Author Topic: Economy restoration (Read 17377 times)

Chipmaster · « **on:** January 05, 2016, 11:37:00 PM »

Almost two years ago I bought a dismantled Economy model engine from a widow. She told me that her late husband hadn't managed to get the engine to run properly and she remembered him starting to make a new piston for the engine. All of the castings are iron, it was just as well it was dismantled because it's too heavy for me to lift it when assembled!
The engine came with the original plans and the box of parts was virtually complete. There was also a trolley for the engine with a nice set of cast iron wheels about 4" diameter.
The aluminium piston looked as though it had seized or perhaps there was an alignment problem. There were no piston rings in the box, that might have told a story. However, the bore of the cylinder looked good, I wondered whether it had overheated or run with insufficient oil. the clearance between the piston and cylinder appeared to be adequate. When assembled all the fitting was accurate and the running gear was nicely machined. My main concern was that the crankshaft was at a right angle to the cylinder, fortunately the alignment was perfect and everything turned over without binding.
It seemed that most of my effort would be making a piston, piston rings, fettling the castings and cosmetic work. I had other models under construction so the Economy had to take a back seat.

Andy

b.lindsey · « **Reply #1 on:** January 06, 2016, 01:40:28 AM »

That is a fine looking engine Andy, and a large one at that! So where are you in the restoration? Obviously you have done a lot of looking and measuring and checking things out. Have you started on the new piston yet? Can't wait to see this one running and it seems like it won't take too much to get it there.

Bill

Chipmaster · « **Reply #2 on:** January 06, 2016, 07:48:31 AM »

Hi Bill, the Economy engine is coming along nicely, I'll add photos of my work.
The first job was to hone the cylinder bore then make a new aluminium piston as specified in the plans.
I milled out a deep slot in the end of an aluminium bar for the interior of the piston then transferred it to my lathe to complete the job - boring the inside of the piston skirt, machining the outside diameter and forming two piston ring grooves. The completed piston was then parted off and mounted on a V block held in a 4 jaw chuck to bore the gudgeon pin hole. Meanwhile a good friend Ray turned down about eight inches of 3" cast iron bar to 2" for me to make 1.75" od piston rings.

Andy

Ian S C · « **Reply #3 on:** January 06, 2016, 12:30:06 PM »

Could the problem be the grade of aluminium used for the piston picking up on the iron bore, or the rings a bit tight. In an ideal world would a cast iron piston be better?

Ian S C

Chipmaster · « **Reply #4 on:** January 06, 2016, 05:09:06 PM »

Maybe ithe wrong grade had been used Ian and I agree I could have used continuous cast iron bar to make a new piston as I have on my other engines. However, at the time I felt like a change from cast iron - easy to machine but such dirty stuff, and tried aluminium as specified by the plan. I don't know the grade of aluminium I used but the engine has run for a few hours and the piston looked fine when I took the engine apart for painting. I'll keep an eye on the aluminium piston, I can easily make an iron piston if necessary.
Andy

Roger B · « **Reply #5 on:** January 06, 2016, 07:51:08 PM »

I can't see from the pictures if there are any balance weights on the crank. Changing from a Al to a CI piston will more than double the weight and upset the balance.

Jasonb · « **Reply #6 on:** January 06, 2016, 08:46:48 PM »

You want about 0.003" per inch dia clearance on the piston, well thats what I allow on an aluminium one in an iron bore.

The photos is a bit out of focus but are the marks even all round or off to one side, if teh gudgeon pin in not square to the bore it may have twisted the piston sideways.

Not seen a piston with that tapered type of skirt before.

J

Chipmaster · « **Reply #7 on:** January 06, 2016, 08:48:52 PM »

You're right Roger, I also reckoned a cast iron piston could make the engine more unbalanced. There are no balance weights on the crank. I tested the engine as soon as I had made a new piston and rings, when running at a low speed the engine was quite docile and stable. However, when the revs were increased it really danced about even when clamped to my hydraulic lifting table. This was not helped by the way the flywheels were machined. Whilst the outer rims were concentric with the hubs the inner rims hadn't been machined at all and were way out. I spent a lot of time trying to retrieve the situation but you can only do so much with a spoked flywheel that wasn't set up properly at the outset. The man that built the engine had a Myford Super 7 lathe so I suspect he had to get someone else to machine the 10.5" flywheels for him. The workmanship on the flywheels was of a much lower quality than the rest.

