Thorp Air Command - T18.net

Hey guys,

Great fun flying. Been doing wheel landings and I think I got the hang of it. Just need practice now to make it look good. Got some really good help from a great anonymous guy over the course of several occasions. Sure smashing a lot of bugs since weather is good now. Looking forward to do some trips when I can. Only 16 hours to go.

Being completely new at this, I spent 2 hours in the beginning just getting used to operating the engine, taxiing, and trying to keep it straight, etc. I did some run-ups with the tail tied down. Unfortunately, I think there was trouble breaking-in the engine, but I didn't have much choice. I wasn't going to just jump in and take off with it. Everything I read and hear says to run a new (rebuilt) engine hard with straight mineral oil in order to seat the rings. CHT seemed to drop significantly at about 7 hours. The engine has 24 hours on it now and twice I had to clean fouled plugs. No. 4 bottom plug is especially oily, so I'm thinking I'll have to get it honed again and new rings (?) A big job, yeah, that's the question. Others not quite as bad but still a small trace of oil and still dirty. I had a regular shop do the original work on the pistons/cylinders/valves; 3 are nitrided-type, but No. 4 was a replacement Cermi-Nil. I think all had the same type of rings.

Ok around home for a few hours at a time, but no long trips for me until I get this fixed. Tell me this is normal and it will all go away by itself overnight.

Les Krumel,
Albuquerque

You go girl ! Regarding the cylinders , has U done a compression check ? Dan in the Valley I think is a motor guy and might have an answer to the engine rumble in the jungle !

RB

Still wondering about engine break-in. Ordered a differential pressure tester and I'll report compression values when I can. Hoping oil consumption will drop off since I don't want to go far and get stranded with fouled plugs.

Meanwhile, here's an early video trying to get the hang of flying a T-18 and doing wheel landings. It's a real hoot! Be sure to use sound and full screen ... Les.


https://vimeo.com/170736737

Password for video is: 0E0Rwy26#

Les, my three cents worth. First I changed to REM37BY plugs, These plugs do not foul easy. Tempest are the best. First run, ran engine at idle (900rpm) until I saw the temperatures start to rise, shut down and let it cool. Restart and increased rpm's 100 until I saw a temperature rise, until reaching 2000, letting it cool between 100 rpm increases. Each time checked for oil, fuel etc. leaks. Did have to clean the lower plugs a couple of times during this run. Buttoned the cowl and flew at max rpm for 1/2 hour flight , came back and landed and checked foe leaks, etc. Each time I flew it it was a max throttle until about 3 hours of flight then all the tempatures dropped well into the green. It did use a quart or two. Been flying it for 1300 hours and oil consumption is quart in 10 hours. I did have to clean the plugs one time during this time. Also the only time I have ore than 6 qts is on a long cross country. I had cermiNil cylinders and not a fan of them ,changed to lycoming at 150 hours

I ran my Aero Sport Power 0-360 zero time as close to full power for the first 10 hours with 100 shell mineral oil , per Aero Sport Power . Limiting ground idle as much as possible . The engine came with a set of UREM37BY plugs and have used them since . Oil consumption is about 1 qt per 10/15 hours. All cylinders are 79/80 . Oil analysis normal .

RB

RB is correct, running the engine at high power (mixture on the rich side) will seat the rings due to the high pressure within the cylinder is the way to go. Watch the CHT temps and try to keep them 400 Deg. and below. You may want to contact ECI (now continental) for the correct rings for the Cermi nil cylinder, if you are using steel barrels on the other 3 cylinders they may be chrome rings and not a good match for the Cermi nil cylinder.

Phil

I think we maybe twisting the knife a bit here. I'm sure Les knows the correct break in procedure. Les, I'd take Bills advice first, if that does not help pulling the jugs, re honing and slapping a fresh set of rings on is not a huge undertaking, I've done it o. A weekend day. In the end it may give you some piece of mind knowing it was done right.

_________________
Lee Walton
Houston, TX
N51863,N118LW
KEFD

What Lee said!

_________________
Bob Highley
N711SH
SN 835
KLAL

Thanks Lee, and the rest of you guys. I do have the REM37BY plugs, suggested by Cubes as well. Got the compression tester and will post results when I can. I think my plan will be to clean the plugs and at least get my 40 hrs done. That should be a pleasant milestone.

Les

Engine Break-in. Here's the compression numbers: 72, 78, 70, 78 on a hot engine, 26 hrs. I expected that last one to be worst. No. 4 is the one to show signs of oil on the plug. Whadya fellas think?

Les Krumel,
Albuquerque

Run it for ten to twenty more hours. Watch oil consumption. By now, you should get about eight hours per quart or more. Lycoming allows up to two hours per quart, but that won't do. If your oil consumption gets worse as you go along, something is happening. A compression check only checks rings at the top of the stroke. There is a phenomenon where the ring gaps line up and allow oil to seep past while the engine is at rest (off), and thus, foul the bottom plug. I have had an issue where the nickel blistered off my Cerminil cylinders. This manifested itself in rapidly increasing oil consumption.



This is the worst of the lot, however all of my ECi cylinders showed signs of failure after about 36 hours. Again, oil consumption was the main indicator. If I were you, I would have the offending cylinder bore-scoped with the piston at BDC.

Let us know what you find.

_________________
Bob Highley
N711SH
SN 835
KLAL

The picture in the last post was after we tried to hone the cylinder.

Another view.

_________________
Bob Highley
N711SH
SN 835
KLAL

What cylinder has the lowest compression and the oil fowling ? If it is the ECI and you have chrome rings they will never seat correctly in that cylinder.
Phil

Hey fellas, here's another update on 48LK:

Just re-honed the cylinders and got new rings. Got tired of oil fouling plugs and afraid to go more than an hour. Yes, one is CermiNil and it has different rings than the other steel ones. Including it, two others were kinda bad so I bit the bullet and did the whole job over. Now 5 hours since and doing well - no taxi testing - just full throttle, 2600 rpm after initial checks and cool downs per Lycoming Service Instruction. Been getting 165 kts, flying 7500 MSL. That's as low as I can go around here, and it gets kinda bumpy at 1000 AGL. CHT's low with rich mix, ~11 gph, EGT 1250F. Oil 185F and replaced about a quart so far. Engine sounds good and no oil fouling this time; don't ask me why. Airplane has 37 hrs total, and should be free from limitations in another nice morning or two. Planning my 1st cross country for family reunion in 10 days. Been looking forward to flying this thing home for years and years. 780 nm, but we’ll try a short hop to Amarillo with wife aboard this weekend to see what she thinks. Doing wheel landings - about 50/50 good and bad. But have walked away from all of them so far, so that's good.

Hoping to get to the KY Dam fly in if they have it this fall, and of course another time at Sedona. Hope all is well with the rest of you.

Les Krumel, 1187
Albuquerque

That all sounds really good, Les! I've sure enjoyed your updates!

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John Evens
Arvada, Colorado
T-18 N71JE (sold)
Kitfox 7 SS N27JE