Practically Classics Forum

Right, picked up a cheap 2002 1.0 12valve 3 cylinder Vauxhall Corsa that has had a snapped timing chain.

I have new chain, guides, tensioner, sprockets etc along with a fresh cylinder head, cams and required bits and bobs.

My problem then, being a modern is that I know squat about injection and ignition. So, I can get TDC on cylinder 1, and set the cams and valve timing to this no bother so that it is on the compression stroke.......

But how do I figure the correct TDC in relation to being in the correct position for the fuel injection and ignition timing ? i.e could I set the valve to piston timing correctly, but then have the wrong timing in relation to spark and fuel delivery ?, and how would I set this up.

Thoughts please or am I thinking too hard about it..... would like some thoughts / guidance before tackling it.

Fuel injection doesn't need timing (in the sense that it squirts once with the valves open and once with them closed, so it doesn't care where the cam is).

It will have a crank position sensor (crank sensor) so it always knows where the crank is.

Spark - does this have a dizzy? If so, this does the timing for you. (i.e. the ECU will tell the engine to spark twice every rotation on a 4-cyl, the dizzy will send it to the right plug).

If no dizzy (in other words distributor-less ignition), it will have a cam sensor, this will tell the ECU where the cam is.

In other words, yes you are thinking about it too much, lol, chuck it together and it will work!

Cheers

Cheers Luxo, its on a cam sensor rather than a dizzy, I had bad thoughts of everything popping and banging at the wrong times but that sounds good to me

Still stuck in the dark ages me, and everything else just looks like voodoo Being a silly 3 cylinder won't make it any different will it?

No mate, if it's on a cam sensor then so long as your camshaft is properly timed with the crankshaft via the new timing chain you just slap it all together and the ECU works out the fuel and sparks etc. - people say moderns are far too complicated but in some ways they're a lot simpler IMHO!!

Good for you, sounds like once you throw that lot together you'll have a cracking little motor, I trust you got it for the right number of £?? These are known for throwing their timing chains but so long as you keep an eye on them they should last OK, quite a decent little motor apart from that I believe. Nice one!

Cheers

Cheers Luxo, should be good to go then.

Picked up for not much more than scrap value, and pretty much immaculate, would have been even better if the spare head that came with it had been the right one rather than a later twinport that didn't match the existing manifold etc, but I'll flog that on to pay for the other head I picked up.

Huge bills in glovebox for bottom end rebuild about a year ago, shame for them they didn't stretch to a new chain etc at the same time. I'm hoping the missus might get the nod to drive again soon (still got her licencse but been advised not to by docs a while back) so it will be a handy addition, and even if she doesn't use it I can keep some miles off the Jeep.

Thanks again, I should be good to go now

Luxobarge wrote: If no dizzy (in other words distributor-less ignition), it will have a cam sensor, this will tell the ECU where the cam is.

DIS systems don't have to have a cam sensor to trigger the ignition. Rover T-series and K-series, for example, use the crank sensor because if the camshafts are properly timed (belt fitted correctly), then their position relative to the crank doesn't change.

Richard Moss wrote:DIS systems don't have to have a cam sensor to trigger the ignition. Rover T-series and K-series, for example, use the crank sensor because if the camshafts are properly timed (belt fitted correctly), then their position relative to the crank doesn't change.

True, but I believe I'm right in saying that this will only work if the ignition system is a) a 4 or 8 cylinder configuration and b) uses a "wasted spark" sytem. Otherwise the ECU has no way of knowing if a given cylinder is on the exhaust stroke (no spark needed) or on the compression stroke (spark needed). I also don't think this would work on a 3-cylinder engine, which was why I said it'd need a cam sensor.

Unless the flywheel (crank sensor) generates pulses for something other than TDC? Dunno but never heard of that.

Cheers!

You need to set the static timing otherwise it wont run, and you'll run the risk of valves meeting pistons if it's not correct

http://www.justanswer.com/uk-car/5xdpp- ... inder.html

should tell you all you need to know, and there are usually alternatives to special tools like flat piece of bar and drill bits.

Just to say thanks chaps,

Little car is finally up, running, drives and sounds healthy. Fingers crossed it stays that way

arceye wrote:Just to say thanks chaps,

Little car is finally up, running, drives and sounds healthy. Fingers crossed it stays that way

Yay! Nice one - well done. Not too hard are they?

Cheers!