Andy

Chipmaster · « **Reply #8 on:** January 06, 2016, 09:21:24 PM »

Hi Jason, yes that was indeed a poor picture, the damage was all round the piston. I was tempted to try cleaning it up but decided to make a new piston, it didn't take long. I don't remember the clearance I allowed but it seemed ok when I tested the engine. The conical piston skirt was new to me, it's in the plans. It was sufficient to allow for the connecting rod movement and might contribute to keeping the piston in shape. $:-\$

Andy

Chipmaster · « **Reply #9 on:** January 06, 2016, 09:42:14 PM »

My friend Ray kindly spent some time turning down about eight inches of a 3" cast iron bar to 2" for me to make 1.625" od piston rings. After machining the od and boring out the centre I ground a very narrow tool so that I could part off as many rings as possible.
Each ring was cracked open by placing it on a steel bar held in a vice then placing a knife blade against the ring and hitting the back of the blade with a small hammer.
For heat treatment a nut was placed between the open ends of the ring which was then heated to red heat and left to cool. Each ring had just the right amount of 'spring'.
The next task was to gently polish the rings using fine emery cloth on a surface plate until they were a sliding fit in the piston grooves. And finally the ends of the ring were filed to achieve the desired gap when fitted in the cylinder bore.

Andy

Chipmaster · « **Reply #10 on:** January 07, 2016, 05:54:23 AM »

The engine was reassembled with it's new piston and jury rigged for a test run. I couldn't get on with the carburettor that came with the engine so I borrowed the mixer from my Alyn Foundry RLE engine and the engine started easily and ran pretty well. You can also see how the inner rims of the flywheel are not concentric.

<a href="https://www.youtube.com/watch?v=hG-1ert_Rmc" target="_blank">http://www.youtube.com/watch?v=hG-1ert_Rmc</a>

Here's the engine running faster, much faster than I'd normally run this type of engine.

<a href="https://www.youtube.com/watch?v=LkDk1wHm46U" target="_blank">http://www.youtube.com/watch?v=LkDk1wHm46U</a>

Andy

rudydubya · « **Reply #11 on:** January 07, 2016, 07:37:21 AM »

I love the way it runs, Andy. I played the videos several times just to listen to it. Thanks for sharing.

Regards,
Rudy

Chipmaster · « **Reply #12 on:** January 07, 2016, 09:28:39 AM »

Cheers Rudy, I like to have the engine running as slow as possible.

Here are a few video clips of the engine running on propane. Didn't bother with a demand valve, simply connected up the gas supply with a rubber tube, set the pressure down to about 1 psi and she started quite easily.

<a href="https://www.youtube.com/watch?v=sJ9zHjN4n1k" target="_blank">http://www.youtube.com/watch?v=sJ9zHjN4n1k</a>

After some extended runs to satisfy myself that the engine was sound I took the engine apart for fettling and cosmetic treatment.

Andy

Chipmaster · « **Reply #13 on:** January 07, 2016, 09:57:39 AM »

The flywheels needed a lot of work. I have circled two holes in the picture below. These were a legacy of drilling a bolt hole through the clamp section of the flywheel. I think most builders wouldn't bother to drill such holes but it was very well done, the saw cut in the hub copied full size practice and it does facilitate tight fitting of the flywheels on the crankshaft. I wanted to fill the holes and make them inconspicuous. The machining marks left on the flywheel rims had to be sorted out, the inner rims needed machining and the spokes needed fettling.

Andy

Chipmaster · « **Reply #14 on:** January 07, 2016, 08:48:25 PM »

I cleaned up each hole in the flywheel rim with a 5/16" reamer then made tight fitting cast iron plugs threaded to accept a 2BA countersunk socket screw. The countersunk head overlapped the 5/16" hole and the screws pulled the cast iron plugs into the holes. I applied a copious amount of Loctite 638 to both screws and plugs. After the rim had been machined you could still see the plug if you looked for it but it was a big improvement on the holes.
The person who carried out the machining of the flywheels failed to centralise the hubs and rims on their faceplate before boring out the hubs. I did the best I could to improve the appearance of the flywheels but decided I could replace them if they let the rest of the engine down. After extensive fettling using grinding points in a Dremel, I used Upol Dolphin Glaze car body filler to build up the surfaces for painting.

Andy

Dave Otto · « **Reply #15 on:** January 08, 2016, 01:35:22 AM »

Nice work Andy, that's a major improvement!

Are you going to go after the rest of the engine in the same way?

Dave

Chipmaster · « **Reply #16 on:** January 08, 2016, 06:35:04 AM »

HI Dave, yes I have gone after the rest of the engine in the same way, lots of fettling and filling.

