Rivers 2.49cc and DC 1cc engines

[TerrydParticipant @terryd72465]

[TerrydParticipant @terryd72465]

Hi there,

 

I have resurrected a couple of old engines from my distant past.  Both are diesel engines.  However after approx 35 yrs storage they are both seized.  I suspect the pistons are gummed up in the liners.

 

My query is to those much more knowledgeable than me, is to ask if it is possible to release these by exposing the piston and liner than applying gentle heat to soften the gum holding them?  If not is there a suitable safe solvent I could use to soak them?

 

Also some parts are missing from my DC (I think it’s a Spitfire) and I need some dimensions to make new ones and I was wondering if anyone has one of these so that I can get some information, dimensions etc?

 

Any help would be gratefully accepted.

 

Terry

[CirclipParticipant @circlip]

NOOOOOOOOOOOOOOOOOOOO, don’t heat them, soak in parrafin or diesel or any soft solvent, it’s the Castor thats solidified, Try the engine site I put up in the thread on the vintage engine.

 

  Regards  Ian.

 

  Found it for you

 

    http://www.modelenginenews.org/

Edited By Circlip on 15/04/2010 13:33:27

[mgjParticipant @mgj]

If it is castor gum, and it almost certainly, one of the best solvents is ordinary bio type clothes washing powder which is specially formulated to munch organic material. Nice and warm and agitate occasionally. Excellent on model aero engines for removing baked on and gummed up castor. (or for other racing engines from the era when the smell of castor overcame the pain of dropping the oil after every outing)

 

Heat – boiling water is pretty good at softening gum, but a flame or oven will merely bake it harder. 

 

Thank God for synthetics.

[LADmachiningParticipant @ladmachining]

Why no heat?

 

Ron’s site even advocates gentle heat to soften castor gum….

 

I had an old engine that was soaking in ATF (automatic transmission fluid) for two weeks without a hint of movement.

 

A couple of minutes with a heat gun, and all was free.  Probably didn’t need to get much hotter than about 100 – 120 degrees.  No damage done, and it runs as well as the day it was put away (but htis time, it was flushed and protected first!).

 

Anthony

 

 

 

[Ramon WilsonParticipant @ramonwilson3]

|Hi Terry, just got in from a very enjoyble and productive day out at Myfords Open Day.

 

Gummed engines – Apply gentle heat around the cylinder by hot air gun or a low flame just hot enough not to touch with bare skin. This will normally allow the engine parts to begin to move slowly and will not harm anything. Apply a small dose of cellulose thinners to the ports and the intake and gently rotate the crankshaft by hand – best if you have a prop fitted for this. The cellulose will very quickly soften the gummed castor but don’t over do it ie soak it  because it will remove all the castor down to bare metal. Personally if they are really gummed I would get them moving enough to strip them right down and clean them thoroughly particularly the Rivers – I guess you are aware that his engine has a roller bearing on the crankshaft. If it is the same as the SilverArrow 3.5 this consists of rollers and curved spacers – no cage – held purely by the reduced diameter of the crankshaft that they lay in. To refit them they need to be held in place with soft grease to enable assembly. The fit of these that I had on an Arrow was nothing short of perfect. They are very well made engines but be careful not to lose any – virtually irreplaceble I would think.

 

Boiling the outside parts as mgj says works well to get rid of outside baked on carbon/castor but can discolour the aluminium to a dark greyish colour that is difficult to remove without recourse to something like bead blasting. I definitely would not boil internal parts however. A quick swish in cellulose will remove all gummed castor ready for oiling and refitting

 

There is a product available at most supermarkets – Fairey ‘Power Spray’ – (normally found around the oven cleaner area) that if sprayed on and left for a few minutes will soften the built up carbon very quickly without any discolouration and can be simply rinsed off under the tap.

 

Ref the DC Spitfire – I think these normally came with a blue anodised head. I think the ‘red heads’ were the Sabre – 1.5cc – though at the latter days I think they produced them in all sorts of colours even gold! I no longer have one but have access to several so if you let me know what parts you need to make I’ll get them measured up for you. I currently have a head to make for a DC Rapier hence the desire for green anodising

 

Good luck with this – it’s good to hear of these old engines making light of day again

 

Regards – Ramon

[TerrydParticipant @terryd72465]

Thanks Ramon and all,

 

I will take all your suggestions and try them from the most gentle upwards.  After 35 years I’m in no hurry and really don’t want to cause any damage to the poor things, as like Ramon I would like to see these old timers running again.  I never really flew them but just used to run the Rivers to listen to it run.

