3298 Exhaust System

05-23-2008, 03:56 AM

Robehouse | 3298 Exhaust System

EXHAUST SYSTEM supercharged IO540. On the way back from Lake Mead to VGT a few weeks ago my #1 cyl. short exhaust pipe broke off just below the temp sensor. The symptoms were as follows: the engine got noisy and my #1 cyl EGT dropped to 1100. My on-board camera system didn’t reveal any smoke. Not knowing what was wrong I throttled back to 100mph and nurse the bird home. When I removed the cowling I found the exhaust pipe completely off but no damage to the cowling or the paint. Fortunately, it was a very short flight. Had it been a longer flight, the result could have been very different as the potential for fire greatly increases. I sent the broken pieces to Knisley Welding, Loomis CA 800-522-6990 (they specialize in aircraft exhaust among other things) and they fabricated a new piece out of thicker material, (.045 stainless), for $225 and had the part back to me in 4 days. They do very good work. NOTE I think the failure was the result of a pipe too thin and pour alignment. Both issue now addressed. Also, supporting the long pipes of Cyl. 1 & 2 could add strength. JR N521GR

05-27-2008, 03:58 AM

keithw | 3299

JR I was lucky in that just before putting the coweling back on I found the same short pipe on #1 cyl cracked in the very same place as yours. 90 % Only a thread holding it on. I did as you and replaced with 045 thk stainless. I always wondered what would have happened if it had broke in flight? Now I know. Thanks for the post. All flying Seawinds should check the pipes every time the coweling is off and if your short pipes are .o35 thk start planning to change out bfore 200 hrs. Keith Walljasper N80CC

01-14-2010, 02:50 PM


Does anyone know where the exhaust heat muffs and be purchased? I don't remember if it is a complete unit (pipe & Muff) or its an assembly. I noticed high C/O levels today and I suspect a leak. DAM it's cold out there..!! Any Ideas..?

03-27-2012, 11:43 PM


Mr. Robehouse:

Who built your exhaust system in the first place? Was it Knisley welding or someone back east. I am about to hang my engine on the vertical tail (which is on a caster cart,) and take it to Aerosuperchargers in Vegas. It would be good to have the exhaust in place before the Vortex plumbing goes in.

03-29-2012, 09:03 AM


Knisley Welding did the repair only. I believe they do custom exhaust systems for aviation as well. As I’m the 3rd owner of GR I don’t know who supplied the original exhaust system however I’m sure PlaneMakers would have good sources. Aero Supercharger Solutions is my neighbor at VGT and installed my supercharger. Let me know when you’ll be in town and I’ll try to meet up.

Jerry 702 234-4737

04-01-2012, 07:46 AM

Russ Kotlarek | OR Inconel

On my "new egine" the EGT's tend to run higher and needed to create a custom Inconel Header. I bought and cut the pipe and had a custom welder weld the pipes here locally.

Inconel requires full purge welding to be done, this welder specializes in Inconel so although hard to find the choice was easy and the work was excellent.

If anyone wants to upgrade to Inconel a high Nickle metal capable of handeling extra heat and stress and is often used on some critical aviation manifolds I am sure I can get them welded here in Wisconsin.

Note: Inconel is more like Gold when it comes to buying the material, but I do have an outlet that might be able to help if one decides to go down this path, feel free to contact me 414-899-1077


01-19-2013, 10:33 PM

Rusty | Exhaust Fabrication

Do any of you "old hands" remember who built the exhaust systems in the first place? I seem to dimly remember a "group buy" mentioned in one of the ancient newsletters.

It seems like a lot of trouble to fake up a system with pvc pipe for a model (especially since I don't know what I'm doing) when there's some professional out there who knows how to do it right.

We closed the left wing last week and can now think about raising it to the ceiling, getting the vertical tail on its cart back into the recycled chicken coop and moving on with engine and cowl work.