There was no crank / splash guard fitted to the engine, I bought a new casting from the Engineers Emporium who were able to tell me that my engine, serial number 1334, was supplied as a set of castings in October 2008.

You can see the surfaces of the castings in the pictures below, filling seemed the best way forward to me. I used Upol Dolphin Glaze car body filler all over the castings, it took a long time but I was pleased with the results.

I decided to dispense with the petrol tank in the base of the engine, I wanted a smaller tank that would be accessible and easy to drain when the engines not in use. The two large holes that had been drilled in the base for the filler and outlet were plugged with Isopon

Andy

Chipmaster · « **Reply #17 on:** January 08, 2016, 11:17:20 AM »

While the layers of primer and filler were drying I decided to improve on the silencer. The existing silencer was a steel pressing with a copper disc covering the opening. I liked the shape of the steel part so I machined a dome shaped cover from a piece of cast iron bar using a radius turning attachment. I did put spacers in between the two halves so the exhaust had a way out.

Andy

Chipmaster · « **Reply #18 on:** January 09, 2016, 03:05:28 PM »

In between coats of paint I made the dummy Webster magneto as set out in the plans. The main body came from a piece of brass bar milled to shape.

Andy

Chipmaster · « **Reply #19 on:** January 12, 2016, 08:44:21 PM »

I started to spray paint the model using a cheap (£18.00) HVLP spray gun that I had used for previous models. However, I kept getting a variety of defects in the paint finish. Even allowing for my lack of experience with spray guns I felt that the results were worse than I could achieve with an aerosol. So I blamed the cheap spray gun which gave me an excuse to buy a DeVilbiss SRi Pro Spot Repair Spray gun which gave far better results straight away using slightly thinned Craftmaster Crimson Lake enamel paint. Using a large cardboard box as a spray booth, I could get nice looking finishes but had a lot of problems with dust. I resorted to using cardboard boxes to cover the various parts while the paint dried and that made a big difference.

Andy

b.lindsey · « **Reply #20 on:** January 13, 2016, 01:14:46 AM »

That is a beautiful paint finish Andy. The whole project is coming together amazingly. What an impressive transformation!!

Bill

Don1966 · « **Reply #21 on:** January 13, 2016, 02:29:54 AM »

Quote from: b.lindsey on January 13, 2016, 01:14:46 AM

That is a beautiful paint finish Andy. The whole project is coming together amazingly. What an impressive transformation!!

Bill

Dido to that...............

Don

Chipmaster · « **Reply #22 on:** January 13, 2016, 05:59:10 PM »

Yes probably over the top, I had to satisfy myself that I could produce a high gloss finish. The downside is that I'm afraid of scratching it!
Andy

cwelkie · « **Reply #23 on:** January 13, 2016, 06:48:40 PM »

Efforts well rewarded!
I'm glad you also did the "dummy magneto" ...
Charlie

Chipmaster · « **Reply #24 on:** January 13, 2016, 07:12:28 PM »

Yes thanks Charlie. The dummy magneto consumed what seemed a disproportionate amount of time but it added interesting detail to the model.
Andy

Chipmaster · « **Reply #25 on:** January 15, 2016, 05:12:49 PM »

A steerable trolley is essential for moving this model around, it's rather heavy. The engine came with a trolley that was clearly intended to be temporary while the engine was under construction. The wheels and axles were fine, it just needed better woodwork to improve the appearance. Using Ash for a light colour, I made up a simple 'ladder' type chassis dowelled together and finished with Rustins Plastic Coating. Stainless steel thread inserts were screwed into the wood to take the studs that hold down the engine.
Andy

mhirst121 · « **Reply #26 on:** January 15, 2016, 08:48:58 PM »

Nice job on the engine Andy. I had trouble with the flywheel castings for mine, one of them has a buckle in it as if it was removed when still hot and layed against something. Had a hell of a jod to get it acceptable, but it will have to do now. Hope mine runs as well as yours !

Chipmaster · « **Reply #27 on:** January 15, 2016, 09:18:49 PM »

Hello Martin, I have also read your build log as you go along and empathise with the flywheel issues. I note that the design of the flywheels have changed - the clamping bolt bits have been dispensed with. My build log is almost up to date I need to make a petrol tank and decide where to position it. It's supposed to be inside the base but I prefer mine to be accessible so its easy to drain when not in use.
I reckon the original builder also had an issue with the castings in the main bearing department from what I could see of the way he machined it.

Andy

b.lindsey · « **Reply #28 on:** January 16, 2016, 12:41:11 AM »

Beautiful cart Andy and it just shows off that paint job even better. Very very nice!!!

