Brison Rattle
 

I just bought my first gas engine. After years of slimers, I decided to try a Brison 3.2. I am at the bottom of the learning curve, and need some reassurance. I have about a gallon of fuel through the engine. I have noticed that there is some slop between the piston and crankshaft. I have assumed that the slop is the play in the needle bearings. It seems more prevalent when warm. The engine runs extremely well, but at idle, I can hear that rattle. Is anything wrong, or am I make a mountain out of nothing? I am running pure synthetic oil, at 80:1, per Brison's manual. 100:1 is my eventual goal, once broken in. Thanks, in advance, for your help!

Andy

RE: Brison Rattle
 

Ahh... This is a Brison 3.2. I doubt if there is anything wrong here. In its first life as a chain saw it was designed to be abused. You might try adjusting the low speed mixture. Now if it was an older DA-50 with these sounds with some of the known problems, I would ship it back.

RE: Brison Rattle
 

Thanks for the input! Before I leaned the low end, I didn't notice the rattle. However, the idle wasn't very steady. After leaning it out, suddenly the rattle appeared. I may be a tad too lean, as the acceleration is a little sluggish, in my ignorant opinion. When I ritchened it 2 or 3 degree's, the unsteady idle returned. My max RPM on an APC 22X10 is 6900 RPM, which I thought sounded about right. Could my high end be off enough to make the low end setting touchy?

Thanks Again!

Andy
Go Packers! Please!

RE: Brison Rattle
 

Only thing on the Brison 3.2 that started life as a chainsaw is the piston, cylinder, and carb.The crank is their own design...They guarantee the crank for 5 years so you could send it back and let them check it out...A cantilever crank is typically a little looser on the big end than the chainsaw type...
The high needle has no effect on the low[8D]

RE: Brison Rattle
 

You can do whatever you want but I would not be using 80:1 in a new engine. I have a 10 year old Brison 2.4 and I don't care what anyone says I still use 50:1 without a hitch.

RE: Brison Rattle
 

I have had 2-2.4ci and 1-3.2ci and they all are like this.
Nothing wrong with the engine. Just how it feels!

RE: Brison Rattle
 

Thanks guy's! I feel better now. A little concerned about the oil mixture though. Brison warns about using too much oil and messing up the piston and ring. Like Don, I question the 100:1 with the synthetic. With my chainsaw and weed wacker, I have always used 50:1 and 32:1. Of course, that is petrolium based oil, which Brison recommends against. Any other thought on that subject?

I really appreciate you guy's sharing from your experience! Thanks!

Andy

RE: Brison Rattle
 

Nobody knows this engine better Gary Allison, owner of Brison. Just do what he recomends & forget it. The Brison doesn't need a break-in period like other engines. My 3.2 has 2 1/2 gal through it, & turns a 3W 22/8 @ 7,470. My next move is to go to a 23/8 prop & 85:1 oil mix. Don't try to reinvent the wheel. You have a great engine, go run the whoopie out of it, that's what it likes.

RE: Brison Rattle
 

Thanks Torqmeister!

RE: Brison Rattle
 

I have been using Amsoil at 100:1 in my Brisons for years. never a problem.

RE: Brison Rattle
 

The Brison manual states that a good synthetic oil, mixed at a ratio of 80-1, should be used on all of their engines from day one. One of my 3.2's has five years on it and it runs just fine. The others have between 1 and 2 years and they also run fine at that oil mix. My 6.4 is run at exactly the same ratio with no worries at all.

It's difficult to go wrong when you go with the manufacturers recommendations.

Pat

RE: Brison Rattle
 

Thanks Again! The synthetics are new to me, so I guess I am a little tentative. I tried to find Amsoil, and struck out. I heard of people having success with the Mobil Synthetic, so I am using that for now. A few hours after I bought the Mobil, I found a local source for Amsoil. I will switch to that once I use up the Mobil.

Our club just got a new field, and no longer have to fly off a postage stamp. I am the first to switch to gas, but many others are planning to make the change also, since we now have room for larger aircraft. I guess this makes me the club expert:D. The guy's that have seen and heard this engine, well, lets just say it wet their appetite. I'm not planning to fly it until the new runway is in, in the spring. It is going to be a long winter!:eek:

Andy

RE: Brison Rattle
 

I use Mobil 0ne MX2T, & I like it. How much are spending on Amsoil?

RE: Brison Rattle
 

The lower the idle the more rattle ya get is normal , Idle should be around 1800 rpms any lower than that and it will rattle .
I have been using amsoill 100:1 for years mixed at 100:1 in all my engines( airplane and utility ) with no problems at all .
Not preaching amsoil just sharing experience. Use it with confidence (or any mfg oil for that matter) as long as you use it as they describe (mix it in the proper ratio)

RE: Brison Rattle
 

I have also noticed on my 3.2 that a large (5") aluminium spinner seems to make the rattle much louder. I have considered putting some new rod bearings in, but just never got around to it.:eek:

RE: Brison Rattle
 

I purchased a used Brison 3.2 last year that I was worried about and after talking to Mr. Brison:), I installed a new rod bearing($3.00) in it for general principles. My 3.2 idles beautifully at 1700 rpms with no perceivable/audible rattle.

RE: Brison Rattle
 

Thanks for all the information! I will fly it as is, and see what happens. I did notice that the lower the idle, the more noticeable it is. Since this seems to be the norm, I won't sweat it anymore.;)

Andy