Hi guys, i bought a 1990 e30 as a project car that was missing the cylinder head, the replacement m40 cylinder head that i have bought was missing the camshaft sprocket as well as the distributor and i have no idea how to find tdc for no1 piston on the compression stroke on the cylinder head, all the inlet and exhaust valves are fully closed on the underside of the head, does anybody know how i could correctly get tdc for no1 piston on the m40 cylinder head so i can put the replacement cylinder head back onto the engine block and get the car running again ?
thanks 2 everyone in advance
tdc m40 cylinder head
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Brianmoooore
- E30 Zone Team Member
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- Joined: Mon Jan 10, 2005 11:00 pm
Under the starter motor there should be a plastic plug in the flange of the block that faces the flywheel. Remove this plug and insert a 10mm rod (10mm drill bit will do). There is a matching hole in the flywheel that the rod will slide into when 1 and 4 are at TDC.
It doesn't matter in the slightest whether you attach the cylinder head with the valves set so that 1 is on its compression stroke or 4. It's impossible to set the ignition timing 180 degrees out, since the distributor rotor is bolted firmly to the cam pulley.
Turn the cam until the valves of either 1 or 4 are both slightly open, then look for a square section on the cam. The cam is positioned correctly when a straight edge laid across the flat is parallel to the head face.
It doesn't matter in the slightest whether you attach the cylinder head with the valves set so that 1 is on its compression stroke or 4. It's impossible to set the ignition timing 180 degrees out, since the distributor rotor is bolted firmly to the cam pulley.
Turn the cam until the valves of either 1 or 4 are both slightly open, then look for a square section on the cam. The cam is positioned correctly when a straight edge laid across the flat is parallel to the head face.