Time for Timing Belt ?

Troubadour said:
Not always - I can confirm what Robg71 said about no damage in an OHC Cavalier (ca 1990) as an example. Definitely not sidevalve!

QUOTE]

I never said it was a side valve im saying mine is!

Anyway who needs an OHC in a boat engine anyway?
is it a yacht ?....or one of those high powered expensive to run silly speedboat/stinkpot things?
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Actually it depends on if the valve system is interference or not and most are!
one could be lucky but normally the valve or valves will hit the piston or pistons if cam belt breaks...not nice!
not trying to scare anyone!...:)
 
Niander said:
They also will in a petrol engine..but not a side valve,
one thing i don't have to worry about then!
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It will depend on the way the engine was designed, just like another poster I had a cavalier engine loose it's timing belt no damage and just fitted a new belt. A few years later did the same with an Escort completely different thing major damage.

PS the cavalier engine was not a sidevalve engine like my first car an Austin 12/4
 
skipper_stu said:
Its been reprinted in the maintenance guide thats referred to in the sticky at the top of this PBO thing
Stu
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You can tell the bloke's a politician. Ask him a simple question , expect a straight reply ... no chance.

April 2010 in the practical project section !
 
Trop Cher said:
To save trolling through the mags, could you please give a date when your article was in the PBO.
Many thanks
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In text, here ya go!

Its not too difficult to change the cambelt, first remove the timing belt cover over the belt and pulleys. Then remove the small bolt over cyl No1 on the camshaft cover, now rotate the engine until you see a hole in the camshaft line up with the hole in the cam cover, you can put a drill bit in and carefully rotate the engine until it drops into the hole in the camshaft, you now have the camshaft locked at Top Dead Centre on No1.
On the front side of the flywheel housing on the right hand side of the engine you will find another hole into which you can slide an appropriate size drill bit, it should locate in a hole in the flywheel, when it does you have now locked the crankshaft. you should now see that the pulley on the left side of the engine (drives the injection pump) is lined up with a mark somewhere around the 9 o'clock position, if the engine is non turbo there will be an 'A' on the pulley next to the index mark, 'B' if if its a turbo engine.

The engine is now timed up correctly and you can slacken the tensioner wheel and remove the belt, you may have to remove the crankshaft pulley also to get the belt off. Fit new belt and re-tension. Now carefully check the pulley with the letters on it hasn't moved when you tensioned the belt, (tension should be that you can just twist it 90 degrees on its longest run between two pulleys). Now remove your two locking pins and rotate the engine by hand a couple of times to check it rotates freely, replace the bolt on the camcover and the timingbelt cover, and fire it up.

Good luck

Steve (Volvo mechanic)

or see Perkins manual at 15A-04 but the belt tensioning is far more involved. Steve's "90degree twist" works very well and is very accurate.



Copyrights acknowledged.
 
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Steve Cronin

Steve
Now carefully check the pulley with the letters on it hasn't moved when you tensioned the belt,

What to do if the pulley with letters has moved whilst tensioning the belt ?

regards
 
hairbox said:
Steve
Now carefully check the pulley with the letters on it hasn't moved when you tensioned the belt,

What to do if the pulley with letters has moved whilst tensioning the belt ?

regards
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If you follow Stu's instructions he also locks the wheel on the injector pump drive but slackens the two bolts that hold the cogged driving wheel on the cam shaft.

That way all vital components, the injector pump, the crankshaft and the camshaft itself are correctly timed and locked. The elongated holes in the camshaft drive wheel allow a bit of movement ... wiggle room Stu calls it.

Once the belt is on and correctly tensioned re-tighten the bolts securing the cam shaft drive wheel to the correct torque.
But make sure the bolts are not at either extreme end of the slots.

usually there are timing marks you can check every thing against. None mentioed either by Stu or Steve so dunno on that one
 
Now I'm really confused maybe it's one of those things you just have to watch someone do to understand

thanks anyway
 
Trop Cher said:
Thanks to all three for replying, I'll go and pull out my April 2010 mag and have a look.

Found it! Thanks again
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The object is to get the new belt on with the crankshaft, cam shaft and injection pump all in the original ( and correct) positions relative to each other positions .

Basically achieved by locking them all before starting.
When the three shafts cannot be locked there may be marks to line them up or put dabs of white paint on as marks before taking off the old belt. On my Volvo car there are marks and there are also marks on the belt but as far as I remember nothing actually locks.

The process is aided on this engine by making the the camshaft sprocket movable on the shaft so it can be moved slightly without turning the shaft

On my Pugeot car the sprocket on the injection pump also has the same arrangement enabling the sprocket to turn a little without the pump turning.
 
hairbox said:
Steve
Now carefully check the pulley with the letters on it hasn't moved when you tensioned the belt,

What to do if the pulley with letters has moved whilst tensioning the belt ?

regards
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I'm not the "Steve" who wrote that article but I have tried his method and it works perfectly well. The pulley with the lettering is lined up with a timing mark and it can be easily noticed if there has been any movement (which will have to be by a whole tooth of course) and just as easily rectified.
 
Cam Belts

Timing belts are the invention of the devil, a proper diesel has gears or a chain, anyway that aside (I could go on all night about this - its bad engineering), the modern timing belt seldom breaks, the main culprit that causes failure is oil - leaking from a faulty seal, it makes short work of the belt and either the notches fall off or the belt slips or both, thats why oil leaks are double bad news in these engines. Either way a failure will cost - bent valves, broken pistons, bent pushrods, and on overhead cam engines a broken cylinder head is not uncommon, few engines survive a huge rebuild cost - BUT NOT ALL, just hope it fails at idle speed and things can be - not so bad.

The annual checks should include looking for wear on the belt and oil contamination - any oil and fix it now. Tensioners on these engines are a weakness and must be changed when the belt is changed.

My volvo car (petrol) has a 100,000 mile interval or 8 years for cam belt life with inspections every year - if that helps.

Edit: bar the engine to TDC on no 1 cylinder (turning it the correct way) then lock the gears in position with drills or bolts, its all explained in the montego manual where the holes are, resist the temptation to turn anything when the belt is off. While the belt is off its a good idea to check the oil pressure relief valve for wear and sticking - its more accessable with the covers off (I would fit a new one regardless).
 
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skipper_stu said:
The MD22 VP engine is what i presume you are talking about. I read in theoriginal VP manual that the belt should be inspected yearly and changed if necessary. This particular engine is the perkins engine which was fitted in maestros and montegos and leyland daf vans. they were are bulletproof. The landrover boys fitted them as an upgrade, more power and improved fuel economy over the lr diesel. I read on one of their forums that the belt, with it being 35 mm wide was almost unbreakable. i changed mine a few years ago, did an article in PBO on how to change it. its pretty easy to do if you hve a modicum of spanner sense.
stu
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I go with this. The belt is easy to examine through the inspection plate. Any deterioration is the signal to replace it. Sudden failure in a sound-looking belt is unlikely. That said, 1500 hrs is probabaly as far as one would want to go before changing anyway or 7 years. On this engine it's one hour's (careful) work with the camshaft locked down of course.

I run a Volvo estate - change routine is 7 years max. I would need to hear the reasons why the VP engine requires a change in less than half that time.

What happens if you take over-stretch your luck? The top gear on the engine runs amok and your dealer sees 4 figures of repair and replacement. Lovely jubbly!

PWG
 
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