Jab engines

[turboplanner]

One issue with these older Jab engines is corrosion of the steel barrels if left idle too long.

It hasn't been a problem in our normally dry inland climate, but I put a few ml of Moreys into the fuel just in case. If planning a long period of inactivity, I run it hard and inject some 2 stroke oil downstream of the carbie.

Facthunter seems to be the professor of engine storage.

[Thruster88]

Facthunter seems to be the professor of engine storage.

 

Lots of lycoming and Continental in private use also suffer long periods of inactivity, I know mine has, just saying.

[turboplanner]

Lots of agricultural engines are only started up once a year; WD40 is all I squirt in, have never had an engine failure from barrel corrosion, but I don't have to make a forced landing if I do.

[Bruce Tuncks]

I have never seen an engine rusted up internally, although I have heard of it happening. What do you look for? Is it obviously rusted inside if you look through a borescope?

[turboplanner]

I have never seen an engine rusted up internally, although I have heard of it happening. What do you look for? Is it obviously rusted inside if you look through a borescope?

You look for sore muscles after you’ve stuck a crowbar through the clutch fingers and it still won’t turn.

[jetjr]

In a Jab, you can feel scaping noise when hand turning prop, only on first rotation

Only one cyl will have open valve so mostly be only one cylinder, once you feel it once you will notice it on every one that hasn't run for a while

A borescope will show it for sure

The Camit inhibitor system works a treat to stop this

[kgwilson]

Aeroshell W100 plus includes a metal passivator and corrosion inhibitor as well as an anti wear additive so while it is important to inhibit an engine if it isn't going to be used for months, the corrosion inhibitor in W100+ will stop rust forming if the engine is not run for a month or so especially in very humid weather. Putting a cap on the exhaust will also assist.

[Guest Machtuk]

Aeroshell W100 plus includes a metal passivator and corrosion inhibitor as well as an anti wear additive so while it is important to inhibit an engine if it isn't going to be used for months, the corrosion inhibitor in W100+ will stop rust forming if the engine is not run for a month or so especially in very humid weather. Putting a cap on the exhaust will also assist.

All I ever use is 100+ In my Lyc & Jab donks, oh as well as flashlube, swear by them both?

[facthunter]

The only way the ambient air can flow through your motor is when both valves are open on any cylinder. When hydrocarbon fuel burns it FORMs water always. If it condenses you have enough for rust to form. There are also other nasties in the residue that cause corrosion. (acidic oxides of impurities like sulphur). One good rule is to always get your engine fully warm each time you fire it up. For most engines this requires about 45 minutes flight time and to achieve an oil temp of 85 or a bit over regularly. One of the worst things to do is leave your plane sitting in front of the clubhouse all day and then start it and taxi to the hangar close by and not fly again for a month . Valve springs, cams and followers can rust and also exhaust valve stems and guides and water causes sludge deposits throughout the engine generally. If you are leaving your plane for a while don't have old oil in it and consider some form of inhibiting Starting and running it for a short time may do more harm than good . Nev

[Guest Machtuk]

What's that saying? "Use it or lose it"?

I operate my engines every week where possible?

[Old Koreelah]

What's that saying? "Use it or lose it"?

I operate my engines every week where possible?

It's good advice, but not many of us get the opportunity; and that doesn't just apply to aircraft engines.

[facthunter]

I think that applies to ones brain as much as anything else. Especially in regard to your flying activities. Nev

[turboplanner]

I think that applies to ones brain as much as anything else. Especially in regard to your flying activities. Nev

Mine's rusty in the bores.

[jetjr]

I recall talk, when Camit working on upgrades, that bore corrosion was a significant problem, more than given credit for, with low time failures and stuck rings etc

[facthunter]

It IS and always will be unless one tends to pretend it isn't. "Ignore it and it will go away". is alive and well. Nikasil bores don't suffer from it.. Older, oilier motors were less susceptible, but any engine left idle for long periods suffers deterioration of some kind as does a transmission also. Ball races get "lined" if they sit in one position except when packaged properly. Valve seats on open valves can rust and the stems /guides also. Nev

[onetrack]

You can virtually eliminate corrosion in moist, enclosed, unprotected places, by installing a small heat source - and that's not hard to do, if you put a bit of thought into it.

In the case of wise old mechanics, who had to contend with tool corrosion in steel toolboxes, that endured wide swings in temperature and humidity - they installed a lit incandescent globe in their toolboxes.

