Bass1

Got an older Brison 3.2 that has always been reliable and smooth running. It was recently involved in a crash. The carb was damaged and the timing linkage (mechanical advance) was bent and twisted. The crankshaft appears straight although it wasn't checked with a dial indicator. I installed a new WT 76A carb and gaskets and replaced the timing and throttle linkage. Checked and adjusted the timing as per manual at 28 degrees BFTDC at max throttle. The engine starts, idles and runs fantastic up until about 3/4 power/throttle. At about 6400/ 6500 rpm (Menz 22/8) it runs rough and misses slightly and sounds as if it is overheating even though it does this after a relatively short warmup of about 30 seconds (cowl on or off makes no difference). When I shut the engine down I notice the crankcase is EXTREMELY hot and takes forever to cool down. The muffler and cylinder cooling fins don't seem to be getting nearly as hot and cool down rather quickly. Brought the plane home and pulled the plug and turned it over by hand so see if I felt any resistance or roughness/grinding to see if the bearings had any obvious problems. It felt smooth and turns over freely. I have another Brison 3.2 (great running) and removed the plug to give it the same test for comparison and it felt identical. Been all over the needles and no amount of richening or leaning will alleviate the problem. Ignition battery checks out fine although I haven't tried bypassing the switch yet. Could the main crank/crankcase bearing be slipping/rotating in the case causing extreme crankcase heat? It appears fine by eyeballing it. Any ideas before I smash it to pieces?

w8ye

My Feedback: (16)

I would get the crank checked?

The Brison 3.2 has a cantilivered crank and is not double ended like some of the gas engines but it could have a bearing problem or be bent right out on the end?

The Double ended cranks get twisted like in a Zenoah G62 or a BME 50

CK1

My Feedback: (60)

I would check the crankshaft as already suggested plus the bearings are usualy damaged on an impact and this will cause the case to get hot as well, and a damaged bearing seal will lean the engine out too.
Most of the time it is usualy the bearings and not the crank but ..........

Bass1

Just thought I'd let everyone know the problem was a faulty Ignition. Borrowed one from another Brison engine I have and all is normal again. Going to try to rework the old one to see if it can be salvaged..

All Day Dan

My Feedback: (5)

Well that's good news. Thanks for posting the cause of the problem. It helps everyone out. I always have a spare ignition around especially at the field. Dan.

Bass1

Hey All Day, Just noticed that your post number and the date you joined RCU closely parallel my specs/history over here. Did you ever fly a Flite Streak with a green head K&B 19?[8D]

w8ye

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I used to fly C/L Flite Streaks. I liked to take off - fly out the tank of fuel - and land without ever moving my feet.

Bass1

Man that brings back memories. I think I was the guy that invented that stationary footed technique Sure helped when it was expertly built and light. A good Veco or Torpedo .19 would kite like fly the darn thing if built real light and flown on 60 foot lines. First noticable "floater" for me indeed. It did need a little more outside rudder with this setup[X(]. My first lesson in wing loading for sure!

w8ye

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I built my first Flite Streak in 1958 and it had a Fox 35.

By the late 60's I using the OS Max S35.

Seemed to me that Monokote weighed less than silkspan and dope and held up much better?

Seems like 26 oz complete dry was my goal? I used a 2 1/4 oz Perfect tank

Tried one with flaps. The distance of the flaps from the aerodynamic center was wrong and it ruined the maneuverability of the plane.

I had two K&B Torpedo 19's. My 1st one was so old (1952) it had a silver head. The second one was a green head though.

captinjohn

Man....you guys got me so excited....I think I will run to the Hobby shop and get a dozen or more ! YA... Green streak!!!!!!!!

Hobby shop said....you must mean Flight streak.

w8ye

My Feedback: (16)

Just Google Flite Streak. They were a Top Flite kit. One of Sid Axlerod's first. There are images etc that pop up. It had a milled leading edge that was hollowed out that would be the biggest obstacle to scratch building one. One might could save some weight by molding a leading edge? Then use a nylon tank and carbon pushrod. I bet you could build one at considerably less than 26 oz with a modern 25-34 and today's materials?

