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8 & 10 cyl Bristol cars Type 407 onwards - restoration, repair, maintenance etc

Starting a 412

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Old 23-09-21, 06:20 PM
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Default Starting a 412

Hello,
I've finally got my Beaufighter running and MOT'd. My main problem now is knowing if it will reliably fire up. It needs about 10 squirts of petrol on the throttle before it will fire up.
The timing is supposed to be set at about 2 BTDC. However I've found to start cold it's best set about 15-20 BTDC. This doesn't make sense, I thought when starting ignition would be retarded. When warm I can adjust down to about 4-5 Btdc with a smooth tickover, but then it is hard to start.
I've rebuilt the Carter carb. The choke operates and when running seems to be performing ok.
The plugs and ignition are all new.
Have I missed something making it so unknown if it will fire-up?
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Old 24-09-21, 05:32 AM
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Smile Beaufighter slow to fire up

I suggest you get hold of the relevant Chrysler educational college handbook for your engine. All the troubleshooting tips a v8 owner will ever need explained in plain (US) English - even has cartoon characters to show you how! You regularly see them on eBay and Chrysler sent them round freq it entry to inform its many thousand mechanics about the mysteries of these devices.
Sadly I failed to buy the factory set last year at Windlesham, when BCL went bust .
Yours in Bristol
Stefan

Ps Didnít quite understand something. BTDC means Before Top Dead Centre, right? So , yes, you are retarding the ignition by increasing BTDC?
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Old 24-09-21, 10:12 AM
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This may be of no help but if you can I suggest that you use a timing light on the engine, you may find that the timing wanders about a fair bit on tickover, if so then the timing chain is worn and you will never be able to set the timing. Changing the chain is not difficult just tedious.
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Old 25-09-21, 05:03 PM
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Ps Didnít quite understand something. BTDC means Before Top Dead Centre, right? So , yes, you are retarding the ignition by increasing BTDC?[/quote]

Increasing BTDC means you are making the spark plug fire earlier, so that would be advancing the ignition according to convention.

https://help.summitracing.com/app/an...tion-timing%3F
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Old 26-09-21, 05:24 PM
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PS Syd Lovesy told me that he liked to tune engines by warming up then running them at indicated 3000 rpm. Then he slackened off the distributor clamp, and simply turned the distributor slightly by hand until the revs were maximised. I suppose this takes out some of the effects of play in slack bearings though not a worn out timing chain.
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Old 02-10-21, 03:10 PM
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Thanks for replies,
Turning distributer by hand and listening to tick-over is how I adjust timing and using timing light.
However, I reckon now that camshaft + chain are worn out. When cold ignition moves about all over, so hard to get a good reading. When warmed up, engine revs scream, so must be getting fuel and good spark
I've concentrated on fuel pump & carb & ignition and hadn't thought of other essentials like valve timing.
It doesn't look like an easy job to replace camshaft with engine in the car.
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