Finding crank TDC without flywheel locking hole

[RustyUK]

I wonder if anyone can shed any light on this.

Putting a new timing belt on a C5 2.2HDi, following some work to the engine (which is out of the car and stood on wood at the moment). The official (and Haynes) method of ensuring crank TDC is via the locking hole into the flywheel at the back of the engine. Nice and easy.

However, the after-market flywheels (certainly the LUK branded ones that were fitted when I removed the engine, and the new replacement) don't have a locking hole in them.

It appears TDC is achieved when the woodruff key is at the very top of rotation, when viewing the engine resting level on the sump. I'm not sure that's precise enough though, I could easily be a few degrees out either side. There are no alignment marks on the sprocket, engine or covers.

Is there any other method to ensure this is spot-on? Or better, does anyone in Yorkshire have an old knackered flywheel that does have the locking hole?

Any hints on getting the correct tensions without a SEEM unit measuring device would be appreciated too!

[Peter.N.]

When I changed the belt on my 2.0. Hdi C5 I fitted the locking bolts in the cam pulley and then put a couple of dabs of paint on the crank pulley and backplate. Providing you have a good view of them and plenty of light you can get it spot on, make sure the marks are still lined up before you remove the timing bolts.

Peter

[citronut]

the back face of the woodruff key lines up to the forward face of the raised block in the casting just above the sprocket,

trouble with tippexing points, if the timing was not quite correct before it will remain like that

[RustyUK]

Thanks for the replies. I didn't mark out where the sprocket was before I disassembled, but then the old flywheel didn't have a timing hole either so I couldn't be sure it was spot-on to begin with.

Citronut, I never took note of a raised block in the casting until you pointed it out!

Below is a reference pic I took of the old belt with camshaft locked at TDC. Assuming it was correct to begin with, is the red line what you're describing?

(And yes, looks like I had a coolant leak for some while - pump replaced along with head gasket, cleaned and re-lapped valves, cleaned out a horrendous amount of muck from the airways etc, turned into quite a project this - still a few worry-points from my lack of experience so hoping it works again!)

[mendedit]

[-o<

[RustyUK]

Not this one, there's a hole on the back of the block which is supposed to allow you to lock the flywheel behind it, which is no good when your after-market flywheel doesn't have a locking hole.

[RustyUK]

None that I can see. I've been handed some Citroen service documentation and even that only makes reference to the flywheel timing hole, no other marks or tricks. Haynes just repeats this information. A little mark and an arrow would be fantastic, but doesn't look like it exists (although I am intrigued by this idea of using the mysterious square lump above as a reference point, it doesn't look documented but doesn't seem to serve any other obvious purpose!)

[Gibbo2286]

Take out an injector on number one or number four cylinder, pop a log thin screwdriver in the hole and wind the engine over until the piston lifts it to its highest point.

[citronut]

i have never seen documentation that mentions the raised square,
but this is in line when the flywheel timing pin/peg is in place on a car you can find your hole on ,

i usually lune this block up then check/lock off cam, and fuel pump when required ( not on HDI's ),

then mostly have to rock the crank forward and back very slightly to locate the flywheel locking poin/pin,

for the flywheel i use a long length of 3 1/6th kunifer copper brake pipe bent to an appropriate shape to over the starter motor and into the hole in the crank case, going up from underneath

[citronut]

ps.

i hope you are fitting a new water pump and tensioners whilst your in there,
as it looks like that pump has definitely been leaking

[wheeler]

On the versions with a DMF there is no locking 'hole' as such on the back of the flywheel like the older ones, its more of a little lug which is why its especily important never to use the locking pin to loosen the crank pulley bolt on these engines. When the pin locates it doesent drop in as much as the models without DMF.

[RustyUK]

Well, aren't I stupid.

There IS a locking hole. As you point out wheeler, it's a lug. One of two 180deg apart, and the one with the bigger hole (bigger than the 6mm or so hole in the block). Not entirely sure why I thought that wasn't it. I could see it on the old flywheel before removal, and it didn't line up, appeared to be quite clear of the hole in the block. Of course, I neglected to consider a 'large' distance of travel on the outer edge of the flywheel looks like a comparatively minuscule difference towards the centre, and that the timing may not have been exact to begin with. The woodruff key still 'appears' to be pointing directly upwards even if the locking hole is turned well clear either side of the locking hole in the block, but is still obviously some degrees different.

I'm as confident as I can ever be now that the timing is spot-on, and that it was a few degrees out before.

And yes citronut, new waterpump fitted, injectors tested (one new nozzle fitted), pressure regulator in fuel pump identified as faulty and replaced, and a bunch of other stuff cleaned / replaced. Should find out in a few days if it'll ever work again! A few reasons it may not, but we'll soon see.

[citronut]

its got two chances
it will or it wont