The steady heat from the lit globe keeps the temperature in the toolbox above the dew point, and drives out any moisture that might find its way in.

I see no reason why a lit incandescent globe inserted into exhaust piping on an engine, wouldn't work in exactly the same way as the mechanics toolbox trick, to keep bore corrosion-causing moisture at bay.

Heat rises, and if there's any moisture ingestion path created by an open valve, then the heat from the globe will rise accordingly, and follow any potential moisture ingestion path.

[facthunter]

As I've said before you need two valves open at the one time to get a flow of air. The only way to stop moisture collecting in oil is run the oil at over boiling point in "enough" of the motor to drive it out the breather as vapour.. IN a gearbox you have to drain it..Nev.

[spacesailor]

ON Ebay someone in Cains (I think) sold silica damp absorbers, that were like sparkplugs. jusy screw in, and change when colour changes.

I couldent get them as not online for banking\ no PayPal.

spacesailor

[facthunter]

They are a part of a "proper" inhibiting process, Space... Nev

[Bruce Tuncks]

I like onetrack's idea. If the engine as a whole can be kept above condensation temperature then corrosion should be prevented.

You can imagine a heater of some sort with a thermostat switch achieving this. The effort involved is high though. The plane would ideally just need to be plugged in before leaving it.

Do engines using Morey's have less corrosion? Just an idle thought...

[Guest Machtuk]

Coinz, 245F is too cold I agree. Was this the max on climbout? How was it measured? I have never heard of such a cold running Jabiru (or Lycoming) engine.

While I can't argue with the results, I can't see how any air which doesn't come into contact with the hot metal removing any heat. I imagine hot engine molecules vibrating strongly causing adjacent air molecules to be shot away, taking energy from the engine with them.

Please don't be offended by my questions, I am quite capable of being wrong. Gosh, it has taken me 20 years to get the 4 temperatures fairly equal in my old 2.2 engine.

 

My 2.2 sits around 95-110C in Crz....ah nice and cool?

[John M]

Happy with my 230 now I have the mixture and cht problem sorted. A pilot up the valley has a 160 apart from servicing no problems and he has around 600 trouble free hrs all leak downs in the 70s plus

[Wirraway]

You eliminated them when you said only owners or operators could respond. A bit like saying you can’t knock a Hilman Hunter unless you own one.

Of course none of those who bought one will denigrate them, although there was someone on this site a few years ago that used to regularly voice their displeasure about how often the Jabs at his flying school broke.

 

Sorry I may be late to this thread, but have just seen your post.

 

Red rag, meet bull.

 

Yes, my poor parents purchased a brand new shit box, otherwise known as a Hillman Hunter in 1971/1972.

3 days after purchase, this was a new car, it could not be started. The dealer had a mechanic on our front lawn for 4 days trying to get it started.

Yep, mechanic spent 4 days working on our front lawn.

Other issues, the glovebox fell into the passengers lap.

Window winders fell off.

 

and numerous other issues. Generally, a piece of excrement.

 

As for your comment, "you can’t knock a Hilman Hunter unless you own one."

No, any sane person is allowed, and encouraged, to knock a Hillman Hunter, otherwise known as a piece of shit.

 

Anyway, back to aircraft.

[kgwilson]

I decided to go for a fly today. I have had something strange happen the last 3 or 4 time on startup. The Prop would sort of hesitate & then spin rapidly & the engine started. I thought my battery might be getting tired but on testing it everything was good. Today it did the same thing but the starter whirred part way through and the prop flicked backwards before catching again & away it went. I warmed up the engine & then realised I'd better get a jumper as on Monday it was warm on the ground but really cold at 4000 feet. I shut down put my jumper on & tried to restart. The starter would not engage. A mate gave it a number of taps & I also used jumper leads just in case. No it was not happening. On looking at the clutch mechanism everything looked perfect. No wear on the components at all.

 

Now this is the second clutch I have had due to something similar happening the first time & I couldn't find any thing wrong. Then I rang Jabiru & they said "You'll need a new clutch". I was not too happy as the engine had only done about 60 hours at the time. I was told there were some bad ones & I got a new one at cost price as it was outside warranty. Now less than 100 hours later it has happened again. WTF. Anyone else had this problem? I am going to ring Jabiru tomorrow for a new one. GRRR.

[Paul davenport]

I don’t know if it’s relevant but on the one I saw replaced there is a shim washer that is fitted at the front of the drive, it sticks to the old drive with oil grease and can be inadvertently thrown away. Without the shim washer there is too much end float which may cause early failure