days/weeks/months/who knows? We still need to organise shed space and a massive concrete foundation for the engine and alternator which together weigh about 40-45 tonnes all up. Also a supply of starting air at about 600psi/40 atmospheres!

Ian.

 

[MuellerNick]

Also a supply of starting air at about 600psi/40 atmospheres!

And that with about 80 l displacement per cylinder.
Do you know the pressure for the blast air? Should be something like 100 atm.


Nick

 

[gunna]

And that with about 80 l displacement per cylinder.

Although it only starts on one cylinder and air is only admitted for a very short time.

Do you know the pressure for the blast air? Should be something like 100 atm.
Nick

According to some original info, 520psi/35atm at idle, 920psi/63atm at full load. The engine driven compressor is rated at 1000psi/68atm. The blast pressure seems to have to be manually adjusted by the operator to suit the current engine operating conditions, but as those conditions were not likely to change from one moment to the next, it probably was not a great inconvenience.
Also Nick, this engine was originally rated at 250hp @ 220rpm but some time during its life, it was downrated to 243hp @ 214rpm, (big difference!).

Ian.

 

[gunna]

Nick, just a correction to a guess I made some time ago. The cylinder casting is 2250mm high, a bit shorter than I thought.
Since you are making bits for the heads, how about some parts you cannot see on the MAN?
A valve and it's cage.

The head of the valve is 135mm diameter and the overall length is 500mm. The bottom of the cage is flush with the face of the cylinder head while the small step about 20mm up is the sealing face against the head.
From the top:-

and with a spring just sitting loose,

Ian.
Note to self: check the colour correction in the camera next time!

 

[MuellerNick]

how about some parts you cannot see on the MAN?

You can't post too many!


Nick

 

[gunna]

Here's one you probably wouldn't guess from the outside. I know it surprised me when we pulled it out. A couple of pistons, as pulled;

One of them a little bit later, actually quite a bit later;

That piston is 850mm long in an engine with a stroke of 560mm. Six piston rings, all 10mm square section.

Ian.

 

[MuellerNick]

That piston is 850mm long

That seems to be the same diameter/length ratio as of the MAN-DM series. They have about 1:2.15. With the bore of 450 mm of the DM100, that are 967.5 mm. But I have no hard numbers about the length, just scaled up from a sectional drawing of a DM70.

Readers have to be aware, how huge the displacement was at that time. The DM100 has 108 liters and just 100 hp per cylinder.

The piston length was so conservative, because at that time, steam engines had two linked con-rod and a separate way at the link. If Rudolf would have seen a piston of todays 4 stroke race engines, he would not believe.


Nick

 

[Mark Rand]

On the other hand, how many modern race engines will run for nearly one hundred years, maybe working 12 hours per day for a lot of it?

 

[gunna]

I forgot a small part of the valve gear, the spring retainer. Here is one that is 'left over'.

That retainer is machined to a bearing surface on it's outer face and runs inside the cage retainer like this,

Not only does it hold the spring in, but it also takes all sideways thrust from the tappet and so protects the valve guide. (There should be a taper pin through the nut!)
Speaking of the cage retainer, it does not sit flush on top of the head, as shown by the ruler,

It has a circular boss on the underside which mates with the top of the cage in order to keep the cage seated. The top of the cage is about 4mm below the top of the head. That gap is about another 2mm.

Ian.

 

[gunna]

Now getting back to the piston and con-rod. The big end is what I think is known as a marine style, ie a split bearing assembly which then bolts onto the end of the rod, common in steam engines. Bearing journal 200mm diameter. Shim plates are fitted in the bearing to rod joint in order to adjust/balance the compression ratios.

That is fine but what about the small end? Would you believe the same!

That assembly cannot be dismantled in situ, so the gudgeon pin must be removed, the rod withdrawn, and the bearing can then be worked on. However, Mr Willans did not want that gudgeon to ever move. It appears to be fitted by heat/shrink initially, then, in case it ever came loose, a big key was fitted on one side to prevent it from rotating.

But, that won't stop it from working out sideways, so the locking bolt which can be seen in the second picture, is fitted to the opposite side of the piston from the key! But wait, there's more! To stop the locking bolt from loosening, a saddle fits over the large hex head and mates with projections in the piston. To stop the saddle coming off, there is another locknut, and to keep it in place, a split pin through the end.

Since we cannot run the risk of damage to a piston, the gudgeon pins are not coming out, and we will just hope the bearings are ok.

Ian.

 

[MuellerNick]

These pictures are really extremely helpful! Thanks a very lot.
The ex/in is the same at my MAN.
I guess, the spring for the injector assembly sits in the cylinder, that is the upmost part of that assembly. And it is an compression spring for obvious reasons.



And keep them coming ... pleeeeeease!


Nick

PS:
You'll have as many free beers as you want, should we ever meet.

 

[gunna]

I guess, the spring for the injector assembly sits in the cylinder, ....... And it is an compression spring for obvious reasons.

Yes it does, and it is, Nick. We have assembled the injectors, but I will see if one can be pulled down again as I don't have any pictures of the internals, although I believe you will not be attempting a working one! That spring basically bears on the end of the needle valve which extends all the way to the nozzle of the injector. The rocker lifts it at the same point. There are no other moving parts inside, only what is referred to as the 'atomiser', a collection of holes and channels designed to let the blast air cause as much turbulence to the fuel as possible when the needle valve opens. For what it is worth, a fully assembled injector is a two man lift!

Ian.

 

[MuellerNick]

but I will see if one can be pulled down again

Not necessary, thanks for the offer!


Nick