misfire then breakdown

Tips and help requests for your cars mechanics. points gaps, timming settings all those sorts of things

Re: misfire then breakdown

Postby hbr341 » Wed Feb 10, 2021 8:10 pm

Hi
The small earth wire in the distributer is good I tend to remove the dizzy and set it up on the bench my plan is to get the engine very hot at home and see if the fault appears then I can test things properly ive put the sparkplug tests on each plug this will show a misfire ive got to get this sorted.

Regards Chris.
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Re: misfire then breakdown

Postby hbr341 » Fri Feb 12, 2021 6:39 pm

Hi
I have spent hours today on the car and it will not start its not fuel its not ignition petrol in all 4 cylinders good strong spark on all 4 plugs it was running last night one other problem Ive had since the restoration is when you first turn the key it turns very slowly then spins fast and starts I have tried to sort this with a new battery changed starter motor cleaned all the earths made no difference had no problems before I did the restoration . Anybody got any Ideas Iam running out of options.

Regards Chris.
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Re: misfire then breakdown

Postby rizzo » Fri Feb 12, 2021 8:14 pm

So at this point the engine is hot and has cut out and wont restart? have you removed and cleaned battery to body and engine to chassis earths? also i would do the same with the Live side, batt to solenoid, solenoid to starter, just checking to see if you have actually taken them apart to clean.
Check compressions while hot, and recheck while cold, check for gasket leaks ie inlet gasket, carb mount, vac leaks etc. are you sure it not flooding the engine, are you happy with the carb and and mixture settings?
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Re: misfire then breakdown

Postby hbr341 » Sat Feb 13, 2021 6:48 pm

Hi Rizzo
Thanks for your reply I have done all of the above it was running Thursday night all fine then on Friday it would not start from cold and still will not I have checked valve timing all perfect been through everything today still no start.

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Re: misfire then breakdown

Postby rizzo » Sun Feb 14, 2021 12:01 pm

As you have an issue with the starter motor playing up, have you checked you have the right voltage at the coil while the engine is cranking, you should have around 12v on the positive side, if you have a suppresser attached to the coil, try it disconnected.
It does make me wonder if its the electrics side thats causing the issue, i wonder if it will bump start?
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Re: misfire then breakdown

Postby Fred Dukes » Sun Feb 14, 2021 4:15 pm

If you say there is petrol in the in the cylinders it has to be electrical - weak spark under compression ( may still look a good spark with the plug out - could be ignition timing - play in dizzy shaft causing variable points gap? As Rizzo have you got a good 12v at the coil when starter motor is cranking (could be failure to short out the ballast resistor during cranking)?
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Re: misfire then breakdown

Postby hbr341 » Sun Feb 14, 2021 7:35 pm

Thanks Guys
I will do some tests on coil voltage there is no play in the dizzy timing is spot on I did take a wire from the battery to coil that made no difference I will keep on checking everything Thanks for your replies very helpful .

Regards Chris.
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Re: misfire then breakdown

Postby hbr341 » Mon Feb 15, 2021 7:41 pm

Hi Guys
Well its good news I removed the starter motor this afternoon fitted new brushes and a good clean inside refitted
Turned the key and started instantly running very well so what the problem was I dont know its a mystery .

Regards Chris.
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Re: misfire then breakdown

Postby rizzo » Mon Feb 15, 2021 8:09 pm

Sounds like you had a voltage drop on the electrics when the engine was cranking, however repairing the starter motor doesn't address the issue with the engine cutting out when hot, just thought id mention it, but hope it does non the less :D
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Re: misfire then breakdown

Postby hbr341 » Mon Feb 15, 2021 9:35 pm

Hi Rizzo
Yes it seems to be running better than ever but as you say could still have problems time will tell fingers crossed.

Regards Chris.
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