Cowl Duct Modification

[MartySantic]

I would also be interested in the same "fish mouth" photo.

[Dave12]

Originally Posted by Bill_H

John - great pics, I may do this. My cowl is painted. How did it look into the fishmouth when you were done before any touchup?

Also a pic of your revised hose routing please!

Bill, I did not have to touch my hoses at all.

[Jetguy]

I'm all done with my cowl mod. Things a learned along the way. You don't want to arch the top part of the tunnel when you reattach the part where the oil cooler attaches as seen in the first pic. I has to go back and redo that area. I had to cut out that area and reglass it with a dip in it as seen in the second pic. There is a point where you can't go any farther forward with out hitting the bottom of the engine because of height of the square frame where the cooler attaches. In the third picture you can compare pics from my earlier post and see now I have about 1 1/2 inches between the cooler and muffler. Before I had about 3/4 inch, use the spring attach point as a reference to compare. The forth pic shows the final product. After I fly it for a while I'll go back and do the cosmetic work and then repaint the inside of the tunnel. I won't know for sure how well it works until the summer kicks end. I'll update when that happens.

[engineerofsorts]

a recent tonsillectomy.

Question: you are removing a 1-inch strip, and basically sliding the remainder forward an inch. By forward, I suspect this means "up a bit" also, hence the interference? Sliding it up, do the two edges basically match up on the same level, or is there a step in the glass at that point to join things back together--looks like it is perdy smooth, at least on the top, but a step discontinuity on both of the sides.

NIce thing about this mod is that its just fiberglass--don't have to deal with the pro-seal/devil's snot on this one--will reserve my aggravation for the tank SB .


Our machine seems to start out with less clearance--< 1/2", and I don't think we hit any red lines during last summer, but will still be doing the mod.

[Dave12]

Looks good John. Are you going to leave the insulation on the muffler?

[Jetguy]

Question: you are removing a 1-inch strip, and basically sliding the remainder forward an inch. By forward, I suspect this means "up a bit" also, hence the interference? Sliding it up, do the two edges basically match up on the same level, or is there a step in the glass at that point to join things back together--looks like it is perdy smooth, at least on the top, but a step discontinuity on both of the sides.

Our machine seems to start out with less clearance--< 1/2", and I don't think we hit any red lines during last summer, but will still be doing the mod.

Yes that is what I did, cut out a 1inch strip and move it forward 1inch. No, the oil coolers frame won't line up perfectly. Just get it close then glass it in place. You might want to wait through the summer and see how yours does. Here are some pics after my final install of the oil pump for reference. You need at least 1/4inch clearance between the the oil pump and the cowl.
If this cowl mod works out ok Ill take the header wrap off. I didn't really see any cooler temps when using it.

[rgmwa]

Looks like Vans have increased the muffler to oil cooler clearance in the current kits by moving the muffler further back.

http://vansaircraft.com/pdf/revision...Section_48.pdf

[Paris12Man]

I would prefer to buy new cylinder exhaust pipes which are shaped differently or longer to move the muffler back than all the fiberglass work required mentioned in the above posts. Oh I forgot to mention I hate to fiberglass! With the NEW cylinder exhaust pipes, I guess a new exit hole would need to be made in the lower cowling......just can't get away from fiberglassing and repainting.

[rgmwa]

Originally Posted by Paris12Man

With the NEW cylinder exhaust pipes, I guess a new exit hole would need to be made in the lower cowling......

Maybe not. Looking at the plans, the exhaust pipe seems to exit a little more vertically than before. Worth checking with Vans anyway. If so, it would (could?) be a simple alternative to modifying the cowl.

[Rick_A]

I wonder how much it would cost to purchase the new system. It does look like you would have to get all 4 pipes and the muffler.

The new EX-000xx part numbers are not on "The List" yet.

I haven't even started my engine yet.