Mailing List flyrotary@lancaironline.net Message #67592
From: Stephen Izett stephen.izett@gmail.com <flyrotary@lancaironline.net>
Subject: Re: [FlyRotary] Milling exhaust manifold flat?
Date: Sun, 28 Jan 2024 22:26:17 +0800
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Hi Finn

I’m not sure how the guy milled the flange, my Father organised it.
Here is an old shot of the manifold.

Intake.jpg


On 27 Jan 2024, at 11:32 pm, Finn Lassen finn.lassen@verizon.net <flyrotary@lancaironline.net> wrote:

Thanks Stephen.

Did you use a carbide end mill to  mill the flanges?

Looking forward to the photos.

In order to  keep it light I may just keep my existing intake. It's 5.87 pounds including throttle body, plenum, flanges and primary injectors.

<Intake.jpg><Intake2.jpg>

Been wondering if I could remake it all in polyurethane resin and still keep weight low.. (Ed Anderson's article in Contact! magazine
https://issuu.com/contact.magazine/docs/contact_magazine_issue_87_rotary_is
).

Finn

On 1/27/2024 1:42 AM, Stephen Izett stephen.izett@gmail.com wrote:
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). 
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’m 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. 
I used the existing OEM secondaries while welding new primary's to the siamese flange/plate. 
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’ve been meaning to put a cable on the VDI valve and see if opening the valve gives me more power above 6500RPM. 
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’m retesting my new cooling system tomorrow hopefully.
Last test revealed best H2O coolant cooling but Oil was way hotter. 
I realised that I hadn’t refitted some fairings at the cowl exits that I’m 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 am, Finn Lassen finn.lassen@verizon.net <flyrotary@lancaironline.net> wrote:

When I welded on my stock Renesis exhaust manifold the end I welded the 270 deg bend on got warped.

It's about 0.04" bent away from completely flat at the top flange at flywheel  end.

Doesn't seem to have been an issue during the 100+ hours the engine has run.

But for peace of mind I'm wondering if I should mill the three flanges flat.

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.

Finn


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