Inner crank plug for fixed pitch

crabandy · #1 11-24-2015, 07:52 PM

My engine is "experimental." I was told it was a core from an enstrom helicopter, best I can tell it was an HIO-360-A1F6D refitted with 8.5 compression cylinders and a carb to more resemble a O-360-A1F6D. My understanding was it was a "solid" crank and I've been running a Catto fixed pitch. Is it possible to run a constant speed prop with this crank assuming the gears in the accessory case are correct to run a governor?
I just removed my outer crank plug due to a minor leak. It appears there is not an inner plug in my crank, on the other hand I can't tell how the oil is supposed to drain. Does the inside of my crank look "normal?"

RV6_flyer · #2 11-24-2015, 08:32 PM

I see a crank setup for Constant Speed Prop operation. The SET SCREW in the middle of the plug needs to be removed for Fixed Pitch operation before you reinstall a front plug.

IF the crankcase has a plug on the outside for a governor line and the accessory case is machined to accept a Governor Drive Adapter, it may be able to be used with a Constant Speed Prop.

See Lycoming SI-1435 on instructions to convert.

Looking up the DASH number, the engine appears to be a 180 HP parallel valve engine with a single dual mag for ignition. I am making the assumption that this accessory case is similar to the ones that have provisions for dual mags when I stated if the accessory case is machined for the Prop Governor Drive Adaptor. Some engines have the governor mounted in front of cylinder #2 and I am not familiar which dash numbers had that configuration.

krw5927 · #3 11-25-2015, 06:54 AM

Would the presence of the rear plug, when being used for fixed pitch, explain Andy's small leak out the front plug?

It sounds like both plugs were in place all along?

A previous post by Mel indicates running with both plugs installed can get rather exciting:
http://www.vansairforce.com/communit...24&postcount=2

RV6_flyer · #4 11-25-2015, 08:50 AM

Quote:

Originally Posted by krw5927

Would the presence of the rear plug, when being used for fixed pitch, explain Andy's small leak out the front plug?

It sounds like both plugs were in place all along?

A previous post by Mel indicates running with both plugs installed can get rather exciting:
http://www.vansairforce.com/communit...24&postcount=2

Never ran an engine with both. According to Mel's post in the link above, I operate with the same motto. Trust but Verify! I once had an FAA Inspector tell me: "In God we trust, everyone else we verify."

crabandy · #5 11-25-2015, 09:13 AM

I think my pic shows the machined surface of the crank after the plug was removed, checkout the pics on Brantel's constant speed conversion post #3.

http://www.vansairforce.com/communit...ght=crank+plug

krw5927 · #6 11-25-2015, 10:40 AM

This is my first rodeo with crank plugs so I'm probably wrong, but the very center of the crank in your pic sure looks like a hex recess for a pipe plug. A pipe plug is one of the 2 possible setups for the rear crank plug according to the Lycoming document that Gary referenced in post #2.

Hopefully someone with more engine experience will chime in.

This has me wanting to remove the front plug of my Titan OX340 (fixed pitch) to make sure the rear plug is either pierced or missing. I ordered the engine setup for fixed pitch, but the common wisdom "trust but verify" seems prudent.

crabandy · #7 11-25-2015, 01:44 PM

After further checking it appears it is the #1102 pipe plug as depicted in SI-1435. Bob from Aircraft Specialties said it does look like the HIO crank and I should be able to remove the plug with an Allen wrench. I also did some probing with a piece of safety wire and a better light and it is a pipe plug, the funny reflections and gunk had me thinking otherwise. Now I need to find/make a 7+ inch long Allen wrench.

When I bought the engine I was told it was a fixed pitch only engine and I never bothered to double check. Not that I even knew what to check for. My front crank plug must have been installed very well, it made it over 160 hours leaking only the last 15-20 hours. Thinking about loosing that plug inflight gives me the shivers.....

I'm so glad I decided to chase this oil leak down, it wasn't the quantity of oil but that it was new and different. Just a few nickel and dime oil drips on the inside of the lower cowling, very clean oil. After looking closer with a good light I could see Clean oil spatter was underneath the right side of the cylinder baffling but that was it.

crabandy · #8 11-25-2015, 10:54 PM

As tempted as I was to buy some Harbor Freight Allen wrenches to cut up I spent a little more $$ for less chance of rounding the plug out. It took me longer to get the Allen wrenches out of the package than to cut the end off with the die grinder. They had some nice T-handle Allen wrenches but were right at the minimum required 7 inch length and double the $$. The 3/16 Allen wrench in place on the plug.

It took all the torque I was willing to give the 1/4 inch drive to break it loose, I didn't have a 3/16 socket in 3/8 drive. A little sigh of relief when it broke loose. I suppose I could've looked into using the governer port as a oil relief drain if it didn not come out.

Inner crank with the plug removed.