BRP who owns Rotax has just axed Evinrude ! Is Rotax next ?

[Blueadventures]

Probably thinking if they had 5 people would ask “why 5 mains” and say should have been 3. ?

[Flightrite]

Air cooled engines especually early built units where done so for simplicity and field servicing. Air is free, simple and effective, Christ there are so many air cooled engines running around with humans onboard that you couldn't count them!

Water cooled in most applications is heavier, more expensive and more complex all unesesary, just ask Mr Lycoming, he has sold one or two over the years successfully I might add!

[facthunter]

3 mains is perfectly adequate for the piston speed /rpm and crank stiffness. Earlier Lycomings were 2 bearing. Extra bearings make torsional vibration problems and larger cylinder offsets from one bank to the other. The centre main bearing is loaded by having no counterweights and It relies on case strength. There are NO issues with the current set up that would indicate the need to change much.. The Continentals have the camshaft below the crank and lubricate slightly better. ALL flat or in line fours have pistons all stopped together twice per revolution so you get reversals of flywheel effect for this reason. The correct angle V4 would be far better in having piston and small end weight flywheel effect more constant.. Much easier on the prop hub, blades, mounting etc.. Nev

[skippydiesel]

Thanks Nev for confirming that diesel is formulated for varying conditions, as I stated.

So altitude/temperatures are no barrier. If ULP, for aircraft , is recommend at no less than 95 RON and overweeningly purchasers go with 95-98 then I think it would be fair to suggest, that purchasers recommended to use of a known grade/standard of diesel would do the same.

Having said that I think we are still some way from a cost effective diesel engine, for RAA level aircraft, so the lurch for a suitable diesel fuel in AU is probably academic.

[onetrack]

It's the wax content in diesel that causes problems with low temperatures. The oil companies initially had a lot of trouble with diesel made from Bass Strait oil containing too much wax, and it led to a slew of fuel blockage complaints in Alpine conditions. In fact, it led to a slew of farm equipment damage. I read about one bloke who had the oil in his truck sump turn to jelly, with the high wax content in the oil, coming from fuel dilution.

He started the truck engine on a very cold morning and left it idling to warm up - but the oil wouldn't pump, because it was jelled. The truck engine ended up with buggered bearings, before he realised the problem.

 

"Summer" and "Winter" blends of diesel production and delivery is carried out with no fanfare by the oil companies - in line with the seasons and expected demand.

In fact, there are up to 4 seasonal blends in some regions. The oil companies cut the wax with kerosene or heating oil to thin it.

The problems start when you take some high wax content "Summer" diesel, from an area where it's being supplied in line with seasonal planning - and travel to an area (or height) where the cold is equivalent to Alpine conditions.

[Old Koreelah]

... The winter diesel may cause injector failure in some systems. as it's got less lubricant properties.. I've corresponded with Shell and they said just add kero. Expensive and probably needs a lubricant additive as well...

 

Nev that raises an issue nobody has been able to explain to me: I’m told that kero is actually an abrasive, and I assume AvTur may be as well. When a diesel is fed Jetfuel (as in the US military) do they add a lubricant?

[Flightrite]

Nev that raises an issue nobody has been able to explain to me: I’m told that kero is actually an abrasive, and I assume AvTur may be as well. When a diesel is fed Jetfuel (as in the US military) do they add a lubricant?

 

A hundred years ago in another life when I worked for a major oil Co often Avtur slops was used in various diesel equip around the yard but the chemist at the refinery always said to add a lubricant because Avtur was very'dry'. Can't recall what lub we used to put in the fuel.

[facthunter]

Kero is used in some grinding processes but is a fire risk from sparks.. It has been called an abrasive but that's not really possible. It is just "dry" and has no lubricant properties worth considering on it's own. Often kero engines use chromed bores. If you are stuck, use kero and two stroke oil but it's dearer than "distillate"as it used to be called.

The thickened oil is from soot. Some Japanese diesels still recommend 5,000km oil changes. Low ash oil or something recommended. That's an outrageously low figure to be changing oil ,but I've seen it when it just won't drain from the engine cold at all. It wouldn't circulate through the engine under the same circumstances either

I've worked on a lot of diesels over a while. Modern oils and good thermostats keep the engines internally clear of sludge build ups NOW, even though the oil itself is pretty black. Back in the 50's they were filthy dirty things to have anything to do with.

Operating machinery in Polar conditions involved adding kero to all lubricants to maintain flow. Before shutting down a big radial you injected a fair bit of avgas into the engine's internals to ensure it would rotate to enable it to start, later. It was called an oil diluter system. In operation it evaporated and went out the breather. ready for the next cycle.

