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Technical Help...Punto 1998 How do I tension cam belt?

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Technical Help...Punto 1998 How do I tension cam belt?

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Mary Faere

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Apr 13, 2012
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Hello everyone... can anyone help?
We've got our Punto in bits to fix the timing belt tensioner. So far so good: we've got the new belt in place and new tensioner. We've figured out the timing marks and feel confident we know how to align the crankshaft and cam shaft...but now we just don't know how to tighten the belt with the tensioner...it's too hard to pull to get it tight enough.
I've read as much as I can find on the forum but everyone just says 'tension the belt', without instruction on how we actually do this.
Also any tips on how do we get the belt tight using the tensioner without the timing going off would be much appreciated? We got so far by putting a pin into the tensioner with a rope on it and pulling but afterwards the timing had been knocked out again.... doh.
Any pointers would help us out a million!

Mary

Ps... does anyone know exactly what a 1998 SX 60 Punto is? It's got 8 valves, I know that, but what 'Mark' would it be? The threads all describe them by 'mark' so it's be handy to know :)
 
Hey hi Wilko :) Thanks. We looked at the guide on how to change the belt on the forum, downloaded the Haynes and asked a few bit and bobs various places...

Since then we seem to have sorted the tension to the 'finger and thumb - quarter turn' advice on the guides, were all back together and tried starting the engine... but now have...
A NEW PROBLEM: (oh no!) when we turned the engine by ignition there was backfire and actual flames out of the air intake... aghh! How bad is this?
Also the belt started in the right place with all the marks on the belt precisely on the crank and cam marks... but after turning by ignition they no longer match up as the belt goes round. Should the marks on the belt match the marks on the crankshaft and the camshaft after each revolution of the belt? Or do they only match up every so often?
Again, any help on any of these points so much appreciated.... we can't afford a new car... gulp... and were so determined to learn how to fix it ourselves...

Mary
 
Hey Wilko, thanks again... I read many posts on the Punto timing again and went back for another go to take your advice with a tooth or two... then I spotted that the 'pin and hole' on the crankshaft pulley (highlighted by Dave in post: Re: PHOTOS of timing marks 8v F.I.R.E Engines ) to the alternator weren't aligned. I put that right and HEY PRESTO it's running lovely.... we were chuffed to bits (and so was our Blue Bubble... but then!!! we hit our..

LATEST PROBLEM :( can there be any more?) The engine's running sweetly but there's a gentle squeaking sound. The new tensioner is got warm after just 45 seconds of running. We're wondering if the bolt (is that what you'd call it?) that the tensioner fits onto has been bent when the old one siezed.... I've read that Punto Mk1s have problems with their tensioners. Could a bend here be possible.... and if that's the problem... can we possibly put it right?

We're amazed and pleased we've got so far! (And that's because of the forum for sure!) But our poor little Blue Bubble looks all sad up in the air there for the sake of a bendy bolt...

Mary
 
Wilko, you're a star... shining out there in the dark night of the timing belt, heh :)

From what I can work out, having a close inspection, when the tensioner is moved fully forward (that increases tension), it's touching the bit that protrudes off the engine block into the centre of the tensioner by what seems to be just a tiny, tiny fraction; not even a millimeter. I'm guessing it shouldn't do that... do you think copper slip would put it right indefinately or should we focus more on stopping it touching altogether?
We considered trying to bend the pin/bolt back a touch with a soft mallet, but wouldn't want to do any damage or bend it too far another way. I also wondered if we could file a tiny bit off the protruding bit to make a fraction of clearance... does any of this sound anything like sensible to you?

We're quietly pleased with progress so far... and determined to give it our best shot at getting the Bubble back in action! But we know how a tiny fault can lead to a whole world of hurt! Ooo!

Mary
 
Mary Faere said:
Also the belt started in the right place with all the marks on the belt precisely on the crank and cam marks... but after turning by ignition they no longer match up as the belt goes round. Should the marks on the belt match the marks on the crankshaft and the camshaft after each revolution of the belt? Or do they only match up every so often?
Mary
Click to expand...
This often confuses people. The belt is designed to walk around the sprockets so as not to be landing in the same place all the time so they will appear out after cranking the motor.
 
fingers99 said:
Other possible cause ofr backfire is that the ignition timing is out. Hold the alternator pulley up to the light aqnd you'll see 5 holes: the big one in the cenre, 3 for the bolts, and a small one. The small one must locate on a pip on the crank pulley.
Click to expand...
Hey Fingers :)
Thanks for taking the time to share your know how!
Yes... you were right. I'd read back over all the posts on Punto mk1 timing I could find and spotted the pip thing.... and that's what was causing the problem! But.... if you look at my last post in this thread ... I've hit another subtler problem concerning the tensioner... maybe you'd have some ideas on it...?

