Hot rear cylinder example Jabiru 3300A-2575 and plenums

[RFguy]

Yeah, I used to use them in Datsun days.

 

The thing is the hot bath  of caustic soda is not for aluminium....

 

I've got hot caustic soda for the valves, and removing some of the gunk with an eye dropper of it around the guides.

 

Have my bores ready to install ,  pistons.. ring gaps are good.   used a scotchbrite to put a pattern on the bores... they're in A1 condition.

The gunk though = looks like the rings (#2 ring)  on the low (and hot) side are the ones that jammed (in 3/6 cylinders) .

 

Still got to clean the combustion chambers. waiting for my MEK to arrive...

[onetrack]

The likes of the Robowash machines do not use caustic soda - they use a proprietary caustic solution, which is amenable to virtually all metals. I couldn't tell you what's in it, it's a commercial secret.

As the majority of engines today have all aluminium components, or have a large majority of aluminium components, the reconditioners can't afford to have different parts wash machines for different metals.

 

The trend today is to move away from solvent cleaners based on hydrocarbons, and to aqueous-based solutions. The main problem being with the more exotic hydrocarbon cleaners is they are being more commonly recognised today as carcinogenic and pose other health effects as well, if serious levels of PPE are not used.

We used to love carbon tetrachloride, it cleaned everything, to excellent levels. Then the authorities deemed it highly carcinogenic, so it's virtually disappeared today.

 

The new environmentally-friendly and health-friendly products such as the one below, are now the preferred cleaning solution.

 

https://simplegreen.com/en-au/industrial/products/parts-washer/

 

 

Edited February 14, 2021 by onetrack

[RFguy]

Hi

yeah that seems to be the way of the Hydrocarbon solvents I have here - MSDS sheets are as long as your arm. Like the MEK, my last resort. 

I have to go to Blackwoods tmw , so I will take your advice and buy some  SIMPLE GREEN, and see how that goes.

 

In the ultrasonic cleaner, I can heat 65-75 C (with or without ultrasonic on). In the big pressure cooker, about 115C is about as much as it will do.

 

 

 

 

[facthunter]

By the way, the usual engine degreasers ARE very caustic and make things RUST and your hands resemble a white prune if you get any of it on them.  Cylinder block scale is removed by ultrasound I believe. It's extensive in motors that run salt water in the cooling jackets. A bad idea in any case. Salt and aluminium don't go well together but cast iron suffers also. 

[RFguy]

(Nev turns out best I have done is some detergent and hot water in the pressure cooker so far, and U/S cleaner with hot water and soap to de grease, rinse cleaning muck hacked off)

 

Turns out that the standard "Simple Green parts wash" is NOT OK with ALuminium (according to their FAQ)

but they do have a Aluminium happy solution :

 

Simple Green | Pro Hd Cleaner Degreaser

 

https://simplegreen.com/products/pro-hd-cleaner-degreaser/

 

[Jabiru7252]

I wonder if electrolysis could be used to clean engine bits and pieces. I saw cogs from an old lathe that were in terrible condition come up really well when electrolysis was employed.

[RFguy]

Hi Kevin

I wonder what the contamination was. certainly electrolysis is used to remove a layer. 

 

 

[Jabiru7252]

10 minutes ago, RFguy said:

Hi Kevin

I wonder what the contamination was. certainly electrolysis is used to remove a layer. 

 

 

The lathe had sat in the weather for 20 years! Everything was coated in rust. The results were quite surprising. Can't find the pictures :-(

 

[facthunter]

Rust is converted metal (to a hydrated oxide). You can't return it to the original surface, only remove it.Removing old electro-deposited chrome or nickel etc uses electricity but has to be done carefully in the right bath and current density or parent metal comes off also.  Nev

[onetrack]

You can use a solution of washing soda in a simple electrolysis bath to remove rust, grease and other deposits from parts.

I don't know how it would work with hardened combustion deposits - I suspect, poorly.

 

An electrolysis bath is only good for ferrous items. It will rapidly destroy aluminium.

