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Technical (156)
 Alfa Romeo forum : Technical (156)
Subject Topic: GTA / V6 Cam Belt Guide Post ReplyPost New Topic
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chris.oates
Junior Alfisti
Junior Alfisti


Joined: 22†December†2007
Online Status: Offline
Posts: 3
Posted: 02†January†2019 at 00:18 | IP Logged Quote chris.oates

Well done on maintaining such a useful resource. Hereís my small contribution. My 2003ish 156 2.5 V6 Q-system had been sorned for most of the year due to some long holidays (Iím retired) and use of sports cars in summer. Before recommissioning it this year I decided to change the cam belts as they were last done 5 years and about 40,000 miles ago. When I went to start it the alternator had seized and took the auxiliary belt out.
I have 40 years experience of DIY car maintenance, a dry double garage with a pit , lots of tools and no time pressures. It took me 4 weeks working on and off so I am so impressed with those of you who did it outside on jacks over a weekend. If your car is like mine you need lots of techniques for removing seized fasteners in very confined spaces. As I had to replace the alternator I had to undo the right upper and lower, and centre rear engine mounts, remove the front exhaust sections, remove the fans, and I also removed the front bumper and upper radiator support. As I had a torn driveshaft boot and snapped spring on the off side I also removed these. All this vastly improved my access to the cam belts.
Hereís my tip, donít try and chisel off a seized lower rear cam cover M6 allen headed screw with a rounded socket if you donít want to replace the water pump. It screws into a lug on the water pump, see photo. My pump had a plastic rotor with a similar crack as shown earlier in this thread, it was replaced at the last belt change so had done about 40,000 miles.




Iíve thought a lot about the tippex v. DTI debate above and semi tried both as I have a white paint pen, a DTI and a set of cam locking blocks. My conclusion is that either method is OK as long as you are happy to reproduce the existing valve timing with tippex but during the cam belt replacement and tensioning the cam wheels have to be free to move slightly. With the tippex method the camshafts are moving with the wheels, using the DTI and locking blocks the cam wheels are freed from the shafts and are moving independently. I put the crankshaft to TDC using the DTI, fitted the cam locks, which not surprisingly fitted perfectly, marked the belt, cam wheels and upper belt cover with their static positions, and marked the crankshaft, belt and crankcase with their static positions. I released the tensioner and removed the belt, transferred all the marks to the new belt and tried to refit it in the same position. Impossible until I released the locking blocks to allow the camshafts to move a little and got the new belt on with all the marks aligned. When the belt was tensioned with the new tensioner the wheels and cams took up their original positions and the locks fitted back on perfectly, the crank hadnít moved. At this stage I saw no reason to attempt to release the cam wheels from their tapers as all was aligned according to the DTI and cam locks.
I fabricated the tensioning tool using a modification of a serpentine belt detensioning tool that I already had, see photos. It just happened to hook onto the water pump at the correct tension freeing hands to tighten the fixing screws.




Chris


Edited by chris.oates on 04†January†2019 at 00:33
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