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Brera 2.4 - new timing belt tensioner not working

2K views 17 replies 5 participants last post by  Pud237 
#1 ·
Hi Everyone

My Brera still hasn't cottoned on that I'm trying to be kind to it buying it new parts...! I'm reasonably able to do most jobs, but still very unfamiliar with my Alfa, so feeling a bit cautious when something doesn't seem right. I'm changing the cambelt using a genuine Alfa cam belt kit - but the tensioner isn't working right - I suspect it's duff and fit only for the bin.

The tensioner groove is lined up with the pin on the crank case and the tensioner will tension the belt, but the indicator arrow does not move at all. I've tried several times - to no avail. I even tried tensioning the belt and physically moving the arrow to line up with its indicator hole, that worked, until I turned the engine by hand and it immediately reverted to its starting position.

Seems bizarre that a new tensioner wouldn't work properly - or is it not the tensioner and just me doing something wrong...? Can anyone please shed any light.

With thanks and best regards
 
#2 ·
Sounds like you’re re-assembly process steps are somehow incorrect. Fact that you can activate the tensioner arrow by hand tells it‘s OK?

1. Put the belt anti—clockwise on, working your way starting from the crankpully, keeping it tight as possible (exhaust sprocket loosened).
2. With tensioner fully loose, you can just put on the belt. The M8 nut just loosened, to enable the tensioner still to slide. Should give just enough clearance to slide the belt on without hassle.
3. With a (tensioner) tool you put maximum stress on the belt, the arrow swings out and then temporarily fix it by its M8 bolt - in order the belts stays under maximum tension.
4. While the cam was still locked, undo the cam locking pin - to avoid damage when torqueing the exhaust sprocket bolt to prescribed value.
5. Torque up the exhaust sprocket bolt, keep another lever tool to counter force the torque. Be careful not to damage the cam sensor sitting behind the sprocket.
6. Turn the crank 2 full revolutions.
7. Carefully loosen the tensioner M8 nut, in order the indicator slowly starts pointing towards the little bore hole from its own support plate.
8. Then you best check a correct timing once again; by putting the locking plate back on the crank pully and screwing in the cam locking pins.

I’ve photos and can upload if it helps to understand better.
 
#3 ·
Mmm..... perhaps you’re indeed dealing with a same kind of issue, faulty new part, as what I found back here on an older topic:

 
#4 ·
Thank you Leo. I pretty much did the belt installation as you described - though notably without loosening the exhaust sprocket. I would have thought that the camshaft locking tool enables the sprocket bolt to be undone? - though I note that you say it should be removed prior to torqueing the bolt back up again?

Also, you mention using a tensioner tool? Are you able to send a picture of it please? Having seen the other topic you've highlighted, I think I will buy another new tensioner - I've lost faith in the one that came in the kit, it's suspect and in my mind not worth the risk.

Thanks for being so helpful

Best regards
 
#5 ·
Update - I've ordered a new genuine tensioner from the Alfa Workshop. When trying to get the original new tensioner to work properly, I noticed that the cam belt was running towards the outer part of the idler/roller, a small amount of belt was over the outer edge of the roller - which didn't look right...?

Please can anyone share their experiences on this? Any advice gratefully received.

With thanks and best regards
 
#6 ·
There have been some bad batches of tensioners, not just on the 159 but also on the 2.0 fitted to the Giulietta.

Does the spring actually work?

 
#8 ·
There have been some bad batches of tensioners, not just on the 159 but also on the 2.0 fitted to the Giulietta.

Does the spring actually work?

Thanks Symon. I'm going to remove the cam belt and tensioner and start again. I will see if the spring works when the tensioner is off the car, though I have already ordered a replacement, as I can't trust this one now.

There's also the concern about the belt sitting slightly off the idler - doesn't look right, though I have no idea why...
 
#10 ·
The pointer will only start to move once the tension becomes significant. How are you levering the tensioner out? Are you pushing against the tensioner's sprocket or pushing against the backing plate? What are you levering off? I suspect you might just not be applying enough force, unless you can see something actually wrong with the tensioner?
 
