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Carb heat box options for my RV-8

MSFT-1

Well Known Member
My A&P and I are in the process of doing the annual inspection on my pretty stock RV-8 (not built by me). So far we have found very few issues:

1) one exhaust bracket needed to be replaced
2) the manifold pressure sensor line was loose
3) one cylinder intake manifold was slightly loose
4) the throttle cable was out of adjustment (couldn't open the throttle to WOT)
5) the EGT probe on cylinder #4 was intermittently not giving a reading
6) the oil cooler cover was too big giving too high oil temps in the summer

The two more difficult problems we found (that I would like suggestions and comments on):

The Van's stock carbuerator heat box was fatigue broken when it mounts to the top of the air inlet scoop. The small manufactured fitting where the SCAT hose connects at the bottom was completely broken. Carb heat has never worked at all (no RPM drop on test) so I am ready to consider another type of carb heat set up (after market or someone's home design). Any suggestions? This is for a Lyc O-360A1A with the precision airmotive carb.

My prop leaks grease. It is a Hartzell C/S with 350 hours on it. It has been this way for about a year. I have asked several people about it and got the common "oh, they all leak like that". My A&P who is very, very experienced says the size of this leak is not normal and I need to get it looked at by a prop shop. The leak in on one blade only and it can put a nice slimey coat on the back of the blade after only a couple of hours. Thoughts, comments?

All thoughts and guidance appreciated.

Bruce
N297NW
RV-8
 
If the prop is throwing a significant amount of grease, i'd agree, and have it looked at. Don't send the prop in for an overhaul (where they grind the blades) simply tell the shop to do a IRAN (Inspect and repair as necessary) on it.

As for the carb heat box, it wouldn't be too hard to design your own, better than Van's. I'd plan on glassing a aluminum intake tube to the cowl side with a screw-on door on the bottom of the cowl scoop that would allow you to attach a piece of scat to the cowl intake scoop. Then shorten up your box and glass into it an aluminum ring for the scat to attach to on the FAB side. Also I'd design to so as to bring the carb heat in after the filter. There is something to be said for having a manually openable alternate unfiltered air source.
 
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