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[Darth Loo-knee]

When you turn the crank to the marks TDC is that the firing stroke of say piston 1?

[TheBoy]

When you turn the crank to the marks TDC is that the firing stroke of say piston 1?

if the marks are on the crank, then not necessarily - could be 180 degrees out....

[Kevin Wood]

It could be either since the firing and intake / exhaust happen on alternate turns of the crank. I think I'm right in saying that with the cam markings also lined up it's the firing stroke for cylinder 1. Remember the other cylinders will all be at different positions in their stroke. The crank marking is only TDC for cylinder 1 (and 4).

Kevin

[Darth Loo-knee]

The reason i asked is I thought on four stroke engines there is the firing stroke, then it goes down, exhaust stroke, then goes down and then starts all over again......
So I wondered if when the TDC lines up with the mark how you would actually know if it was the firing stroke or exhaust stroke?

I was asking with the rangey in mind as I am working on it this week but must be the same with other four stroke engines....

[Marks DTM Calib]

Crank mark aligned means that number 1 piston is at TDC...........whether its on the top of the compression stroke or the exhaust stroke depends on the cam position.

[Darth Loo-knee]

So can you tell from where the rotor arm is pointing then?

I have taken the old leads out, I have a manual so it tells you where the leads go on the dizzy, so I was just going to have a look if the rotor arm is actually pointing at the correct plug at TDC..

[Golfbuddy]

The reason i asked is I thought on four stroke engines there is the firing stroke, then it goes down, exhaust stroke, then goes down and then starts all over again......
So I wondered if when the TDC lines up with the mark how you would actually know if it was the firing stroke or exhaust stroke?

I was asking with the rangey in mind as I am working on it this week but must be the same with other four stroke engines....

Couldn't you determine this by looking at the opening of the valves? Presumably by looking at the opening and closing of the inlet and exhaust valves as the crank moves past TDC you would be able to work out which stroke it was on???  :-/

[Darth Loo-knee]

The reason i asked is I thought on four stroke engines there is the firing stroke, then it goes down, exhaust stroke, then goes down and then starts all over again......
So I wondered if when the TDC lines up with the mark how you would actually know if it was the firing stroke or exhaust stroke?

I was asking with the rangey in mind as I am working on it this week but must be the same with other four stroke engines....

Couldn't you determine this by looking at the opening of the valves? Presumably by looking at the opening and closing of the inlet and exhaust valves as the crank moves past TDC you would be able to work out which stroke it was on???  :-/

I suppose I could have done this morning, but it is all virtually back together now

[smoothomega]

Yep, if the rotor arm is pointing at number one you know the engine is at TDC compression stroke and all valves on number one pot are closed  

[Golfbuddy]

The reason i asked is I thought on four stroke engines there is the firing stroke, then it goes down, exhaust stroke, then goes down and then starts all over again......
So I wondered if when the TDC lines up with the mark how you would actually know if it was the firing stroke or exhaust stroke?

I was asking with the rangey in mind as I am working on it this week but must be the same with other four stroke engines....

Couldn't you determine this by looking at the opening of the valves? Presumably by looking at the opening and closing of the inlet and exhaust valves as the crank moves past TDC you would be able to work out which stroke it was on???  :-/

I suppose I could have done this morning, but it is all virtually back together now

Can't you see the tappets with the rocker cover off the top??? You could see which valves were open or closed from the position of the tappets?

[Marks DTM Calib]

Or if you trying to work out when No1 is on the top of its compression stroke then look fror when both tappets rock on number 6 (1-8-4-3-6-5-7-2 firing order) cylinder as number 1 will be TDC compression

[Darth Loo-knee]

Think I will leave well alone and just stick the new dizzy on;D

But the distributor can be moved around, i made marks so i could line it back up again, but surely if I had got it not exactly in the correct place the rotor arm wouldn't be in the right place for firing?

[Golfbuddy]

Think I will leave well alone and just stick the new dizzy on;D

Stick to the baking mate. You'll feel better in the kitchen.  

[Marks DTM Calib]

Think I will leave well alone and just stick the new dizzy on;D

New dizzy or dizzy cap?

Best place for leads by the way is the bosch ones from Halfords!

[Darth Loo-knee]

Think I will leave well alone and just stick the new dizzy on;D

New dizzy or dizzy cap?

Best place for leads by the way is the bosch ones from Halfords!

cap sorry :-?

Oh and now you tell me about the leads