Triumph Repair: Distributor drive gear position., exhaust stroke, haynes manual

Question

Distributor gear   QUESTION: Hi!
I have a 1972 Mark IV Spitfire and am rebuilding the engine. I am trying to install the distributor drive gear. I have a Haynes manual and it tells me to install it at TDC just like the picture. Only one problem. No picture. There are marks in the block that are almost perpendicular to the block. Does the slot in the top of the gear align to those?
Thanks!

ANSWER: Hi Henry,
You are holding the gear/drive in your picture so that the offset slot is running 12:00 to 6:00 and the slot is offset towards your hand. Just rotate the gear 90 deg to the right so the slot is 9:00 to 3:00 with the slot offset towards the engine. The gear will rotate a little as you install it due to the angle cut gears so take that into account as you install it. You will have to preset the oil pump so as to allow the blade to engage it. Good picture.
Be sure you have set the #1 piston at TDC of the compression stroke not the exhaust stroke before proceeding.

Howard

---------- FOLLOW-UP ----------

QUESTION: Hi again.
Your information was very helpful!
Is the slot supposed to be exactly parallel to the block, or askew slightly. I find that when I  put it in, the closest I can get it is at a slight angle. Maybe 5 degrees tops. If I advance the engine about 15 degrees It is perfectly horizontal. I am sure the gear is inserted all the way because if I insert it at any other angle, it doesn't go down as far. I suppose the timing chain could be a tooth out.
Please advise.
Thanks!

Answer
It does not need to be aligned exactly because you need to set the timing afterward anyway. It is just a general setting so the vacuum advance is in roughly the right place. Some mechanics don't even bother to set that gear at all and just set the distributor where they want and set the wires in the cap so that it works out correctly.

Howard