3.9i disco timing?

hi all i have a few questions to ask/ my disco runs on gas but seems to drink it rather fast so i knew that the guy before me had the headgaskets done by a friend and it appears he just turned the dizzy till it started.
so i have found out that it should be 9 degrees before so i used my snap on and turned the dizzy till it lined up but the advance and vacumn part is know right up against the top pulley on the right hand side looking from front of the car/ my question is does this seem the right possition or could he of put the dizzy in wrong when he timed it up as it seems to far over towards the pulley for my liking when timed at 9 degrees ?

9 degrees seems a touch much. I'm not sure what you need to run on gas but the 3.9 should be at 4 degrees BTDC +/- 1 degree or 5 degrees +/- 1 degree after 1993 on 9.35:1 CR as standard. I think on gas you need a couple of degrees of advance. Certainly a V8 will run 12+ degrees advance but it will protest.

Only a guess but try backing it off a bit, say 7 or 8 degrees, see if it will run O.k. on petrol then switch to gas, let it idle then grab the throttle linkage and give it a sharp tug to WOT (wide open throttle) and see if it will rev quickly and smoothly. Also make sure the engine comes back to a smooth steady idle after being revved.

If that looks O.K. road test it, under load - find a hill and floor it. If timing O.K. it should pull smoothly throughout the rev range, if it struggles anywhere then the timing will need tweeking.

Hope that helps ya.

ok i will start at 5 btdc then increase to 7 then in multytudes of 1 degree un till its happy by the way can the dizzy lock into only 1 possition or could he of turned it to much to the right ? and am i right in thinking the fireing order starts with no1 on the passenger side looking from the front of car ?

rummins said:

ok i will start at 5 btdc then increase to 7 then in multytudes of 1 degree un till its happy by the way can the dizzy lock into only 1 possition or could he of turned it to much to the right ? and am i right in thinking the fireing order starts with no1 on the passenger side looking from the front of car ?

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Number 1 pot is the first plug on the right when facing the engine. I.E. steering wheel in on your left if you see what I mean. Firing order is
1 - 8 - 4 - 3 - 6 - 5 - 7 - 2. The dizzy is only held in place by one nut (15mm). You should do the clamp nut up so the dizzy is held firm but can be turned by moderate hand pressure.

BTW you should always mark the dizzy before moving it so you can quickly and easily get it in the right position to make it run. Don't forget when dynamic timing the engine disconnect and plug the vauum advance pipe and make sure the engine is at normal operating temperature.

ok thanks do you mean plug the vacumn pipe or the unit itself when i disconect ? also if you would be so kind its got a ticking niose that only appears when i take my foot off the throttle and slowwing down does this sound like chains

rummins said:

ok thanks do you mean plug the vacumn pipe or the unit itself when i disconect ? also if you would be so kind its got a ticking niose that only appears when i take my foot off the throttle and slowwing down does this sound like chains

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Plug the pipe.

Ticking noise...mmmmm. Probably just the injectors firing, but hard to diagnose a noise on a forum if you get my drift LOL. If your timing chain is stretched you may not necessarily hear it but your ignition timing may wander. You might try putting water on the belts to quiet them down for a few seconds to see if the noise is "mechanical" but bear in mind there is a lot going on and a V8 won't be silent but it should be smooth.

You could always use a big (long) screwdriver or a solid steel bar like a sthethoscope to listen to the internal noises and see if there is anything "harsh" - listen to rocker boxes and water pump; if screwdriver/bar long enough, listen to exhaust and inlet manifolds and the timing case but BE CAREFUL - lots of belts, lots of heat one slip and it could be all over! you have been suitably advised etc etc.