Mazda 2 -2012 model - timing chain removal/loosening question

B

Bram1982

Member
:
Mazda 2 LPG
Hello,

Having a little trouble loosening the timing chain on my Mazda 2 from 2012… Contrary to title it doesn't have to be totally removed, only loosened.... Sorry about that.

Reason is I need to change the valve buckets. I have the help from an experienced technician, but we still can’t figure it out….The Mazda workshop manual states the following steps:


1)
Remove the drive belt (so two service holes are easy accessible)

2)
Remove the two blind plugs from the service holes

3)
Insert M6 bolt (45-80mm) into the right-side service hole. Leave +- 2mm space from where it contacts the tensioner arm.

4)
Release tension on the timing chain by turning the crankshaft pulley counter clockwise. The M6 bolt should be pressed in.


Problem is nothing really happens with the timing chain when I turn the crankshaft pulley counter clockwise. The timing belt doesn’t seem to loosen at all and the plug doesn’t get pressed in.

Next, the manual also states in a separate note section that I have to insert a precision flat head screwdriver into the left service hole. Then I have to rotate the crankshaft pulley (again???) counterclockwise with the plunger lock released.

The manual is kind of confusing and doesn’t clearly tell me in what order I have to do things. Can someone explain what to do in which order?

Thanks!
 
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I made a small change to the original post. I don't need to totally remove the timing chain, only loosen it. Reason is I need to change the valve buckets. For that I need to loosen the timing chain to be able to remove the timing chain gear and lift the camshafts so I can finally replace the valve buckets.

I'm using the Mazda manual from here:

http://www.reddit.com/r/mazda/comments/167a34/all_mazdas_service_manuals_online/


I downloaded the whole online service manual to PDF file btw.

Example screen
manual.jpg
 
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Did some more digging in the service manual and found a bit more about the chain tensioner. This section is actually from the part where the chain is to be removed and the engine front cover is already removed:

manual2.jpg


The general idea still seems to be the same: Push down the link plate with precision screw driver and push back the plunger. But in my case (where the front engine cover is still in place) we use the left service hole to access the link plate and we turn the crankshaft pulley counterclockwise to push back the plunger (or so I assume?)

Finally put the M6 bolt in the right service hole to keep the chain tensioner in place?

This sounds like the most logical thing, but the section that actually addresses the loosening of the timing chain I can be interpreted very differently.

Maybe someone who has already done this can explain what really has to be done?
 
Its a pretty crappy description.


I think what is happening is that when you turn the crank CCW, with the tensioner lock undone, it allows the plunger to contract because turning CCW is trying to pull the chain tight between the crank and exhaust cam. When the engine is running the tensioner isn't under a ton of stress because the crank is pulling the chain from the intake side(so all the slack is by the tensioner).

The M6 bolt looks like you screw it in until it bottoms out, back off 1-2 turns, release the link plate to allow the tensioner to be collapsed, turn crank CCW to release tension, the tensioner arm should move to the left(as viewed looking head on), now the ridge allows you to screw the M6 bolt in more(probably bottom out again), so now it locks it in the untensioned position.

So it will be "tight" feeling on the exhaust side, but you should be getting some slack in front of the intake can gear.

I think it might be more effective if you hold the exhaust cam in place(locked solid). This is how a Mini Cooper timing chain is released basically.
 
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Thanks, sounds logical! Perhaps locking the exhaust cam will help. Maybe someone who has actually done this procedure on a Mazda 2 can confirm? Don't want to end up getting stuck halfway again...
 
If you have to pull the chain it isn't too bad to get back on and everything lined up. We had to rebuild a motor at the Runoffs and the chain was pretty easy to get setup again. I do recommend an extra set of hands though.

-Derrick
 
CorkSport said:
If you have to pull the chain it isn't too bad to get back on and everything lined up. We had to rebuild a motor at the Runoffs and the chain was pretty easy to get setup again. I do recommend an extra set of hands though.

-Derrick
Click to expand...

Thanks for the reply, but how did you loosen the timing chain exacly?
 
We had the whole cover off so I simply squeezed the tensioner to get the slack.

-Derrick
 
Will give it another try while locking the exhaust camshaft. I think there wasn't enough pressure against the tensioner.
 
Well guys, again we couldn't get the chain tensioner to loosen. As a last resort we removed the exhaust camshaft while holding the big gear in place. That didn't work out too well because the tensioner did manage to extend even further and now we can't put the camshaft back in place.

Tomorrow we will tow the car to a specialised garage. They will remove the side cover so there will be a clear view of the chain and the tensioner. Not feeling like doing this myself... enough frustration for today ;)

I'm really curious why this is giving me such a hard time... Gonna ask the guys at the garage to give me a look while they are working on it...
 
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Dear Bram1982.is is possible for you to upload your mazda 2 service manual & send the link.the reddit link now is not working.

regards.
 
Ok guys, here's the final answer:

IMAG1159b.jpg


Not sure why the little lever is already downwards? No surprise I could't get the tensioner unlocked... I can only guess I might have forced it downwards in my previous attempts.

And p.s
You don't actually need to remove the water pump and you don't need to drain the engine coolant and you also don't need to drain the engine oil in order to remove the side panel.
 
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