Ignition Timing I Think

[djinuk 2]

I believe i may have a ignition timing..

 

i have recently done the head gasket, and the head was skimmed by 30 thou, however i set the ignition timing to where it was previosuly.

 

the car has had new, plugs, leads, dizzy , rotor arm, ignition coil, ignition amp, fuel filter,.

 

It ticks over well at just below 1krpm, but when driving at a constant revs i.e 2/3krpm, it missfire and jumps, same goes when you change gear from 1st to seconds, although when accelerating it feels ok.

 

Am i right in saying my ignition timing is to blame?

 

If so where do i start to get it sorted.

[sutol 0]

Best way to find out is to mark the dizzy with tipex so as you know where it was and twiddle with it.

Twist about 3 to 5 minutes either way and check what happens, if the tickover speeds up then you are on the right track. Test it on the road untill it feels right and dosen't pink under load at say 2500rpm and off you go.

You can always return it to the tipex marks if no result.

[hodgy 0]

exactly what i did with mine

[djinuk 2]

should i not do it propelly with all the strobe light etc ? also is there a chance my timing belt could be a tooth out ?

[djinuk 2]

ok, i have just read around the boards a lot and i think i have put the belt on a tooth out, reason i say is to get the two bolts two line up was a nightmare (i am guessing this was due to the skim), so i played with the belt, and struggled to get it on but i did in the end by turning the cam backwards i think.

 

There we go i think i have possibly answered my own question there, could anybody give me a quick run down of moving it a tooth, i took the car out tonight and it seemed to run out of juice at 93mph , no matter how ever much i gave it, it also feels very flat and empty, however its my first 205 gti so i dont really know what to expect.

[DamirGTI 327]

Hi !

 

If done "by ear" , you can squeeze a little bit more power/torque then after adjustment with the strobe light according to the OE standard static/dynamic deg. settings , because standard ignition timing values don't necessary mean good settings for all engines , especially if the engine is old , if you use some different grade fuel , if you have non standard gearbox with short/long ratios , if the head is skimmed down etc. etc.

 

So the best advice is - fill it up with the best grade fuel ( which you must use all the time after you adjust the ignition timing "by ear" on this precise type/grade/brand of petrol..) take the spanners with you and do that by feel/ear on the road ! advance the timing till it starts to detonate slightly in 4-th or 5-th gear driving up hill or when accelerating from 2000-2500 , and when you hear/notice first sing of detonations - rattle sound , back of (retard the timing) from this position 2-3mm. back or until you find the first safe non detonating degree position - balance position in between when detonation occurs and first position back when it stops (well a little bit more back but not too much ! ) this is also the best setting for the power economy and torque

 

Cheers !

Damir

Edited January 20, 2008 by DamirGTI

[djinuk 2]

awesome, well ive had a little fiddle with the timing , and it dosent seem to be making much difference, its not really even making much difference to the tickover... strange, u think i could be right about the cam belt on wrong.

[DamirGTI 327]

Yes sure it can , if it's a tooth out it'll be bad for power and for idle aswell - remove the belt completely out recheck everything , time the crankshaft/camshaft and fit the belt again

 

How much did you skim the head ?

 

Damir

[djinuk 2]

30 thou buddy, how do i make sure the cambelt is spot on, as im sure i used the dowels, but to make it fit it kind of sat half a tooth wrong so i just turned it so that the dowel would fit.

 

however it does seem to idle ok really, a bit below 1krpm, however making adjustments on the idle screw dosent really seem to make a difference

Edited January 20, 2008 by djinuk

[DamirGTI 327]

Hi !

 

First lock both the cam and the crankshaft (use exactly 10mm locking pins measure them if you're not sure that they are 10mm thick !) , recheck afterwards and make sure that it's fine , then refit the belt - start from the bottom and work clockwise upwards , like this -> on the crank pulley/gear -> on the water pump -> arond the tensioner roller -> on the camshaft , always keep the belt tense when moving from the crank to the -> water pump -> tensioner -> cam gear , try to fit him initially as tight as possible with no slack in between the crankshaft water pump and camshaft gears ... after this tense the belt (which type of tensioner you have ? roller type or sliding/spring type ?!) remove the locking pins and turn the engine with your hands (with a spanner on the crank pulley bolt ..) a few revolutions (but don't turn in opposite direction of the engine rotation !!) then check if you can still fit the locking pins in crank/cam timing holes .. if not repeat the procedure .. also be careful on the end when tightening the crank pulley bolt as you really don't want the flywheel to slip during the tightening , not even a little bit !

