From: "Stephen Izett stephen.izett@gmail.com" <flyrotary@lancaironline.net>
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Subject: Re: [FlyRotary] Milling exhaust manifold flat?
Date: Sat, 27 Jan 2024 14:42:20 +0800
References: <list-2836417@lancaironline.net>
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
In-Reply-To: <list-2836417@lancaironline.net>
Message-Id: <ECD51307-CA67-49CF-84A2-E5D81E405312@gmail.com>

Hi Finn

We modified the OEM headers by welding a new flange to the sawn off =
version with a sweeping bend back to the exit through a resonator (see =
photo).=20
We discovered that the flanges warped and the gasket leaked. We had the =
flanges milled but the same thing has happened.
As we have a slip joint down stream from that flange I=E2=80=99m about =
to remove most of the flanges OD back to round and weld the flanges =
together.
This will reduce weight and allow me to wrap the wend back to the =
headers more effectively.

As far as intake manifold, you could purchase the aluminium section of =
an old 4 port OEM intake and cut it back and weld on some new runners.=20=

I used the existing OEM secondaries while welding new primary's to the =
siamese flange/plate.=20
In the photo you can see where I cut the secondaries and turned the =
upstream section through 180 deg and rewelded the secondaries.
This made the manifold point down rather than up. You can see the new =
primaries that meet the secondaries at the VDI valve manifold (I cut off =
the SSV Secondary Shutter Valve).
I had to lengthen a grinding stone shaft but managed to smooth the weld =
(that penetrated the secondary runners) nicely in the end.
I=E2=80=99ve been meaning to put a cable on the VDI valve and see if =
opening the valve gives me more power above 6500RPM.=20
My primaries and secondaries ended up different lengths so the VDI might =
not work very well.

If I had my time over I think I would weld new straight runners onto a =
cutoff OEM flange with an intake plenem and TB. A bit short but simple.

Hoping your mods work well Finn.

I=E2=80=99m retesting my new cooling system tomorrow hopefully.
Last test revealed best H2O coolant cooling but Oil was way hotter.=20
I realised that I hadn=E2=80=99t refitted some fairings at the cowl =
exits that I=E2=80=99m hoping messed up the exit air flow and so are =
retesting tomorrow. Hoping for a better result.

Photos following

Cheers

Steve
> On 27 Jan 2024, at 4:08=E2=80=AFam, Finn Lassen =
finn.lassen@verizon.net <flyrotary@lancaironline.net> wrote:
>=20
> When I welded on my stock Renesis exhaust manifold the end I welded =
the 270 deg bend on got warped.
>=20
> It's about 0.04" bent away from completely flat at the top flange at =
flywheel  end.
>=20
> Doesn't seem to have been an issue during the 100+ hours the engine =
has run.
>=20
> But for peace of mind I'm wondering if I should mill the three flanges =
flat.
>=20
> Is it true that I'll need a carbide end mill to do this? Even a 1/2" =
carbide end mill is close to $30.
>=20
> Finn
>=20
>=20
> --
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