View Full Version : Sutton Exhaust on O360.

04-21-2010, 05:24 PM
Would any of you fine folks have a photo of the Sutton exhaust on an O360? Specifically the right side. I have installed mine, and wow is it tight on that side. I had to modify the lower cowl rail on the right side just to clear the exhaust pipes. In looking at it, it appears that the right lower edge of the muffler can will still be below the plane of my belly pan. I'm still building my cowl, so have not installed the belly pan yet, but........straight edge still shows the lower right end of the can isn't gonna make it. Just wondering if I'm way off somewhere else, or if the Sutton is generally that tight on an O360. Help!!

I,m gonna call Dave as well, but he is real busy in the fields.


Edit: Just talked to Dave Sutton on the phone. I am on the right track and everything is normal - gonna be a tight fit on the O360. Would still entertain a photo. Thanks again.

04-21-2010, 06:18 PM
It look's like a very tight fit.

Where do you guys cut the end pipe for fitting nicely and easy cowling removal??

04-21-2010, 09:03 PM
JayH - What conversion and mount are you running? Tight fit I am guessing dynafocal? I have the Sutton on a Penn Yan conversion O360 with a conical mount and the thrustline mod. If photos of that set up would help let me know, I can get some posted by tomorrow.

I love my Sutton - gobs more room in the engine compartment compared to stock and no more annual AD.

Darrel Starr
04-21-2010, 09:25 PM
This is a friend's 0-360 powered wide body Super Cub with Cub Crafters cowling and Sutton exhaust. This airplane is another jewel built by Bob Schefter in Fergus Falls, MN.
See the tape on #3 valve cover? We ended up adding a "bubble" (Super Cub Aileron bubble from Univair minus the slot) to the cowl door to clear that cover.

04-21-2010, 09:53 PM
Dynafocal - Experimental Smith Cub. Lyc O360 A1A. If you have the conical and thrustline, you should have plenty of room. I would still be interested in a pic of yours if you would be so kind.

Thanks for the pic. I see that lower right cowl rail has been modified as well. Makes me feel better. I think I'm on the right track. I modified my cowl rail, and everything looks good. However, the lower right edge of the muffler can still has me thinking. It may work out fine when I get that far. Worst case scenario, I can blister out the lower cowl around that muffler edge with a bubble cover.

I'll try and post some pics tomorrow.

Thanks again guys.

Darrel Starr
04-21-2010, 09:58 PM
Jay, I added a third picture to that last post showing how we cleared the #3 valve cover with a bubble. I've heard that the later Cub Crafters cowls are wider but this one was too close.

04-22-2010, 08:07 AM
I used a Sutton exhaust on my North Star, which is a 2-3/4" wider body than stock Cub. O-360-A1A (ECI) with CubCrafters cowling and baffle set, heavily modified. 4-degree tip-up on engine mount, same as thrustline. I'm using dynafocal mount; no problems with interference, no bubbles needed, no rail mods. The cowling was purchased from CubCrafters almost two years ago. The baffles needed extensive cutting and hacking.

Sutton mods: I trimmed off the exhaust stack per Sutton instructions and attached the removable bent elbow. This keeps the overall length the same, but can be removed to make lower cowl removal easier. Also less frontal area in slip stream = less stress on stack-to-muffler weld. It was tricky cutting hole in cowling for stack. I originally put three standard washers between right lower rail and firewall, but left them out in my haste to get flying; it made a BIG difference in stack clearance, and I put them back in.

Second picture shows mod to #1 baffle for scooping more air into Sutton shroud. I put this on right side because that is where my Sutton intake air is. Sutton also added thicker screen between muffler and shroud for more heat; so far it works great. With outside air in 30s I only need to crack the flapper valve and there's enough hot air to overcome air leaks around doors.


