Coil breaking down?

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simonjrwinter
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Coil breaking down?

Post by simonjrwinter » Sat Aug 08, 2020 7:53 pm

Had a lovely drive out to the Anglian meet today. Dual carriageway all the way there, no problems. However on the “slower” route home the car started to misfire and run badly. Im wondering if my coil is becoming temperamental with the heat? The car was running a few degrees hotter (nothing to worry about) on the slower road but when I got back on the dual carriageway the problem slowly got better and had disappeared by the time I arrived home. The coil and ballast are pretty close to the engine block so must get pretty damned hot (see pic) where has everyone positioned their coil?
Thanks
Simon
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DavidA
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Re: Coil breaking down?

Post by DavidA » Sat Aug 08, 2020 8:24 pm

Could be the coil but sounds more like like fuel vaporisation which can happen when things get hot.
Depending on what carb/injection you have you can stick an insulating block between the manifold and the carburettor.
Others may have different ideas
Best Wishes DavidA

simonjrwinter
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Re: Coil breaking down?

Post by simonjrwinter » Sat Aug 08, 2020 8:33 pm

Had that when I had my fuel pressure too low last year. I have a phenolic spacer but no room to fit it.
I’m also going to get some spark plug heat shield boots as well.
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StewbieC
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Re: Coil breaking down?

Post by StewbieC » Sun Aug 09, 2020 12:30 pm

Sounds like the coil.
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Azzy83
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Re: Coil breaking down?

Post by Azzy83 » Mon Aug 10, 2020 2:04 pm

Hmmmm try Putting ohm meter on coil, normally should read 1.5 on 1st circuit, secondary circuit should be 6000-7000. (If I recall for ballast coils)
Most carbs like min 5-6psi fuel pressure.
Have a squiz at one of your plugs aswell, visual and also check and make sure you have the right heat rated plugs. (Plugs might be getting too hot and pre-igniting)
Looks like you have some playing around to do, let me know how you go ?
Aaron

simonjrwinter
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Re: Coil breaking down?

Post by simonjrwinter » Mon Aug 10, 2020 2:17 pm

Thanks Aaron,

The engine was fully built and very comprehensively specified by Real Steel. Ill try the coil test, but if it is the coil breaking down under heat, It may be fine at normal temps. I had a problem last year with the car cutting out when really hot. I found this to be fuel pressure of about 1.5 - 2psi! An increase to about 5.5psi solved that.
Will inspect further when it's not so bloody hot in the garage.

Simo
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peterc
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Re: Coil breaking down?

Post by peterc » Mon Aug 10, 2020 9:12 pm

My coil is mounted on the inner wing close to the front corner of the engine and the alternator. My exhaust manifolds are lagged but the coil was so hot I couldn’t touch it after a relatively short but fast run. Original cars had the coil mounted on the engine.
Suggest you check the connections are tight. I had the starting of a misfire as the revs increased and it was nothing more than a slightly loose spade connection.
With a fibreglass body the engine bay will always be hotter as the heat can't be conducted away.
Peter C

simonjrwinter
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Re: Coil breaking down?

Post by simonjrwinter » Mon Aug 10, 2020 9:18 pm

Thanks peter, yes mine mounted similar place....
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kdavies3
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Re: Coil breaking down?

Post by kdavies3 » Tue Aug 11, 2020 8:46 am

Not sure if you're running electronic ignition or points?
But if it's points it could be they need adjustment or maybe the condenser is on the way out.

FIAJack
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Re: Coil breaking down?

Post by FIAJack » Tue Aug 11, 2020 5:22 pm

+1 for the condenser if points - been there, done that.

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