Bill

Dave Otto · « **Reply #29 on:** January 16, 2016, 01:41:19 AM »

Yes it is all coming together nicely!

The paint and wood work are beautiful.

Dave

mhirst121 · « **Reply #30 on:** January 16, 2016, 09:58:23 AM »

Hello Andy, I think the patterns are made for cast iron and they are now making them in aluminium, this is where the shortages in the castings come in.
I am hoping to make up a drop bed cart for mine and stick a saw rig on the back, we will see how we get on. Love your cart, looks just right for the engine.

MartinH

Chipmaster · « **Reply #31 on:** January 17, 2016, 09:17:33 PM »

Other completed Economy models that I had seen on the internet often have 'Economy' and 'Hercules' transfers so I wanted them for mine. I couldn't locate a source for such transfers so I copied images from the Internet and spent hours and hours using Gimp Image Manipulation Program to resize and retouch the images pixel by pixel so that I could make my own transfers using inkjet decal paper. I was very pleased with the results.
However, when I went to the Midland Model Engineering Exhibition I found that I could have bought the transfers from the Engineers Emporium, I hadn't thought of asking them in the first place !

They looked better before I protected them with varnish, oh well

Andy

mhirst121 · « **Reply #32 on:** January 17, 2016, 09:30:39 PM »

Nice work on the transfers Andy, when looking at your engine it looks like the governor assembly mounting plate is thicker than it should be and has been cut away to mount the governor. I wonder if this was done to overcome the shortage in the castings!! I have made my plate up today, but I have not done the recess in the side of the block yet. I have no faith that anything will fit without making the part and then measuring how much to remove.
If mine turns out as nice looking as yours, I will be very happy.
MartinH

Chipmaster · « **Reply #33 on:** January 17, 2016, 10:17:13 PM »

Hi Martin, there is a recess milled out of the side of the base where the governor assembly mounting plate fits. I'll measure the thickness of the mounting plate and see whether I have a photo of the recess for you on my PC tomorrow - I'm using my iPad at the moment.
I doubt whether changing the thickness of the plate is significant but I can imagine amending it to help line up the pushrod.
The finish on mine was due to filler and lots of rubbing down then several attempts at spraying paint.
I haven't taken that much trouble finishing models I've made in the past however, will this be durable? Hopefully your aluminium castings will be easier to fettle.
Andy

Chipmaster · « **Reply #34 on:** January 18, 2016, 12:30:15 PM »

Hello Martin, the governor assembly mounting plate or 'timing plate' is 3/8" thick on my engine whereas my plans (drawing EF0102) specifies 8 mm. I attach a few cropped pictures of the governor assembly that show how the thickness of the plate was reduced to make room for the governor wing plates. The recess for the timing plate milled into the side of the base is only deep enough to achieve a vertical surface for mounting the timing plate.

Andy

steam guy willy · « **Reply #35 on:** January 18, 2016, 03:31:08 PM »

I have drilled holes in flywheels on the periphery inserted magnets ,then used a cycle odometer suitably recalibrated to record the RPM !
Willbert

mhirst121 · « **Reply #36 on:** January 18, 2016, 03:59:26 PM »

Thanks for the pics Andy. The drawings that I have specify the plate to be 7mm thick, the plot thickens.
This is the reason I am not machining any of the castings any further till I know by measuring that it is correct. There must be alot of variations on this model drawing wise. I have seen another set with the head mounting studs that were cutting into the side of the liner !!!!

Regards,
MartinH

Chipmaster · « **Reply #37 on:** January 18, 2016, 08:26:14 PM »

This is how the engine looks at the moment.
I'm thinking about the location of the petrol tank and ignition system - whether to use a buzz coil or a MiniMag system.

Andy

Chipmaster · « **Reply #38 on:** April 09, 2016, 08:23:18 PM »

I decided to take the Economy and a couple of other model stationary engines to a club get together next Saturday 16/4 so I'm trying to finish off the model to make it presentable. The finishing details take a disproportionate amount of time, I hope it will run too.

There are two holes in the cylinder head that were drilled to form the inlet and exhaust ports that have to be plugged afterwards. The original builder had made a couple of hex headed brass plugs that I didn't like.

000 (264) by Andy, on Flickr

000 (266) by Andy, on Flickr

000 (251) by Andy, on Flickr
I assumed they were 1/4" BSP threads the same as the connections to the exhaust and fuel mixer and bought a couple of 1/4 bsp socket head plugs, they should have looked ok. Drat! he'd threaded the holes 1/2" x 32tpi so I had to make my own plugs from mild steel.

