Boot Cowl install problem with 0-235

[Wayne Vance]

I have built a Wag Aero Sport trainer patterned on a PA 11 with modifications of a PA 18 tail, gear, struts and wing tanks. The airframe is nearly complete and I just mounted an O-235 with a standard Lycoming cub PA 18 mount, and discovered the engine oil filter sits just above the boot cowl. It is easy enough to change out to a straight filter screen and the cowl would clear (just) I measured a PA 18 firewall and discovered it is about 3 to 4 inches taller than my (PA 11). Has anyone encountered this problem and is it really a problem? I still have to construct the engine cowl so it's anything goes at this point or do I need to back up and rebuild the entire firewall/boot cowl. Second question is which nose bowl is right? I don't believe the PA 18 bowl will work under this configuration because it would make the entire engine cowl slope up from the boot which would look and be terrible. I realize it's a long question but thanks for the help

 

[citabrickr]

You haven't given enough info to be able to give you an answer. I assume you're meaning the oil "filter" is sticking above the boot cowl, not cooler? Also, you say it's a Wag J-3, with PA-11 mods...so what boot cowl do you have? Either way you say you are using a PA-18 cowling? You have a lot of dissimilar parts trying to go together. Is the mount a Lycoming mount for a J-3 or PA-18? No matter how you slice it you've created a real worm casserole. I think you're going to end up with an open J-3 style cowl or will be building a custom boot cowl. At least you're experimental!

 

[Luke_theDrifter]

0-235 doesn't use an oil cooler on a PA-11......maybe it does on the copy-cat version. Are you trying to mount the oil cooler on the rear baffle like a Cub? Maybe this answer your front cowling issue also...on a PA-11 there is a hole for in the center for the crank/prop and then the small hole for the starter nose.....NO oil cooler hole in the front because this engine doesn't use an oil cooler.

....> Respectfully, not to mention this is a junk engine that doesn't produce adaquate horsepower (107/108) and espesailly the top "rated" 115 hp that is un-achievable because it can't/won't turn RPM that high, can't run a big prop because it has the small crank flange, plus you have an engine that is hard to get parts for, known history of cracked jugs & stuck valves.... and cost [rebuild] more that a common 0-320.

 

[Fortysix12]

Do you have the short oil filter intalled. And second, a firewall mounted oil filter would solve your problem. Airwolf makes ones. I know someone who might want to sell his used one.

 

[JimC]

Might be a good time to mention that the nosebowl that Wag-Aero sells as a PA11 bowl isn't one. It appears to be a PA17 bowl instead, and has significant differences from the 11 nosebowl.
JimC

 

[DaveG]

A quick look through the PA-18 parts manual shows the PA-18 Firewall as PN 12365. This is the firewall for the early Lycoming powered cubs.
Christian Strums site also has the drawing for the PA-11 firewall PN 10792.
The PA-11 firewall fits a C-90.
The PA-18 firewall is 1.24 inches taller (above the upper mount bolts). Probably to fit the taller Lycoming engine.
DaveG