Author Topic: Crankcase breather and isv  (Read 60 times)

Offline hey pauley

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Crankcase breather and isv
« on: May 06, 2020, 04:55:44 pm »
I know this has been covered a lot with the boost return mod. I am trying to build a turbo setup and it’s getting to the point I’m ready for these.
1st- can I do away with the isv and leave it unplugged? Not bothered about it too much won’t be running around to the shops and through town.
2nd- the crankcase breather. I only have the domed outlet at the back of the block ( how easy are these to turn?) no flying saucer. There no way I’ll be able to get back round to the inlet, what’s the best way to plumb a catch tank in/ not spray oil all over the bay. I’m tight for space as I’m doing it in a mk1, you don’t really realise the size difference till you put it all in. Any help would be great but no 25mm hose and coke bottle.

Offline hayesey

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Re: Crankcase breather and isv
« Reply #1 on: May 07, 2020, 09:01:44 am »
There is no ISV on a G40, you probably mean the aux-air valve which is used when the engine is cold and closes off when it's warm. Why would you want to leave it unplugged? I can't imagine you're going to gain any usable space by removing it. I think you'd have running issues when the engine is cold but it would probably be usable still.

You wont be able to turn the crankcase breather it's an interference fit so very tight. You'd need to remove it and hammer it back in at a different angle, it'd probably also mean replacing it since it wont come out without a fight (in my experience). I think it needs the outlet to be pointing upwards though so it lets vapour out but not liquid, I'm sure you'd get away with angling it a fair bit though. Then run a 25mm pipe from it to a catch tank, don't use a smaller pipe or you'll be restricting the breather and a turbo converted g40 breathes heavily. I'm also in the process right now of adding a 2nd breather to mine from the cam cover and getting a new catch tank made up (which is being a pain because many fabrication shops are closed).

Offline hey pauley

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Re: Crankcase breather and isv
« Reply #2 on: May 07, 2020, 09:26:23 am »
Yes that air valve. So I can do away with the boss off the boost pipe really, it’s a lhd so not got a lot of space that side and just something else to leak. The breather looks like they pushed it in with a folk lift, got a dent in it. If I could get a new one I’d knock it in so I could pull it over to the other side. Same Iv got my cam cover stripped  so might have a boss welded in. Thanks 👍🏼