000 (252) by Andy, on Flickr

Now I put the head together using sealant, stainless steel elbow for the exhaust so it wont tarnish.

000 (255) by Andy, on Flickr

000 (256) by Andy, on Flickr

Andy

Chipmaster · « **Reply #39 on:** April 09, 2016, 08:56:08 PM »

Putting it back together, I made a brass petrol tank, fuel mixer and put a trembler coil in a cheap wooden box...

000 (258) by Andy, on Flickr

000 (259) by Andy, on Flickr

000 (260) by Andy, on Flickr

000 (263) by Andy, on Flickr

000 (268) by Andy, on Flickr

000 (269) by Andy, on Flickr

000 (270) by Andy, on Flickr

000 (271) by Andy, on Flickr

Andy

Roger B · « **Reply #40 on:** April 09, 2016, 08:58:14 PM »

Very nice

Chipmaster · « **Reply #41 on:** April 09, 2016, 09:15:48 PM »

Thanks Roger, I now have to decide where to position the petrol tank. Behind the trembler coil close to the mixer or about ten inches away at the flywheel end of the trolley. The plans for the model position the tank inside the base of the engine. However, I prefer to be able to reach the tank particulaly to be able to drain it. Some say it's risky having a trembler coil near petrol vapour which is why I put it in a box.
Has anyone heard of a trembler coil setting off petrol vapour from an engine?
Andy

Chipmaster · « **Reply #42 on:** April 11, 2016, 08:46:34 PM »

Had a hard time getting this Economy engine to run after its paint job. I've got blistered thumbs and aching hands after turning over the flywheels over and over again for a few hours - the compression is very good on this engine. I made up a starting handle in the end.

I knew that the two carburettors / mixers that came with the engine didn't work very well - way too rich. So I made my own simple mixer (just a needle opening a jet in a venturi) but that wasn't very good either, also too rich. The only device that worked well was a mixer borrowed from my Alyn Foundry RLE. I'm hoping to exhibit the engine at my stationary engine club do next Saturday.
This video shows the engine running (just about) fitted with one of the original Engineers Emporium mixers, the results are greatly improved if the fuel tank is lowered.... well below ground level

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

This is the engine running with my old home made mixer borrowed from my RLE engine this allowed the engine to run fast enough for the governor to work.

<a href="https://www.youtube.com/watch?v=RjZpkPao6gM" target="_blank">http://www.youtube.com/watch?v=RjZpkPao6gM</a>

Reckon I'll have to make and fit a much smaller jet and finely tapered needle and / or increasing the bore of the mixer might have the effect of leaning the mixture?

Andy

zeeprogrammer · « **Reply #43 on:** April 11, 2016, 10:14:32 PM »

Nice videos. What a difference in the second one.

Jasonb · « **Reply #44 on:** April 12, 2016, 07:33:49 AM »

I do find that a lot of the H&M engine carbs are more on/off than a decent adjustment so tend to make then with finer threads and more pointe dneedles from the outset, even then they just need a tiny tun to go from closed to running.

Larger dia venturi would slow the air and draw less fuel. The Monitor had a good design where the venturi just slipped into the parallel carb barrel and the screwed in jet retained it so if needed you could have swapped out the venturi quite easily to try different sizes

Chipmaster · « **Reply #45 on:** April 12, 2016, 08:28:59 AM »

Thanks for that info Jason I'll have a go at making a removable jet and needle today.

Andy

Chipmaster · « **Reply #46 on:** April 26, 2016, 04:53:58 PM »

Here's a three minute video of my Economy engine running this afternoon. The focus isn't as sharp as I'd like, perhaps the light wasn't right.

<a href="https://www.youtube.com/watch?v=okLfIZSP80Q" target="_blank">http://www.youtube.com/watch?v=okLfIZSP80Q</a>

I haven't sorted out the mixer yet, the engine is using one borrowed from my Alyn Foundry RLE engine.

Andy

b.lindsey · « **Reply #47 on:** April 26, 2016, 05:01:24 PM »

It sure sounds good Andy!! Can you just make a copy of the mixer from the RLE engine to use on this one since it seems to work quite well on the Economy? The paint work is fantastic too!!!

Bill

Chipmaster · « **Reply #48 on:** April 26, 2016, 05:53:30 PM »

Hi Bill, I have to admit that I made a copy of the RLE mixer but it didn't function anywhere near as well as the original which I made about 20 years ago - must have been a fluke. Reckon the problem is making the needle, I'm thinking of using a gramophone needle for my next attempt.

Andy

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Author Topic: Economy restoration (Read 17377 times)