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DATE

PROCESS

HOURS

CATEGORY

08/26/04

Carb Heat Cable, Mixture Bellcrank, Oil Filter

4.0

engine

DETAIL:

Started the building season about 5 weeks early.  It's still hot as hell out here (102° today) but I'm anxious to get this bird flying so I figure a head start will help things along.

I bolted the remote oil filter mount to the firewall.  It's a nice oil filter mount that I got from Canton Racing Products. It has 2 in's and 2 out's.  All 4 ports are 1/2" NPT female fittings that will accept an AN hose adapter.  What's nice about the extra ports is I can use them to mount up the oil temp and pressure senders.  The mount is 100% CNC'd aluminum not the cheap cast aluminum ones you might see on a VW.  It set me back about $85, but money well spent.

I also mounted the coil wire bulkhead pass-through.  My two coils will be mounted behind the firewall on a small shelf.  The MSD coil joiner will also be behind the firewall.  Only one coil wire needs to pass through the firewall this way.

Next was the carb heat control cable.  I used 3/16" (.050 wire I think?) cable with a black ratchet push/pull knob.  I mounted the carb heat knob under and slightly in front of the mixture/throttle quadrant.  The wire runs along the left side of the fuse all the way up through the firewall.  I used one of them nifty blue anodized cable clamps like I did on the throttle and mixture, only difference being since the carb heat cable is 3/16" and not 1/4" like the others, so I had to put on a small sleeve bushing.  Aircraft Spruce sells the bushing for about $2.

From the firewall the carb heat cable goes straight forward about 5" and then makes a 180° downward bend and gets the carb heat box from the front.  Because of this 180° turn I had to "flip" the control horn on the carb heat box so it operated the opposite way.  I didn't actually flip it, I just welded on a .050" 4130 arm going the other way. Works great.  From there I secured the end of the cable with a bug nut on the carb heat control horn. For an extra level of safety I will put on two 1/16" model airplane wheel collars on either side of the bug nut. 

The carb heat cable will get fixed to the engine mount with a clamp and will also get fixed to the carb heat box a couple inches from the control horn.   I get good free carb heat control movement with little drag and the ratchet holds the carb heat flap in any position.

The last bit of work I did was finish up the mixture control bellcrank mounts.  I had to use a bellcrank to get proper control movement to the mixture arm on the carb.  The bellcrank itself is a bearing pressed into an aluminum flange which is riveted to a .063 4130 bellcrank. The last picture shows the bellcrank setup.