Omega Owners Forum
Chat Area => General Car Chat => Topic started by: omega3000 on 23 May 2013, 15:34:58
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Ive read that its best to take head off to replace stem seals "vectra b" and then lap the valves :-\ Is this right or would you just replace seals without lapping :-\ :-\
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The seals are known to be a weakness on the Vectra B, that said I would hesitate on changing them unless something is wrong. The reason for lapping the valves is that it is worth doing while the head is off. It is a quick way of improving the seal in the cylinders and thus performance. Over time carbon deposits on the valve accumulate and weaken the seal ever so slightly.
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Thanks guffer , no eml on . Just a puff of smoke on start up , so was thinking of changing the seals in due course .. didnt want the catalyst to clog up and start playing up as its a new one . Didnt quite understand are you saying replace the seals ?
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Didnt quite understand are you saying replace the seals ?
Valve stem oil seal are one of those thing you change as a matter of course when the head's off because they are then easy to get to & change and they're relatively cheap (£1 a piece). But you wouldn't remove a head just to replace them - unless you can remove the collet retainers while the head is in place, not sure that there's anything about to enable you to do this on the Omega V6s
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Didnt quite understand are you saying replace the seals ?
Valve stem oil seal are one of those thing you change as a matter of course when the head's off because they are then easy to get to & change and they're relatively cheap (£1 a piece). But you wouldn't remove a head just to replace them - unless you can remove the collet retainers while the head is in place, not sure that there's anything about to enable you to do this on the Omega V6s
2.0 vectra b andy ;)
Ive been reading that you can pump air into the cylinder to hold the valve up or/and have piston TDC to stop the valve dropping so seals can be replaced without head coming off :)
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Are you sure it's oil smoke coming out and not condensation in the exhaust?
White puffy cloud = moisture
Grey/blue cloud = oil
If the latter I would investigate further.
I had a Vectra which had a knackered stem seal. It took a while to diagnose because it would smoke a little puff of blue/grey on startup and every now and then while cruising there would be a misfire and the EML would come on which would clear after restart.
Leak-down and compression tests were normal but when I pulled the plugs it was obvious that one of them was getting contaminated with oil which was leaking down. So Pull your plugs after running the engine up to temp and if they are clean and the cloud is more white than blue/grey then do lose any more sleep on it :y
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Ive been reading that you can pump air into the cylinder to hold the valve up or/and have piston TDC to stop the valve dropping so seals can be replaced without head coming off :)
Stopping the valve from falling into the bore is the easy bit ....... a load of string/cord dropped into the bore & then slowly raised by the piston. The hard bit is compressing the valve spring under control to remove the collets from the retainer.
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Are you sure it's oil smoke coming out and not condensation in the exhaust?
White puffy cloud = moisture
Grey/blue cloud = oil
If the latter I would investigate further.
I had a Vectra which had a knackered stem seal. It took a while to diagnose because it would smoke a little puff of blue/grey on startup and every now and then while cruising there would be a misfire and the EML would come on which would clear after restart.
Leak-down and compression tests were normal but when I pulled the plugs it was obvious that one of them was getting contaminated with oil which was leaking down. So Pull your plugs after running the engine up to temp and if they are clean and the cloud is more white than blue/grey then do lose any more sleep on it :y
Done that guffer ;) Did a full service 2 weeks ago and plugs were all showing normal wear signs , nothing unusual , cars not using any oil and no misfires :y
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Ive been reading that you can pump air into the cylinder to hold the valve up or/and have piston TDC to stop the valve dropping so seals can be replaced without head coming off :)
Stopping the valve from falling into the bore is the easy bit ....... a load of string/cord dropped into the bore & then slowly raised by the piston. The hard bit is compressing the valve spring under control to remove the collets from the retainer.
They made it look so simple on a video i watched ::) When compressed he used a magnet to hook the collets out .
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Ive been reading that you can pump air into the cylinder to hold the valve up or/and have piston TDC to stop the valve dropping so seals can be replaced without head coming off :)
Stopping the valve from falling into the bore is the easy bit ....... a load of string/cord dropped into the bore & then slowly raised by the piston. The hard bit is compressing the valve spring under control to remove the collets from the retainer.
They made it look so simple on a video i watched ::) When compressed he used a magnet to hook the collets out .
The video was posted here wan't it :-\ I've only ever used a conventional valve spring compressor, and a keen eye as to where the collet might disappear into the depths of my garage.
