Omega Owners Forum
Chat Area => General Car Chat => Topic started by: Webby the Bear on 18 May 2015, 20:09:53
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Evening fellas, how are you?
So. As you may know I'm learning real life timing belts. And apologies if I'm boring you. however I want to run a technique past you.
The below timing belt only has marks and I've been told that there's no lock tool available.
(http://i1226.photobucket.com/albums/ee402/webbybear1/suzuki%20cbelt_zps24llygir.png) (http://s1226.photobucket.com/user/webbybear1/media/suzuki%20cbelt_zps24llygir.png.html)
So you get the cam and crank to the timing marks. Fine. You undo tensioner, remove belt, fit new tensioner loosely and fit new belt up the non tension side and over the cam sprocket and over round the tensioner. Fine.
Here is the question.
As there is no tool to hold the crank you tension the belt, and as you do the crank will move out of line. Correct?
I've been told the best way to combat this is to back the crank off about a tooth and then when you tension the belt the crank will move in to correct position AND any slack that was in the non tension side will be taken out.
Your thoughts? Any experience of doing just this?
TIA
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That's the way - so long as the marks line up when the belt is correctly tensioned, Robert's your mum's brother.
Just one thing - if you are working with an old school mechanic, they may recommend checking the tension by twisting the longest run through 90 degrees. Don't do this, because its putting forces through the belt that could potentially weaken it.
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Thanks GK..... if they don't line up after tensioning.... you simply slacken the tension and back off / bring forward the crank until you get it it right when tensioned?
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ps I take the note about the belt deflection :y
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This also prompts another few question.... (sorry)
1.) As there is also no cam lock on this set up presumably the cam sprocket could also move out of time when the tension is set .... if so is it best to make a tool / use something to hold the cam? therefore all movement will be the crank and thus pulling the slack out of t'other side and coming back in to line?
2.) With the Ford set up (see below) you use the camshaft locking bar at the back and the crank lock tool (pin in the block) so literally nothing moves. So, what do you do to take the slack out of the non-tensioner side? presumably the only thing you can do is pull up as hard as you can and struggle to get it tight on the cam starting non-tension side?
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oops, ford set up below
(http://i1226.photobucket.com/albums/ee402/webbybear1/ford%20cambelt_zpslrkom2qw.png) (http://s1226.photobucket.com/user/webbybear1/media/ford%20cambelt_zpslrkom2qw.png.html)
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Your procedure is exactly how it's done.
The key to getting it right is knowing how much to back it off, so that the tensioner lines everything up correctly. Each engine type tends to be different, so can only get that expertise by doing lots of them.
I used to be able to do a 2l Capri timing belt in 20minutes, but no longer have the knack for aligning the auxiliary pulley, so would expect to have a couple of tries.
The really important thing is to turn the engine a couple of rotations, checking that the timing stays correct. But that's best practice, and applies to almost any belt/chain job.
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Thanks Nick, exactly what I wanted to hear! This is the way the head mech. is teaching me :y
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also nothing wrong with highlighting existing marks with tippex,or if you can't find any marks make your own,if it ran when you stripped it down it'll run when its back together if the marks all line up,obviously better to do it by the book but sometimes info can be sketchy on some motors :y
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couldn't agree more henryd... I have now acquired a tippex pen for exactly this :y
so will the cam sprockets move out of time as well? Thus backing these off too may be required?
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On your first example a key point to highlight, the right hand side (cam to crank) run is the key timing run, fit this so there is no slack and it matters not what the tensioner does as long as its set finally after turning the crank through 720 degrees back to the timing mark.
True of any setup, the tensioner only acts upon the non-timing run to remove the slack.
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I recall seeing something years ago where the timing belt was slit along it's length with a Stanley knife and the new one fed onto the created gap, rest of the old one cut off and new one fully pushed home, thus not altering the timing . Or am I imagining it :-\
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I recall seeing something years ago where the timing belt was slit along it's length with a Stanley knife and the new one fed onto the created gap, rest of the old one cut off and new one fully pushed home, thus not altering the timing . Or am I imagining it :-\
They did that on car SOS last week on a skyline gtr,looked proper bodgy tbh :-\
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Another tip when doing belts like this without tools is that after tensioning, if the marks are out use a temp florescent pen (like the ones they use in pubs to do their boards and wall menus) to mark on the crank and camshafts where you are now so you can offset it for your second attempt. Once lined up, wipe of the marks :y
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I recall seeing something years ago where the timing belt was slit along it's length with a Stanley knife and the new one fed onto the created gap, rest of the old one cut off and new one fully pushed home, thus not altering the timing . Or am I imagining it :-\
They did that on car SOS last week on a skyline gtr,looked proper bodgy tbh :-\
Yep mad eit look very easy , 2 minute job jobbed :(
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Thanks for your input guys.
One thing I'm confused about is how on a set up like the ford as cam and crank are both locked and cant move, how is the slack taken up on the non-tensioner side?
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Thanks for your input guys.
One thing I'm confused about is how on a set up like the ford as cam and crank are both locked and cant move, how is the slack taken up on the non-tensioner side?
I would assume that if the return tension is different to the feed side they would equalise once the crank and cam are unlocked so the timing is very slightly out.
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ok, so am I over thinking this?
like with the ford belt I fit it as tight as I can up the non-tension side, over the cams and then set the tension,as long as they all line up after a few turns of the engine all is good correct?
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Thanks for your input guys.
One thing I'm confused about is how on a set up like the ford as cam and crank are both locked and cant move, how is the slack taken up on the non-tensioner side?
