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More on Cooling Duct

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yankee-flyer

Well Known Member
I think all the tweaking to get the lower cowl to fit has caught up with me on the cooling duct. The first fit shows two problems:
1) There's no way I'll have 1/2" under the exhaust pipe

2) The cooling duct is literally touching the valve cover of the #4 cylinder-- I'm sure that's a no-no. Trimming and tweaking the part will probably help some but I think some fiberglass surgery will be called for.

Is the solution to both to cut holes in the cooling duct and then put "bumps" on the inside of the duct? Gotta mess up the airflow!!

I don't see any indication of the vertical location of the duct with respect to the water radiator face. Is anyplace it comes out OK as long as the radiator core isn't covered OK?

I'm really hating all this fiberglass work and noting that the farther you get into the project the less explicit the instructions are. Looks Like Van's got tired of it too.

Bad feeling that the final solution will be all new fiberglass pieces to try to get things located better.

Wayne 120241 N143WM maybe
 
Cooling Duct!

Have you glued the cooling duct in place yet?
Have you finished installing the lower and upper cowls yet?
John
RV12 N1212K
 
Cowls done

Both cowling pieces, prop, spinner, and cabin heat door are done. First test fit of cooling duct today, read all the posts I'd printed out, thinking about it over the weekend. I marked some places to trim and will see how things fit after that. I still think I'll need some "bulges" in the duct. How close does everyone's duct come to that #4 valve cover???


Wayne
 
Cooling Duct!

Ok, Try lowing the duct down some at the rear to clear the #4 valve cover. If that works with the duct lowered then how does it line up with the radiator? Lowering the duct will also give you some room between it and the #2 header to. Try lowing the cooling duct at the front all the way down so it rests on the top of the oval hole on the lower cowl. Furthermore it might be time to take a break for the evening if you have been working on it all day. Sometimes a good night sleep will fix a lot of problems the next morning.

John
RV12 N1212K
 
What was the outcome?

I'm resurfacing this post to find out the outcome of fitting the cooling duct vs. the valve covers.

I have about 1/16" inch clearance (maybe less) between the cooling duct and #4 valve cover. I'm assuming there should be more clearance. I tried lowering mine but that doesn't seem to help. Any other thoughts?:eek:

What clearances do others have between #4 valve cover and the cooling duct?

Thanks,
 
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My duct just barely clears the valve cover, and I had to cut the duct and add a fiberglass bulge to provide clearance from the exhaust pipe.
 
Any other duct troubles and solutions?

We are going to tackle this thorny problem over the weekend and was wondering if anybody else had these issues and how they were resolved.

A quick test fitting last weekend revealed what looked like major problems - touching the #4 cover, the exhaust and just a general lack of adequate clearance all round.

Can't say that I like fiberglass work at the best of times so any advice would be appreciated!

G
 
G,

Go here and check the next few pages after that for the saga of my cooling duct. That duct was a lot of work, but it came out great! Just be aware you will have to take the lower cowl on and off a lot of times to get the fit right.

The bulge for the exhaust pipe is absolutely necessary, IMHO. It is not hard to do and gives you the clearance you need to have assurance of no future problems. Cosmetically it looks fine.

Check my blog and if you have any more questions just ask.

John
 
Some of the early builders had to make the bump also, I think it was Pete or John. I, and several others did not for what ever reason, the cowl fit great right out of the box and cut to the line. I think it depends on how the bottom cowl is handled and installed.

It will not adversly effect the cooling, there is plenty of air moving though the duct for cooling the radiator and a little bump on the top is not going to cause a problem. The CHT temps in the -12 have not been an issue at all except in the winter when they are too low. The Bender Blender works well for cutting airflow for winter flying. ;)

Build a bump and move on.
 
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Thanks Larry ( I think ) - -

Mine fits ok. ( no bump added ). I am going to change oil today, so I will try to remember to look at those areas. Thanks also, the "Heater Damper Door" does work well. I have had to open the door a little now that we are getting above freezing in Iowa. Going to add the remote oil sender hose today also.

John Bender
 
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