Anyhow you should be fine even if the head is skimmed as you can tense the belt to compensate for this skimmed spacing .

 

Cheers !

Damir

Edited January 20, 2008 by DamirGTI

[djinuk 2]

ok , im going to tackle this tomorrow, when i previously did it , i didnt use 10mm pins i just used whatever i could find, random bolts i think, will 10mm drill bits do the job ?

 

 

if not , where can i get some 10mm pins from

Edited January 20, 2008 by djinuk

[DamirGTI 327]

Yes , you can use drill bits but measure them and make sure that you use 10mm ones

 

Cheers !

Damir

[djinuk 2]

Brill, ive just be browsing the boards, it seems a few people have had similar problems as me , and it came down to the tps,.

 

 

I am going to get my engine back together, and if it still feels the same, i will try disconnecting the tps and go from there.

[djinuk 2]

its like this... I am a pleb

 

brought a new cambelt today, fitted it with 10mm pins, and a new machine she is, took her out.. so much quicker, not played with the ignition timing at the moment though at all, seems i must of been a tooth out or something.

 

my question is where abouts should the oil pressure be on tick over, it was around a quarter on mine, then on a quick drive it sat at half, then with the loud pedal down is went just above half, is this about right. At the moment i am running halfords cheap oil 15w 40 , but only for a week or so to clean the system as then i want to put some better stuff in , but what would you recommend.

 

just to add the top end is indeed noisy after revving the engine.

 

and also the lumpyness between 1st and 2nd gear was still there, but after about 30 mins driving it seemed to dissapear , ?? any idea what this is , could this still be down to the ignition timing?

[DamirGTI 327]

Hi !

 

So you've sorted that belt now ?

 

Regarding the oil pressure , sounds fine , on my car it's like this - gauge up to the 6 mark/bar (or in between the 5 and 6 mark) on idle when i start the engine , then on cruising it's around the middle (around 3.5 and 4 mark depends on the revs ..) and when i floor it then it rise up to 5 -> 6 mark ... the important thing is when you go faster , when you press the acc. pedal harder , then the pressure must risen up like from the middle of the gauge up to the top – on 5 or 6 bars ... if it's like that it's fine ..

 

Check the valve clearances and adjust if necessary , also check the exhaust manifold for cracks and leaks from gaskets area and lower part of exhaust pipework around the wire mesh ring on manifold to downpipe joint ..

 

Not sure about the last question , but try with different ignition timing settings

 

Cheers !

Damir

Edited January 21, 2008 by DamirGTI

[djinuk 2]

you say check the clearances, i have not got a clue how to do this on the 1.9 8v engine, only ever done this on a tu engine, and not sure i did that quite right ,

[DamirGTI 327]

Well it's not a hard job to check them but adjusting is a bit of trial and error basis cos you'll need to calculate the value a bit and change the shims (they vary in thickness ...) like if the clearance is too big - fit thicker shim under the bucket and the other way around if it's to small to fit a thin shim ... anyway the worst case is when you have valve clearances too tight as this is dangerous because the valves can burn out - better more then less clearance ..

 

OE and Haynes recommendations for valve clearances are :

Inlet - 0.20mm

Exhaust - 0.40mm

But myself and a lot of us here find the exhaust reference too big ...

 

Im doing like this :

Inlet - 0.20mm

Exhaust - 0.30mm

... as the engine works much quieter on 0.30mm exh. settings with no fear of valve burning out

 

Anyway for the valve clearance adjusting you must remove the timing belt and camshaft

 

Do you have Haynes joke book ? cos in there you can find detail explanation on how to check/adjust the valve clearances ..

 

Regards

Damir

Edited January 21, 2008 by DamirGTI

[DamirGTI 327]

...download "joke book" from here if you don't have one yet : http://www.205gti.com/downloads.htm

 

Damir

[djinuk 2]

remote the timing belt... i am going to kick your arse what i test the clearance from the skim what am i judging it against ? the cam when the lobe is pushing the shim or... ?