Running on

Started by chrisx1, 10 Apr, 2026, 15:44

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chrisx1

10 Apr, 2026, 15:44
My recently rebored engine is running on after switching ignition off. The engine also feels excessively hot and I'm pretty sure there is a metallic knocking sound.
What's the verdict on this one?

limeyrob

#1
10 Apr, 2026, 15:54
How do the plugs look?
Could be getting hot - weak mixture or timing off.
Since there's no carbon its probably running on from the hot exhaust valve or plug.

chrisx1

#2
10 Apr, 2026, 16:22
I'm trying to post some photos from iPad but app is telling me it can't accept that type of file. Anyone know how to convert iPad photo to normal JPEG's

chrisx1

#3
10 Apr, 2026, 16:50
Plugs show Possibly slight fouling. Insulator is brown electrode is dark brown to black

chrisx1

#4
10 Apr, 2026, 16:50
Running Champion N3C's

briancairns

#5
16 Apr, 2026, 10:23
Quote from: chrisx1 on 10 Apr, 2026, 16:22 I'm trying to post some photos from iPad but app is telling me it can't accept that type of file. Anyone know how to convert iPad photo to normal JPEG's


Open photo on any photo editor you have on ipad and then save in the format you wish e.g jpeg

scifi

#6
18 Apr, 2026, 12:29 Last Edit: 18 Apr, 2026, 12:31 by scifi
Champion N3 is a plug to be used in a highly tuned engine.  Maybe it is too highly tuned for today's rubbish petrol.   If you have a compression testing gauge, I hope the pressure is not over 140 psi.
What engine is it..?   You didn't get a high compression piston, for the re-bore did you..?

Jean-Luc

#7
18 Apr, 2026, 15:09
This may happen with some électronic ignition kits.
Which is yours ?

limeyrob

#8
18 Apr, 2026, 20:06
Good point, can it run off the alternator pulses with the ignition off?

cdsdorset

#9
18 Apr, 2026, 22:13
Sounds like the timing is a touch advanced.
Knock it back a bit and try it.

chrisx1

#10
28 Apr, 2026, 13:48
Quote from: Jean-Luc on 18 Apr, 2026, 15:09 This may happen with some électronic ignition kits.
Which is yours ?
Apologies Jean Luc, I have only just seen your message. I am running a Boyer Bransden electronic ignition. Black box I think it's a Mk4

scifi

#11
29 Apr, 2026, 09:36
The metallic knocking sound could be Pinking or Pre-ignition.   Are you using the highest grade of Petrol for your high compression engine..?

DAVE BRADY

#12
29 Apr, 2026, 09:46
Hi,

Never had this issue with EI and running 9:1 pistons and nearly always on E10.
Being hot could be to do with recent rebuild so this may reduce after a few more miles.

Dave.
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