Omega Owners Forum
Chat Area => General Discussion Area => Topic started by: Darth Loo-knee on 30 January 2008, 21:15:24
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When you turn the crank to the marks TDC is that the firing stroke of say piston 1?
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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....
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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
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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....
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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.
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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..
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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??? :-/
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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 ;D
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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 :y
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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 ;D
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?
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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
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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?
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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. ;D ;D ;D
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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!
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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 ::)
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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. ;D ;D ;D
Your only jealous cause you daren't have a go ;D
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The dizzys are known to cause problems to so when you fit the new cap, check for play in the main drive when the rotor arm is removed.
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The dizzys are known to cause problems to so when you fit the new cap, check for play in the main drive when the rotor arm is removed.
You make these Rangies sound a bag of s*** ;D
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Just to clear something up then, if the distributor body was not in the correct place ( I hadn't marked it, which I have :)) then would the rotor arm still be firing on the right plugs? or does the rotor arm move with the body?
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Body mves but rotor stays where it is, this is how the ignition timing is set
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Body mves but rotor stays where it is, this is how the ignition timing is set
So how do i know then that it was in the correct place before I marked it? if it was slightly advanced or retarded? do i need a timing light for that?
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Body mves but rotor stays where it is, this is how the ignition timing is set
So how do i know then that it was in the correct place before I marked it? if it was slightly advanced or retarded? do i need a timing light for that?
If the timing is done by moving dizzy, then yes. Not sure of the setup on that motor. Some have dizzys, but all timing done electronically
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Body mves but rotor stays where it is, this is how the ignition timing is set
So how do i know then that it was in the correct place before I marked it? if it was slightly advanced or retarded? do i need a timing light for that?
If the timing is done by moving dizzy, then yes. Not sure of the setup on that motor. Some have dizzys, but all timing done electronically
I see what you mean, but the distributor body is held in position by a clamp, which would allow you to move it 180 degrees and then tighten it up again if you see what i mean..
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If you're only replacing the cap surely the body of the distributor (the position of which sets the timing) dosn't have to be disturbed? If it's loose and can be turned by hand it needs to be set correctly and secured in that position.
The cap is usually keyed so it will only go on in one position, and then you just have to make sure you got all the leads on in the same positions as they were on the old cap.
Kevin
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If you're only replacing the cap surely the body of the distributor (the position of which sets the timing) dosn't have to be disturbed? If it's loose and can be turned by hand it needs to be set correctly and secured in that position.
The cap is usually keyed so it will only go on in one position, and then you just have to make sure you got all the leads on in the same positions as they were on the old cap.
I have just done the head gaskets, the alternator and power steering pump have to be unbolted of the n/s head. To get at one of the bolts i had to turn the dizzy body as the ignition module was in the way, so i marked it before moving it. It just crossed my mind, was it right beforehand.
Kevin
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I thought with the title, this was going to be a thread about Funeral Homes ;D
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Ahh, ok. Didn't realise you were doing major surgery. In that case, you also need to make sure that the distributor shaft meshes properly with the drive gear when reassembling, so that it is in the correct location relative to the engine, otherwise the marking you made will not correspond to the correct timing.
Does this engine have points in the distributor or an electronic setup?
.. and if it's been apart it might be worth finding something that will engage with the oil pump drive on the lower end of the distributor shaft and give it a whizz on an electric drill until you get oil pressure before refitting the dizzy just in case the pump priming issue that Mark mentioned rears its' ugly head.
Kevin
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Just re-read your post and ifyou haven't removed the dizzy, just turn it back to where it was and ignore my last post entirely ::) since the mesh of the drive gear won't have been disturbed.
Kevin
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I have had a brainless manager telling me what to do so I am so happy we have clever guys on this forum ;D
No didn't remove the dizzy just turned it, but i did mark it beforehand.. But a few months ago the tick over wasn't quite right, it was a bit slow, so i altered the tick over screw which lifted the tick over.
But I wondered tonight if the timing could have been out slightly when we got the car, it goes well and doesn't pink so i would think it more than likely is right.........
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It'd be worth checking the timing with a strobe once it's up and running, especially as you're relying on markings. Also check for play as Mark said. If there's a bit of jitter in the timing it might be why the idle has deteriorated.
Kevin
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It'd be worth checking the timing with a strobe once it's up and running, especially as you're relying on markings. Also check for play as Mark said. If there's a bit of jitter in the timing it might be why the idle has deteriorated.
Kevin
I will check that tomorrow....