When it's pulled forward so the belt's tensioned to where it appears right (by forum advice of 'turnable by finger and thumb one quarter on the longest stretch of the belt) it seems to be rubbing on the block behind, which the mounting stud protrudes from... by a tiny, minute fraction, but you can just feel and hear the contact when you turn it by hand. After getting the engine running sweetly (by lining up the pip) we heard a quiet squealing sound and the tensioner got warm/hot after less than a minute of running... we're now trying to figure out why this is and what to do about it. We're frightened to leave it as it is in case it wrecks the new tensioner...

This forum's amazing though... everyone's so helpful and knows so much!

Mary
 
wilko1992 said:
Put a washer on as it should have 1 and copper slip with it been high temp grease and anti sezie as well, :)

Where should I put a washer Wilko and what kind? There is already one between the knut and the tensioner centre piece... is that the place?

Mary
Click to expand...
 
Brendan W said:
This often confuses people. The belt is designed to walk around the sprockets so as not to be landing in the same place all the time so they will appear out after cranking the motor.
Click to expand...
Brendan, thanks for that nugget of pure sense. Now that I think about it as you describe it's clear that wear should be spread out... we were scratching our heeds wondering if we'd messed the process up, heh! You've helped with the doubt :)
We finally got our Blue Bubble running, and sweetly too... we were amazed. Only thing is, now we've hit a subtler problem with the tensioner touching the mount (so, so slightly, causing friction and heat) when it's in position... details are in my ramblings above... would you have any insight as to why this might be? Our old tensioner siezed, blew apart and has left slight scaring on the mount the mounting stud protrudes from... we were wondering if maybe the stud had got a bit bent... or if there's something else going on we just don't have the experience to imagine.

We learned enough from the forum to undertake the task on our own, and now replies like yours are coming in and it's amazing! We don't know what'll happen next but feeling condifent if we just keep looking we'll find the answers :) Wilko1992 suggested to try some copper slip.

Mary
 
fingers99 said:
Guessing here, but is the adjuster eccentric (the thing that fits in the middle of the tensioner bearing) on the right way round? Fat end should face outside.

Otherwise, I would just put a washer on the stud to give clearance.
Click to expand...

Hi Fingers, yes the adjuster is eccentric and the wider end is outside so the other side fits neatly into the tensioner. (It's great everyone seems to know wht I'm talking about!) All looks well; spangly and new.... just it rubs a iddy biddy bit when tensioned up. I can't figure out where to put a washer to add clearance because the inside of the tensioner is hollow! So there's nothing for a washer to butt up against...the stud is just in air until it goes through the centre piece that's on the outer side of the tenisoner. :shrug:
We ran the engine and the timing belt seemed to run to the inside of the tensioner, rather than the middle... it didn't fall off the edge but was right on the edge. Looking at the old tensioner the wear marks indicate it ran in the centre of that one. We're wondering again if the stud got bent a bit when the old tensioner collapsed. Do you think that could be a cause of the belt running on the inside and the rubbing? I'd love to find out if anyone else has ever experienced this problem to gain a bit of confidence as to the solution...

Mary
 
wilko1992 said:
I'm puzzled to what it could be might bre the stud but not shure on that 1 what ever you do don't hit it with a hammer as U might cause a crack in the block.
Click to expand...
Well... we finally came to the conclusion that we must have the tension too tight... hence the inside of the tensioner touching the mount. So we put it all back together again in the methods learned from the forum and Haynes (the forum being more concise) and tensioned it just slightly less. He's running! With no squeaks! We've taken him a mile up the road and back and he's sounding well. WOW!

Just couldn't have done it without help from the forum! We're gonna see how he goes over the next few days, replace shocks, fix back brakes then back to the MOT station with fingers crossed :D

Thanks ever so much for welcome help and support! Our Blue Bubble says thanks too :)
 
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