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Castor oil in 4 stroke engines

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Ron Gray15/03/2019 21:37:48
1900 forum posts
759 photos

A few drops of Castor in the mower’s fuel tank, makes mowing the lawn a bit different!

J D 815/03/2019 22:06:08
1439 forum posts
84 photos

My old lawn mower is well outside Jon's 25 year rule so I may well give that a go.wink

Wihtgar15/03/2019 22:33:00
61 forum posts

So, should I use synthetic in a new PAW diesel and a Ridley Oliver Tiger?

Jason Channing16/03/2019 06:58:39
147 forum posts

ML 70 is not a modern synthetic neither is EDL neither of which would I use in a YS or other top range engine which generally leaves Klotz and a few less known others,Luckily Klotz in its various forms does work superbly.

Jon - Laser Engines16/03/2019 07:05:55
5415 forum posts
263 photos
Posted by Wihtgar on 15/03/2019 22:33:00:

So, should I use synthetic in a new PAW diesel and a Ridley Oliver Tiger?

I would say that diesels, especially old ones are the only place for castor these days.

Jason, ML70 and EDL are old in terms of when they were originally developed but as with everything they have been developed continuously so are not the same as when first introduced.

Jason Channing16/03/2019 07:22:34
147 forum posts

Lets us not forget though that EDL was and still is a transformer coolant. Cheeky but true.

Wihtgar16/03/2019 10:15:37
61 forum posts

When you say old Jon, do you mean an old design or actual age? Can these engines be run on modern synthetics with no adverse effects.

Engine Doctor16/03/2019 11:56:09
2466 forum posts
39 photos
Posted by Wihtgar on 16/03/2019 10:15:37:

When you say old Jon, do you mean an old design or actual age? Can these engines be run on modern synthetics with no adverse effects.

Old engines , as in Vintage had poorer tolerances and most had iron piston liner technology so Castor oil is probably the best option for them . Diesels don't generate the heat and have such a large large ammount of cooling fuel flowing through them that they will be fine on castor . An old vintage engine if its fits are ok would also be fine on synthetic based fuel

David Davis16/03/2019 12:30:03
3671 forum posts
688 photos

What about Enyas?

Manish Chandrayan16/03/2019 13:33:22
630 forum posts
73 photos
Posted by Jason Channing on 16/03/2019 07:22:34:

Lets us not forget though that EDL was and still is a transformer coolant. Cheeky but true.

And I know of full size turbine manufacturer practice where transformer oil was used as preservative oil on many a parts.

And yes that oil is an equally good anti termite treatment 😊

Don Fry16/03/2019 14:01:33
4557 forum posts
54 photos

But you wouldn't use EDL to clear blockages like you would castor.

brokenenglish16/03/2019 14:54:08
539 forum posts
29 photos

I shall probably be a minority of one, but I disagree with some of the statements above.

Between the late forties and early sixties, all the well-known British diesels had individually fitted and hand-lapped piston/liner fits. To suggest that expert hand lapping, which it was, gives poor fits, just isn't true.

I know I'm not the only one, but I happen to be an old engine collector, who runs and flies as many old engines as possible. I still have several hundred "fifties vintage" diesels, mostly but not all, British, and most of the P/L fits are still superb today. At least as good as my modern engines, including Laser.

It's the technology that's changed. Engines are now much bigger, with ringed or ABC or similar P/L assemblies.
CNC machining, etc. is obviously excellent for modern engines, but I don't think it gives better fits than hand-lapping, and suggesting that vintage hand-lapped P/L assemblies had poor fits and depended on using very viscous (thick) lubricant to run, is very untrue, ridiculous even.

Maybe I've misunderstood the above posts, but does anyone really think that all the ED Bees, Babies and Hunters, all the Mills engines, the Kalpers and all John Oliver's production ran superbly (which they all did and still do) with poor P/L fits?

Edited By brokenenglish on 16/03/2019 14:55:26

Engine Doctor16/03/2019 17:01:03
2466 forum posts
39 photos

Hello brokenenglish . I didn't make that very clear . Diesel engines obviously have to have good piston liner  fits to run and as they virtually all use iron piston liner technology then and Castor was /is fine for them . Although some of the engines from that period had plain main bearings that were just a reamed bush and had a fair amount of rock or a poor fit and needed a rich mixture to start them . Model diesel fuel also seems to prevent the castor from forming a varnish .

Earlier Vintage engines like the petrol engines and some of the low production run engines from the 1920/ 30's up to the war had terrible fits by today's standards . They needed a good drop of castor to make a seal . In fact as the varnish built up it improved their running . Modern Diesels are fine and don't varnish like modern glow units again perhaps its the fuel that prevents the varnishing.


Hello Dave Davis . Enya two strokes that used iron pistons /liners , I have to admit that I have never had one affected by the castor oil varnishing. Perhaps its the iron technology that prevents the varnish build up ? but the four- strokes suffer from varnished pistons and clogged valves /exhaust as do the ringed two strokes with alloy pistons that gum up and varnish .

ps John -Laser Engines . Sorry I din't mean to hijack you post , just got carried away



Edited By Engine Doctor on 16/03/2019 17:10:41

Jon - Laser Engines16/03/2019 18:06:01
5415 forum posts
263 photos

Nah its all good ED, dont worry about it.

David, Enya's will be fine on it. I have several enya fs's and a friend has a bunch more. All run on synthetic with no issue.

Andy Remedios16/03/2019 18:24:33
16 forum posts
7 photos

I'm confused, just purchased an ASP 90. Just engines said use Model Technics Irvine Sport 5% but this has caster oil in??

Peter Christy16/03/2019 18:44:20
1773 forum posts

Andy: Is that a a 4-stroke or 2-stroke? Doesn't really matter, as I run *all* my engines on Bekra heli fuel (2-stroke and 4-stroke). It contains NO castor, and I haven't had an engine problem in all the years I've been using it.

I run everything from Cox .049s to OS 70s on it, the only variable being the amount of nitro (mostly 16% or straight).

My classic aerobatic model is flying on a Webra 61 that I bought in 1967, still going strong, and far cleaner now than it was a few years back! Synthetic will eventually shift a lot of the old castor varnish.....!



Andy Remedios16/03/2019 19:20:35
16 forum posts
7 photos

It's a Four stoke. Brand new un run, just getting back in to flying, just purchased 2 gallons of the stuff!!

michael kuss16/03/2019 19:26:01
12 forum posts

Jon how do you get that valve cleaned like that . Also any news on the gasser ? Cheers Michael

Jon - Laser Engines16/03/2019 19:57:32
5415 forum posts
263 photos
Posted by Andy Remedios on 16/03/2019 18:24:33:

I'm confused, just purchased an ASP 90. Just engines said use Model Technics Irvine Sport 5% but this has caster oil in??

yup its got castor in it. Use your 2 gallons, but after that go for something else. That of flog it off to some unsuspecting soul

Michael - Swearing, a great deal of it. Nothing removes castor like a good swearing session...also, 400 grit wet/dry and scotchbrite. Oh and time

No news on the petrol front, i will post on the relevant thread when i have something

michael kuss16/03/2019 22:39:26
12 forum posts

Thanks Jon , I thought you may have had some magical solvent we could all get . I want another twin or gasser . No pressure ( well not much anyway ) .

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