A good aluminium cleaner is a mild solution of phosphoric acid, and this is the major ingredient in "Mag Wheel" cleaners.

 

Trisodium phosphate is worth a try on combustion deposits. It's a major ingredient in laundry powders. A strong hot solution of laundry powder is a pretty potent cleaner.

Some of the "stain remover" laundry solutions can also be very effective.

And of course, there's always the citrus oil cleaners, which are quite effective at removing deposits and stains.

[Kenlsa]

Had a mate that used to restore vintage cars. First thing to do was remove the motor, empty any oil that may be in there, then place the whole thing into a drum with a mix of fresh water and molasses, generally 10/1 but can go up to 20/1. Leave for up to 6 months if very corroded. Remove —-and all the rust was gone. Nuts screw right off with no stripped parts.

 

done it myself on any iron or steel, even complete exhaust systems that would normally be thrown away. Everything comes up looking new. Took about 2 weeks.

 

trick then is to immediately spray with light oil coz you can see rust forming almost straight away, I kid you not.

 

I even restored a cast iron frypan that was so bad you couldn’t tell the rust from the pan.

 

it sure does smell but is very cheap

 

Ken

[onetrack]

Yep, the old molasses trick is well known amongst the car, truck, and machinery restorers. Another thing you can do, is round up all the rotting citrus fruit from your local fruit and vegie shop.

Throw a sizeable number of oranges, lemons, grapefruit, or mandarins in a 200 litre open-top drum, half-fill with water and leave for about 3 weeks. Give it a stir occasionally to help break up the fruit.

 

After 3 weeks, throw your old rusty items in there, and leave them for anywhere between 2 and 4 weeks. Pull the item out, and it will be cleaned of any corrosion.

The only downside is the smell of rotting fruit - so you need a semi-rural spot to do this. In suburbia, you may strain your friendly relationships with the neighbours.

 

I prefer buying commercial citric acid powder (you can get it from food wholesalers, bulk food shops, and sometimes even your local friendly bakery). The bakeries use large amounts in making bread. Citric acid is an anti-oxidant, a food preservative, and is 100% safe to use. Kids can paddle in the solution without fear of injury.

I have an IBC cut down to about 3/4 size, with a galvanised steel plate lid. I put about 500 litres of water in the IBC and add about 2 to 3 kgs of citric acid powder.

 

I can acid bath items up to nearly 1.2M long with this setup. You keep the solution lidded at all times, as UV light destroys the citric acid. After about a week, I pull the item/s out and pressure wash them.

If they aren't 100% clean, I put them back in for another week. Only the very worst corroded items require 3 weeks in the bath.

 

When I pull them out the final time, they get pressure-washed again, and then get a squirt all over, from a spray bottle, with about a 10% solution of Ranex (phosphoric acid) in it.

This prevents flash rusting, and you can then store the item indefinitely under cover without fear of it going rusty again. I restore a lot of items, and I've been doing this successfully for over 30 years.

 

Edited February 15, 2021 by onetrack

[RFguy]

well got my MEK. wow that stuff works on the brickwork like deposits on combustion chambers....

 

still got to get my ring grooves cleaned up like new .  clearances (height) on cleaned surfaces are at the minimum specificed.... (#2 ring) .  so wonder the gunk jammed the rings. 

 

probably needs soemthing put into the fuel periodically, or  poured in the pots every 100 hours or so (and throughly flush out  the system) ...

 

[kgwilson]

Just use 98 Mogas - problem solved.

[Kenlsa]

RF, our entire fleet has been on 98 for a while now and we are in the final stages of installing a bowser.

Result, no loss of compression due to stuck rings or valve face deposits. The camera does not lie, you can eat your dinner off the piston crowns.

I have been on 98 most of the time and saving $12 an hour, that will be $18-20 in your 230.

