Had my bus timed by a local garage to 28 BTDC (vac disconnected), checked it myself and drove it to Belgium but it was very sluggish, popped and banged at tickover and on the over run and felt 'strangled'. I then set it up by ear, much more responsive, no spitting and farting, more mpg and generally 'nicer' to drive, it did run about 10 degrees hotter but drove all the way back with no other issues. Have now checked it with the timing light and my best guess is that it's somewhere North of 45 degrees which just can't be right. So is it possible to fit the pulley 'wrongly'? It's a 1700 type 4 motor that has done 304,000 miles and had a top end rebuild at 180,000. It does burn a lot of oil when thrashed (60 mph +) on the motorway but less so when cruising around the back roads at sub 55 mph. Finally why do you measure it with the vac off and what would it read if the vac was on?
I always time them to 7.5°btdc with the vac connections off at idle... Then I check for full advance with the vac disconnected and connected!! (28-32°, and 45°ish respectively!!) As for the timing marks being out, did the time it on the timing scale correctly? as you have before and after on the one scale... It is possible for the timing marks to be out, but they would be massively out as you can remove the pulley from the fan, and put it back on in 2 other positions!!
Aha! Mr Weeding comes up trumps again, this time without knowing it! The vacuum advance is not working! So setting it by ear was giving me 45 degrees of mechanical advance at full revs (hence the nicer running) but was then incorrect at tickover. The garage had set it correctly and my check agreed but neither of us bothered to check if the vac advance was working.
Sorry, I missed this... The fan can only fit the hub on the end of the crank in one position, but if you separate the fan pulley from the fan, then you can put it back on in one of 3 positions, and only one is right Glad you sorted it dude
