andy0075 9 1 Cars Posted October 1, 2007 Hi all, I have made a carb conversion on my 205 GTI 8V with motronic. The motor is a 120hp version with cat and the motronic management. I have fitted the jetronic ignition system from a 128hp non-cat model, but i have no marks on the gearbox and on the flywheel to adjust the timing exactly. How can i find out when cylinder number one is exactly at TDC ? I have done it with a stick through the sparkhole but this method is not really exact. In the future i will run a megajolt and therefor i need to know it really exactly that it make sense to program the ignition timing. Any ideas ? cheers, Andy Share this post Link to post Share on other sites
Daxed 7 Posted October 1, 2007 http://www.cadvision.com/blanchas/54pontiac/tdc.html HTH Share this post Link to post Share on other sites
ORB 227 1 Cars Posted October 2, 2007 bugger that. whip out the plugs, put a bit of a wooden dowel or a plastic tube or something into pot one, turn the motor with a socket on the crank, when the dowel is at its highest point, that is TDC (make sure it is on its compression stroke) Share this post Link to post Share on other sites
andy0075 9 1 Cars Posted October 3, 2007 @orb i did it exactly that way. but because its the dead end, the problem is that there is a period where the piston is on the top position when you turn the crank and with this method it is not really possible to say that is exactly the TDC. The piston is on the dead end position for about 10° when i rotate the crank. @daxed thanks for the link....sounds very complicated because i have not one of these things i need to build this equipment.... Is it possible to look through the hole of the original vr sensor and count the teeth from the missing one and for example when i see the tooth number 10 i have TDC or so ? Andy Share this post Link to post Share on other sites
Richie-Van-GTi 70 2 Cars Posted October 3, 2007 the only true method is using a DTI but if all you need is the tooth number under the sensor for setting up a simple dowel job will suffice. The angle at TDC is less than 4 degrees I found and each tooth is 6 degree's. Share this post Link to post Share on other sites
snillet 1 Posted October 9, 2007 http://www.cadvision.com/blanchas/54pontiac/tdc.html HTH That "oil in tube" trick was neat i must say. Share this post Link to post Share on other sites