The plane could be flown the full pattern but was not smooth like a Nobler or even a Magician. It was originally sold as a combat plane but I liked them as a control line fun fly plane which they were better suited for.

All Day Dan

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bass, I had so many control line models so long ago I can barely remember them. I switched to RC around 1952 or 1953. A little while after that, it finally dawned on me why girls were different than boys. That was it for the models until I got out of college. Here are a couple of images to load up your thread. That's me with a Barnstormer and a recent shot of me with a pusher using a Brison 3.2. Dan.

Bass1

Dan, That Barnstormer photo looks like a shot straight out of a "Leave it to Beaver TV show! I built a Barnstormer back in the early 60s. Got a picture of it somewhere around here. Seems I remember the plans called for running the leadouts on the opposite wing so it flew a clockwise circle instead of counter clockwise. It's been so long ago I might have dreamed that though. W8ye, As far as the Flite Streaks, most of us were using .29 or .35 sized Fox or Veco and a few "red head" Mc Coy engines and they flew real good with those. Then one day (1964) in Newfoundland, a sailor gave me his beautifully built and painted Flite Streak with a Torpedo .19 on the nose. He had orders back to the states and couldn't bring it with him for some reason. I remember how lightly he had built/sanded it but was real skeptical about how it might fly with the measley .19 for power. To my shock, I had the most fun flying that plane. It was almost like flying today's 3-D models with it's super low wing loading. I also remember a school bus full of kids pulling over to watch me fly it standing in on place, not moving my feet doing consecutive inside loops then a series of outside loops to untwist the lines. Then lather , rinse and repeat the procedure[8D]! The loops were so tight they were almost unbelievable and it floated in for landings like a butterfly. AHH, Those were the good old days!!!

w8ye

My Feedback: (16)

Good post

I remember doing that with a Flite Streak. I think I had more fun flying a flite Streak that way than any other control line flying.

Monokote was a great weight saver. I never used the wheel.

I must have built a half dozen?

All the early silkspan ones had the original sweeping color scheme and colors.

In the very late 60's I used semi transparent Monokote with some trim do-dad pieces here and there.

Though I had several MCoy Red heads and the silver ones before that, I don't think I ever used a McCoy on a Flite Streak?

I used my 1958 Fox 35 and 1963 Fox 29 for years and the monokote ones had OS Max S35's in the late 60's.

Bass1

Looks like this thread has gone a bit off topic but what the heck, it's the 4th of July. We had it made while living on the Navy base in Argentia, Newfoundland. We had a fully stocked hobby shop and an awesome control line club in the basement of the library fully equipped with all the power tools you could ask for, airplane storage racks, personal lockers and dozens of 5 gallon cans of military issue clear and white dope and a great short grass flying field directly across the street. The hobby shop was next door with all the Flite Streaks and Ringmasters of all sizes and types for under $2.00 apiece. The Noblers and the more expensive Veco kits were a whopping $2.25. Can't remember what the Veco 29 and 35 engines cost at that shop as my dad would occasionally pick one or two up for me on the way home from work if I had been a good boy Oh yeah, and a bottle coke and a hershey bar were a nickle each for a grand total of 10 cents in the hobby shop vending machines. Candy, caffeine, Ambroid glue, clear dope fumes, model airplanes and great commraderie OH MY!!........ One more thing, upstairs in the library were all the Model Airplane News magazines you've ever seen!

Lifer

My Feedback: (1)

G21-35's, pen bladder fuel tanks, Sullivan lines and a half-dozen Nemesis. Lots of fun!

Bass1

2 years later after being problem free the trusty old Brison overheated several times yesterday. No amount of needle tweaking, carb screen cleaning solved sagging rpm and several deadstick landings. I'm thinking maybe bearing problems at this point maybe finally giving up the ghost from the 2 year old crash. I do hear a slight clicking sound when I rock the prop back and forth. Any tricks for removing and replacing bearings on this engine?

Truckracer

My Feedback: (19)

Does the engine still have normal compression? Sometimes, even with a straight crank and good bearings a stuck ring will cause the overheating symptoms you described. Just something else to check. Considering the age of the engine, it probably just needs a complete overhaul.

