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Misfire

Posted: Mon Jun 24, 2019 8:52 pm
by rebel alliance
Ok i have a misfire i can't seem to fix.5a manual..changed points condenser rotor arm plugs, checked for leads shorting in the dark hotwired coil, changed coil.changed carb,checked for airleaks,compression test ok......i did reset the tappets a while back to book figures...now i have a feeling this engine may have a hotter cam so what sort of gaps do common fast cams need......battery voltage and tyre pressures all ok 😊

Misfire

Posted: Mon Jun 24, 2019 8:56 pm
by philhoward
You haven’t actually changed the leads though?

The misfire - at idle, cruise, under load, or all 3?

Misfire

Posted: Mon Jun 24, 2019 9:09 pm
by rebel alliance
Funny you saying that next test i have lined up..its across the entire rev range Phil..my money was on fueling but i remembered it started after i tried to quite the tappets down

Misfire

Posted: Mon Jun 24, 2019 9:11 pm
by rebel alliance
Whoever rebuilt this one 20 years ago ported and polished the heads and inlet so i am assuming he uprated the camshaft

Misfire

Posted: Mon Jun 24, 2019 9:16 pm
by philhoward
Having a quick look at the Kent Cams site, their V63 fast road cams suggest 0.40mm (16 thou) for both inlet and exhaust. Others have lower figures, between 12 and 16 thou generally.

Misfire

Posted: Mon Jun 24, 2019 9:21 pm
by rebel alliance
Ok i will give that a go if its not the leads or cap.

Misfire

Posted: Mon Jun 24, 2019 9:26 pm
by philhoward
Rule no.1 - what’s the last thing you touched before it started...

Misfire

Posted: Wed Jun 26, 2019 9:03 pm
by rebel alliance
Decided to have another more thorough air leak check.Somewhat suprised to find the W plate had a big bow in it, gap must be 0.3 mm in the middle on the manifold side with a matching hump on the top face.....removed the rusty one off a stage two engine i got lying around ,tatty but flat 😊
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