Omega Owners Forum
Omega Help Area => Omega General Help => Topic started by: bob24 on 24 August 2013, 11:11:50
-
Does anyone have any advice on how to get a new timing belt on to the sprockets of this engine. I have done this job 3 times now and keep saying the car will die before I do this again so have not fully investigated how to do the job. No matter what I do the belt is always VERY tight despite setting the tensioner "off tension". Haynes ( bless) says mount the belt on the crank shaft sprocket and around the cam sprocket. Ensuring the belt is taught between the two sprockets. Then it say fit the belt on the water pump sprocket and tensioner. This is not possible due to the flange on the front face of the water pump sprocket which is wider in diameter than the tops of the sprocket teeth so you can't slide the belt on to the pump and tensioner from the front given the lack of slack. This means the belt has to be located on the water pump first which makes it a very high angle of attack on the tensioner wheel. Again due to the lack of slack this makes it impossible to do it that way. The picture in the Haynes manual shows this flange. Perhaps the early production pumps did not have these flanges? As usual I wired the tensioner back to it's fully "off tension" position and left its securing bolt loose to give as much freedom of the belt as possible. This time I used a bar in one of the cam sprocket holes, packed a buffer of cork between it and the belt and levered the belt up high enough to push it forward onto the cam shaft sprocket. It make me cringe to think of putting such a load on the belt. I replaced the water pump this time which has a cam action but am sure it was positioned properly as this will effect the belt run length. The lug on the pump is at about 11 o'clock, left of the top bolt looking at the front of the engine, turned as far anticlockwise as possible. Is this lack of belt slack problem typical or am I missing something? Is there a tool which helps to refit the belt? Any advice please.
-
There aren't any special tools needed for the 2.0litre belt but water pump position is important as you correctly point out it will affect belt tension,why not just turn it a little to get a little slack into the belt which the tensioner will then take out :y
-
Thanks Henryd. The pump is in the most off cam position. You can't turn it any further as the lug hits parts of an alloy castings bolted onto the front of the block. The previous time I changed the pump I tried it in various positions and settled on the one I used this time as all the others made the belt tighter. It has just struck me that perhaps there is a snug recess in the alloy casting that is not obvious without viewing upwards from beneath the radiator? With the lug in that position it would make the belt travel shorter thus giving more slack. That would explain why I am struggling. Perhaps someone who has change a water pump will confirm this.
Bob.
-
8 valve omega?
Can only find twin cams in technical data or is a different vehicle?
-
The rarest of omegas :y
-
THIS IS MY OPINION, NOT OFFICIAL OOF ADVICE ;) ;) ;)
I'm not sure I'd change it as a matter of maintenance as the 8V engines tend to be non-interference :-X :-X I'd make sure I had good recovery though ::) ::)
But, I think on the last 8V belt I did I took the tensioner off and fitted it and the belt together
-
tuen water pump more slack needed-then use tensioner to do rest---this has already been said-engine is more old cavalier/carlton--lug on pump not around then---lug is mainly for 16v
-
From memory, only some of the 8v engines were free-running.
....and just how often do real live 8v Omegas pop up ?
-
Thanks for all the replys so far. To answer your comments not necessarily in the correct order:-
Believe me it's just not possible to get the belt back on by fitting it and the tensioner at the same time. That idea we dismissed after about 35 minutes of two of us straining our guts out.
Yes it does seem to be a rare combination x20se and Omega estate. It was a BT fleet car.
It is single OHC so not like the V engine or 16 valve twin cam.
If the lug on the water pump is for another engine, by removing it with an angle grinder I can rotate the pump further. This would make it more "Off Cam" and so give more slack as the lug hitting a casting stops you turning it more in favour of giving maximum slack for the belt run. Having got the belt fitted I can then rotate the pump back to where I know it normally sits.
Just to be clear though is anyone else having a swine of a job to get this belt on an X20SE engine? I have rebuilt entire engines before and don't consider myself an amature and tye guy helping me knows his way around the mechanics of a car. If others who have done it think it is straight forward then I will look harder for what I am doing wrong. Very helpful info would be was your water pump lug at about 11.00 o'clock having been rotated anticlockwise until it hit an alloy casting bolted to the front of the block? Cheers folks.
-
Yes. The old astra and cavalier engines, the tension was applied only by rotating the eccentric water pump housing. There was only 3 pulleys, and no tensioner. behind the water pump pulley there were large hexagon sides which you could turn with a large spanner. They were usually non-interference engines. Having seen several snap. Also... changing the clutch was a 1/2 hour job... happy days! :-)
Quick question, do the old and new belts match? The old one must have gone on ok?
-
The old belt was the same number of teeth and length. I put the old belt on and I struggled the same with that one. And the one before. There must be someone out there who has done this job. Is it easy or not?
-
How about posting some pictures so we can have a look?
-
Good idea Tidla but it's now all back under covers.
It seems the folks who have done this job have moved on so I guess I'll just carry on struggling. I'll cut off the lug on the old water pump next time and experiment with how that helps. If it's an improvement I'll then cut the lug off of the new one and fit it that way.
-
old pumps didnt have lug :y so take old pump grind lug of and trial fit---it will work mate :y :y