Ken

[facthunter]

As long as the depth is such as to have the ring surface below the piston's surface extra space achieves nothing.  A protruding ring can cause breakage. Generally the top ring groove wears more and runs hotter.  Have the rings distorted at all? A gentle lap onto plate glass might be in order.  Nev

[Blueadventures]

10 minutes ago, facthunter said:

As long as the depth is such as to have the ring surface below the piston's surface extra space achieves nothing.  A protruding ring can cause breakage. Generally the top ring groove wears more and runs hotter.  Have the rings distorted at all? A gentle lap onto plate glass might be in order.  Nev

Glass is flat.  The piece I use to lap ship valve faces on is 1” in thickness, one mean piece of glass.

[facthunter]

Thicker and ground flat is best. Plate glass is pretty good. You can easily measure any variation of thickness with an ordinary 0-1" micrometer  as you go.  Nev

[RFguy]

thanks for the comments. 

 

Ken- I would run 98 if it was convenient. I will put some 98 in it from time to time.  winter. 

 

I have new rings of course. I will see what they are like on dimensions.

 

I will also look at the old rings I got out that are intact. 

 

[Blueadventures]

21 minutes ago, RFguy said:

thanks for the comments. 

 

Ken- I would run 98 if it was convenient. I will put some 98 in it from time to time.  winter. 

 

I have new rings of course. I will see what they are like on dimensions.

 

I will also look at the old rings I got out that are intact. 

 

If I was in your position I would change to 98, setup a refuelling pump unit and take fuel to your plane in 20 litre jugs. I refuel from 20 litre plastic jugs via an aero quip 12volt pump. About 3 minutes per 20 litres.  From others reports the use of 98 will get you off the build up merry go round / less unscheduled maintenance.  Sounds like more than enough evidence pointing to nice clean engine internals to me.  Cheers

[facthunter]

See if you can  assemble a Jabiru that bounces off compression. Most of them end up stiff to turn. Nev

[kgwilson]

It's easy. I keep a 20 jerrycan in the car & fill it on my way to the aerodrome. I top up when I get below 40 litres and only fill the wing tanks plus main when going away. That's 170 litres so its a couple of trips with my 3  x 20 litre cans. The 230 has 135 litres & requires a step ladder or something but with either a syphon or battery pump not hard. All the Jabber wockys around here don't have a problem though a few are blinkered AVgas users so have to fly 40 minutes to get it & 40 minutes back just to get fuel that gums up their engines. I think they've all been brainwashed by the AVgas advocates and the Jabiru manual that says 95 & above is OK but recommend Avgas to ward off possible litigation.

 

We don't fly high enough to have vapor lock problems especially if you have gravity feed and a supplement electric pump and if the engine is correctly timed detonation is also not an issue

[facthunter]

I really don't think avgas will GUM up the engine. It doesn't have that sort of ingredient in it. Certainly avgas is not a good idea with a Rotax. The worst engines I've ever seen for gumming up internally were mogas fed Croppies  like Ag Kats with larger Radials in them. .  Your plane goes fast so has few cooling problems. Nev

[RFguy]

And its also possible this engine is running on the rich side..... jetting , cowl neg pressure (confusing the carb etc)  etc. 

 

still cleaning ring grooves. 

 

In the 2nd ring groove, where they (3 outof 6 #2)  got stuck, half circumference,  it was a mild 'black gum' that pushed away pretty easily.

 

But ! under the 1st ring, about half circumference, the 0.3mm of hard black carbon . I'm talking hard like diamond. like bl00dy diamond . attempts to remove it only polished it like glass ! WTF ! I still havent got it all out. soaking in the MEK overnight. 

 

We have 98 in the club rotax.  We may be getting drums.   I'd like to figure out a good fuel return system. others have done it... Or an intercooler for the fuel.

 

Jeeez, I am not going through this again, getting this back to decent looking had been a hard job. 



 

[kgwilson]

1 hour ago, facthunter said:

I really don't think avgas will GUM up the engine. It doesn't have that sort of ingredient in it. Certainly avgas is not a good idea with a Rotax. The worst engines I've ever seen for gumming up internally were mogas fed Croppies  like Ag Kats with larger Radials in them. .  Your plane goes fast so has few cooling problems. Nev

I agree poor choice of words. What I should have said was running on Mogas 98 will result in an engine with fewer piston head and valve deposits. A side effect is it is better for the environment as well and cheaper.