Jonamat Posted September 12, 2015 Report Share Posted September 12, 2015 Hi. I have just attempted a cambelt change on my ABZ (4.2L-32 valve) engine. I have all the appropriate Audi service tools but met with a big problem...the spline head screws on the rear camshafts covers where the locking tools are supposed to be fitted have been damaged by a previous combatant and it has proved impossible, without violence, to remove them. I did make a tool to hold the cambelt sprockets rigid and managed to change the belt, however I can't be sure that the timing is spot on, the engine starts and runs well but is a bit lumpy on idle so may be a tooth out on one or other of the spockets. The question is...does anyone know if there any timing marks on the actual camshafts, under the covers, which can act as substitutes for the proper locking tools which unfortunately are still in their box. Any advice would be appreciated. John. Link to comment Share on other sites More sharing options...
cruiser647 Posted September 12, 2015 Report Share Posted September 12, 2015 Wow! Brave man! The only way I'd have thought was to have marked the belt and sprokets/rollers as you took the old one off. Link to comment Share on other sites More sharing options...
E-bmw Posted September 13, 2015 Report Share Posted September 13, 2015 Brave indeed? I wouldn't have even started the job when finding that! Link to comment Share on other sites More sharing options...
Mechcanico Lee Posted September 13, 2015 Report Share Posted September 13, 2015 Mmmmm. , did you make your own marks on the cam sprockets when you realised you could not get the timing pin plugs out ? Assuming here the engine has 4 cams , is it 4 cam sprockets under the front cover or does it have link chains internally between inlet and exhaust cams . I'm not very familiar with the engine but normally if it uses pins for alignment there won't be other marks on the cams but the fact that it's running you are probably one tooth out on one of the cams or both . Could you knock a torx key into the rounded spline hole , obviously here you have to mind not to smash the cover in Are you getting any cam / crank correlation fault codes referring to a particular bank . Did you undo any of the cam sprocket bolts ? they may not of been dowled or woodruff keyed , this being the case you will have to get the timing pin blanking plugs out and start again . Link to comment Share on other sites More sharing options...
Jonamat Posted September 17, 2015 Author Report Share Posted September 17, 2015 Thanks for your comments. Out of interest and having taken a cam cover off and found no marks, it appears that the only way to properly time a 32 valve ABZ 4.2 is by using the cam lock tools on the blank end of the two driven camshafts. I did mark the cam pulleys and the old belt and repeated the marks on the new belt. Locked the cam pulleys as best I could with a DIY tool and fitted the belt, which would not fit exactly to the marks(1 tooth out) the pulleys are not keyed so I dare not release the bolts. I counted the belt teeth 199 on both!. So... I don't know which way the 1 tooth error is. The engine runs really well but shakes a bit at idle. I think the only answer is to get those wretched screws out of the rear camshaft covers somehow and check it properly. Unfortunately there is no room between the firewall and back of the engine to knock a torx bit in so violence might be on the cards ! As an aside ...as usual with these motors, found the breathers at the back of the engine completely rotten, fitted new and mpg has improved by 3-4 mpg.. so something good has come out of this. Keep smiling. J. Link to comment Share on other sites More sharing options...
Mechcanico Lee Posted September 18, 2015 Report Share Posted September 18, 2015 Ok , which cam is out by a tooth ? is it the cam that is furthest away by means of counting teeth in an anti clockwise direction from the mark on the crank pulley . If you think about the belt will have wear on every tooth and the rubber will of stretched albeit marginally, so normally when you mark the old belt and pulleys to a fixed point on the casing then fit the new belt the last cam furthest away from the crank pulley tends to come more advanced (pulley will be turned somewhat in the normal direction of rotation So if it was the last cam in distance of teeth away from the crank pulley the mark on the pulley that you made you would expect it to be 1 tooth advanced of the mark you already made. You see the same with timing chains when they get stretched the cam will always be retarded with the old stretched chain, then when the new chain is fitted the cam will become advanced or rather will come to be where it should be . 1 Link to comment Share on other sites More sharing options...
Jonamat Posted September 18, 2015 Author Report Share Posted September 18, 2015 Thanks for that..very logical point. I think that I might have retarded it further! I will post a summary when I have sorted it. Keep smiling. J. Link to comment Share on other sites More sharing options...
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