#11 ·
Hi and thank you for your help. I've been pushing against the tensioner backplate, the tensioner physically tensioned the belt a fair way - but there was no movement at all from the arrow...?

I tried 4 or 5 times - and even moved the arrow physically whilst pushing on the backplate - I can't see anything wrong with the tensioner - but got the feeling something wasn't right and packed up for the night. I've ordered a new tensioner to be safe - and will remove the belt and start again. The outside edge of the belt is sitting just over the edge of the idler - not by much - but doesn't look right, hence taking it all off again and starting afresh.

I appreciate your help

best

Andy.
 
#12 ·
OK, so that's the correct method, but it is awkward. I always do this from below, I screw another long bolt of the correct thread into the crank pulley to give my prybar a fulcrum to lever against. Despite this, I need to use a pretty long heavy duty bar and plenty of force to get that tensioner pointer to move. I think before writing off your tensioner, you need to try tensioning the belt a bit harder. You'll need a second person to tighten it up once the pointer has moved to the mark.
 
#13 ·
For counter-locking the cam sprocket I've a simple universal tool: LASER 2869
Although normally reasonably satisfied with LASER/MIDLOCK solutions, this one is really poor as it easily bends.Yet, it has helped me numerous times on a variety of engines.

Hood Motor vehicle Automotive tire Automotive design Automotive lighting


Laser Tools 2869 Cam Camshaft Sprocket Multi Use Holding Tool | eBay

Then, as for adjusting the tension very conveniently and in a controlled manner, I've invested once in a special tool for our JTD's: HAZET 3087-1
Not sure though if there's enough clearance in your 5-cylinder engine-bay, compared to mine having 1 less.

Wheel Tire Automotive tire Crankset Motor vehicle


Hazet Spannrollen Betätigungswerkzeug 3087-1, verzinkt : Amazon.de: Baumarkt
 
#14 ·
P.s. as Jon already warned above: never use the cam lock tools to undo the sprocket nut or bolts.

It's usually not designed for that; i.e. like a locking device put on the flywheel ring gear to really lock the crank/engine (but not the cams). The problem isn't so much the strenght of the locking tool (pin or caliber like in Twinspark engines), but that of the cylinderhead (ripping out the just M7 cam cap threads for instance.)
 
#15 ·
Thank you Leo - that's super helpful. I've ordered the Laser cam locking tool - I need to be 100% sure I get that cam sprocket bolt loosened safely. I'm just about to look at the special tool for the tensioner.

Tonight I closely followed Pud's advice and double checked the tensioner functionality. I got a long lever bar onto the tensioner base plate and tensioned the belt as hard as I could. The tensioner baseplate moved back far enough for the locator pin on the front of the engine to be almost level with the cut-out opening in the baseplate - I don't believe it was possible to move it back further...and still the indicator arrow did not move.

I've already ordered another genuine new tensioner, as I'd suspected the original new tensioner was defective. Having tried it again tonight, I am now convinced of that. I will have to wait a few days for the tensioner and the cam lock tool to arrive, but I will post back when there is progress early next week.

Thank you to everyone who has helped with this - greatly appreciated.

Best

Andy H
 
#16 ·
Update;

I completed my Brera 2.4 cambelt change tonight - using the new genuine tensioner supplied by Alfa Workshop. I initially struggled to get the tensioner pointer to move - just as with the previous one, but thinking that 2 x tensioners couldn't be defective, after some perseverance, the arrow moved to align with the hole in the tensioner baseplate.

I now believe that Pud was right, the original tensioner was probably fine, I couldn't get the pointer/arrow to move even though I put plenty of effort into it - due to lack of know how and poor technique.

Next up is the changing of my alternator/air con compressor belt - really looking forward to that...!

Thanks again fellas for sharing your experience and know how - greatly appreciated.

Best regards

Andy H
 
#18 ·
Congrats on persisting and getting there in the end.

It is surprising how much force is required to move the tensioner. It's all to do with multiplication of effort due to distance from the bar to the fulcrum to where you are pushing. Lack of space really doesn't help either.
 
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