Print

Please login or register.
1 Hour 1 Day 1 Week 1 Month Forever
Login with username, password and session length

[Webby the Bear]

An excellent point I think! Would be interested in seeing if theres a way to test it. but certainly sounds feasible imo 

[Entwood]

Interesting points ..   however, my gut reaction is ....  if the amount of "blowby" due to wear was sufficient to "overcome" a correctly cleaned and working breather system, and still cause the crankcase to pressurise .... then the performance of the engine would be noticeably so poor that you'd be looking at other things ?? (and buying earplugs to mask the piston slap ??   )

No proof whatsoever, as said .. just a gut reaction ..

[05omegav6]

So what do we know about the ventilation system...
All engines will pressurise the crankcase - hence the need for it to be vented (into the intake system these days)
All engines create pressure because of blow-by. Which as the engine wears, increases...
The harder and faster the engine works, the bigger the bang, and there's more of them! hence the greater the blow-by....
The breather system uses tiny pipes + holes, which limit the amount of crankcase ventilation into the intake.

So, could... and this is only a 'COULD' it be that if you add up all of the above... you exceed the amount which the standard breather system 'USED' to cope with when it was a new engine?

Just my thoughts... 

My gaskets have been fitted for about 150k, with minimal weeping, ie next to none. Engine has done nearly 263k and isn't pressurising in any way shape or form, so I really don't buy that

Sorry.

[Ian_D]

So what do we know about the ventilation system...
All engines will pressurise the crankcase - hence the need for it to be vented (into the intake system these days)
All engines create pressure because of blow-by. Which as the engine wears, increases...
The harder and faster the engine works, the bigger the bang, and there's more of them! hence the greater the blow-by....
The breather system uses tiny pipes + holes, which limit the amount of crankcase ventilation into the intake.

So, could... and this is only a 'COULD' it be that if you add up all of the above... you exceed the amount which the standard breather system 'USED' to cope with when it was a new engine?

Just my thoughts... 

My gaskets have been fitted for about 150k, with minimal weeping, ie next to none. Engine has done nearly 263k and isn't pressurising in any way shape or form, so I really don't buy that

Sorry.

I scrapped an Omega a couple of years back for a number of reasons - one of the reasons was the engine: Oil was like tar, Needed cambelt, cam covers were leaking and it ran a bit lumpy. BUT, the decider was it had a slight rattle/tapping noise from the bottom end and the blowby was excessive. Yet, this car had only covered 84k miles.... All down to how its been looked after / serviced. Pitty really as it was a facelift (X reg i think, 2.5 GLS) in good condition (only mark was on the front bumper).

[dublin.jd]

Interesting points btw I haven't had time to change my rocker gaskets yet, so no point in trying to mod yet either.
Anyway I don't recall having this problem with any of my other cars (not Vauxhall) although I had a 1.6 vectra with blocked breather and never blew cam cover or crank seal.
Is it just bad design or what?
Thanks

[omega2018]

what a weird thread and what a great idea. the intro of seatbelts must of got the same reception here - 'just dont crash' repeated 100 times. airbags must have been laffed off the forum. 

ive ordered a small prv for a fiver and will install it in the oil filler cap.  releases at about 5psi which should save a gasket eventually.

[chrisgixer]

T o use a catch tank, would I need to redirect breathers away from plenum and into catch tank?
Basically bypassing plenum preventing gases going back to the intake?

And loosing any facility for the crank case to run at negative pressure. How will this help?

[chrisgixer]

Just make the holes in the cam covers and tee it into the existing breather system. Lots of vehicles use the cam cover as the vent system anyway.

They do, the ls1 has similar. However the ls1 is a pushrod design, so doesn't have two cams per bank spinning around inside splashing oil over the inside of the cam cover. If breathers are attached here, inlet vacuum will just hoover up oil from the engine and spit it out of the exhaust as smoke, and increasing oil consumption.

The location of the crank case breather box behind cylinder 5 is chosen as its a still atmosphere as far as oil splash goes.

There is a combination of air ways that lead to pre and post throttle to manage the pressure during closed and open throttle situations. These pin holes, about 1mm or so are obviously set sizes the factory made to choose vacuum levels and manage oil loss through oil vapour.

I have had a car where somebody felt the need to open up the oil hole on the breather box behind cylinder 5 by an extra 1mm or so. The oil consumption on that car was decreased by a litre a month by fitting a breather box with the standard size hole again.

[dublin.jd]

T o use a catch tank, would I need to redirect breathers away from plenum and into catch tank?
Basically bypassing plenum preventing gases going back to the intake?

And loosing any facility for the crank case to run at negative pressure. How will this help?

Do you always answer questions with a question?
I was looking for advice, not cynicism. I've already gathered that you're against the modding/improving of original set ups.

[dublin.jd]

what a weird thread and what a great idea. the intro of seatbelts must of got the same reception here - 'just dont crash' repeated 100 times. airbags must have been laffed off the forum. 

ive ordered a small prv for a fiver and will install it in the oil filler cap.  releases at about 5psi which should save a gasket eventually.

Thank you for getting that point across.
You're one of a few that are willing to keep an open mind.

[chrisgixer]

T o use a catch tank, would I need to redirect breathers away from plenum and into catch tank?
Basically bypassing plenum preventing gases going back to the intake?

And loosing any facility for the crank case to run at negative pressure. How will this help?

Do you always answer questions with a question?
I was looking for advice, not cynicism. I've already gathered that you're against the modding/improving of original set ups.

Hold up, am I in trouble for asking questions? On a forum?

Shall I quote your stroppy response from earlier? No that would be childish.


Seriously now. How does it help?

[05omegav6]

what a weird thread and what a great idea. the intro of seatbelts must of got the same reception here - 'just dont crash' repeated 100 times. airbags must have been laffed off the forum. 

ive ordered a small prv for a fiver and will install it in the oil filler cap.  releases at about 5psi which should save a gasket eventually.

Thank you for getting that point across.
You're one of a few that are willing to keep an open mind.

Not really a question of open or closed mindednes... If summat can be improved, great... I'll wager that fiver would have been better spent on a scratch card though

[dublin.jd]

T o use a catch tank, would I need to redirect breathers away from plenum and into catch tank?
Basically bypassing plenum preventing gases going back to the intake?

And loosing any facility for the crank case to run at negative pressure. How will this help?

Do you always answer questions with a question?
I was looking for advice, not cynicism. I've already gathered that you're against the modding/improving of original set ups.

Hold up, am I in trouble for asking questions? On a forum?

Shall I quote your stroppy response from earlier? No that would be childish.


Seriously now. How does it help?

Not at all, I'm not here to argue and bitch with anyone! And I respect/accept some of ur earlier posts.
I asked a question and u replied as if I had made a statement.
How does that help

[dublin.jd]

On another note, when the breathers become blocked would the point most likely to blow not be the dipstick?
Surely it would take more pressure to blow the gaskets than to pop the dipstick?
Again I'm just guessing.
And regardless of mods, I doubt anything will stop them leaking once they get old and dry out. So either way I accept its important to change them every so often. (depending on mileage and age)

[05omegav6]

How about changing them when they leak, regardless of age/ mileage?

Just asking, like