Engine 850: B5234T/2.3/20v/T5: - Timing

stevepcar · May 22nd, 2020, 10:05

Decided to tackle the timing belt change. Got proper Volvo belt & new tensioner. Checked timing was correct before I took the old belt off & highlighted cam sprockets' timing marks & crankshaft notch. I have tried about 20-times to get the new belt on in the correct position, but when I stretch it between the 2-cam sprockets it is always 1/2 a tooth out when the timing marks are properly aligned. If I do get the belt teeth to match the sprockets, then I do not have enough slack to get it over the tensioner pulley. I have tried taking the tensioner out getting the belt on & then putting the tensioner back on, but there is insufficient slack in the belt to get the tensioner back in place. I have followed the method in the Forum's articles section, I have tried following the Haynes manual method, I have tried Robert's DIY method on You Tube & looked at the FCP method, but he uses a tool to lock the cam sprockets. Anybody any useful tips on how to get this right please?

stevepcar · May 22nd, 2020, 10:23

Addition to my previous posts. How accurate do the marks have to be? Looking at Robert DIYs video, he has the exhaust sprocket mark lined up the v of the timing belt cover, but the intake sprocket mark is lined up with the top edge of the notch, so the tooth lines up with the notch in the timing belt cover. Would half a tooth out make any difference?

400-ascona · May 22nd, 2020, 11:59

I always mark on the belt the position of a tooth on each pulley (including the crank). I then transfer these marks to the new belt so I know they line up tooth for tooth with the marks I've made on the pulleys. I then know the timing is exactly as it was when I stripped it regardless of the timing marks. I've used this method on T6 engine, T5 engine, D5 engine. Rob.

stevepcar · May 22nd, 2020, 20:54

Had time to look at various You Tube videos & noticed that very few situations result in the timing marks on the cam sprockets, lining up with the bottom of the v notch. Most of them are withing the width of the v notch. So I have set mine up the same & it all seems to line up after several turns of the crankshaft, so all is well. However, I have just changed the serpentine belt, only to find that there is no tension in it. The tensioner needed , quite a lot of force to slacken it off, but I weas able to get the belt on even after the tensioner had been released. I thought the belt was the wrong length, but I refitted the old belt with the same result. Can the belt tensioner have failed?

happy diver · May 22nd, 2020, 21:13

https://www.google.com/search?q=850%...AAAAHQAAAAAQBg

ITSv40 · May 23rd, 2020, 07:31

Quote:

Originally Posted by stevepcar

Had time to look at various You Tube videos & noticed that very few situations result in the timing marks on the cam sprockets, lining up with the bottom of the v notch. Most of them are withing the width of the v notch. So I have set mine up the same & it all seems to line up after several turns of the crankshaft, so all is well. However, I have just changed the serpentine belt, only to find that there is no tension in it. The tensioner needed , quite a lot of force to slacken it off, but I weas able to get the belt on even after the tensioner had been released. I thought the belt was the wrong length, but I refitted the old belt with the same result. Can the belt tensioner have failed?

A new tensioner should be fitted when replacing the serpentine belt.

stevepcar · May 23rd, 2020, 11:27

Thanks Happy Diver. The link you sent solved my problem. I was following the belt layout as shown in my 1996 owners manual, but it was changed later in the year, using a longer belt that goes most of the way round the alternator, but only part of the aircon pulley. I didn't think there was anything wrong with the tensioner, the slack was too much & I compared it with the one on my non-aspirated 850 10 v and it looked pretty much the same position when under tension. Great now I can stop kicking myself!!!!

stevepcar · May 23rd, 2020, 11:30

Just a small tip that may help anybody looking for the timing notch on the crankshaft. I put a piece of stiff white paper between the back of the pulley & the casing. You can then clearly see the notch in between the teeth. I then marked it with tippex on the end of a long thin brush. You can then remove the paper & align the notch with the mark on the casing easier.

