Rebuilding a Jabiru with the after market. (Experimental Only)

[gofastclint]

For experimental Jabiru pilots I think it would be a good idea to use aftermarket components to rebuild your engine as more time and development goes into these specialty parts making them a safer option over standard and in some cases, the parts can be cheaper.

 

These are the manufactures I would use for a Jabiru build, as they have a very large range of parts, a good reputation and are commonly used in tough builds:

 

CP Pistons, Carrillo rods, Ferrera for all the bits in the head and a set of ACL bearings.

 

With these components you can reliably get 500hp out of a 2.2 liter 4 cylinder with boost on pump fuel, so I know they will last for ages turning out only 100hp.

 

 

[Dieselten]

These are automotive after-market bits, right? For car engines? Racing-car engines? Engines which produce massively varying levels of output power via gearboxes? Engines which are never operated in anything like the same manner as an aircraft engine? Engines which are never asked to warm up, then operate just below redline for five minutes, then spend a couple of hours at constant 75-80% power (and speed), then coast back home at idle, right?

 

In other words, you are trying to convince me that parts for an engine designed to operate in one way are going to cut it in an engine run in a totally different manner, with completely different thermodynamics, stresses and horsepower-ratings?

 

Go ahead - make my day! But the only way to rebuild a Jabiru engine is to use Jabiru engine parts and only Jabiru engine parts. If you don't, it's no longer a Jabiru engine. It may be a CP-Carrillo-Ferrere engine, but it isn't a Jabiru engine, but it most certainly isn't what the aircraft designer envisaged bolted to the front of his airframe, it isn't what the engine-designer envisaged assembled as the powerplant, and it isn't anything other than a pudding of parts which may - or may not - prove compatible.

 

By all means experiment - and be an unpaid test-pilot. The strange thing is that in experimental aircraft, it's amazing how many builders choose to put in a reliable, proven Lycoming or Continental engine into their experimental airframe. I guess they want at least one part to be a known quantity.

 

As Lenin so truly said, "everything is connected to everythign else", and nowhere is this more true than in the field of aircraft reciprocating piston-engines.

 

 

[BLA82]

These are automotive after-market bits, right? For car engines? Racing-car engines? Engines which produce massively varying levels of output power via gearboxes? Engines which are never operated in anything like the same manner as an aircraft engine? Engines which are never asked to warm up, then operate just below redline for five minutes, then spend a couple of hours at constant 75-80% power (and speed), then coast back home at idle, right?In other words, you are trying to convince me that parts for an engine designed to operate in one way are going to cut it in an engine run in a totally different manner, with completely different thermodynamics, stresses and horsepower-ratings?

 

Go ahead - make my day! But the only way to rebuild a Jabiru engine is to use Jabiru engine parts and only Jabiru engine parts. If you don't, it's no longer a Jabiru engine. It may be a CP-Carrillo-Ferrere engine, but it isn't a Jabiru engine, but it most certainly isn't what the aircraft designer envisaged bolted to the front of his airframe, it isn't what the engine-designer envisaged assembled as the powerplant, and it isn't anything other than a pudding of parts which may - or may not - prove compatible.

 

By all means experiment - and be an unpaid test-pilot. The strange thing is that in experimental aircraft, it's amazing how many builders choose to put in a reliable, proven Lycoming or Continental engine into their experimental airframe. I guess they want at least one part to be a known quantity.

 

As Lenin so truly said, "everything is connected to everythign else", and nowhere is this more true than in the field of aircraft reciprocating piston-engines.

 

:thumb_up::thumb_up::thumb_up::thumb_up::thumb_up::thumb_up:

 

 

[gofastclint]

Then why do they use these components in the race engines at Reno? Its because they are better, safer and more reliable components. They are not miss matched as they are custom made for every build. Sitting at an aviation red line would no stress these components out at all. Look at the constant high revs NASCAR engines go through without an engine failure using similar components.

 

The holden pistons Jabiru use are not as good as CP pistons. The ring lands crack far easier than a good set of forged pistons if you get a bad batch of fuel and have some bad pre ignition.

 

Regardles of the engine, car or plane, the pistons, rods and valves have the same job. I'll take the better quality components over the b grade Jabiru parts any day.

 

 

[Captain]

I think gfc makes a valid point.

 

IF standard automotive bits are being used, and are giving good service, then rational use of the same components that are better made or from better materials, should offer something ..... but it will cost more and a detailed check would be needed on compatability with the other components with which thay mate (eg expansion rates of the forged pistons in the air cooled barrels).