Once the cams are locked with the bar both pulleys are slackened so they spin freely,new belt is fitted and tensioned correctly them can wheels retightened and timing is spot on :y
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right, ok henry that makes sense!. so basically I can slacken them off and pull them round towards the tensioner so slack side is tight. and then tensioner tensions the, err, tension side? lol
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right, ok henry that makes sense!. so basically I can slacken them off and pull them round towards the tensioner so slack side is tight. and then tensioner tensions the, err, tension side? lol
Yep,get it tensioned then tighten up sprockets and job should be a good un :y
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Sprockets are on a taper fitting.....this is actually something of a weakness on these and I have seen it cause trouble on a few occasions!......quite possibly due to some pros aversion to torque wrenches!
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Ok, so basically in the two set ups I've shown pictures of.... the first one you can back the crank off to allow for the tensioner to pull the slack out of t'other side and the ford set up you loosen the sprockets so they free-wheel and move thus also pulling the slack out.
That all makes perfect sense.
Soooo.
is there any modern-ish set up where you don't take the slack out and you simply lock crank and cams, stick the belt on and you're done? or is there always one way or another of getting the slack side tight?
hope that makes sense lol
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Hmmm, now a tad confused.
Just watched a 02 Honda civic sohc cambelts done on youtube.
Now I was going to do one of these last week but woman never turned up grrrrrrrrr
Anyways as this engine also doesn't have a lock tool kit, he lined the cam marks up with the cylinder head and marked the belt. Fine. He then made sure the crank Mark was lined up and marked it with tippex too. Fine. He then fitted the belt. But he DEFINITELY didn't back the crank off cis when he pulled the tensioner spring up on to the pin on the block it didn't move (his camera was from below at that point so you could see crank and tensioner in one).
Yet he turned it over with no trouble and all marks lined up.
Why am I not getting this? Lol
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As already said, the key is to get the non tensioner side of the belt tight, you can do this without knocking the crank back, its personal choice.
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Also, single cam engines don't move as much as twincams.
If you have a nice short timing chain like on OHV engines, they rarely move at all.
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Also, single cam engines don't move as much as twincams.
If you have a nice short timing chain like on OHV engines, they rarely move at all.
Ha ha, dream on!
They stretch like no tomorrow unless you fit expensive ones (which manufacturers never did), Rover V8 is an absolute classic example of that one :y
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Surely they don't stretch whilst you fit them, which is what we're discussing here?
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No, but then a belt doesn't either :y
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So, if knocking the crank back isn't necessary (although I suspect that'd be my preferred method) we must be talking a bit of
gorilla brute force power to get the belt over the cam and to have the non-tension side tight?
:)
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If there is enough slack in the tensioner side to allow you to offer up the belt to the camshaft pulley straight and then wrap it around the top of the camshaft pulley then the teeth on the belt should drop neatly into the teeth on the pulley.
{I don't know if my description makes any sense to anyone else - it barely makes sense to me ;D )
Edit - wrap the belt round the crank pulley and make sure the teeth on the belt and pulley have fully engaged. Make sure they stay engaged for the next bit. Pull the drive side of the belt tight and hold it with your fingers just above the centre line of the camshaft. Push the belt against the camshaft pulley and the teeth should just engage, if they don't then bend the belt slightly to make the teeth open up a little. Once the teeth have engaged then wrap the belt around the top of the camshaft pulley. :y
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Thanks Andy.... I fully understand your explanation :y
''Drive side'' being the side without the tensioner, correct?
So basically this is the way to do it without using the backed off crank method? :)
I'm promised another timing belt next week ::)
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Basically yes.
Before you take the old belt off apply some pressure to the drive side to create a bit of slack.
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Thanksfor all your help :y :y :y
Moving the subject on...
What is a floating crank? I'm told this method cant be done with one that has a floater :D
Sadly.... ive never even heard of this at college :-[ :-\
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I think they are referring to the (mostly French) engines with a floating crank pulley. They don't key them to the crank. The pulley bolt(s) are loosened when the belt is fitted then re-tightened when (if) the timing is correct.
One of the engineers at work serviced his sons French car (I was told the make but it was instantly forgetable) last year. He didn't have a good word to say about the timing procedure...........
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Got you Andy. So floating crank is the crank version of fords cam sprockets. Ie the pulleys aren't keyed to the cam shaft and thus will go back on in any position?
so what's the procedure with them? Generally speaking of course? :y
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I will ask him, I never saw the car and I think his son got rid not long after because his father said he never wanted to work on it again :-\
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Haha that sounds about right! Hate renaults in particular.
Ok mate thanks very much :y
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Got you Andy. So floating crank is the crank version of fords cam sprockets. Ie the pulleys aren't keyed to the cam shaft and thus will go back on in any position?
so what's the procedure with them? Generally speaking of course? :y
Baby petrol fords have the same set up,cambelt pulley on crank spins freely :y
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henry is that also with free spinning cam sprockets....so cam AND crank spins on smaller engine fords?
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So basically, if you have crank pulley spinning freely and cam sprockets running freely then you 1 million percent need the lock kit.
yet, whilst having to use the lock kit I imagine its easy cos you just slap the belt on and spin the pulleys to remove the slack?
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henry is that also with free spinning cam sprockets....so cam AND crank spins on smaller engine fords?
Yep,1.25 zetec lump everything spins free so locks essential :y
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Cheers Henry.
So basically, fixed cam sprockets and crank pulleys. . . No lock kit required. Tippex to mark cam and crank, back crank off to allow tensioner to pull crank round and take slack out the drive side.
Any engine with floating crank, floating cams or both. . . Lock kit essential and pulleys loosened to take slack out of drive side?
:y