04-22-2010, 10:09 AM
I have a sutton exhaust on a standard supercub with 0360... Your right,, everything is tight,,, I also have the dynafocal mount with thrustline. Yes, you have to trim the right rail,, and the clearance between the top of the flywheel and the top cowling can be an issue if the cowling "sinks" a little lower... I put a piece of nylon block on the little tab that would come down and hit the top of the engine block. This keeps the cowl from lowering itself and letting the flywheel rub... Yes,, you are right about the exhaust rubbing on the bottom cowl.. Mine rubbed a hole in it and at some point I am going to put in a little "bubble" just for looks... I have the clearance now that it rubbed a hole in it,, didnt hurt the muffler. :)

I have no issues with it rubbing the valve covers,, but it is tight.. I put a piece of duct tape on the inside of the cowl door,, kinda like a feeler guage.. if it rubbs,, I can see it.

Here is another problem,, using the stock nose bowl, which I did,, you might have tight clearance between the nose bowl and the plate the spinner hooks to.. so watch it there too..

ALSO,, make sure you hook up the cabin heat and the carb heat to the correct fitting on the exhaust.. I sure could burn carb ice,, but froze in the cabin before I figured out it was wrong.

I think the cubcrafters nose bowl is a little wider,, and is split.. makes for easier install,,, but it is EXPENSIVE :o and I chose not to go that route.

04-22-2010, 01:21 PM
Eaton sell one of your tractors--- you can't keep track of them anyway :crazyeyes: and buy a two piece nose bowl.

04-22-2010, 01:27 PM
Thanks Lytle for that info. I think that thrustline mod saves a lot of hassle and tight fit in this area with the exhaust up front.

You have hit on absolutely everything I'm dinking with here. I've spent all morning adjusting nose bowl to find the best combination of clearances all around. The best fit on the bowl to where the spinner is good, really dinks things up in clearances in the cowl area. I think I'm just about there now, but my spinner clearance sucks now. I think I will just run a skull cap, which was kind of the plan anyway, and maintain the clearances in the cowl. Thanks for all the info, there may be hope. Or at least I can quit throwing tools at the wall.

Thanks again all.


04-22-2010, 01:45 PM
Jay,, we had to put an 1/8 piece of aluminum spacer behind the spinner plate to get it out far enough from the nose bowl..

DW,,, tractors keep showing up at different places... stay tuned

04-22-2010, 02:06 PM
JayH - just posted a bunch of photos in an album in my member gallery. You can see them HERE. (http://www.supercub.org/photopost/showgallery.php?cat=1042)

I hope it helps and that we got a picture of what you were looking for. If not let me know and we can take some more. Good luck with the install.

04-22-2010, 03:07 PM
Cutting lower cowl hole for Sutton stack:

I used two pieces of pvc, sized so one fits inside stack and the other just fits over it to allow it to slide in and out. I mounted up the exhaust system with wheels chocked, so everything stays in place in space. Then clamped the outer pvc with a bicycle maintenance stand (allows clamping in any position) so the inner piece slides straight up into the stack. Being careful not to move the bicycle stand, slide the inner piece back out and down, remove exhaust, mount cowl. Then slide inner pvc back up and draw a line where it meets the cowl.

Hope this makes sense. Worked for me.

04-22-2010, 06:54 PM
Lytle, makes sense to me. I'll figure something out when I get that far. Right now I'm fighting the support tubes that come down from the engine mount to the lower cowl rails. I think I've made 4 per side now and still not satisfied, what a pain in the azzzzzzzzzzzz.

Yep, 1/8 is exactly what I'm shy on the spinner. I moved the nose bowl in an 1/8 for clearance on the spinner. It's amazing the other clearances that are effected when you do that. So, I moved the nose bowl back out and things fit pretty good. Good idea on the 1/8 spacer. Always an option, thanks.

Gunny, thanks, I'll take a look and let you know.

Thanks for all the help and tips - much, much appreciated.

04-22-2010, 07:08 PM
Outstanding. Thank you much, I gleened some more info as well as the exhaust stuff. That thrustline really makes a difference in the clearance there. Thanks.