Wires' 12a Turbo

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Wires
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Joined: Fri Feb 12, 2016 10:24 am

Re: Wires' 12a Turbo

Post by Wires » Mon Sep 10, 2018 10:47 am

Here's a shot when it was fresh back form the engine builder:

Image


and a shot from after the first leak, before it was skimmed:

Image

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MelloYello
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Location: London, England.

Re: Wires' 12a Turbo

Post by MelloYello » Mon Sep 10, 2018 11:23 am

Hmm.
For peace of mind, i would get new exhaust gasket and use a smear of high temp silicon on each face of gasket.

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Wires
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Re: Wires' 12a Turbo

Post by Wires » Mon Sep 10, 2018 11:49 am

Paste went on both sides, but I've ordered some more gaskets, will have another go at it.

Chud
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Re: Wires' 12a Turbo

Post by Chud » Mon Sep 10, 2018 1:11 pm

Weird that it seems to be blowing out both the front of front rotor and rear of rear rotor. What make gasket is that, not seen them in two separate pieces like that.
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Wires
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Re: Wires' 12a Turbo

Post by Wires » Mon Sep 10, 2018 2:31 pm

I think maybe its from an FD?
Was supplied by the engine builder, who knows his stuff so it should be suitable.

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ian65
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Re: Wires' 12a Turbo

Post by ian65 » Mon Sep 10, 2018 7:46 pm

Wires wrote:
Mon Sep 10, 2018 10:47 am
Here's a shot when it was fresh back form the engine builder:

Image


and a shot from after the first leak, before it was skimmed:

Image
is this the right inlet gasket? it doesn't look as if it's sealing the EGR port and looking at your inlet manifold when you tore it down there looks like there's blowby.

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Wires
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Re: Wires' 12a Turbo

Post by Wires » Tue Sep 11, 2018 9:21 am

is this the right inlet gasket? it doesn't look as if it's sealing the EGR port and looking at your inlet manifold when you tore it down there looks like there's blowby.
Yeah, good spot.

71-85 and the 71-73 gasket are very similar, the latter the better match perhaps?

https://www.atkinsrotary.com/store/Mazd ... d-Gaskets/

seaglen
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Re: Wires' 12a Turbo

Post by seaglen » Tue Sep 11, 2018 11:21 am

Hi There
You have two leaks from the look of your inlet gasket.

The exhaust leak is from the air injection port just under the primary intake runners (the rectangular hole that has blow by around it in the later photo). This accepts air coming from the air pump via the air control valve you have blocked off on the inlet manifold. The air goes down and into the exhaust ports. So you have a direct path from the exhaust port to outside.

Second leak is above the primary intake runner. You will notice a large hole between the runner and two small holes over the port. They are the air bleed into the injector port. Basically air is drawn in at low rpm past the injector nozzles to help atomisation of the fuel at idle. It helps combustion stability at idle. Your gasket is not covering that either so you will be getting un-metered/un-filtered air into the engine.

I have attached a photo of a 12a turbo inlet manifold showing the air injection port at the bottom and the air bleed holes at the top (you can also see this on the photo of yours). Also attached is a photo of a 12a turbo inlet manifold gasket (You may meed to make one). Hope that helps.
12Aturbo012.jpg
12aT Inlet manifold
12Aturbo012.jpg (89.79 KiB) Viewed 75 times
12aIMG12AT1.jpg
12at Manifold gasket
12aIMG12AT1.jpg (19.74 KiB) Viewed 75 times

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Wires
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Re: Wires' 12a Turbo

Post by Wires » Tue Sep 11, 2018 4:12 pm

Thanks for the help, very much appreciated.

New gasket ordered!

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