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Post by shrimp on Jul 26, 2014 20:11:01 GMT 1
The head gasket went on my corsa c so I've stripped it down and replaced the valve stem oil seals but now I've put it back together two inlet valves and 2 exhaust valves are open slightly when the camshafts are locked off. So would anyone know if this is correct.
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Post by Karl on Jul 26, 2014 20:27:18 GMT 1
I don't know what you mean
But if your saying the valves are open with the cam lobes at there lowest point , then no it's not right
Does this engine have shims or hydraulic lifters ?
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Post by shrimp on Jul 26, 2014 20:32:13 GMT 1
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Post by Karl on Jul 26, 2014 20:52:01 GMT 1
If you mean are the valves open once the timing tools are installed then I'd suspect that to be correct
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Post by Joepublic on Jul 26, 2014 20:53:55 GMT 1
I suspect the valves on number 1 cylinder are closed with the locking device in place? I suspect the valves you're looking at are for cylinders 2 / 3 and 4? of which some will be open and that's normal
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Post by chippie on Jul 26, 2014 21:03:06 GMT 1
If you look at the end of the camshafts where the flat locking bar fits, you will see the slots are not central to the diameter....
That is they are offset...if the flat bar is resting flat on the surface of the head where the cover seats, then the shafts are aligned correctly and the crank locating pin will fit into the respective hole....if the cams are 180 degrees out from this position then the crank locating pin will not fit.....
This applies to both 3 & 4 cylinder engines....
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Post by shrimp on Jul 26, 2014 22:41:51 GMT 1
When I was searching for how to set the timing chain I found a post where someone said that the valves should be all closed when the camshafts are locked. I don't know which side is number 1 piston but the valves are closed for number 1 and 4 cylinder but the inlet valves are open on number 2 cylinder and the exhaust valves are open on number 3 cylinder. |
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Post by Joepublic on Jul 26, 2014 23:29:00 GMT 1
Its a four stroke engine, firing order is 1 3 4 2 - (2 complete revolutions of the crank)
Suck (intake)
Squeeze (compression)
Bang (ignition)
Blow (exhaust)
To time most engines you need number one cylinder on top dead centre and the valves closed on that cylinder, this is how the cylinder is on the ignition stroke.
If no1 is on the ignition stroke
No 3 is on the compression stroke
No4 is on the intake stroke
No2 is on the exhaust stroke
Hence some cylinders have there valves open whilst timing number one with the piston at TDC and the valves closed
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Post by shrimp on Jul 27, 2014 7:18:21 GMT 1
If you look at the end of the camshafts where the flat locking bar fits, you will see the slots are not central to the diameter.... That is they are offset...if the flat bar is resting flat on the surface of the head where the cover seats, then the shafts are aligned correctly and the crank locating pin will fit into the respective hole....if the cams are 180 degrees out from this position then the crank locating pin will not fit..... This applies to both 3 & 4 cylinder engines.... I read on the internet that the bar that fits in the cams should lie flat on the head. If you fit the flat bar in the cams on my head on my head the bar is about a mil or 2 off the head. |
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Post by chippie on Jul 27, 2014 8:53:46 GMT 1
Read what I said above.....
Yes the bar will fit when the slots are horizontal, you will find that the bar isn't flat on the head if you got wrong....
To recap,
No1 cylinder is at the chain end
The cam lobes should point outwards away from the engine when No1 cylinder is at TDC, you should at this point be able to insert the crankshaft positioning pin into the hole at the front of the engine( after removing the blanking plug)
Have you got a workshop manual?
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Post by shrimp on Jul 27, 2014 9:24:49 GMT 1
Read what I said above..... Yes the bar will fit when the slots are horizontal, you will find that the bar isn't flat on the head if you got wrong.... To recap, No1 cylinder is at the chain end The cam lobes should point outwards away from the engine when No1 cylinder is at TDC, you should at this point be able to insert the crankshaft positioning pin into the hole at the front of the engine( after removing the blanking plug) Have you got a workshop manual? I got a Haynes manual. I have the head off the car at the moment but the cam lobes closest to the sprockets are both pointing outwards with the flat bar inserted in the cams. I cannot fit the bar flat on the head and insert it into the back of the cams as the slots on the cams are higher than the head. |
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Post by chippie on Jul 27, 2014 10:20:48 GMT 1
Ok,
Turn each of the camshafts, so that the lobes nearest the sprockets are pointing outwards as per previous post
Look at the far end of the shafts and ensure the slots are horizontal, I used a piece of flat bar 1/8 inch thick and that fitted perfectly.
Now turn the crankshaft so that No1 piston us at TDC.
Refit the head to the block, after fitting the new head gasket.
Did you remove the sprockets?
If so, add the sprockets to the cams, loop the chain over each as you put the sprockets on the cams.
You will need the timing tool shown in the manual to set the sprocket positions....I made mine from card
Once the sprockets are fitted, tighten each bolt while holding the cam shaft with a spanner and timing tool in position , repeat for the other sprocket .
If you're happy with the sprocket positions and have torqued the bolts, remove the crank locking bolt if you used it, then turn the crank over slowly with a spanner on the pulley bolt.....
If you didn't remove the sprockets, slip the chain over the sprockets, loosen the retaining bolts sufficient to allow the sprockets to turn, then follow the above....
(New bolts should be used if they are disturbed...my advice would be to change them as they are stretch bolts)
If everything is aligned, two full turns of the rank should put the cam lobes in the same position as you started...I.e pointing out over .....
I've missed out locking the hydraulic tensioner, but if you follow the process described in the Haynes manual all should work for you.....
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Post by Deleted on Jul 27, 2014 11:19:03 GMT 1
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Post by Deleted on Jul 27, 2014 11:47:03 GMT 1
Shrimp  some very good information/advice given above . Reading your post I understand that you are not a mechanic in the trade but are having a go yourself , good on you . Reading your first post above you advised that you removed the cylinder head to change the cylinder head gasket, and that you changed the valve stem oil seals and replaced the cylinder head, I hope you remembered to fit the new cylinder head gasket before locating and fitting the cylinder head onto the block face  |
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Post by shrimp on Jul 27, 2014 15:45:41 GMT 1
No I'm not a mechanic but I thought I would have a go myself when the garage quoted £500 just for labour. I'm using the old gasket when I give it a spit and polish  |
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some very good information/advice given above 
