Technical Marea 16v 1.8 Timing Belt Change

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Technical Marea 16v 1.8 Timing Belt Change

rigsby935

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Hi to all. My daughters Marea ripped its belt last week and I am in the process of repairing the damage. I note that there are many references to timing belt tools when resetting belts on 20v and 1.2 engines but not specifically on the 1.8 16v. There are clearly manufactured (not DIY added)marks on both cam sprockets as well as the crank which leads me believe that it's possible to set it up without these expensive tools. But I cannot see any obvious markings on the surrounding housings to line these marks with. Can anyone help please?:worship:
 
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Not all 1.8 engines have timing marks, if they do the locating peg on the crankshaft pulley should align with the depression stamped in the sump at TDC. The peg is at the bottom of it's circle for this, clearly you can confirm this with a dial gauge, or a bit of dowel, down the plug hole. I cant help with the camshaft marks, I have suggested setting by "rule of 9" on here before but have never had a reply as to if it worked. This means that no 1 is on the back of its cam when no 8 is fully open, 3 and 6 etc etc. When its right the teeth facing each other horizontally will line up exactly. Finally a new water pump and tensioner are recomended. Good luck
 
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rigsby935

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Thanks for the advice. All eight exhaust valves are bent as are two of the inlets. Seems strange that while it is obvious that the engine went through several cycles thus bending exhaust valves in all cylinders it didn't damage all inlet valves. I've left oil around the undamaged valve seats overnight but they are obviously tight as no oil has dripped through.
Local mechanic states that QH belts have three markers on the outside which line up with the three sprocket/gear marks when timing is right, my mechanicing days started on Metros, Allegros and TR7's but nothing much in between and I have never come across this before, any comments?
 

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All eight exhaust valves are bent as are two of the inlets. Seems strange that while it is obvious that the engine went through several cycles thus bending exhaust valves in all cylinders it didn't damage all inlet valves.
when the timing is lost completely it is simply random chance if any given piston will be in contact with either of the valves when it rises (as long as the cam is still turning). it could hit both or neither valve every time the piston rises, realistically there is a chance that both valves would remain undamaged for several revolutions. once the cams stop moving it is likely that some of the valves on both cams will be in a position where they will not hit the pistons.

when a belt slips a few teeth it can end up with a few results depending on where the slip occurs, you could have one cam out (slips between crank and cam pulley) or both (slips on crank) cams out, there are many variations when a slip can occur and what effect that will have on the timing on each cam. if both are out you usually see damage on all valves, but if only 1 cam is out you often find the other is fine and all the valves on it remain undamaged.

Local mechanic states that QH belts have three markers on the outside which line up with the three sprocket/gear marks when timing is right
thats true but i've never been in a position where i thought it was worth the risk when more reliable and accurate methods are available. if you use the belt markings make sure you carefully and slowly revolve the engine with a spanner on the crank pulley bolt to check for any valve contact and check the marks still line up after the revolutions are complete. dont loosen the cam pulley bolts unless you have to, you shouldnt need to if they've never been moved since it was new. the inaccuracy in the belt mark method is that there is a large potential for error in the amount of movemnet posible when the campulley bolts are loosened. this loss of timing can kill performance, although it should not be enough to cause valve damage.
 
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