 

I’m really a tyro as far as ic miniature engines are concerned and know little about them really, so excuse me if I appear a little ignorant about the naming of parts etc and please feel free to correct me if I make any boo-boos.  Give me any engine from 125cc upwards and I can do anything with them, but these little things…………….

 

The main parts that are missing from the Spitfire (it is a Blue top Ramon)  is the spray bar, needle and thimble etc.  I don’t know if I can get standard parts to fit but I’m quite capable of making them if not.

 

Also missing is the pressure screw from the Cylinder head, but that’s easy. What I don’t understand is the function of the other two tapped holed in the cylinder head next to the pressure screw.  Could someone please enlighten me?

 

 Thanks all for your advice I really do appreciate it and hope that I can reciprocate in the future.  This is one of the best forums I have used over the years, keep it up.

 

Best regards

 

Terry

 

 

 

[Ramon WilsonParticipant @ramonwilson3]

Terry,

 

When the Rivers first brought out the Silver Streak in the sixties it was seen as something quite special and though it never quite managed it in the long term it posed a considerable threat to the dominance of the Oliver Tiger. That honour was left to the ETA 15D a couple of years later. Like against like the Rivers engines – 2.5 and the 3.5 – were outstanding examples of the model engine builders craft. Easy starters and superb handling characteristics. I can’t remember whether they produced a 1.5 – have a vague idea that it was talked about but not sure if mass production ever came to fruition – perhaps someone else knows.

 

On the DC the extra ‘two’ holes is unusual. DC used to fit a (one) small vertical pin screwed into the head as a stop to prevent over compression. This was about a 1/16 diameter and was positioned radially just short of the ‘tommy bar’ length. Normally only one hole was there as I recall but without seeing it if these are diagonally opposed I would guess this is incase the comp needs just that bit more than one position would allow. Many would remove this pin as it was rather a ‘nuisance’ compared to other engines. Unlike most other manufacturers DC compression screws on the smaller engines were frequently ‘one sided’ ie the tommy bar protruding from one side of the screw only.

 

The DC spraybar assemblies were virtually identical throughout the entire range – brass spray bar, ally threaded boss on the needle valve and a spring steel clamp to prevent rotation from vibration – not very effective on the smooth aluminium boss.

 

I don’t have an original but have made a copy for the Rapier so will take a couple of pics and some measurements for you tomorrow.

 

Regards for now

 

Ramon

Edited By Ramon Wilson on 15/04/2010 23:10:25

[mgjParticipant @mgj]

LAD – is that light aid detachment or something else? – rather like you I recovered a DC Merlin from my teens with little trouble and a couple of PAW 1.5s..(are the PAWs still made – I think yes?)

 

10 mins in a jug of boiling water from a kettle with bio detergent, a rinse with hot fresh from the kettle and it was free and dry internally, ready to oil up in no time. No reason to take it apart even. I think that’s why its such a good idea to get these things quite hot.  Gun barrels and anything where you want it bone dry before oiling up.

 

Discolouring – well possibly if you actually boil it – ali does that – but that wasn’t what was suggested. However if necessary a very few crystals of citric in there gets it looking like new very quickly (or one can drop it in marmalade if you want. Apple sauce if  preferred! True, but useless info)

 

I can’t see that sensible heat is a particular problem – cylinder head temps? – but in any case, a lot of the ball raced engines need a bit of oven type warmth (more than 100C) for the bearings to drop out cleanly, and some gudgeon pins are heat shrunk in. Equally liners on some small 2 strokes  have to be got up to nearly blue before they’ll drop out. – obviously or one could have a disaster at normal running temps.

 

[Ramon WilsonParticipant @ramonwilson3]

Merrick

That’s interesting – are you saying that citric acid will remove that grey discolouration after boiling? I shall try it.

 

Boiling – I have only done this to engine parts – crankcases and cylinder heads – where the carbon build up has been particularly bad. Not for getting an engine ‘moving’ when gummed. Boiled for a few mins with some washing powder certainly does the trick but it does leave this discoloration – easily removed by bead blasting but that’s not always the surface finish that’s wanted especially on die cast cases – if citric acid will bring the shine back on that, that is good news.

 

Can’t agree with not taking it apart though especially if it’s lain for many a year the gum and gunge has to be seen to be believed if it hasn’t been cleaned after running. This Rapier I’m refurbing was the worst I’ve seen for some time especially in the bearings. There’s not much can go wrong in taking them apart – well worth the exercise.

 

BTW – PAW are still going strong

Edited By Ramon Wilson on 15/04/2010 23:31:45

[TerrydParticipant @terryd72465]

Hi Ramon,

 

Thanks for the offer of pics and measurements etc, all contributions greatfully accepted.

