280ge timing data required...
All,
whats the timing for a 280ge at tickover (with all vacuum pipes still conected)??
...its on standard unleaded
cheers Andy
Hi Andy it should idle at 700rpm when hot..cold it should start and run at 1200rpm slowly reducing to 700 rpm as the water temp rises.....with no significant vibration... with no vacuum leaks further fine tuning consists of 1. fuel mixture 2. air mixture 3. ignition timing.. the exhaust note at idle when hot should be an even purr no fluff or mssed beats and the pipe inside residue after a ten minute drive should be light grey to beige...no soot......uneven running can be caused by a cylinder down on compression either from bad valve seating or spark plug seal leaking.more serious a cylinder head gasket failure which may not be obvious other than loss of water and rough running......
hi fixwin,just read your post on how a 280 should run :(
recently mine is not running as you mention :shock: i think i have a cold start valve problem as i have to give it some throttle in the morning.it also "flutters/pulsates at idle" especially when its in drive(4). i am not happy at present :!: i spoke to a friend about this and was advised to have the fuel meter checked.i was also told by a good merc mechanic that it could be the injectors :?
well,it will be in for a service after christmas and hopefully sorted :wink:
funny thing is that although the G should be quicker on petrol it seems to run better on lpg :?
Hi a dirty fuel filter can affect the engine performance at high revs and cause the electric fuel pump to be noisy.I have found that the balance between fuel and air is a critical factor and MUST be right....ignition timing by rotating the distributor head should done with a timing light but if you have an ear for engine sounds you can tell when the engine is "on song"you can screw at the air and fuel mixture adjustment points all day long but if you have ANY vacuum leak at all you are not going to be able to solve the rough idle/running problems......
where are the airline pipes to be found fixwin :?:
Hi Hus there are seven runs of vacuum pipes.three under the inlet manifold and out of sight.two on the airflow sensor.one on the distributor.one on the EGR valve. on last one we did part of the nylon tube section had cracked across the front of the cylinder head and a rubber elbow had perished underneath the inlet manifold...once the vacuum system is suction tight the air/fuel mixtures can be tweaked and then the distributor timing. after completion and with the idle set at 700rpm (hot) you should be able to stand a glass of water on the air intake bridge without even a ripple..... the cold start valve feeds the 7th injector and is a valve containing a bi-metal strip fitted to the side of the engine to the rear and underneath the inlet manifold.when the engine is cold this allows fuel to the injector(like an automatic choke) and as the water in the engine gets hot the Bi metal strip shuts the fuel off...hence the increased rpm when the engine is cold.this will not work properly if there is a vacuum leak which reduces the suction to draw fuel into the cylinders..so if you are not getting 1000/1200 rpm at cold start or it is lumpy then chances are there is not enough suction because of a vacuum leak .....do some diagnostic and report back ......
Was pretty sure it should be smoother than it is.......but balance a glass of water on air inlet pipe without a ripple mmmmm, defo something amiss.
Mine starts first time every time and have sprayed wd40 all over place with no increase / change in tickover....
thoughts anybody?
Ah but does it idle at 1200 rpm when cold dropping to 700rpm when hot.WD40 will not cure a vacuum leak or out of adjustment fuel / air / timing.......
difficult to say as rev counter replaced by temp gauge......previos overheating problem.
gut feel is revs remain pretty much same hot or cold
andy
great tips and advice fixwin!
thanks alot,i will look into it in the new year and hopefully find a leak 8)
where can i source these airlines from?are they universal or oe?
it seems as if my 280 is suffering these symptons :roll: especially when cold.does this affect economy and performance at all? my G (auto) seems sluggish on take off unless i kickdown at the lights :shock:
the engine is very smooth though once warm,almost whisper quiet unlike most 280 twin cams.
rgds hus.
Hi,
read all the manulas and am more confused.
My girl ticks over around 750 rpm has just passed m.o.t on emmissions.
What should the timing look like at tickover with all vacuum lines attached??
Also, when looking from front which way does crank rotate clockwise or anticlockwise?......I may have 10 degress atdc or 10 degrees before based on this answer!!!
does that sound about right? :?:
Hi does she run at around 1200rpm at cold startup reducing to 700/750 after 60/90 seconds..and when hot give a slight rev as she starts (5 seconds) before settling at 700/750 idle....got to get the fuel/air mix right in order to optimize on the timing which may not be the most efficient when set "by the book" engine wear and worn teeth could mean as much as 5 degrees deviation from the "book" settings..the exhaust outlet noise at 700/750 hot idle should be a gentle purr...no spits, sputters. vibrations or hesitation...there should be no soot inside the tailpipe just a light brown/grey film on your finger...I have just finished tuning one today.took about an hour to reach the smoothest settings and the distributor is 4 degrees more advanced that the factory setup for a new engine....get the fuel/air mix right then undo the clamp at the base of the distributor with a long allen key and rotate the distributor in 2 degrees either way stages..the engine idle will increase or decrease accordingly... the air/fuel mix and ignition timing adjustments are correct when you get the rpm figures indicated above along with the hot / cold increased idle responses.
To check for air leakage at the vacuum hoses, one needs to carefully use an aerosol dispensed brake/clutch cleaner.
The propellant contains flamable hydrocarbons, if there is a vacuum leak in the inductive tract, it is then only, you will notice a difference in engine tone, reducing.
TAKE care on how and where you spray this stuff, it is flamable!!! Keep it away from high tension ignitions systems. Spray near the inlet let manifold, injectors, underneath the inlet manifold. This should be sufficient to cover a vacuuum leakage area you seek.
10 degrees BTDC without vacuum hose is the correct Ignition timming for unleaded running.
I would sugguest checking through your valve clearences, a tight valve can give simillar faults.
Regards,
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Thanks for this.
I am exoeriencing a slight stutter as engine tickover (like its running on 5). Have checked all leads are tight and checked that each lead is delivering spark (using my timing light).
The next thing I wanted to check was static timing - looked like at tickover when warm was 10 degrees after tdc