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Castor oil in 4 stroke engines

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Jon - Laser Engines15/03/2019 11:25:02
4417 forum posts
162 photos

Just a little example showing why you should not use castor oil in modern 4 stroke engines.

The following photos are from a laser 100 returned for service with poor compression and very poor performance. As you can see, the exhaust valve is a little unhealthy. The exhaust is also blocked up with it and needs to be replaced.

exv1.jpg

exv2.jpg

And after cleaning

exv3.jpg

Admittedly the engine in question does have a good amount of running on it but even so, this would not have happened if a fully synthetic fuel had been used.

This is not a Laser post but a general post for all those running 4 stroke engines. Stop using castor in your fuel. The exhaust temperature of modern high performance 4 stroke engines is extremely high and it just cooks the oil onto everything. 15% fully synthetic oil fuel will be just fine.

I dont care what all the club experts think, castor is dead, please stop using it.

Paul C.15/03/2019 11:59:57
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546 forum posts
123 photos

+1 👍

Peter Christy15/03/2019 12:35:24
1243 forum posts

Haven't used castor in engines for years, either 2-stroke or 4-stroke. Its not just 4strokes that suffer higher temperatures, 2-strokes in helicopters or other closely cowled installations can also run hot!

I remember, many years ago, a heli flyer complaining of poor performance from his engine. When we removed the silencer, there was a huge lump of coke in there, rattling around and substantially reducing the exhaust flow.

And don't get me started on the varnish (inside and out!) that castor causes.....

--

Pete

Ernie15/03/2019 12:54:56
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2483 forum posts
17 photos

Oh no Jon, Surely the most important thing is the wonderful smell of burning castor

ernie

Jon - Laser Engines15/03/2019 13:12:25
4417 forum posts
162 photos
Posted by Ernie on 15/03/2019 12:54:56:

Oh no Jon, Surely the most important thing is the wonderful smell of burning castor

ernie

If that smell is worth the £100 bill for rebuilding the engine then by all means go for it

Peter, yep i agree with you. I wouldnt use it in anything either.

Jason Channing15/03/2019 13:12:30
73 forum posts

This guys a flyer , he should be commended. Instead of just staring at it he's out their causing harm and abuse to the motor.

 

Edited By Jason Channing on 15/03/2019 13:14:00

J D 815/03/2019 13:31:09
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1037 forum posts
65 photos

Ernie, for the lovely smell of burning castor get a couple of old diesel engines and run them.wink

Doc Marten15/03/2019 14:30:38
42 forum posts

It's odd Jon, depending on which fuel you use e.g The Southern Modelcraft Laser mix is 100% synthetic oil yet other manufacturers Laser mix still contains 2% Castor, which would you recommend and avoid?

Brian Cooper15/03/2019 15:18:47
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394 forum posts
17 photos

Phew... Looking at the title to the thread, I thought it was going to be about recommending using castor oil. crook no

It is filthy stuff and kills engines. I really can't understand why people use it in any percentage in their fuel.

I wouldn't even leave an opened bottle of the stuff in the same room as an engine.

B.C.

Engine Doctor15/03/2019 15:24:48
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2164 forum posts
20 photos

With modern synthetic oil you don't need the castor, even at 2% it will either varnish on pistons or build up on valves .

As John says modern engines get much hotter than earlier versions due to producing a lot more power.

Remember when car engines had to be de-coked or re-built every 30,000 miles or so due to burnt on fuel and inferior oil . Modern oil is far far better so why do people persist in using castor oil ? On model diesel or a vintage engine with poor clearances or iron pistons and much lower power then yes use it but not on modern engines. On Model diesels there is little heat generated and with high fuel volume passing through none or very little build up will occur .

We had a member in our club , now retired from modeling who would load up with gallons of straight castor fuel at the shows because it was cheap . During the year he would loose model after model and moan about his engines stopping or breaking. This was all down to his modern engines being clogged up with varnish and muck.He couldn't see that spending a little more on his fuel would have saved him £'s in the long run .

Don Fry15/03/2019 15:35:44
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3256 forum posts
39 photos

Lubricant of choice for kitchen scisssors.

Cuban815/03/2019 16:34:44
2348 forum posts
8 photos

Took Jon's advice about fuel a couple of years ago and all my four stroke ASPs and OSs get 15% oil and 5% nitro Laser mix. Never looked back, models stay much cleaner as well.