 

Re the two smaller threaded holes in the cyl head. They are diametrically opposed either side of the main compression screw.  I will post a pic later today when I return home from work.  They are the same diameter as 8ba but the thread appears to be coarser.  Would these be BSF or BSW threads?  I don’t want to keep trying various bolts etc in case I damage the threads.  I suppose that I could re thread them with metric but I don’t want to spoil the origiinality.

 

Cheers again

 

Terry

Edited By Terryd on 16/04/2010 09:19:38

[CirclipParticipant @circlip]

I will illucidate (Explain) my reaction to “Gentle heat”

 

  I can apply gentle heat with a blowlamp and without trying to demean the O/P’s capabilities, I  have also seen trained monk– er  Mechanics fitting taper outer races with a ball pien whilst they were standing beside a bench press.

 

  I can do less damage to a piston when de-coking with a sharp object than many can with the industry “Sharpened stick of Lead” or plumbers stick solder. (Washing with Carbon Tet is MUCH quicker).

 

  “Heat to cherry red” Oh yea, WHICH part of the season???

 

   Regards  Ian

[TerrydParticipant @terryd72465]

Hi Ian,

 

I can quite understand your point of view. 

 

“Cherry Red”, would that be the nice bright glace cherry that use to adorn every ladies “snowball” or the lovely dark red Morello so beloved of the Black forest Gateaux brigade?

 

“One Man’s meat”  etc.

 

Terry

[TerrydParticipant @terryd72465]

I’ve now created an album,  here are a couple of pictures from it, I hope!! 

 

 

[mgjParticipant @mgj]

Terry – those holes are for vertical pin stops for the contra piston screw to limit the range of adjustment. The Merlin had them (one?) too, but whether all DC engines did I don’t know.

Edited By mgj on 16/04/2010 17:54:33

[Ramon WilsonParticipant @ramonwilson3]

Hi Terry

 

Lovely to see that Rivers – most envious (drooling now )

 

Had a friend over today so got him to bring a couple of DC motors (Sabre 1.5 and a Spitfire).

 

I think it fair to say that one of the two holes in yours has probably been put in after purchase. His two and a Merlin I forgot was still here all have one only. These are definitely threaded 8BA for the stop pin

 

The Needle valve assemblies are all identical – here are some pics of them and a drawing.

 

My memory had ‘shortened’ the tommy bar as you can see it exceeds the head diameter

 

 

 

 

 

 

 

 

 

 

Hope this will help to get yours up and running.

Going back to the Rivers – you have a very low castor build up on the crankcase and I’m sure the Fairey Power Spray will bring that back like new. It’s not expensive and works really well. I have an OS silencer in similar state so I’ll do that shortly and you can see the results.

 

Regards for now – Ramon

[Ramon WilsonParticipant @ramonwilson3]

Well I have just surprised myself.

 

Having had it highly recommended for this application for a while now it is only quite recently (fortnight or so) that I have actually bought some of this ‘Power Spray’.

 

The pics below are of an OS silencer last used in 2006 – (How can I be sure of that ? Well the airframe it was fitted in met it’s demise after a pushrod failure and that was a week after the ’06 ‘Nationals’ – the last time I flew control line actively). Since then it’s been lofted along with all the other ‘stunt stuff’.

 

I sprayed on this not unpleasant smelling product about 6.15. Within two mins the lighter stuff brushed off with a toothbrush. Just less than 30 mins and most of it brushed off leaving only the really hard baked stains. A rinse under the tap and most of the surface is near new without any apparent adverse effects to the ally. I have given it another coat and will check it every hour or so to see if it will eventually soften these hard patches.

 

 

Before coating

 

 

Well saturated covering

After 2mins the end cleaned with a light brushing

 

After 30 mins

Washed off after 30 mins.

This is much better than the ‘old boiling technique’ though it remains to be seen if a longer saturation time will eat into that baked on carbon.

Does make your hands smell like a T——-ish boudoir though – even using gloves!

 

Hope this of interest Terry

 

Regards – Ramon

 

Edited By Ramon Wilson on 16/04/2010 19:11:17

[TerrydParticipant @terryd72465]

Hi Ramon,

 

We’re off to Tescos for the weekly shop in the morning and I will definitely try to get some of that stuff. I’ll let you know the results!!

 

Best regards

 

Terry

Edited By Terryd on 17/04/2010 04:55:01

[Ramon WilsonParticipant @ramonwilson3]

Hi Terry

 

Thought you might like to see it after a four hour coating! I forgot to check it regularly!! This really is a very good product indeed. I will try to see if I can get hold of a really badly carboned up engine and see how well it does on that.

 

Might pay to buy two bottles – bound to come off the market now it’s found to work!

