Oil cooler for 1413.

Nope, never.

I have had my Cruisair since 1991. When I removed the old cooler recently what I did find was that the hoses where not 5/8" ID and they were not oil pressure hoses. They were heater hose and they were 1/2" ID, as long as they were on there they were so tight I had to cut them off, they would not slide,turn, or pull off. The hose clamps were a stirrup style hose clamp (1" ID) used a lot on Stearmans and have 'IDEAL AN748-38 4/45' engraved on them. I found a replacement through a vintage aircraft supplier, so I bought some new surplus and installed them with new 5/8" ID oil pressure hose, engraved 'WITTEK MFG CO FB-9'.

The original AN 748 on left and the replacement WITTEK on right, to AN loop can be disengaged but the WITTEK cannot.


First bought 1/2" oil pressure hose because that's what I measured the old hose, got the 1/2" hose before I figured out that the old hose was heater hose - 1/2" would never go on the oil cooler hose connections. The 5/8" ID oil hose was very tight. The new stirrup hose clamps have safety wire holes drilled in the thumb screws as the old ones did not, so I saftey-wired them. I can't imagine that I'll ever have any leak issues with these hoses or clamps.

The other item I bought recently to install at the first oil change is a 3/8 NTP Brass Pipe Street Tee at the POC 102C bottom fitting, with a 3/8" brass plug, so I can drain the cooler when I do an oil change without removing the brass elbow. A drain fitting on POC's cooler would have been a nice addition.
 
I'm wrapping up my 102C installation this weekend and will post some pics. I'm running a little behind because of some obligations at work and the discovery of some seriously dry and brittle fuel hoses under the cowling - so I'm replacing all of them while I'm in there. My 337 for the 102C doesn't have any wording regarding switching to AN fittings, we just did it and it'll be documented in the logbook entry. I can't envision a set of circumstances where a Fed or an outside mechanic / IA would give me trouble about utilizing AN fittings in lieu of the old automotive style hose clamps and barbed fittings, but who knows. I'll cross that bridge if I ever get to it.

For those of you who are running the 102C cooler - what did you do about the extra space in the air plenum from the nose bowl to the oil cooler face? The 102C is noticeably narrower than the original Fedders unit and the peanut gallery at the airport has many opinions on the new space that will be on the aircraft's right side of the plenum. Some say 'no big deal'. Others say that the open space will create a low pressure area across the face of the cooler and there won't be enough air going over the cooler - necessitating a plug or baffle to close the excess space between the narrower 102C cooler and the right side of the plenum. Decisions, decisions.

Best Wishes,
Brad Donner
NC86916
 
The 102C installation in my airplane has hit a minor snag. The 102C has top AND bottom mounting flanges that render the cooler exactly 1/2" too tall for my air plenum that runs from the nose bowl to the oil cooler. The plenum is in excellent condition and fits perfectly under the engine, so I don't want to modify it. I'm going to call Wayne at Pacific Oil Cooler and see if they, as the manufacturer, have any objections to cutting the bottom mounting flange off with a cutting wheel. If they don't like the idea, I'll send the 102C back to them and ask them to alter it accordingly or supply a cooler without a lower mounting flange. Pics later in the week.

Brad Donner
NC86916
 
Sorry for the very delayed post on the oil cooler installation, but I had the bad luck to be in a car wreck - hit by a ditzy teenage girl who was 'multi-tasking' (texting and driving).

But enough about dumb teenage girls and their cell phones - the oil cooler installation! My airplane has a very elaborate air duct / plenum that routes air from the nose bowl to the front face of the oil cooler. The duct continues in a much smaller dimension UNDER the oil cooler - this air goes to the carburetor. Very elaborate, to say the least.

I ended up cutting the bottom mounting flange off my 102C cooler so the cooler would match the height of the air duct. That magnified the fact that the 102C cooler is significantly narrower than the original Fedders cooler and hence, narrower than the duct / plenum that comes off the nose bowl. So what to do about the extra width of the duct and the fact that it will now be routing a bunch of air over the sides of my oil cooler instead of through the cooler itself? I elected to attach aluminum ramps / angles / widgets to the inside of my air duct. They are bent 45 degrees and come to rest against the front flange of the oil cooler. I mitigated the metal to metal contact between the ramps and the face of the oil cooler with baffle seal material attached to the back of the ramp. The initial fit of the ramps inside the air duct is shown in the attached pic.

I also contacted the FSDO that approved my 337 for this installation and asked if we could file an addendum or update that documents this aspect of the installation. The maintenance inspector approved and was appreciative of my willingness to show how the installation was actually done. He said my installation instructions would be classified as an addendum for informational purposes only and would not require a new 337 or compromise the 'approved' status of the 337 that I have in hand.

Best Wishes,
Brad Donner
NC86916
 
Some more installation pics:

As mentioned before, the plenum is wider than the new cooler and the peanut gallery concluded that the air going around the sides of the narrower cooler might disrupt airflow through the face of the cooler, which would suck.

My solution was two air dams / widgets that I made from .032 aluminum. Bent to the proper angles; alodined / primed / painted; then I attached a length of engine baffle seal material to the back side of the air dams to prevent the aluminum air dam from sawing or rubbing a hole into the aluminum oil cooler. The screws and nuts that attach the baffle seal material are reversed from the convention (my screw heads are aft) so the sharp end of the screw shaft doesn't rub a hole into the face of the oil cooler. If I ever do this again, I'll rivet the baffle seal material to the air dam instead of using screws and nuts.

The oil temp probe extension off the Fedders cooler is too long for the new cooler and mine had 'issues' with the condition of the threads, so POC is machining a shorter extension for my installation.
 
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