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Re: Wires' 12a Turbo

Posted: Mon Sep 10, 2018 10:47 am
by Wires
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

Re: Wires' 12a Turbo

Posted: Mon Sep 10, 2018 11:23 am
by MelloYello
Hmm.
For peace of mind, i would get new exhaust gasket and use a smear of high temp silicon on each face of gasket.

Re: Wires' 12a Turbo

Posted: Mon Sep 10, 2018 11:49 am
by Wires
Paste went on both sides, but I've ordered some more gaskets, will have another go at it.

Re: Wires' 12a Turbo

Posted: Mon Sep 10, 2018 1:11 pm
by Chud
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.

Re: Wires' 12a Turbo

Posted: Mon Sep 10, 2018 2:31 pm
by Wires
I think maybe its from an FD?
Was supplied by the engine builder, who knows his stuff so it should be suitable.

Re: Wires' 12a Turbo

Posted: Mon Sep 10, 2018 7:46 pm
by ian65
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.

Re: Wires' 12a Turbo

Posted: Tue Sep 11, 2018 9:21 am
by Wires
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/

Re: Wires' 12a Turbo

Posted: Tue Sep 11, 2018 11:21 am
by seaglen
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 221 times
12aIMG12AT1.jpg
12at Manifold gasket
12aIMG12AT1.jpg (19.74 KiB) Viewed 221 times

Re: Wires' 12a Turbo

Posted: Tue Sep 11, 2018 4:12 pm
by Wires
Thanks for the help, very much appreciated.

New gasket ordered!

Re: Wires' 12a Turbo

Posted: Mon Oct 01, 2018 9:26 am
by Wires
Looks like Seaglen was right, got the new intake gasket on, a dry set of plugs on and she no longer blows! - thank you very much for the spotting that issue. Also replaced the positive battery terminal as it was getting abit loose.

So, I need to check the handbrake as that isn't holding very well and only just scraped through the last MOT, I'm thinking probably the caliper seized (had to do both the rears on my Prelude a few months back) but I'll adjust it first and see.

Then, the not so small task of turning my raised garage entrance into a ramp so I can get it in and out quickly. Currently it's a two man ramp and planks job which is a little nerve racking.

Of course, the weather will now take a nose dive, but at least she should be good for next year.

Gives me time to get the Watanabe's powder coated, I've got 6 samples of metallic bronze coming in the post so I can get it just right, will report back once they arrive.

Also thinking of doing a rear wiper delete to tidy up the back end. Always little improvements to be made.