10 replies to this topic

[smikey]

Greetings, friends. I'd like to substitute a non-Lotus part for the non-return breather valve provided between the crankcase breather valve and the T-piece vacuum rail take-off (fuel rail). I've found a similar non-return valve from Saab and Volkswagen. I've also found one from Tyagi Racing, which is called a fuel tank breather non return valve, and looks quite nice (aluminum). Are all non-return valves the same? Do I need to use the Lotus part? All constructive comments are appreciated.

1989 Esprit Turbo

[andydclements]

!s long as it doesn't' need a large pressure differential to open I cannot see any reason why it wouldn't be suitable.

[Mike6]

Is this item actually what it says. If we are talking about that green unit on the crankcase breather then it doesnt seem to contain a valve at all. When I dismantled mine all I could find were some metal plates which are supposed to be seperators and a small pipe which I think is meant to take reclaimed oil back to the cranckase whilst the other pipe takes away fumes/condensation.
If there is something else in there then I had better get one.

[Bibs]

The part from the factory is £17, do you really need an alternative?

[dodge1979]

Are we not talking about the little black and white disc shaped one way valve on the vacum lines? one either side of the intake manifold...if so 17squid for one of those is a bit much surely! They do however look the same as the ones on the T-Series engines I have...just so long as the tail pieces are the same diameter!

[smikey]

Hello, all. Thank you for the comments. Yes, I am talking about the cylindrical / disc shaped non-return valve (black top with white bottom) - not the bright green crankcase breather. I agree, 17 quid ($27) is a bit ridiculous for the black and white valve. I removed this non-return valve from the vacuum line and blew air through it from both ends. It does not appear to be working properly because air flows freely through it from both directions. Which direction should the air flow through - from the black side to the white side? See attached photo from LEW.

Attached Thumbnails

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[lotus4s]

Mike,

Air should flow through from white side to black. You can usually find ones that will work in any auto parts store on the "fix-it" rack although the ones I've found had smaller diameter stems and I had to replace part of the vacuum line to make them work.

Here's a similar one from NAPA part # CRB 21015

NAPA

[dodge1979]

Silly question..does anyone else have two fitted to theirs? One either side of the manifold? One of mine works, the other does not..and if the flow are white through to the black side...then on one side should not the black side be on the manifold, as shown in the pic above, and on the other the white side be on the manifold..or as Ive got them on black side both on the manifold...make sense?

[smikey]

Dodge1979,
There are two (one on each side of the manifold) and the black side is nearest the manifold on each side, but I'm also trying to understand "why."

Edited by smikey, 27 May 2011 - 02:04 AM.

[lotus4s]

Well, the short answer is they are there to allow air/fumes to flow back into the manifold at low rpm (vacuum) but to prevent loss of manifold pressure at higher rpms. They both do basically the same thing for two different systems that are part of emissions control.

The one on the rear is part of the crankcase breather sysem and allows crankcase fumes to be sucked back into the manifold at low rpm instead of being released into the air through the air box.

The one on the front of the manifold is part of the fuel vent sytem and charcoal cannister and allows fuel fumes from the cannister to be sucked back into the manifold at low rpm when the manifold is producing vacuum. This is controlled by a solenoid on the charcoal cannister and the ECM.

Without the one-way valve at higher rpms and the engine creating pressure in the manifold, that pressure would be released to atmosphere or basically an intake manifold leak and the engine runs like poop...

[dodge1979]

Ah,.,so simple when you think about it really!Just because its small doesnt mean its not important