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Checking static ignition timing on crossflow


ashaughnessy

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OK, now I've got oil pressure when cranking my new crossflow (thanks to those who helped me) I'm trying to get it to cough into life and it won't.

 

I've checked for fuel - I'm fairly sure there's fuel in the carbs.

 

Next I'm checking for sparks. I've done this by removing number one spark plug and turning the engine over using a spanner on the crank pulley. I'm turning clockwise from my point of view in front of the car looking backwards. The spark plug is connected to the HT lead and earthed. I do get a spark but I don't know if it's where it should be. The ignition timing should be 12 degrees BTDC checked at 1000 rpm. I'm checking at zero rpm and it occurs at somewhere around 35 to 40 degrees BTDC. Is this correct? I would expect any increase in engine speed to advance the spark, not retard it, so if it's 35 degrees statically it will be that or even more advanced at 1000 rpm, wouldn't you agree?

 

If I'm correct, what's the procedure for fixing it? Do I line the crankshaft up so the timing mark on the pulley is at 12 degrees, then turn the distributor until the spark plug sparks?

 

Thanks for any help. Starting a brand new engine for the first time is definitely the most stressful and worrying thing I've ever done with my car!

Anthony

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At around 900 rpm you should be looking at around 12 degrees. At around 5000 rpm it will advance to 35 or so degrees. You will need to set this with a strobe but in order to get you started make sure that the timing mark on the crank is lined up and that the rotor arm is pointing to number one ht lead. It can be 360 degrees out. Once at this point you should get a spark on number one but you may have to turn the dizzy a small amount to achieve this.
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180 degs out maybe!

 

The rotor arm moves anti clockwise. When I got my engine started, had the firing order wrong, but soon sorted that out.

 

Apart from that, the engine fired straight away. It sounds like ignition timing, if you have set the rotor arm to point to No1, get someone to crank the engine and move the dist until a little until it fires.

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As a starting place, at 0rpm it should be the same as 1000rpm - i.e. between 10' and 14' depending on the engine. So the easiest way is to set the engine to this point and adjust the dizzy until it sparks. Then you have only two options (one of which is that you are 180' out)!!!

 

With the dizzy in the correct position, check the firing order for the engine and ensure that the spark is going to the correct cylinder.

 

There is no way that the engine will fire with a static timing of 35-40 degrees.

 

Low tech luddite - xflow and proud!

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Thanks for all the ideas, you've given me some things to check.

 

Another idea I'd like to check before cranking again is the carbs. I was wondering how likely it is that the jets, etc. are clogged with sludge. While the carbs were off they were upside down, right way up, on their side, every which way. Is it likely that sludge deposits in the float chambers might have been dislodged and blocked the jets? Is it easy to remove the jets to look at them?

 

Thanks for all the help

Anthony

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If you take off the inspection disc on the top then you can get at idles and mains.At the front are the pump jet covers. If you take off the top plate complete then you will have access to the float chambers and can clean them out if req'd. I think that its unlikely but worth checking.
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Success! Success! I've done it! I've done it!

Reset the timing statically, it was at least 20 or 30 degrees too much advanced. Then primed the carbs by carefully putting petrol into the holes where the filters go. It started on almost the first turn! Ran at 2000rpm for ten minutes, no oil leaks, no water leaks, wonderful.

Of course it runs like a dog, but it needs the carbs rejetting for the new set up.

Thanks for all the help.

Anthony

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