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[doz]

This may of been discussed before but I new here so apologies if I'm going over old ground. We all know the V6 has a tendency to block it's oil breathers and then pop the cam cover gaskets. If you try and improve the cam covers it apparently will try to come out some where else I think the rear crank seal is a favorite. My question is what would happen if you were to add another breather? I'm not thinking to hi tech you could add a simple breather to the cam covers and plumb it into the plenum chamber. I've been involved when I was a wee lad doing this before on a midget 1800 and later on a pug 309 1.9 gti (we use to rally) with no adverse effects but is there such a thing as having to much breather capacity. I'm really thinking out loud at the mo. A well maintained breather does the job it's just a PITA when it does block and you end up removing the plenum etc when you may be able to prevent it with a easy mod.

[tunnie]

The v6 does not need extra breathers. If you clean them and stick to 4 or 5k oil changes you will have no problems.

I change the oil in my 2.2 every 3 months, i do 600 miles a month. It costs 10 quid for 5L of gm oil and a gm filter.

[doz]

as said in the post I know they work fine but 3 monthly oil changes would be daft for somebody like me after all I only do 3k a year in the omega and theres no way I'm gonna recycle oil every 600 miles but I want to try and find the down side of adding extra breathers

[tunnie]

Your millage is very low. Do you do town runs only?

For the cost and time you will prob cause more problems than you solve adding more breahersm

Just change the oil every 6 months in your case. It costs less than 20 quid.

I don't see the problem....

[aoliver]

Sounds like a good idea to me Doz, I'm intending to do something similar myself.

[doz]

I'm trying to find an alternative to doing oil changes all the time and maybe improve on the breather system. Some people don't do oil changes themselves they have to take it to a garge which means 20 quid becomes 70 quid due to most garages charging a hours labour to do it. I'd also like to find a way of improving the current system maybe by a catch tank or extra breathers.

Were getting side tracted from the idea here which is a alternative to the exsisiting system. Not what you need to do to maintain the exsisting system

[Kevin Wood]

The real problem with breathers is that mayonnaise resulting from moisture from short journeys and particles resulting from dirty oil get drawn into the breathers and eventually block them.

Increasing the amount of air the breathers flow will not help and effectively causes an unmetered air leak which will cause poor running.

It really is a case of keeping the oil and breathers clean and how frequently you need to change the oil depends on use. A couple of oil changes a year if usage is low or often on short trips isn't too bad, and cleaning the breathers at the same time will ensure you have no problems.

The breathers frequently block right down at the separator on the block so unless you are going to modify this I can't see it helping.

Kevin

[doz]

The idea I'm toying with would be to fit a breather to the cam covers. It might be 2 or it might be able to do it with one. This is where the leak starts and the weak spot in the gaskets. I'm not trying to replace the existing but you made a good point about the over breathing which is my main concern. I also want to avoid the possibility of sucking oil into the plenum when the throttle is at idle and the vacuum in the plenum is at it's greatest. Then theres the oil splash from the cams I would need to fit some kind of splash guard I guess. If it needed a catch tank then costs rise and all so it's another maintains item which must be empty ed. The logical place to fit a extra breather would be in the oil filler neck with some additional baffling to stop oil running into the breather system when adding oil. Peugeot's used a similar idea on there old 1.9 engine but they also added a small breather from the cam cover

[Entwood]

I understand your thought processes .. but must disagree with them ...

Vx probably spent a fair amount of time and research to get the breather balance right, and if the oil system is looked after properly it works very very well ..   don't fix what isn't broken .....

Trying to "bypass" the "problem" of the cam covers acting as a "safety valve" by adding more "vents" will not prevent the existing breathers blocking if the oil system is neglected.

The plan should be not to neglect the oil system IMHO

[tunnie]

The idea I'm toying with would be to fit a breather to the cam covers. It might be 2 or it might be able to do it with one. This is where the leak starts and the weak spot in the gaskets. I'm not trying to replace the existing but you made a good point about the over breathing which is my main concern. I also want to avoid the possibility of sucking oil into the plenum when the throttle is at idle and the vacuum in the plenum is at it's greatest. Then theres the oil splash from the cams I would need to fit some kind of splash guard I guess. If it needed a catch tank then costs rise and all so it's another maintains item which must be empty ed. The logical place to fit a extra breather would be in the oil filler neck with some additional baffling to stop oil running into the breather system when adding oil. Peugeot's used a similar idea on there old 1.9 engine but they also added a small breather from the cam cover

Thats maybe where the leak starts, but its not where the blockage is.

as Kevin mentioned its the seperator on the block which gets clogged.

[Kevin Wood]

Thats maybe where the leak starts, but its not where the blockage is.

as Kevin mentioned its the seperator on the block which gets clogged.

I don't think it really matters where you locate the breathers. The crankcase and the area under the cam covers are connected and thus pretty much a single volume. Working breathers keep this at a negative pressure with respect to the outside air. Blocked breathers can cause it to pressurise and then the problems start.

Since It's really only cylinder blowby gases that pressurise the crankcase, it makes sense to locate the breathers here rather than have the gases flowing up to the cam covers against the flow of returning oil, IMO.

Kevin

[alank46]

The idea I'm toying with would be to fit a breather to the cam covers. It might be 2 or it might be able to do it with one. This is where the leak starts and the weak spot in the gaskets. I'm not trying to replace the existing but you made a good point about the over breathing which is my main concern. I also want to avoid the possibility of sucking oil into the plenum when the throttle is at idle and the vacuum in the plenum is at it's greatest. Then theres the oil splash from the cams I would need to fit some kind of splash guard I guess. If it needed a catch tank then costs rise and all so it's another maintains item which must be empty ed. The logical place to fit a extra breather would be in the oil filler neck with some additional baffling to stop oil running into the breather system when adding oil. Peugeot's used a similar idea on there old 1.9 engine but they also added a small breather from the cam cover

I have to say, I am with you on this one.  Since the year dot it has been common practice with competition engines to run extra breathers, partly because they run wider clearances than road engines.  Most of our engines are getting on a bit now and perforce are running wider clearances than when new, so extra vents makes perfect sense to me.  It is something I have done on Ford, BMC and Porsche engines as they have got older and I see no reason not to do it on Vauxhall ones as well.
Alan

PS  As a 67 year old I like the idea of being referred to as a "Junior Member"

[doz]

That's my way of thinking. I think the breather system is magic when the engine is new but as they age they cause problems and at some point however often you change the oil it will block. A blocked breather is nothing to sort but new cam cover gaskets is a bit of a ballsache. Without checking the breather all the time (which by the way is not a service item) you don't know it's  blocked till it's to late.

Anyway going back to my proposal. I think for starters I'm going to mod one side of the cam covers first and let it breath through a small (read coke can)catch tank to atmosphere. If this looks successful I'll start thinking about tapping a union in the plenum. The most difficult bit will be determining the best size for the pipe. I'm still worried of pulling to much vac when the car is at idle after all I don't want to suck any gaskets in instead of blowing them out!!!

[TheBoy]

TBH, there is nothing wrong with the breather system fitted - it just needs occasional maintenence.

GM oil does seem less prone to the mayo on short journeys.

I tend to do my breathers annually...