GolfGTIforum.co.uk
Model specific boards => Golf mk2 => Topic started by: rubberdubber on 15 December 2008, 23:13
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Hi all, replaced the cambelt on my mk2 1.8 8v digi today, been searching on here and looking in the haynes manual and it seems that the timing marks i have are different. there was already a tippex mark on the bottom pulley and this lined up when i lined the camshaft o.t mark up with the o.t on the plastic semi circle on the rocker cover. From looking on here it seems that the camshaft tdc mark can only be seen by removing the rocker cover, i didnt have to remove the rocker cover, there was a big plastic semi circle thing with ot and a line on it :huh: Whats occuring there?
Anyhow i fitted the belt as ive explained above with the camashaft being lined up with the ot mark and the bottom pulley lined up with its previous tippex mark, all as it was with the old cambelt on there. Apart from the intermediate sprocket, when i removed the dizzy cap when the camshaft o.t mark lined up and the crankshaft was lined up with its tippex mark, the rotor arm wasnt quite inline with the notch in the dostributer, so i religned this so that the rotor arm points directly and the notch when the top and bottom pulleys are aligned with there marks. I assume this is correct?
Nows rather than idling at 2000rpm like it was, it idles smoothly at 1000rpm but when driven is flat and has slow throttle responce, so im thinking moving the intermediate sprocket to where it should be has put out the ignition timing. Am i on the right tracks here?
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I've never repositioned the rotor arm after replacing a cam belt - that's usually a sign that its been done wrong!
You sure the cam and crank were both aligned TDC?
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always ignore the intermediate shaft marks, they almost never line up. line the rotor arm up with the notch in the dizzy instead! The intermediate shaft sprocket marks are unimportant, what matters is the position of the distributor, you have probably moved the dizzy a fair bit out of line, further proof of this is that your car is now slow!
If you have the plastic timing belt cover then you should be able to line up a mark on the cam sprocket with the OT mark on the inner face of the belt cover, but this is not always the case. My 90spec GTI didnt have a cam sprocket OT mark either! In this case you have to take off the inner cover and rocker cover, then line up the punch mark on the rear face with the head surface. When this is lined up the cam lobes should point up & away from each other like so: |\ /|
If the cam lobes dont line up with either the punch mark on the inside face or the outer OT marks then someone has probably put the cam sprocket on the wrong way round, take it off, flip it round, and recheck the marks.
Next you should have a line on the crank pulley which lines up with an arrow on the lower belt cover, once you get that lined up take out the green cap from the top of the gearbox, it unscrews but can be a pain to remove. I use a hammer & screwdriver to tap it round, patience & perseverance are the key! Once out you should see the flywheel timing marks, if not either the flywheel is on wrong, or the crank pulley is on wrong! There is a small punch mark, this is the TDC mark and you should always use this instead of the crank pulley marks if possible as its much more accurate. The large arrow/diamond on the flywheel is the ignition timing mark, we'll get to that in a bit.
If the punch mark is nowhere to be found, take out sparkplug #1 and shine a torch down there, if you cant see the piston spin the crank over till you see it reach the top of the bore, then re-check the flywheel mark. If the piston is at the top and the punch mark isnt there then someone has put your flywheel on wrong, which is a pain in the arse but not the end of the world. Go back to the crank pulley marks, you'll have to use these instead! Mark the arrow and line with tipex, try to get the line as fine as you can to help accuracy later on.
Still with me? Good! On to the distributor. Pop off the dizzy cap and note the position of the rotor arm. If you look around the edge of the distributor there should be a mark, its hard to see biut it is there. Check the plastic dust cap under the arm, it has a notch cut out of it so you can see this line, it might help to take the rotor arm & dust cap off and give the dizzy a good clean. Once you have located the notch, you need to spin the dizzy round till it lines up with the rotor arm. Loosen the clamp bolt and if you're lucky the dizzy will turn, if not you'll need to dig out the crud from around the base of the dizzy and drown it in proper penatrating oil. Leave if for a while then get some mole grips round the stem of the dizzy. I find gently tappign the mole grips with a hammer helps to shock it loose, ratrher than trying to spin it by hand.
Once the dizzy is free, line it up and nip the clamp bold down to stop it spinning when the engine is started. If the dizzy wont line up without the hall sensor plug hitting the block, you'll have to move the intermediate shaft a bit, but since you lined it up earlier it should be ok!
Once all 3 are lined up, tigten up the belt tensioer till the belt has 90mm twist at the longest part, and spin the engine over by hand 360 degrees. Recheck the marks & tension, adjusting accordingly.
