Help me understand timing please. :)

[ollieboy]

I was replacing the cambelt on my car, its been drawn out because it's been crap weather and I have been studying but I finally got into it the other day. The timing marks were lined up and I was about to remove the cambelt when it began to rain again. I lowered the car and then the next night somebody tried to steal the car, I left the keys in it but was on the back yard where I thought it would be safe. So now the timing is off again and because the tensioner wasn't there(the reason cambelt failed) the timing is completely out of whack.

I want to understand how I set it back to how it should be. Is it just a simple matter of lining up the marks and its all good to go? Or are the pistons set at a certain point in the cycle and if I just line up the marks theres a chance the timing will be off? Maybe 180 degrees off?

Sorry for all the questions its just the first time working on a twin cam engine and first time doing everything on my own.

Thanks in advance

[Zak]

Depends what engine it is, if it's a 4age you can just line them up and off you go. Some others though are a little trickier.

Just make sure you have the right mark on the crank pully, or just double check your on top dead center.

[Mr Revhead]

first up....

you live in the middle of no where.. how come so many ppl try and steal your cars!?

you need to set the crank so no 1 piston is at TDC and then set the cams to the correct place. they should still be there as they wont have turned when the engine was cranked...
so check the cams, if they are ok, then all you need to do is set the crank back to where it needs to be. by the timing marks on the pulley. you want it at 0

if the cams are moved...
theres a mark in the inlet cam you can see through the oil cap, line that up with the edge of the ledge under the cap, line the exhaust up by the marks on the pulley

before you start make sure you nderstand the above
before you start it yup, double check!

[ollieboy]

Oh sorry yeah 4age. So it doesn't matter if I twist the crank say around once more, it should still work if its lined up with the marks again. I'm working off the marks in the Haynes manual so I think I'm right on that part, it just doesn't explain about how crank and cams work.

Cheers thats what I needed to know.

Thanks man.

[Mr Revhead]

yeah its a non interference engine so oyu can keep turning it till its lined up.

[ollieboy]

I'm not too sure why people try and steal my cars, it happens every so often, a few months someone broke into my skyline out the front of the house and ripped out all the panels round the ignition, they never would have started it anyway because its diesel and I control the glow plugs with a hidden switch- also there hasn't been a motor in it for six months. Our town has a wee bit of a youth crime problem at the moment, A lot of interesting stories lately- I could fill a small book.

That helps me understand it a bit better Mr Revhead, cheers for that. I was a wee bit unsure if getting the crank wrong would mean something else related (maybe distributor) would also be wrong and the timing off.

Thanks heaps, it's really appreciated.

[Mr Revhead]

yeah on the 4age the dizzy is driven off the exhaust cam
so will be in the right place when the pulley is in the right place.

iirc (double check this) the 16v has marks on the pulley that line up with marks on the backing plate, ie the pulley marks are at the top.

edit: just checked the manual, i remembered right!

[ollieboy]

Oh cool, that makes it clear now. Yeah the marks are on the backing plate, I think they are still all lined up when I checked this afternoon so thats good.

[pc]

yup, the 16v is really easy, just put the marks where you think they should be and it will be correct.

match the marks on the backing plate for the cams, the marks on the crank gear & oil pump, and the marks on the dizzy gear and housing.
If you already have the crank pulley on, then match it to the timing mark 0.