GrahamWh15/03/2019 16:53:19
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317 forum posts
38 photos

The great thing about castor oil other than the smell is that it puts a lot of 4 stroke engines onto the second hand market due to poor performance, where bods who like to can buy them cheap-ish and clean them up and use them or sell them on!

Chris Walby15/03/2019 16:54:28
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847 forum posts
204 photos

Darn, I still have 4 gallons of R40 from my motorcycle racing days and I though they might be worth a few quid!

Mind you they never had enough run hours to gum up in competition.

Seriously, always follow the manufactures recommendation especially when its free! wink

GrahamWh15/03/2019 17:04:17
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317 forum posts
38 photos

I wonder if we could use a chemical additive like the e-cig people do to get that caster smell back in the modern fuels? Could try raspberry or caramel to confuse the guys on the flight line instead!

 

Edited By GrahamWh on 15/03/2019 17:05:36

Peter Christy15/03/2019 17:53:36
1243 forum posts

Dunno about that, but some years ago (Brian Cooper may remember!) Mick Wilshere was given some synthetic oil to try by Shell. The oil was brilliant! The trouble was that it smelt like putrified camel dung - whether burning in an engine or stoppered in the bottle!

If you put a can of it in your car, the stench hung around for weeks! It was also very good for clearing the less hardy flyers from the strip!

laugh

--

Pete

Brian Cooper15/03/2019 19:58:59
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394 forum posts
17 photos
Posted by Peter Christy on 15/03/2019 17:53:36:

Dunno about that, but some years ago (Brian Cooper may remember!) Mick Wilshere was given some synthetic oil to try by Shell. The oil was brilliant! The trouble was that it smelt like putrified camel dung - whether burning in an engine or stoppered in the bottle!

If you put a can of it in your car, the stench hung around for weeks! It was also very good for clearing the less hardy flyers from the strip!

laugh

Pete

Oh gawd, yes. ... That Shell oil was a bit pongy. dont know

Thank goodness modern oils are kinder on the nose. thumbs up

B.C.

Jon - Laser Engines15/03/2019 20:01:39
4417 forum posts
162 photos
Posted by Doc Marten on 15/03/2019 14:30:38:

It's odd Jon, depending on which fuel you use e.g The Southern Modelcraft Laser mix is 100% synthetic oil yet other manufacturers Laser mix still contains 2% Castor, which would you recommend and avoid?

The old SMC laser fuel used to have 2% castor but they dropped that a few years ago. One of the good things about SMC is you can call them and tell them what you want, then they make it. winner winner.

But this thread is not a Laser thread, i just used the 100 as an example. This information applies to all brands of engine and if i thought shouting it from the hill tops would help then i would do it.

When it comes to fuels, one issue is that castor hides in some fuels like contest 10 and sport 5 as its a small part the generally synthetic oil. It boils down to about 2% in those two fuels.

As a side note, i really hate contest 10. Using that stuff is like going on one of those game shows where they cover you with gunge and asphyxiate you with smoke . Could be worse though, could be duraglo

For those who just cant resist the castor perfume then i dont know what to suggest...medical help? therapy? perhaps dob a little on your chest like vicks? Or just fire up some old nail on castor straight (assuming its not gummed up solid) and just have a little sniff. Just dont put it near anything manufactured in the last 25 years and certainly nothing new!

Graham, nice idea about the scented smoke. And yes, i guess one mans junk is another man's treasure.

Just to touch on a point ED makes. Castor was great in old engines and it never really caused them a problem..why i hear you cry? well, they were rubbish thats why. In tolerance terms they were utterly hopeless compared to modern motors and so the varnish didnt really make any difference. In a modern ABC two stroke the piston/liner fit is everything and once run in any deposits from castor just make the fit tighter, the engine hotter, and the owner miserable. Dont forget too that castor is an excellent glue and before long all manor of dust and debris is baked deep in all the cooling fins reducing cooling performance still further.

Geoff Sleath15/03/2019 20:06:13
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3188 forum posts
247 photos

I was known to put a few drops of Castrol 'R' in the fuel tank of my vintage (actually post-vintage because it was 1932) Scott TT replica just for the smell The lubrication was a bit hit and miss anyway with its Pilgrim pump drip feed.

Certainly wouldn't use it in a model engine though.

Geoff

Edited By Geoff Sleath on 15/03/2019 20:07:55

GrahamWh15/03/2019 20:28:02
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317 forum posts
38 photos

"Castor was great in old engines and it never really caused them a problem..why i hear you cry? well, they were rubbish thats why."

laugh

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