Now put the engine back together again and set up the ignition timing as per my digifant FAQ! If you found your flywheel marks were not aligned, or the gearbox plug wouldnt come out, you need to buy a more expensive timing light that can also check ignition advance & retard. Set it to 6 degrees BTDC and use the marks on the crank pulley that you made earlier :)
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Thanks for the replys! :smiley:
Had a look into it this morning and the cambelt has slackened right off and it appears to be a tooth out, so i set the bottom to tdc by looking through the no1 plughole, the notch in the flywheel is about 2mm away from the arrow when no1 piston is at the top so it would appear that the flywheel has been off in the past, as for the green bung! I found a bolt with the same size head so i put that into the geen thing to undo it and it must have been abit cold as it shattered into about 1000 pieces! So ile have to be carefull not to drop anything down the hole! :laugh: Anyhow with no1 piston at the top of its travel the o.t mark on cam pulley lines up with the ot mark on the semi circle thing. Time to give it the big key now.
cheers
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ok the timing is now spot on fires up and runs lovely! ayhow i left it for 5 mins, came back to realise the car was on fire!!!! thankfully i had a fire extinguisher in the garage so put it out before it did any damage, the new cork rocker cover gasket i had put on hadnt sealed properly and it was pissing oil onto the manifold which caught fire. How annoying, time to ring round the autofactors for another one. The engine bay is now an inch deep in powder! :sick:
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Unlucky mate. Hope you can get it sorted.
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2mm is nowhere near enough for the flywheel to be on wrong, it will only go on 1 of 3 ways. What caused it is the 'dwell angle' of piston #1, that is the ammount of time it stays at the top of the bore while the crank is still moving. I meant to line up the punch mark on the flywheel then check the piston its at the top, not the other way round ;)
See here, the small round mark is TDC, the large diamond is the ign timing mark :)
(http://vwtech.no-ip.info/images/golf/flywheelmark.jpg)
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Ok good news! fire didnt damage anything, i sprayed aload of brake cleaner down the back of the engine and poured some soapy water down there. Fitted a new rocker cover gasket and no more fires! :smiley: Anyway on to the ignition timing, this was absolutely miles out! So i set that as per your guide and it idles nice and smoothly and the engine sounds sweet and picks up quickly when revved, ive not taken it down the road yet but will do after ive set the co on the computer tomorrow. Double checked the valve timing and when the tdc mark on the flywheel is aligned, the ot on the camshaft lines up with the black semi circle so all happy days! The mark on the inside of the camshaft sprocket looks to sit a tiny bit higher that the head surface but the ot mark is spot on and i think it runs too nicely for it to be a tooth out.
thanks for all the help, ile report back on the performance after ive set the co tomorrow.
cheers :smiley:
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yeah as you say max it can be out is 1 tooth, slightly above the rocker cover isnt enough for it to be out a tooth :)
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Cheers :smiley:
Set the co today and it seems to perform much better now :smiley: Quick question about the cambelt, is it normal for it to tighten when the engine is hot? Its the correct tension when the engine is cold, bordering on the loose side but if you check it with a warm engine its very tight. this normal on these? never really noticed it before.
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cant say i have either, i guess heat expantion would move the head up a wee bit, never thought it would be noticable though?
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yeh im a vehicle mechanic for Peugeot and ive never noticed it before! I suppose as the pulleys will expand slightly when they get hot, i dont think ile worry about it too much :smiley:
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belt tensioned on cold engine, if it gets a bit tighter when its warm it probaly meant to
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Yeh i think your right, i suppose the pulleys are going to expand when it gets hot so increasing the tension
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just about to set up the timing on a '86 mk2 gti 8v, when the "V" on the crankshaft is matched to the mark on the block, (there's a mark down on the side of the block) the cylinder is at full height in the first cylinder what i belive is TDC.
the head is off at the moment but when i set the punch mark on the cam pulley level with the front rim of the head (where the rocker cover gasket sits) one of the valves is open.
is this right? I'm a bit doubtful that I'm setting this up right and am worried that if i get this wrong that the valves will hit the top of a cylinder when I try to turn it over.
is there a second way of checking that I've got everything right before i bolt it all back together?
Should I pop off the dizzy cap and check the mark against the rotor arm and also remove the gearbox plug to check that mark, if so whats thew best way to remove that plug?
I just want to get the car to run ok-ish before i get it timed up better by a mate when i take it down for its mot.
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sounds like the cam sprocket is fitted the wrong way round, when the camshaft is at TDC both valves on #1 are fully shut, the lobes on the cam point up and away in a V shape like this: |\ /|
You need to remove the gearbox plug anyway as you need to see the flywheel marks to time it up properly with a timing gun, so take that out and verify the punch mark is lined up. It should be pretty much spot on using the crank pulley marks though. As for the dizzy no need to remove it, just spin it round so the rotor arm is lined up with the notch on the outer lip of the dizzy.
To get the plug out I tap it round with a hammer & screwdriver, sometimes they come out easy sometimes they fight you. If you happen to have a lambda probe or diesel injector socet, flup it upside down so the spanner flats fit inside the hex cutout in the top, its a bit too small but it should be big enough to spin it out.
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Just had a look at the head and it look like i was seting the cam sprocket with the mark on the outside!
Ive turned it over so the lobes are sitting in the point up and away position and ive found that it marries up with a punch mark on the inside of the sproket level with the front edge of the head.
so is there marks on both sides of the sprocket? why, I dont know!
anyone know the correct torque setting for the cam bearing caps? I can't seem it find it in the Haynes manual!
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I was told 20Nm for those.
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that sounds right aye, reason there is 2 marks is that sprocket is also used for the intermediate shaft, the punch mark on the outside is for timing that up :)
bit pointless really as i say its the rotor arm position that matters not the int shaft, specially on old cars the marks on the int shaft are usually nowhere near!