11 replies to this topic

[BVY]

Hi,

 

Hopefully one of you can hit me with some instant and concise knowledge!!

 

I'm changing my timing chain and sprockets. Which i am not trying to fit. The Haynes manual says the crank and cam woodruff keys shouls be at 12o'c and 2o'c respectively. My crank is at 12 but the cam has the woodruff key at about 7o'cish

 

I have TDC and confirmed it by seeing 7 - 8 rockers rocking  

I'm pretty sure nothing moved while undoing the cam sprocket. Certainly not 180 degrees!

 

Have I done something wrong? If so what?

I put the new chain on the new sprockets with dots facing. Then I rotated the chain and the cam key groove is pointing to 8o'c, pretty much the same as the cam woodruff key...

 

So have i simply got TDC on the wrong stroke? If so do I just have to rotate the chain as above to get it back on the right way??

 

Please help quickly as I don't want to still be in the car park at midnight trying to sort things out!!!    

 

Nearly forgot to add, 1986 city 998

Edited by BVY, 24 May 2013 - 03:30 PM.

[Ethel]

Probably, just turn it by hand until the dots align. Pretty sure that's tdc with cylinder 4 firing, but it makes no difference to the crank tdc is tdc for 1 & 4 

[mrbridger]

this is what you need to see at TDC...

I used a piece of steel ruler to ensure I had things straight and lined up across the sprockets.

 

 

[minidaves]

crank turns twice to the cam 1 rotation

[BVY]

I justr took a pic of mine but I can't upload it because it's too big!

 

But it works out on mine that the crank is 1 revolution out and the dots are aligned but the cam dot is on the opposite side.

 

So given that I can't have accidentally spun the cam 180 should I just put it back together as it is?

 

Gonna try to put a pic on again now...

[lrostoke]

I made this mistake confused the heck out of me.

 

No 1 cylinder nearest the rad isn't the one at TDC when you fit a timing chain and sprocket.

It's No 4 furthest from the Rad.

 

As long as the 2 dots are next to each other and inline with the center of the camshaft and crankshaft everything is fine.

 

Your picture looks right above.

[BVY]

Ok so that makes sense. I've got No 1 piston at TDC on firing stroke instead of No 4.

Yeah the dots seem to be properly aligned just the cam sprocket dot is 180 round which I have corrected by rotating the chain and sprockets as one. 

 

Basically I'm gonna put it all together how I've got it, tighten it up and turn the engine 1 rev and see how the dots look....

 

The pic above is the minidaves pic to show me what I should have.

 

Cheers guys!

[BVY]

Ok I put the chain on and torqued it all up, turned the engine 1 rev and the dots line up. so all good.

 

I also re-read the Haynes description thinking I must've read it wrong, but it does say to have No1 piston at TDC and not No4... Slightly confusing 

[BVY]

So hopefully my valves will survive the first start up when i'm done   

[Jordie]

Piston 1 (rad end) at TDC (both tappets rocking)

 

Crank key should be 12 o clock

 

cam shaft key approx 2 o clock

 

dots will line up.

[GraemeC]

Most likely that you've misunderstood what is meant by tappers rocking - it is common mistake. It means rocking as in changing direction on the valve (either closing or opening) and NOT rocking as in loose.
So No.1 cylinder is at TDC of the exhaust stroke, inlet opening, exhaust closing.

[BVY]

Yeah I just had it the wrong way around. It's been one of those day.

 

Not to mention I had a nightmare re-fitting everything. Every nut and bot was a battle!

After all that, just when I finished everything and had a nice quietly purring engine, I realised I forgot to bend the lock tab back on the cam sprocket    @@%&**      

 

Total knob!!!