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ignition mgb #1
peymen ron westenberg echt, limburg, Netherlands Sign in to contact	Topic Creator (OP) Oct 25, 2014 09:28 AM Joined 9 years ago 1 Posts

i got a question about the ignition of a1968 mgb with a lucas 25D p/n 41155B1068 2 distributer
the motor is a 18V883AEL024808
I set the static timing withe a 12V test bulb and the rotor to cylinder 1 to 10 degree BTDC, with the timing mark on the middle pin (there are 5 pins).
after this I checked the dynamic timing with a stroboscope light (vacuum advance loose and 800 rpm) now I see a ignition of ca. 40 to 50 degrees BTDC and not the 20 degrees BTDC which it should be.
which timing is the right one to use the static or dynamic?

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Re: ignition mgb #2
dipstick Kenny Snyder (RIP) La Center, WA, USA Sign in to contact 1941 Ford N-Series 1958 MG MGA 1500 Coupe "Rosie" 1970 MG MGB GT "Pat's GT" 1971 MG MGB "Gifted To Me" & more	Oct 25, 2014 12:59 PM Top Contributor Joined 15 years ago 7,564 Posts

When static timing using a test light with one hand hold the rotor in the extreme clockwise position to eliminate the mechanical advance, and with the other hand rotate the distributor body until the light goes out (points opened).

Given the age of your 41155B distributor ('68 to '71) there may be issues with the mechanical advance mechanism (under the breaker plate) such as broken or stretched springs, stuck advance weights, worn posts, ...

If the distributor is operating as designed at your idle speed of 800rpm the mechanical advance will have developed 10*+, plus the 10* static, for a total of 20* strobe at the crankshaft.

Be safe out there.
Kenny

41155B Advance data.png 70.8 KB

41155B Advance curve.png 57 KB

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Re: ignition mgb #3
RAY 67 TOURER Ray Marloff Fort Bragg, CA, USA Sign in to contact 1967 MG MGB "My Girl"	Oct 25, 2014 03:40 PM Top Contributor Joined 14 years ago 17,490 Posts

If your timing was actually set at 40 to 50 degrees BTDC, the engine wouldn't even start nevertheless run. Check the settings on your timing light. Something's off. RAY

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