Edgar Westbury Wallaby ignition

[Andy CameronParticipant @andycameron27025]

Thanks i didnt think about that, i dont like using a drill to start engines but it would be difficult to hand flick the flywheel. I do have the twist starter and pulley which i use on the Gannet but the flywheel is very smooth with no groove. I will see if i can fashion something so i get a more positive centre on it.

[Tim StevensParticipant @timstevens64731]

Andy Cameron says:

Throttle closed = spins easy
Throttle open = harder to spin

Exactly as one might expect. With no air getting in there is nothing to compress, but allow the air in and I expect you have a 10:1 CR or thereabouts = hard work.

If ever you coast down a hill in gear, (ignition off) then you get more effective retarding as you press the loud pedal. But don't do this in a modern car with a key-linked steering lock, or you will also explore the hedge.

Cheers, Tim

[Andy CameronParticipant @andycameron27025]

I was hoping someone would confirm that i.e. open throttle more compression, so that to me is good news. I assume there would be little difference using a CDI unit as opposed to a coil ? i.e. does one spark sooner/later than the other effectively changing the timing. I will try the CDI unit on the Gannet which currently has a 6V lucas coil setup with points. This CDI i have sparks on the points opening so acts the same as a coil setup but i guess it could be possible that one sparks sooner/later than the other.

[Howard LewisParticipant @howardlewis46836]

As an aside about ballast resistor coils, it was not unknown to have a wire on the starter that fed the coil directly (effectively shorting out the ballast resistor )

So when cranking and the load pulled down the battery voltage, from 12V to about 7 or 8, that was applied to the primary of the coil. Result a nice big fat, high energy spark, and first fire!

Releasing the starter returned the feed to the coil through the ballast resistor, so the battery, no longer loaded by the starter, returned to 12V , or more (aided by the dynamo or alternator) and the coil lived to fight another day.

The magnetos on Fordson N and E27N was a "Trip mag", so that at low speeds (hand cranking ) the rotor was given an additional "flick" by a spring, generating a higher voltage for the spark; to aid starting.

Until powers rose to the point where greater flow rates were required (And hence pump circulation ) many of the older low specific output side valve engines were thermo-syphon cooled.

For Fords, this persisted until the OHV engines such the Consul, Zephyr and 105E Anglia came along. Ford did offer a pump "For Export" which mounted on the front mounting bracket, to be belt driven off the front pulley, as was the fan.

It was popular with those tuning the 1172cc engine for specials and 750 Club racing.

The prewar, and postwar Vauxhall H and J types, being OHV and more powerful for their displacement, did have pump assisted cooling. The seal was a small carbon disc with three ears. If it wore and began to leak, a "Get you out of jail card" was to strip the pump, reverse the seal and continue. Before it wore and leaked again, you, if wise, had a new seal in stock!

As powers increased, so did the heat rejected to coolant, and the need for greater mass flows of coolant. The 230 bhp (24 bhp / litre ) Perkins TV8-640 required 80 gallons per minute when at full power

The Gardner 6LW delivering about 11 bhp / litre made do with a simple brass paddle wheel to circulate coolant, and much smaller pipework.

Howard.

[Roger BParticipant @rogerb61624]

A CDI and coil may trigger differently, the coil will spark when the contact opens a CDI may spark when it closes.

I suggest you make a simple check of the operating sequence. Remove the spark plugs and rest them on top of the engine so you can see when they spark and then slowly turn the engine by hand.

The inlet valve should open at or just before top dead centre and the exhaust valve should be just closing.

The inlet valve should close just after bottom dead centre.

The plug should spark just before top dead centre.

The exhaust valve should open just before bottom dead centre.

The exhaust valve should close at or just after top dead centre and the inlet valve should be just starting to open.

Repeat for the second cylinder.

If you don't get this sequence some deeper investigation of the camshaft and ignition system will be required.

[Andy CameronParticipant @andycameron27025]

All seems ok with that sequence, the CDI unit is designed to act as a coil i.e. it sparks when the points open. With the plugs out i can also see that the spark occurs when holding the plug on the block just before TDC. Its a wasted spark setup as the crank is 360 degrees so one cylinder sparks on exhaust the other on compression and so on. I checked the oil again and there is definitely fuel in it so maybe i was just flooding the engine, i would have expected some sign of ignition though.

[Roger BParticipant @rogerb61624]

How good is the compression? The usual description is that it should be 'springy', something like this:

[bernard towersParticipant @bernardtowers37738]

Surely Howard the second wire to the primary on the coil from the starter solenoid feed gave 12 volts to the coil while the key was turned for starting then reverted back to the ballast wire for running when started?

[Roger BParticipant @rogerb61624]

Has the engine ever been running or don't you know? What carburettor has it, the Westbury one?

By a dogbone do you mean the bar and pin that goes into the starting dog?

[Andy CameronParticipant @andycameron27025]

Compression seems good, especially if the carb is opened. By hand there is a noticeable compression point. I have made up a better dog bone drill attachment as the commercial ones are too small that i have found. I tested the CDI unit on my Gannet engine which usually has a 6v lucas coil. The engine ran well with the CDI unit and points as a trigger so i know thats not an issue. I have noticed that the Wallaby has been spitting oil from somewhere, looks like its from the fill point which seems to double as a crankcase vent, its hard to tell the oil level on the dipstick so i have emptied it and will refill. I did notice when i first put oil in that compression increased. the engine has run previously and is setup on a nice bench rig, the plugs also show signs that it has run.