 

Regards –  Ramon

 

 

 

 

[Jens Eirik Skogstad 1Participant @jenseirikskogstad1]

I am using the ultrasonic cleaner to remove castor oil of the gummed engine. Look at this movie: http://www.youtube.com/watch?v=wOlcxZrdCTQ

The engine are a ED Seaotter diesel engine.

[TerrydParticipant @terryd72465]

Hi Ramon,

 

Thanks for the pictures and drawing.  i just have a couple of queries.

 

Is the taper on the needle crucial? and

 

What size should the fuel hole in the spraybar be, it looks quite tiny on your drawing, is it to scale, sort of?

 

Oh, I just thought of a third one! How should the fuel hole be positioned when the engine is assembled?

 

Best regards

 

Terry

[Ramon WilsonParticipant @ramonwilson3]

Hi Terry,

 

The taper on the needle isn’t usually that critical particularly on a sport engine like the Spitfire. I usually make needles from either 18 or16 swg piano wire grinding the taper by hand on the side of the wheel on the off hand grinder. Needs to be a fairly slow taper but not excessively so – only thing to keep in mind is to get it reasonably concentric. Silver steel would be a suitable alternative left in the soft state but of course could be easily bent.

 

Big problem with using ally for the housing is that this needs to be a good fit on the needle (if it’s brass then a quick dash of solder sorts that out). Using a piece of the piano wire itself ground across at an acute angle as a reamer produces a good hole, and if you stone the diameter of the wire first you can produce a tight fit. To establish the position in the housing first put the housing on the spraybar and screw home then back off a turn. Measure from the engine to the end of the housing. Remove the housing and put the needle into the spray bar until it stops then mark the needle at the previous dimension. Pushing the needle into the housing (off the engine that is) to this mark will ensure the needle closes before the housing bottoms out. A smear of Loctite helps too.

 

The hole in the spray bar is a # 65 drill. It goes right across and the accepted way is to have the holes set at right angles to the intake ie across the bore though it will work in virtually any position.

 

You may these days have a problem getting fuel – very few model shops seem to stock it in small quantities – let’s hear how you get on.

 

Regards – Ramon

 

Just watched the video on the ultrasonic cleaner  – truly amazing – and to think I have one bought for cleaning airbrushes (another life – don’t ask!) as yet still unused. ‘Change of intention’ coming up then – thanks Jens.

Edited By Ramon Wilson on 17/04/2010 09:36:44

Edited By Ramon Wilson on 17/04/2010 09:54:52

[TerrydParticipant @terryd72465]

Thanks for that Ramon, I’ll work on those this weekend. 

 

Your description of the manufacture of the needle is exactly how I envisaged making it except that I intend to stone the final finish in the lathe with a medium and then fine carborundum stone. I will probably support the needle on a suitably sized wood block so that I can apply reasonable pressure.

 

Now the Good News. After a suitable overnight soak in Meths and a morning bath in Mr Muscle Kitchen Cleaner (my wife’s preferred version of the Fairy stuff) and a final 1 hr simmer until tender, the Rivers finally gave way to my tender ministrations and turned over beautifully.

 

There appears to be little or no play anywhere but I stripped down the back end to decoke and de-gum etc.  I intend to assemble later after cleaning (using a little light oil on reassembly – I trust a little 3 in 1 would do the trick?).

 

I didn’t bother stripping the front end as the bearings and crank felt like new, silky smooth movement with no slop or apparent wear, I feel very lucky.

 

I’ll post some more pictures later.

 

 Best regards and thanks for the advice – I’ll probably need more when I try to run it

 

Terry

 

[TerrydParticipant @terryd72465]

Hi All,

 

I should also have said thanks to everyone for your help.  I have taken all your advice to heart.  I want to especially say thanks to mgj for his advice to use boiling water, it was that which finally freed the engine. 

 

I took this route after Ian warned about the dangers of direct heat, it is of course all to easy to overdo these things and cause more damage, I appreciate the warning Ian.

 

I do intend to post more pictures so that you can see the results of your advice.  I am very grateful.

 

Thanks all – I’ll be back!!!

Edited By Terryd on 17/04/2010 13:33:22

[Ramon WilsonParticipant @ramonwilson3]

Hi Terry,

 

That’s good news – doesn’t matter how you get there as long as you are comfortable with the journey.

 

I’m not surprised at the ‘silky’ feel to the bearings they really are a remarkable piece of engineering for a model engine – unique (certainly in their day), I think, to Rivers as I don’t recall any other manufacturer going to such limits.

 

Reassembling with 3in1 should be okay but at one time this was not recommended for storing an engine (it would stain it) Best thing found for that is hydraulic fluid.

 

Happy flicking, watch the digits and post those pics – Ramon

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