Sooty Deposits

This seems to be a bit coked up Matt, a bit like a two stroke motorbike gets in it's exhaust, port and head after
lotsa miles. It has quite a coating on the piston crown already.
I was thinking the unthinkable and (whisper it) putting some synthetic in it this weekend to see if it makes a
difference.....

The only time I have seen the black goo was on an engine I ran before cleaning. Prob just some old carbon deposits. Break it down and clean er up! Prob should go away.

Yup older engines tend to trow out this "sludge"

.

2 runs at over 30 minutes run time is a long time per flight with engines made for a few minutes at best. Could be some galling going on. I have a stunt plane with 1 1/3oz. fuel that uses a TD .049. Got alot of black ozzee all over. Engine seems fine and runs strong but replaced it with Norvel .061. I save my TD's for Nostalgia type FF planes. Sometimes fuels don't have the best oil. Ever see the mess a Diesel makes?? Plus Diesel's are rantid stink bombs.

Old fuel will cause more soot buildup than fresh fuel. the anitfoam additives start to break down over time. Then the motor is gobbeling weak fuel and you have to tune a bit richer to compensate,,almost dieseling.

A much higher oil content will cause soot buildup over time.

If it is throwing out dark muddy sludge all of a sudden, then you might have a internal component wearing fast.

Diesels do not have to make a mess.
But most people run them with about 30% castor oil, run that in a glow engine and the mess will be just as bad.
Another reason diesels behave like that is many of them are old and have not been cleaned like old glow engines so trow out all te goop they accumulated.

Thanks Guys.
I got food for thought.
I haven't really seen sludge though, certainly no more than any of the other Cox's I've run recently.
I think it's new fuel time.
J

John Goddard wrote:I think it's new fuel time.

Maybe do a quick de-soot, snap some pics and then run say.,,10-15 oz thru it and then take a peek. See how quick the fuel you run causes a buildup,,if any.

Sorry for lack of clarity boys. I've re read my first pre bucket
Of coffee post....
The engine is a sure start bottom end with Bernies new Td cylinder, piston
And new teeDee head. The whole has about a 10 tiny tankfuls and 4 big
Tankfuls through it which although not brand new is hardly
Knackered either.

John Goddard wrote:Sorry for lack of clarity boys. I've re read my first pre bucket
Of coffee post....
The engine is a sure start bottom end with Bernies new Td cylinder, piston
And new teeDee head. The whole has about a 10 tiny tankfuls and 4 big
Tankfuls through it which although not brand new hardly
Knackered either.

Okay then so I am sure it must be your fuel.
I told ya the gx25 stuff was dodgy but then I also recommended it to you.........

I'm using glow plug boy 24%. It is pretty old, but I always remembered the black stuff. No hole in the piston, and it is not coming out of the bottom end. I suppose I need to try a different engine.

How much run time wil a TeeDee get on that tank? Thinking of building up my first TeeDee CL model with a .051 purchased from ebay. Thanks.

Obvious really............................

The new bottle of fuel I started on Saturday is Sh Sh Sh no good.
010 would not run for more than a 2 second burst with it in tank.
Much head scratching then
A drop of YS 30 in the tank and guess what?
Perfect

I'm gonna be messing around with head gaskets and different fuels with the 010 in
near future stay 'tuned' folks

I really hate the clear bottles and jugs that fuel suppliers use, they are like a magnifying glass and if left in the sun, you can see condensation droplets on the side/inside of the jug.

The bad part is that you dont know if the hobby shop where the purchase was made, allowed them to set in the sunlight. Its a gamble for good fuel nowadays. I shy away from the clear jugs, or if I am forced upon them they stay in the dark cold areas wehn not in use.

If I go to the field with a full jug, it stays in a cooler with a single packet of refreezable Blue Ice.

ODonnell racing fuel uses the white opaque jugs, and I usually rejug the stuff I buy into my string of leftover whites.
http://www.odonnellracing.com/racingfuel/index.html

PV Pilot wrote:I really hate the clear bottles and jugs that fuel suppliers use, they are like a magnifying glass and if left in the sun, you can see condensation droplets on the side/inside of the jug.

The bad part is that you dont know if the hobby shop where the purchase was made, allowed them to set in the sunlight. Its a gamble for good fuel nowadays. I shy away from the clear jugs, or if I am forced upon them they stay in the dark cold areas wehn not in use.

If I go to the field with a full jug, it stays in a cooler with a single packet of refreezable Blue Ice.

ODonnell racing fuel uses the white opaque jugs, and I usually rejug the stuff I buy into my string of leftover whites.
http://www.odonnellracing.com/racingfuel/index.html

I'm sure lots of them are thinking this Keith so I'll ask it..........
Is glow fuel degraded by sunlight?
Or does it just seperate the water content of the methanol?

You get the greenhouse effect from the sun hitting the jug and oil and other properties in the fuel so in a sense it degrades it, rather quickly if let unnattended or not attended to properly

Methanol is hydroscopic, which means it aborbs moisture. Once you shake that jug and wash those greenhouse droplets of water into the mix it dillutes the fuel value of the Methanol.

With a 1/2 full jug, you can squeeze the fuel level right to the lid threads, then be Jonny Goddard on the spot and quickly cap it off, this eliminates that greenhouse air gap between fuel and empty space. Something else I used to do when racing in the heat of the summer betweeen qualifying days and main event days.

The best quick thing to do though is to just keep it out of the sunlight or from near heat sources. Cool shady spots, ect, when at the field,,like under the worktables if your field has those.

Update update
After I blew the front of the crank off ahem I stripped
the little so and so and the piston crown (aided by some
new fuel with a drop or 3 of synth) was a clean as a whistle.

10 out of 10 Keith.

John Goddard wrote:Update update
After I blew the front of the crank off ahem I stripped
the little so and so and the piston crown (aided by some
new fuel with a drop or 3 of synth) was a clean as a whistle.

10 out of 10 Keith.

Excellent,,Excellent,,very good to read Mr Goddard!.