I was at a meeting where a fellow who had taken an RV to the South Pole gave a talk and the biggest difficulty was keeping the lubeoil from freezing in flight when some severe conditions were encountered. Some radial engined transports get oil cooler "coring". and the cooler effectively gets bypassed. Nev

[Old Koreelah]

I've read of Swedish WWII military aircraft having their engine oil removed and preheated, to speed up response times in winter. Japan's enormous aircraft carrier submarines also used that trick to reduce warm-up times.

[onetrack]

One time when money was tight (early 1980's), and the price of fuel had rocketed to 4 times what it had been, 18 mths prior - the brother decided he'd use up some surplus lighting kero in his diesel HJ60 Landcruiser.

The kero was surplus because we'd had a kero fridge on our gold mine, and the kero fridge had caught fire, and burnt the building down that it was located in!

 

So he mixed in about 3% lube oil with the kero, added a fair portion of it to some diesel, and the Landcruiser ran on the mix quite happily!

 

The lube oils for diesels have always contained a much higher level of detergent, than the lube oil for petrol engines. If you use diesel lube oil in a petrol engine it will glaze the bores.

The more recent lube oils for diesels have much higher levels of detergents, and newer chemical types of detergents, than the diesel lube oils of the 60's, 70's and 80's.

This is because, with low emission diesel designs, the pollutants from combustion are being forced down past the rings, rather than blown out the exhaust.

So a higher level of detergency in the lube oil is needed to cope with the extra pollutants from combustion coming down into the sump past the rings.

 

The story behind the detergent in diesel lube oil is quite interesting. Caterpillar pioneered the diesel tractor and industrial engine in America in 1931 (although MAN and Atlas had commercially successful diesel engines, prior to Cats diesel).

The early Cat diesels were going O.K., until about 1934-35 - then suddenly, they started choking up with huge amounts of sludge in the engines. The Cat engineers couldn't figure out what was going on.

Then they found Standard Oil had been trying a new refining process for their lube oil that removed a naturally-occurring detergent in the original crude oil. That natural detergent had been keeping the Cat diesels clean, up until that point.

 

Cat went to Standard Oil and told them what they'd discovered - so Standard Oil started adding the detergent to their diesel lube oil - and voila, all the Cat engine sludging problems disappeared!

[facthunter]

Some fire truck and emergency vehicles have electric oil preheaters for immediate high power responses. In ALASKA they use firepots under the aircraft engines to keep them able to be used (I nearly said "fired up".Nev

[onetrack]

I can remember reading about the Nazis in the bitter Russian Winter of 1941-42, fighting in temperatures that were recorded down to -50°C around Moscow. They had to light fires under their truck engines so they could get them started!

 

In the Nordic countries, it's common to add 3% methanol to diesel for Winter.

[Old Koreelah]

I can remember reading about the Nazis in the bitter Russian Winter of 1941-42, fighting in temperatures that were recorded down to -50°C around Moscow. They had to light fires under their truck engines so they could get them started!...

I bet those fires weren't easy to start; some fuel needs be vaporised and a Russian winter is orders of magnitude worse than ours.

Our VRA squad once experimented with showering sparks across a tray of petrol on an Aussie winter night, with no effect.

[onetrack]

But they probably had Vodka to start the ignition!!

[skippydiesel]

 

........................................................................

The lube oils for diesels have always contained a much higher level of detergent, than the lube oil for petrol engines. If you use diesel lube oil in a petrol engine it will glaze the bores.

The more recent lube oils for diesels have much higher levels of detergents, and newer chemical types of detergents, than the diesel lube oils of the 60's, 70's and 80's.

nt to Standard Oil and told them what they'd discovered - so Standard Oil started adding the detergent to their diesel lube oil - and voila, all the Cat engine sludging problems disappeared!

..........................................

 

Just a point or two Onetrack -

 

Your information is about 30 years or so out of date - almost all engine oils now have detergent qualities and a great many are suitable for both petrol & diesel engines.

Back in the day when oils for diesel and petrol were "different" we were told it was okay to run a petrol engine on diesel engine oil from new (no suggestion of glazing the bore) and this was a way of reducing oil stocked in store, when operating a mixed fleet of cars, trucks and tractors.

[skippydiesel]

It is usually in countries that experience very cold winters for internal combustion engines, petrol & diesel, to to be fitted with externals powered (mains) heaters for the cooling system, battery and sump . Not all have all three. Almost all will have a heated cooling system. The larger the engine the more likely it will have all three.

 

Its many years since I have been in a Canadian winter but back then when you went past a truck stop, in the middle of the night, all the big rigs would be idling to keep their systems and sleeping drivers warm.

[walrus]

The Rotax engines are used in American military drones.