Timing marks for a Nissan ga15 twin cam?
How do you know if the timing marks on the cam pulley and the crank are on the right spots a Nissan ca20 twin coil motor the head has been rebuilt before you bought the car idling badly?
The Twin Spark Engines In Alfa Romeo have been in use for some years. these engines are difrfrent from each oter and it depends on what sise,, 1.6 or 2.0 or even V6 so without any information what engine you are talking about this question is not able to answear . Never heard of twinspark v6. But certainly 1.6 1.8 & 2.0 Cant tell you about timing marks but if changing cambelts etc. would not attempt without using "CAM LOCKING TOOLS." It's the only assured way if you want to do it right. Good luck.
First put the #1 piston all the way up in the cyl.Make sure your crank shaft timing mark is lined up.There's another timing mark on the left side as you look at the crank shaft on the other gear(intermeteate gear).It too must be lined up. Put your cam gears timing marks together with all the valves closed on #1 cyl.
There should be punched marks on the cam sprockets which need to be lined up with factory punched marks on the rear timing belt cover, immediately behind and just above the sprocket. Line those 2 gears up and bring crank shaft damper to 0 degrees top dead center according to first mark on dampers, left side as you face the motor check to see if your distributor rotor is facing the number one terminal if not complete full rotation because motor is on exhaust stroke.