Top Dead Centre

Morning all,
Thank you for the add.
I am replacing the head gasket on my Citreon C3 1.4 petrol and wanted to confirm that the position of the pistons are TDC.

I have put the head back on put cannot rotate the engine more than 45 degrees before there is contact valves and pistons.
All the marks on made on crank are aligned and the cam is locked in position.
I did cam seal and valve seal as well.
Could the cam be 180 degrees out?

Hi

Do not set TDC when changing a cam belt or removing the head.


There are locking points for the cam and crank that use a bolt or bar to lock (prevent rotation) of the cannot crank while they are disconnected from each other by the belt.

This is the SAFE position. It match the locking pins location.



Obviously the pistons are not TDC here, so hopefully you have locked them both properly and kept them locked.


Don't use only marker paint to aid realignment because it doesn't prevent movement of the crank. All you need is to lock it off.




With the cam and crank both locked in their safe position the timing belt can be removed, head removed and it will all go back together just as it came off. Perfectly timed.


Did you remove the cam locking when the head was off?
Were you tempted to rotate the cam shaft while it was off?

The pistons are not in TDC position (that's good) so don't set your cam in TDC.

Cossiejoe wrote: ↑Mon Dec 07, 2020 7:46 am Could the cam be 180 degrees out?

Could be, but I'm not going to guess.
I would start again and 'pin' the crank shaft. Then pin the cam shaft after installing the head gasket but before installing the head.
Look at my post on installing the timing belt.
tips-for-a-petrol-powered-c3-f7/how-to- ... t3868.html
There are instructions for making your own locking pins and how to lock the crank and cam shafts.
Any markings on the crank shaft sprockets are irrelevant. They do not indicate TDC of any cylinder, as your photos show.
On some of the PSA engines the crank shaft is pinned and locked with all pistons half way up the cylinders and not with number 1 cylinder at TDC!!!! This means you can put the cylinder head on with the cam shaft in any position and not fowl the top of the pistons.
I do not know if this is the case with the TU3JP engine!!
You could do us a favor and pin the crank shaft and take a photo of where the pistons are.
Typically with PSA engines the number 1 cylinder is closest to the flywheel and not the crankshaft pulley!!!!