May 22nd, 2020, 10:05	#1
stevepcar Steve Last Online: Yesterday 17:10 Join Date: Jul 2012 Location: Bristol	Timing Decided to tackle the timing belt change. Got proper Volvo belt & new tensioner. Checked timing was correct before I took the old belt off & highlighted cam sprockets' timing marks & crankshaft notch. I have tried about 20-times to get the new belt on in the correct position, but when I stretch it between the 2-cam sprockets it is always 1/2 a tooth out when the timing marks are properly aligned. If I do get the belt teeth to match the sprockets, then I do not have enough slack to get it over the tensioner pulley. I have tried taking the tensioner out getting the belt on & then putting the tensioner back on, but there is insufficient slack in the belt to get the tensioner back in place. I have followed the method in the Forum's articles section, I have tried following the Haynes manual method, I have tried Robert's DIY method on You Tube & looked at the FCP method, but he uses a tool to lock the cam sprockets. Anybody any useful tips on how to get this right please?

May 22nd, 2020, 10:23	#2
stevepcar Steve Last Online: Yesterday 17:10 Join Date: Jul 2012 Location: Bristol	Timing belt marks Addition to my previous posts. How accurate do the marks have to be? Looking at Robert DIYs video, he has the exhaust sprocket mark lined up the v of the timing belt cover, but the intake sprocket mark is lined up with the top edge of the notch, so the tooth lines up with the notch in the timing belt cover. Would half a tooth out make any difference?

May 22nd, 2020, 11:59	#3
400-ascona Premier Member Last Online: Apr 15th, 2024 10:13 Join Date: Mar 2008 Location: Derby	I always mark on the belt the position of a tooth on each pulley (including the crank). I then transfer these marks to the new belt so I know they line up tooth for tooth with the marks I've made on the pulleys. I then know the timing is exactly as it was when I stripped it regardless of the timing marks. I've used this method on T6 engine, T5 engine, D5 engine. Rob. __________________ 1997 V70R AWD, Saffron, Manual; Lotus Carlton; Ascona 400; Mini Cooper S Works; 4.2 Supercharged Range Rover; Land Rover Discovery 4; Suzuki GSF1200N; BMW R80/7; Velocette Venom; Daimler V8 250.

May 22nd, 2020, 20:54	#4
stevepcar Steve Last Online: Yesterday 17:10 Join Date: Jul 2012 Location: Bristol	Timing belt marks Had time to look at various You Tube videos & noticed that very few situations result in the timing marks on the cam sprockets, lining up with the bottom of the v notch. Most of them are withing the width of the v notch. So I have set mine up the same & it all seems to line up after several turns of the crankshaft, so all is well. However, I have just changed the serpentine belt, only to find that there is no tension in it. The tensioner needed , quite a lot of force to slacken it off, but I weas able to get the belt on even after the tensioner had been released. I thought the belt was the wrong length, but I refitted the old belt with the same result. Can the belt tensioner have failed?

May 22nd, 2020, 21:13	#5
happy diver Active Member Moment Last Online: Apr 29th, 2023 05:58 Join Date: Jul 2012 Location: Brisbane: perfect for one day, asleep the rest	https://www.google.com/search?q=850%...AAAAHQAAAAAQBg __________________ 20,000 leagues under the sea diving to adventure in a silent world with my ceiling the waves...Emile

May 23rd, 2020, 11:27	#7
stevepcar Steve Last Online: Yesterday 17:10 Join Date: Jul 2012 Location: Bristol	Timing belt marks Thanks Happy Diver. The link you sent solved my problem. I was following the belt layout as shown in my 1996 owners manual, but it was changed later in the year, using a longer belt that goes most of the way round the alternator, but only part of the aircon pulley. I didn't think there was anything wrong with the tensioner, the slack was too much & I compared it with the one on my non-aspirated 850 10 v and it looked pretty much the same position when under tension. Great now I can stop kicking myself!!!!

May 23rd, 2020, 11:30	#8
stevepcar Steve Last Online: Yesterday 17:10 Join Date: Jul 2012 Location: Bristol	Timing belt marks Just a small tip that may help anybody looking for the timing notch on the crankshaft. I put a piece of stiff white paper between the back of the pulley & the casing. You can then clearly see the notch in between the teeth. I then marked it with tippex on the end of a long thin brush. You can then remove the paper & align the notch with the mark on the casing easier.

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