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A Few Thoughts On Changing The Cambelt And Tensioner

#1 User is offline   eldoodarino 

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Posted 13 August 2013 - 08:48 AM

A thought i'd share a few thoughts with you guys on timing the 1.7....

Notice I say TIMING THE 1.7 and not changing the cam belt..lol this is really the key to what this thread is about as I feel many people are getting their cam belt changed PRESUMING the engine is now sorted and bullet proof for the next few years.. :nono:/>

anyway, so here goes...

no.1

Think about it logically..would Yamaha/Ford have really setup the engine and timed everything up with the engine still in the car... of course not! it's just too ridiculously awkward and you can't get round both sides of the engine to get a correct grip/purchase on the said nuts and bolts..

2.

holding the engine at TDC (Top Dead Centre) against the Timing pin and inserting the timing bar will NOT re-tension or re-time the engine it will only hold it in place while you pull off the belt and replace it... half the job in my opinion and you could say a WASTE OF TIME AND MONEY as there was probably nothing wrong with the belt and tensioner in the first place..lol :roflmao:/>

3.

check out this little rough picky iv'e done to help explain why...

Posted Image

ok, so we all know from previous documents that the cambelt tensioner has 2 bolts...one securing it to the block and one which secures the pivot system of the tensioner... The Larger bolt is secured to the block and the smaller bolt is done up FINGER tight only and then tightened up AFTER the pin is withdrawn and the tension is applied to the belt.... no problem!.. most decent mechanics can manage this one...

OK, now look at the picture...

with the TDC pin in place and the cams locked with the locking bar, the area of the belt which is now being tensioned is shown with the YELLOW line.. you can probably guess where this is going already.. :bleh:/> :excl:/>

Now, EVEN if the cam bar went in without any wiggling and the timing was PERFECT, Your still only tensioning half the system, and your certainly not tensioning the CRITICAL area shown by the BLUE line...

On this particular engine the cam bar did go in without any wiggling, but I still undid the Exhaust cam bolt so that the cam pulley (wheel) was COMPLETLEY FREE TO MOVE..

Using this method, you are tensioning right back round to the VCT cam pulley (which is spring loaded)...now you have tensioned a hell of a lot more of the system, showed clearly by the RED line... with the system tensioned correctly now the exhaust cam can be re-tightened to spec...

4.

When I have let other people do my cam belt in the past, the replacement bolt for the VCT has always been thrown in the bin..LOL! because they can't be bothered to "re-time" the engine

the Cam pulleys have NEVER been loosened off...again, can't be arsed!

the bottom pulley bolt which holds everything in time relative to the crank has always been blasted on and off with an Impact gun, torgue settings (40nm + 90 Degrees) completely ignored because it's quicker with a gun and just too dam awkward to do it properly with the engine in the car

No effort was ever made to clean down that side of the engine thoroughly or address any leakage issues (grub screws etc), again, because it's too awkward with the lump in the car..

5.

one final point...

Turning the engine over to the TDC pin does not 'Hold' it in place...to do that you need the SPX flywheel locking plate..it's quite easy when playing around with the cams for the crank to wind back very slightly, this will mean when you've finished timing and turn it over a couple of times you'll have to re-time it all over again to insert the cam bar...locking the crank at the flywheel gives you a pullet proof way of holding it securely whilst you time it up, but of course you need the gearbox off to do this!... again more time (and money I guess)... but even more reason why you should really do this job with the engine out and mounted to a stand

Hope this has been useful info... i'll update it as I think of more..

:beer:/> :beer:/>

Chris
FRP453
Wizards Of Nos 60hp progressive delivery.... yeah baby yeah :-o
Denso Iridium Plugs
Helix Clutch
Mobil 1


#2 User is offline   Dave93 

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Posted 13 August 2013 - 11:57 AM

So after all of that chris, are you now offering a cam belt change as part of the eldude services? I would love for you to do 007 cam belt! :-)

#3 User is offline   eldoodarino 

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Posted 13 August 2013 - 09:11 PM

Time is running thin for this month..may be able to squeeze it in... when you thinking?

PM me..

Rgds
Wizards Of Nos 60hp progressive delivery.... yeah baby yeah :-o
Denso Iridium Plugs
Helix Clutch
Mobil 1


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