All Day Dan

My Feedback: (5)

Send it to Bill Jensen. Dan.

[email protected]

Bass1

Chain of events leading to problem. Engine had been running fantastic and my normal 2 stroke oil (Penzoil aircooled) is now hard to find in this area so I just switched over to Stihl XP Ultra synthetic. I decided to take the engine apart and clean off the caked carbon from the top of piston and top of cylinder with my Dremel and soft brush. I've done this several times over the years with good results. Cleaned the engine up nicely, replaced carb and cylinder gasket and retweaked the needles. Engine was running great. The following day (last week) I flew the airplane 4 -12 minute flights and the engine performed flawlessly. Went out to fly yesterday and cranked up the Brison and noticed rpm was down a few 100 revs from normal at full throttle. It was quite hot and humid so I attributed that to a possible density altitude thing. Went to check throttle response (after a decent warmup) from idle to a quick 3/4 throttle and the engine gained a few hundred rpm, bogged down and stayed there and sounded kind of funny. Tried it again but advance the throttle slowly and it throttled up but still a few hundred rpm lower than normal. Opened up the low needle 1/10 th turn (higher than the norm) and that didn't help. Opened up the high needle a tad and really lost rpm. Pulled cowl off, removed and checked needles for debris and no issue there. Checked the little carb screen it was clean. Squirted fuel in and blew out all orifices. Then changed out my CH Ignition with a spare. An hour later I cranked her up again and it seemed good with decent transition and better top end so I decided to fly. Throttle up to full power and right at the end of takeoff run The engine lost quite a bit of power. I had to takeoff or crash into thick corn rows. Nursed it back to runway. Stopped the engine and it felt real hot. I let it cool for 15 minutes opened up the high needle some (higher than the norm) and started it up. Started right up and went to full power and in about 4 or 5 second at full throttle it started to sag and lost a quick 500 rpm. That was it. I packed it in for the day. So here is where I'm at now. Was thinking bearing problem because everything else appears Ok. Compression feels good and no noticeable bearing noise or grinding. Just remember Gary's dad saying to replace crank pin needle bearing after a crash or prop strike. He said it might be fine for awhile but eventually it will fail or maybe be on the outs to create an overheating issue??. The engine was in crash several years ago with same bearing. Almost sounds to me like I forgot to put oil in my mix but I did the night before @1.25 oz to 1/2 gal. of gas to give me 50:1. Geez Long story long! Truckracer, when I decarboned the piston and cylinder the ring seemed fine and was floating however I did not clean the ring groove. Could the oil change play a part in a stuck ring possibly turning the old congealed oil in the groove into JB Weld lol? Trying to fix the problem without sending it in if possible. Between jobs and money is tighter than you know what!!

All Day Dan

My Feedback: (5)

Dumb question. Did you change the spark plug and/or sensor? Dan.

Bass1

I put a brand new plug in last week coinciding with the oil change and decarbonization. I pulled the plug after all the problems to check the color and still looked brand new. In fact it looked scarey brand new, all shiney. Not a sign of a light tan colorization nor hint of oil residue. If I had to make a choice I would say the plug looked like a lean running engine being so clean and still factory white on the inside. Didn't 't think to try a different sensor. By the way, The plug is gapped at .022. Seems that's what I've always used for that engine. Is that what you're gap
ping your plugs at? Starting to think there might be an air leak somewhere. Might have to pull the motor and go through everything on a test bench.

All Day Dan

My Feedback: (5)

I've been using .020 with the Brison 3.2 and a CH ignition. It is timed at 28 degrees BTC. Dan.

CK1

My Feedback: (60)

Bass1 ,A list of a few things I have found to cause simptoms similar to yours on Brison and other engines over the years.
Low ignition voltage - bad or discharged battery or switch.
Ignition timing incorrect .Its not difficult to get a Brison's timing linkage out of wack.
Cracked carb isolator block . Goes lean as it warms up .
Very rarely - an ignition sensor , but have seen them cause weird problems intermittently . Usualy a wiggle test or heat applied will cause problem to appear.
If there is an ignition kill switch or optical isolator - bypass them and test run
Carb diaghram gasket in wrong position? .gasket goes between diaghram and carb body