200tdi timing issue

Hi all
rebuilding my engine after stripping out cam etc and have just fitted new timing belt and tensioner but I am not 100% happy. Pegged off fuel pump and left it bolted to back plate, cam centre pop marker is dead on the cast lug, crank is lined up with arrow on timing housing but groove in flywheel to accept timing tool moves about 5mm anti clock looking on flywheel when tensioner is set. I have tried moving belt one tooth but then flywheel tdc groove is about 35mm clockwise past centre of drain hole - ive put it back to 5mm anti clock but im not gonna sleep well! Anyone else had similar probs or am i missing something basic?

thanks
steve

Are you SURE that you are taking up ALL the slack on the timing belt TENSION SIDE as you fit the belt and align the timing marks?

I think the ONLY way what you describe can happen is when there is SLACK in the timing belt between the pump wheel - the camwheel - and the crankshaft pulley, that's to say the sections of the belt TOP and RIGHT looking from the front.





CharlesY

Dunno if this helps, but this is a correctly fitted / timed cam-belt.
Try counting the number of belt teeth between each cog and compare it to yours. You should be able to see if you've got slack in the wrong place if you've got one too many teeth.

Thanks for the pic - thats exactly how ive got it - definitely tensioned up with no slack BUT - its the timing mark at the other end on the flywheel which you can screw a locking tool into through the bell housing drain hole to keep the crank at TDC - its either 5mm one way or about 30mm the other - ive set it on the closest - looks perfect from the front.
Just noticed too that on your pic theres no idller wheel between the cam and crank - is that a 300?

thanks
steve

That pic is of a 1992 Defender 200TDi. I thought they were all like that.

Anyway, the flywheel timing mark is on the outside of a big disc on the other end of the crankshaft. The cumulative effect of all of the play / backlash in the sysyem, multiplied by the angular effect of the distance to the outside of the flywheel means that I'm not surprised that it looks a bit out.
Have you tried moving the flywheel a little whilst the pump is locked off? Can you move it the 5mm so that it lines up?
To be honest, I don't even look at the flywheel when doing cam belts - I just align the timing marks on the crank, cam and pump. Never had a problem.

this is good,thanks for pics trew

Thanks Treworgy - ive realised that mine is a Disco engine so thats prob the reason why its got the idler wheel and the defender hasnt! If i line up the crank at tdc with the cam on the mark and the fuel pump locked, i can fit the belt ok, but when i tension the belt, you can see the crank pulley move very slightly - think ill be happy know with what youve said - cant get it any better anyway!
thanks all
steve

Thinking about it, you say it's 5mm out at the circumference of the flywheel. What's the radius of the flywheel - at least 150mm? - I've never measured one.
Therefore the angular "error" is Tan-1 5/150 = about 2 degrees (probably less).

I don't think that's anything to worry about.

IF ..... and it can be a very big IF ....

1. the crankshaft is at TDC set by the pin
and
2. the camwheel timing marks are lined up
and
3. the injection pump is pinned
and
4. there is NO slack on the right and upper two sections of the belt

then ....

the basic timing should be OK, and the engine should run.

After that you MAY wish to do a bit of fine tuning of the injection timing, which sometimes has an amazing effect. There are threads about doing this.

CharlesY

i take it you have slackened the 3 bolts on the pump pulley?

Why would you want to do that?

because you cannot tension the belt without slackening the 3 bolts on the pump pulley. Thats what takes up the slack in the belt whel you tension it, keeping the cam and crank on the timing marks.

Well I've never done that.
Wouldn't the locking pin stop the pump pulley moving anyway?
And it still won't tension the length of belt between the cam and crank pulleys.

Tig9619 said:

because you cannot tension the belt without slackening the 3 bolts on the pump pulley. That's what takes up the slack in the belt when you tension it, keeping the cam and crank on the timing marks.

Click to expand...

I think this means that

a. the crankshaft is pinned,
and
b. the camshaft is set to the mark
and
3. THE PUMP ITSELF IS PINNED as per diagram with drill bit,

THEN you can unlock the three set-screws, THEN you can rotate the pumpwheel WITHOUT TURNING THE PUMP, to take up the slack, (but in many cases there may not be any).

Then you can re-tighten the three pumpwheel setcrews,

then you can check it all, and then torque the tensioner.

After that you un-pin everything and by hand rotate the engine a few revs and check the timing and the belt tensioner torque again .. and again ...

CharlesY

no the locking pin locks the backplate bolted to the shaft of the pump. the correct way is to slacken the 3 locking bolts and the pulley will rotate abot 10mm. it has elongated holes in it to allow this.
No it wont take up the slack between cam and crank, something else is wrong there but thought i would mention it just in case he doesnt know.