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MS1-Extra MegaSquirt This/Next Ignition ModeOnly for use with the MS1 Extra code (MS1 - 68H908 based microprocessors) By Philip Ringwood (daxtojeiro), James Murrey (jsmcortina) and Ken Calver (muythaibxr) |
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Please Note:
All of these instructions / diagrams are to be used at your own risk, like most things there is more than one way to do the same thing, what we have tried to do is to offer a method that we have tested or that others have tested for us. No warranty expressed or implied. Use at your own risk. |
For both This Cylinder Mode and Next Cylinder mode, the distributor must be modified. All advance mechanisms have to be locked. Since MegaSquirt will provide timing from a table based on MAP (manifold absolute pressure) and rpm the mechanical advance and the vacuum advance/retard is no longer required. In cars after mid 1980's the distributor may already be locked.
First remove the vacuum advance or disable it by disconnecting the vacuum line(s). If the vacuum advance is removed fasten the distributor plate to keep it from moving. In the figure below the distributor plate is held in place with some washers, nut and #10 screws. The advance plate was modified so that the optical trigger can be rotated by about 100º on the plate.
To disable the mechanical advance you will have to disassemble the distributor. Find out where the mechanical advance is located and either remove it or leave it in place but keep it from moving. The final result must be that the top and bottom of the distributor shaft are connected (fixed) such that there is no movement between top and bottom.
This is an example of a Lucas distributor where the vacuum advance weights have been removed, and the posts for the weights are used to lock the advance mechanism.
