BTDC for 123 ignition, 1275 engine

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Johann
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BTDC for 123 ignition, 1275 engine

Post by Johann »

Hello,
I would like to install an electronic ignition distributor from 123 ignition in my Traveller. My vehicle has the 1275ccm engine (code 12CE). Can someone tell me which is the correct BTDC (stroboscopic timing).

Kind regards
Johann Robert
philthehill
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Re: BTDC for 123 ignition, 1275 engine

Post by philthehill »

You have either the Sprite Mk4 or MG Midget Mk3 engine fitted.

The timing settings for a standard CE prefixed 1275cc engine are:

7 degrees BTDC static

13 degrees BTDC dynamic (engine running at 1000 RPM).

For a 12CE engine fitted with a 23D4 distributer the dynamic setting is 22 degrees at 1200 RPM.
The 23D4 distributer can be identified as not having a vacuum advance.

Only use those settings as a base line - when road tested the timing may have to be adjusted to suit the current engine spec.
The above timings are for use with leaded fuel- unleaded fuel timings will have to be determined from either road testing or the use of a rolling road.

Johann
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Re: BTDC for 123 ignition, 1275 engine

Post by Johann »

Hello, thanks for the quick answer.

It´s the engine from the Midget and the distributor has an vacuum advance.

A bit unusual compared to the standard engine are the pointers for the timing. see the photo. By comparing the circumference of the pulley an the width of the pointers it must be 5 x 4°.
philthehill
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Re: BTDC for 123 ignition, 1275 engine

Post by philthehill »

No attached photo!

Johann
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Re: BTDC for 123 ignition, 1275 engine

Post by Johann »

I hope it`s now with picture
philthehill
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Re: BTDC for 123 ignition, 1275 engine

Post by philthehill »

Still no pictures!

Johann
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Re: BTDC for 123 ignition, 1275 engine

Post by Johann »

Attachments
Pointers.jpg
Pointers.jpg (116.1 KiB) Viewed 1372 times
philthehill
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Re: BTDC for 123 ignition, 1275 engine

Post by philthehill »

Thank you for posting the picture above relating to the timing marks.
The location of the MG Midget timing marks is different to the Minor.
The large pointer which appears to be painted white is TDC.
The other pointers before the TDC pointer are set at 4 degree intervals (going anti-clockwise) are 4 degree, 8 degree, 12 degree, 16 degree & 20 degree. All before Top Dead Centre (TDC).
There is notch cut into the rear rim of the crankshaft pulley. When the notch of the pulley and the large pointer of the timing chain cover are aligned No: 1 & No: 4 pistons are at TDC. If not already done paint the notch white as it makes seeing the notch so much easier.

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Re: BTDC for 123 ignition, 1275 engine

Post by Johann »

is there also a maximum timing setting at higher speed rpm?
philthehill
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Re: BTDC for 123 ignition, 1275 engine

Post by philthehill »

The maximum advance re the timing will depend upon the specification of the engine.
I would suggest that anything over 30 degrees (total) of advance at 1200rpm will cause the power to fall off.
The correct timing for the engine specification can only be determined on a dynamometer, rolling road or extensive road testing.

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