Go for it. Tell us how you get on. :y :y
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Ive been reading that you can pump air into the cylinder to hold the valve up or/and have piston TDC to stop the valve dropping so seals can be replaced without head coming off :)
Stopping the valve from falling into the bore is the easy bit ....... a load of string/cord dropped into the bore & then slowly raised by the piston. The hard bit is compressing the valve spring under control to remove the collets from the retainer.
They made it look so simple on a video i watched ::) When compressed he used a magnet to hook the collets out .
The video was posted here wan't it :-\ I've only ever used a conventional valve spring compressor, and a keen eye as to where the collet might disappear into the depths of my garage.
Go for it. Tell us how you get on. :y :y
Note to self : "spare box of collets" ::) ;D
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I don't see any reason to do this job going by what you have said. If the plugs are clear then there is nothing wrong with the seals.
To do what you discuss without removing the head requires a lot of pressure in the cyl otherwise it will not withstand the pressure of pressing the spring and then you are in a world of hurt. If you are really adamant and want to do this (even though I think you don't need to) I would instead look at something which compresses the springs in situ, however if you can find one that will fit the 2.0 engine you are better than me (I spent months trying to find one for mine and failed)
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You can change stem seals with the head on.
Valve lapping is required much less these days as valve seats are much better, valves better, fuel considerably better plus the modern computer controlled combustion process is far more advanced. All these things result in minimal if no seat wear.
In fact, all the V6 heads I hava done I only lapped the valves becasue they were out, none of them actualy needed it and even then it was only a few wipes with fine paste (gone are the days of BL heads and grinding 8 valves for bloody hours!)
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You can change stem seals with the head on.
Valve lapping is required much less these days as valve seats are much better, valves better, fuel considerably better plus the modern computer controlled combustion process is far more advanced. All these things result in minimal if no seat wear.
In fact, all the V6 heads I hava done I only lapped the valves becasue they were out, none of them actualy needed it and even then it was only a few wipes with fine paste (gone are the days of BL heads and grinding 8 valves for bloody hours!)
Been there, done that ;D
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You can change stem seals with the head on.
Valve lapping is required much less these days as valve seats are much better, valves better, fuel considerably better plus the modern computer controlled combustion process is far more advanced. All these things result in minimal if no seat wear.
In fact, all the V6 heads I hava done I only lapped the valves becasue they were out, none of them actualy needed it and even then it was only a few wipes with fine paste (gone are the days of BL heads and grinding 8 valves for bloody hours!)
Been there, done that ;D
yep,me too :-\
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Well just to be sure ill pull the plugs again and double check :y If it comes to it and i replace the seals i think i would take the head off for ease of access , change the head gasket and cam belt too .. mite as well go the whole hog eh :)
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I don't see any reason to do this job going by what you have said. If the plugs are clear then there is nothing wrong with the seals.
To do what you discuss without removing the head requires a lot of pressure in the cyl otherwise it will not withstand the pressure of pressing the spring and then you are in a world of hurt. If you are really adamant and want to do this (even though I think you don't need to) I would instead look at something which compresses the springs in situ, however if you can find one that will fit the 2.0 engine you are better than me (I spent months trying to find one for mine and failed)
Not true. The valve spring acts between the cylinder head and the spring cap. You don't need the valve to bear the force of the compressed valve spring (although with a traditional valve spring compressor it is required to take the force of the spring AND the force required to break the taper)
I found that compressing the spring initially caused the valve to open slightly but rocking the spring cap broke the hold of the taper between the collets and the cap and the air pressure then popped the valve shut. I think I set the regulator on my compressor to about 25psi but the pressure didn't really seem to matter
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I don't see any reason to do this job going by what you have said. If the plugs are clear then there is nothing wrong with the seals.
To do what you discuss without removing the head requires a lot of pressure in the cyl otherwise it will not withstand the pressure of pressing the spring and then you are in a world of hurt. If you are really adamant and want to do this (even though I think you don't need to) I would instead look at something which compresses the springs in situ, however if you can find one that will fit the 2.0 engine you are better than me (I spent months trying to find one for mine and failed)
Not true. The valve spring acts between the cylinder head and the spring cap. You don't need the valve to bear the force of the compressed valve spring (although with a traditional valve spring compressor it is required to take the force of the spring AND the force required to break the taper)
I found that compressing the spring initially caused the valve to open slightly but rocking the spring cap broke the hold of the taper between the collets and the cap and the air pressure then popped the valve shut. I think I set the regulator on my compressor to about 25psi but the pressure didn't really seem to matter
:y