[Andy CameronParticipant @andycameron27025]

In addition the carb looks like a more modern RC engine carb typically seen on glow plug engines.

[Andy CameronParticipant @andycameron27025]

ok i had a better look at the timing, it would appear that the plug sparks when the piston is at a slight dwell at TDC i.e. not before TDC, its hard to tell for sure. I cant find where i last saw the timing references but 10deg BTDC seems familiar ? i have a timing disc for it, only way i think i can try changing is by sight of the piston to set TDC on the timing disc then adjust the points to open earlier.

[Roger BParticipant @rogerb61624]

10-15° before TDC is fairly typical.

I am surprised you are not getting any signs of firing. Normally something should be happening even if it won't make a sustained run. It has run so the basic mechanics should be ok unless significant leakage has developed past the valves or pistons.

One suggestion from another forum was to hold a flame by the exhaust whilst cranking to see if any burnable mixture was getting through. I haven't tried it myself but generally turning the engine over with a drill and gradually opening the needle valve has resulted in a start.

[Andy CameronParticipant @andycameron27025]

i will try that, it did fire briefly for about 2 secs very early on but since that absolutely nothing. I will try the above before messing with the timing, even if a valve was leaking its a twin cylinder so unless very unlucky one cyclinder should show some form of life.

[JasonBModerator @jasonb]

The candle method works quite well but be careful with liquid fuel, not such a problem with gas (propane)

Don't have the ignition hooked up, just turn the engine over by hand and look at the flame as the exhausted fuel/air mix is exhausted and ignigted by the candle or lighter. If it's a big soft orange flame you are too rich, aim for a bluer smaller flame.

[Andy CameronParticipant @andycameron27025]

well i gave that a go and with the needle 1.1/4 turns open i got a small blue flame from both cylinders. So i backed the needle to only 1 turn out now so will give it a go soon. I guess at least having unspent fuel being kicked out on the exhaust stroke is a good sign.

[Andy CameronParticipant @andycameron27025]

I have now had the engine run for about 10secs, i advanced the timing. To get to run for around 5-10secs i prime the carb then disconnect the fuel from the carb. Start it and she runs for a short duration of time. tried a few needle settings without any luck, it does fire with the fuel line connected i.e. brief fire then smoke from exhaust or sometimes blowback out carb. So closer but not quite there yet.

[Roger BParticipant @rogerb61624]

How high is the fuel level in the tank compared to the carb? It sounds like there is too much fuel being delivered.

Can you post some pictures of the set up?

[Andy CameronParticipant @andycameron27025]

certainly will when i can figure out how too (my next challenge) the tank is actually about level with the carb. I did notice when i filled the tank that the fuel shot up the fuel line towards the carb no i guess it could be high. I can try it lower. I was also wondering about the idle mixture setting as well which does look to be well wound out which i beleive would make idle leaner so would seem correct.

[Tim StevensParticipant @timstevens64731]

Hello Andy

If you have no fuel pump the carb must always be below the fuel level in the tank. Fuel will not run uphill – and you can waste hours trying to get the mixture right if the fuel is too low.

With a fuel pump (and something to power it) things are different but more complicated.

Cheers, Tim

[Andy CameronParticipant @andycameron27025]

yeah i was wondering what could match the symptom. Prime the carb by throttle wide open finger over ventura, watch fuel come into carb along the fuel line. Disconnect the fuel line and start….engine runs well for 5-10secs. With fuel line connected it will start very briefly then die. I guess the prime got fuel in manually whereby with the line connected only its not getting enough flow. I will try raising the fuel tank as thats quite easy to try.

[Andy CameronParticipant @andycameron27025]

Thinking about it Tim it might lend well to the testing i did, because i was testing i only put a small amount of fuel in the tank which is small and approx 2/3 way up the tank is the level with the carb input, so its possible the fuel level was below or very minimally above the carb input meaning not a great flow if any. I will test this tomorrow by raising the or filing the tank fully.

[JasonBModerator @jasonb]

Can't agree with that Tim, I've several models with the fuel tank below the carb that run fine. Just need a N/R valve to stop the fuel draining back when the engine is in "Miss" mode. Intake stroke simply creates a vacuum in the fuel line that will lift the fuel.

A picture of the carb would help as some of Westbury's designs had a float chamber which will shut off the fuel when the float is high so it doe snot flood from a high tank position. If it does have a float chamber then worth checking the float actually floats and the needle is opening & closing the fuel flow correctly.

How to post photos

[Andy CameronParticipant @andycameron27025]

The attached photo shows the bottom of the tank is just below the carb intake.

[Roger BParticipant @rogerb61624]

That looks to be a reasonable set up as long as the tank is less than half full.

The system will prime if you choke the air inlet but does not seem to get enough fuel to run. Could there be an air leak between the carb and the cylinder head? Have you checked that the needle moves in and out of the jet and that there are no obstructions.

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