 

But in the case of the J, I'm not so sure that rods and pistons are such an issue that forged items are needed (although I am a huge fan of Carrillo rods).

 

Now ...... valves might be an issue in point where better material might be warranted. If mine go I'm planning in modifying a set (3 sets actually) from BMW bike valves.

 

I think that the use of after market components in Reno engines comes from the need for more power, maybe higher revs and the willingness to accept less life before a strip-down due to flogging them harder (current MotoGP bike engines are getting 500 kms (say 3 hours) but the revs are thru the roof).

 

Regards Geoff

 

 

[Guest brentc]

It is a common myth that Holden pistons are used in Jabiru engines. They are not! If you look closely they are different, for starters they are reversed.

 

 

[Guest watto]

I am all for using genuine parts as well but Jabiru did tell me that they use a modified Holden piston, it is machine to allow for different gudgeon pin clips I think but that may not be exactly what it is I cannot remember exactly what they said the mod was.

 

But that does make sense to use commonly available parts that are proven and cheap to obtain as raw materials as this will keep your reliability high and overheads low which is smart business sense.

 

You will find that most engine manufacturers source pistons from engineering companies that specialise in this technology so even though you have a Jabiru, a Rotax or a holden the components are from common sources and not necessarily made by those with the name on the block.

 

As long as the parts are compliant with Ac standards there should be no problem.

 

But in saying that, if you stay standard and you or the next owner have a problem then life can be a whole lot easier!!!!!!!!

 

 

[Guest brentc]

Correct you are Watto...... modified. We don't want people thinking they are the same as one well known warbird identity found out when he replaced them of his osn accord to find out later when it all blew up in pieces that they weren't actually the same.

 

I think you'll find that they come from the same supplier, are similar, but certainly not interchangeable.

 

 

[gofastclint]

The cool thing about custom pistons is you can order them with 3 options well suited to air cooled operations. first option is a high silicone content to stop the pistons expanding under high heat, second option is a ceramic top coating that has many benefits in the heat transfer, reduces fatigue on the pistons and as less heat is transferred into the piston the energy makes the gas expand more, giving an increase in power. also the piston skirts can be impregnated with a dry lube that reduces wear on the bores as the motor warms up.

 

I have rebuilt many air cooled motors in my time and I swear by quality parts. In saying that, prepping an engine before a build is so crucial. A poor engine build with top quality parts can fail well before a stock built engine that has been prepped well.

 

It all come down to research before and patience during a build.

 

 

[BLA82]

I think the point is being missed here GFC you have very valid points as I too have owned high performance engines BUT there is always a trade off. As Captain said amongst others the Reno racing engines are built for Max Power Max Rpm and a very short lifespan. I used to have a excessively modified motorbike and I can honestly say there was no money spared nor was the build done poorly and the life between builds was short. It might have had all the top grade parts but in the end it was still a stressed motor.

 

Your comment "With these components you can reliably get 500hp out of a 2.2 liter 4 cylinder with boost on pump fuel, so I know they will last for ages turning out only 100hp. " is not quite correct.

 

You either have one or the other and as far as modifying proven engines in aircraft I can't honestly see any advantage.

 

 

[Barefootpilot]

Reno engines run for about 20 hours.... (if they make it that long!) I'd like a little bit more than that out of mine!

 

 

[gofastclint]

Reno engines run for about 20 hours.... (if they make it that long!) I'd like a little bit more than that out of mine!

They also have massive amounts of boost pumped into them. The only boost needed in a RA style aircraft is to compensate so you have the same pressure at 10000ft as you would at sea level. Any more than this and you will use too much fuel.

 

 

[kevinfrost]

Talking all this horse power from a 2.2 has my amagination going wild with visions of stripped through bolts and barrels flying off hitting people.

 

 

[Yenn]

What sort of revs do those Reno engines pull to get the high hp? Do they use a gearbox to reduce prop speed?

 

 

[Guest watto]

I think the reno engines are used in race cars Ian, welcome back by the way mate.

 

 

[Barefootpilot]

Are you asking about the Reno air race engine Ian? or a car engine?

 

 

[gofastclint]

Are you asking about the Reno air race engine Ian? or a car engine?

Reno Engines run at up to 30% greater revs but the main power is achieved by adding boost.

 

 

[gofastclint]

I think the reno engines are used in race cars Ian, welcome back by the way mate.

Some of the planes in the sports class used automotive engines. For example, there is a blue version of Jon Sharp's sports class Nemesis that has just taken on a car based V8 engine with hopes of beating the 540 Lyc used in last years aircraft.