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Timing Belt Troubles


tpk241
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Hi All,

300TDI defender engine in a disco - later model before EDC - AFAIK

After successfully replacing tensioner, idler and crank with the timking belt kit i proceeded to fit the new belt .. Following numerous guides and manuals to set up the timing i got it on and felt it was aligned properly ..

First off it fired but was Lumpy as hell and smoking like a chimney .. so i assumed the fuel injection timing was out a tooth. Took the belt off and redid the whole proceedure to get the same results !

I am now soooo frustrated after trying to get the timing right over 9 times I need some help from the experienced among us !

To summarise :-

I loosened the 3 pump sprocket bolts

Align cam

locked pump

locked flywheel

all this seems to line up ok .. if anything the pump pin is tight once the belt is on but i thought this was just the pumps tendency to want to turn ... Also i locked for the pump locking pin (the one with the keeper plate which is behind the timing belt housing) and I dont seem to have one, could this be a problem ? maybe the injection timing needs resetting but i need the locking pin and keeper plate for this no ?

Also to add to the confusion when i did have started (timing was wrong though) it didnt want to shut off and i had to stall it to do so .. does this suggest a dodgy stop solenoid and can this contribute to the lumpy-ness or reluctance to start up ?

A lot of questions there i know .. someone please dive in a help !

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Hi All,

300TDI defender engine in a disco - later model before EDC - AFAIK

After successfully replacing tensioner, idler and crank with the timking belt kit i proceeded to fit the new belt .. Following numerous guides and manuals to set up the timing i got it on and felt it was aligned properly ..

First off it fired but was Lumpy as hell and smoking like a chimney .. so i assumed the fuel injection timing was out a tooth. Took the belt off and redid the whole proceedure to get the same results !

I am now soooo frustrated after trying to get the timing right over 9 times I need some help from the experienced among us !

To summarise :-

I loosened the 3 pump sprocket bolts

Align cam

locked pump

locked flywheel

all this seems to line up ok .. if anything the pump pin is tight once the belt is on but i thought this was just the pumps tendency to want to turn ... Also i locked for the pump locking pin (the one with the keeper plate which is behind the timing belt housing) and I dont seem to have one, could this be a problem ? maybe the injection timing needs resetting but i need the locking pin and keeper plate for this no ?

Also to add to the confusion when i did have started (timing was wrong though) it didnt want to shut off and i had to stall it to do so .. does this suggest a dodgy stop solenoid and can this contribute to the lumpy-ness or reluctance to start up ?

A lot of questions there i know .. someone please dive in a help !

Hi TPK241,

1. Is the crank key at 12o'clock when the crank is locked this iis where it should be

2. cam wheel is a dot on outer face lines up with arrow on timing chest

3. pump lock pin is 5/16 drill bitIIRC loosen 3 bolts

4.fit belt from crank to cam to pump to end up with all the slack over tensioner/idler

5. tension/tighten up incl 3 pump bolts. remove pin(s) turn over twice on crank recheck

That should be it . You may well find something in the tech archive by Les or white90 too

HTH

Steveb

ps not stopping could well be stop soleniod

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sounds as if u're timing it right, IIRC the timing pin is 3/8 diameter.

was it running right before you started all this? or did the cambelt snap etc?

are you sure your injection pump isn't on the way out? check the breather on the back of the pump hasn't got swarf in it, this is a sign of the pump wearing out

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sounds as if u're timing it right, IIRC the timing pin is 3/8 diameter.

was it running right before you started all this? or did the cambelt snap etc?

are you sure your injection pump isn't on the way out? check the breather on the back of the pump hasn't got swarf in it, this is a sign of the pump wearing out

The belt didn't snap but it did slip ..... The Tensioner wheel bearing broke up thankfully whilst the engine was only idling.

I have checked the Push-rods and rockers which were all ok .. These are the first thing to take the damage if i am correct ?

It was running fine before the bearing broke up ... can the pump be damaged by this ?

Thanks

TPK

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are you absolutely sure all the push rods are 100% straight, there are no missing valve caps etc etc? maybe worth double checking, I don't think I have ever seen one with no bent pushrods, sometimes it can be very subtle and only shows by rolling it along a flat surface.

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a snapping belt wont damage the pump at all.

i'd lay money on that some of the pushrods are bent though.

you say you have inspected rockers and pushrods, did you take the pushrods out to inspect them?

have you reset/or had to reset the valve clearances after the slippage? take rocker cover off and just wind the engine over by a socket on the crank and see if all the valves are opening the same, or feel the rock in the rockers.

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When I do the 300TDi timing belt I align the crank and cam sprockets, but because it's such a tight fit in general, I put the inj pump 1-tooth out, and then when the belt is tensioned - it pulls the sprocket back into the correct position.

Les.

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Thanks all ...

I have done that much research on belt changing and timing that I was confident I had done it right ... So it does suggest that something else may be the culprit !

Next port of call is to accurately recheck the puch rods and reset valve clearances ...

Thanks a million

TPK

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We always adjust the timing on ours to 10deg btdc using the timing marks on the damper and on the casing. Unfortunately to do this you need a fancy thing which senses the pulse of no 1 injector. Ours is made by Snap-on and was not cheap. Old engines are often a bit retarded, about 4deg. What you can do is take off the plate or aircon bracket, undo the 3 10mm bolts and oink the big nut a bit clockwise, this will advance the 'ignition'. If it gets worse, turn it the other way. There isn't much adjustment, maybe none depending on which tooth the belt is on. We try to fit the belt with the slot in the pulley in the 'middle' to allow adjustment in both directions.

The difference between 4 and 10 deg advance is tremendous.

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Cool,

Thanks for that Jim .... I will give that a go i reckon...

Couple of people have advised a compression test to see if this is down. I am still convinced its just the timing ..

Are the Valves likely to be damaged from a slipped belt / tensioner collapse ?

Thanks

TPK

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Once you have set the timing and started it see if everything still lines up, if it does the you either have bent pushrods, damaged the rockers or bent some valves.

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You need to remove the rods to check to see if they are bent. Roll each one across a flat surface and look to see if the centre is bent. If you had bent a valve (and I've never known this to happen), you would have worse symptoms than you describe.

Les.

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Thanks for all your help on this (everyone)

Got a local mech to come and have a look .. turns out i had it right all along ... No1 cylinder wasn't firing cos of excess diesel .. maybe cos my pumps turned up ? run it through for a while and smoked the whole town out .. all running fine now it cleared through .. starts first turn of the key again ..

Gonna recheck push rods and valve clearances at the weekend for peace of mind ..

Thanks

TPK

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