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Old 07-11-2003, 10:14 PM
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John Murdoch
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Old 07-14-2003, 11:42 PM
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Default I've had none...

and really love the motor...It ran well right out of the box, and has given me increasing power as it has broken in.

What problems have you had?

Lets talk about them here so everyone can benefit....
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Old 07-15-2003, 12:00 AM
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For those of you who would like to know. This guy is disgruntled with his BME50 and wants to burn us down. He is threatening us and cursing us. If anyone would like to see the other side of his story please e-mail us.


Keith
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Old 07-15-2003, 12:37 AM
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Kris^
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Default Patience, John-san

Before this gets blown out of proportion, I'd like to hear what the problem is, John. If you are unhappy with the engine, I'm sure there must be a reason. How bout giving us a look at the problem. . maybe the collective knowledge base of RCU can figure out a fix.
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Old 07-15-2003, 12:40 AM
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One additional thing. . .do you have a picture of the engine, installed on your plane? Always helps to be able to see the installation. I once fixed a guys "horrible running" engine by merely turning the cover plate for the pressure regulator 90 degrees, so that the vent hole was not facing directly into the prop wash, but was under the lip of the cowl, in calm air. Engine ran great after that.
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Old 07-15-2003, 12:49 AM
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walton
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Your already trashing them. Why don't you go ahead and spill the beans so we can hear both sides?
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Old 07-15-2003, 12:52 AM
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Kris^
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let me see. . .flak jacket, helmet, flame retardent clothing, foxhole with sandbags, 2-week supply of food and water, gas mask and MOPP suit. . . . .Yup. .ready for this one. . . . . .
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Old 07-15-2003, 01:33 AM
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While we have the dynamic Duo here, I have a question on a new non-Evo 102 BME. Here are the basics. About 3 gallons through the motor. Running a Menz-S 26x10. Tachs 6300 rpm. Sounds and runs good on the ground. Runs good in the air for 5-6 minutes, then starts to sag and lose power. Checked the cylinder temperatures and it's very hot (260F on both cylinders). The cowl is baffled. Tried richening the mixture and it just never makes good power. Flew it without the cowl, both cylinders now around 205F, but still sagged aft 6 minutes in the air (at full throttle). Fuel was Lawnboy 32:1. Tried a couple of tanks of Mobil MX2T synthetic, same problem (maybe it ran a little longer before it started to sag). Engine has good compression hot or cold. Swapped ignitions, no difference. When the cowl was off, noticed some oil around the snout of the crank. Thinking maybe it's a crank seal leaking air? Or is a Menz-S 26x10 too much prop for this motor?

It's not my motor, but yesterday I was trying to help the owner who has been struggling since last season with it.
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Old 07-15-2003, 01:46 AM
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Kris^
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Definitely getting too hot, Diablo. Any motor getting over 180-200 degree is gonna be in trouble, IMHO.

The coolest running oil I've tried is the Amsoil 100:1 synthetic, at about 90:1 ratio (one 8 ounce bottle to 5.5 gallons of gas) Every engine that I had which got hot using other oils now runs much better and never overheats, using the Amsoil. Maybe its just me, or maybe I am getting lucky, but it seemed to definitely improve things. . As well, Jason S. said they did back-back tests with Amsoil 50:1 series 2000 and the 100:1 synthetic, and the 100:1 was notieceably cooler, by about 25-30 degrees.

As for cowl baffling, all the baffling in the world will do absolutely no good if there is not a low pressure area for the heated air to dump into. I ahve not seen your friends setup, but you might want to check to see if he has a good 1/2" tall lip on the front of the air exit from the cowl, and about 8-10" of cear space behind the opening so that the air can flow easily out of the cowl. On my planes, I also make a relief in front of the LG plate, so that there is a back and down angle from the firewall to the gear. Anything to get the air down and out of the cowl will help. also, sealing the top of the cowl so that no air gets bhind the motor plate will make sure that ALL the air goes over those cylinders. i use a piece of .010" aluminum sheet that goes across the cowl, and angles forward and upward, to seal the air into the front of the cowl and force it over the fins.

All the 'ducting" in the world does no good, though, if the air does not come out of the cowl. This is the area I would concentrate on the most, and switching to Amsoil 100:1 synthetic can not be a bad thing, either.

Hope this helps, and please keep us all informed.
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Old 07-15-2003, 01:54 AM
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Thanks Kris. I agree it's a heat problem, but there must be something mechanical that's putting it on the path to thermal meltdown. We couldn't keep it cool enough to prevent sagging after 6 minutes even without the cowl. I would think that any engine sticking out in the breeze at 60+ mph should stay cool enough. The owner will call Keith.

PS, what about prop load? These can handle a Menz-S 26x10.......? Right?
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Old 07-15-2003, 02:16 AM
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If it was mechanical, Diablo, it would take a lot less than 6 minutes to cause a problem . .more like 60 seconds or so. You'd lose a bearing, or seize a piston in a cylinder, or something like that.

One other thing. . the older 5.8/6.2 engines LIKED to rev .. they ran cooler that way for some silly reason. I ran a 26-10 Mejzlik, or even a 26-10N Mejzlik, which is a prop with a lot less drag than a Menz-s 26-10, even though the Menz is 3/8" smaller in diameter. Keith used to really brag about that "6400 with a Menz-s 26-10" quote, but I found the engine was a LOT happier zinging up to about 6700-6800 rpm, and unloading in the air a bit more.

Personally. . I'd run a 26-10 Mejzlik on an old style 102/6.2, and a 26-10N on a 5.8 or first generation 6.2 upgrade. Let 'er spin. . I think you will see a difference, and it will sound OH so good ! !
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Old 07-15-2003, 03:01 AM
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Default Engine Problems

In 16 years of repairing engines, very few few "problems" were the fault of the engine...You would not believe some of the things people do and blame the engine....ANY manufacurer or representative will almost bend over backwards to resolve a real or supposed problem....There are a few notable exceptions, both of them are no longer around.....
One of the most frequent problems involves the supposed "factory" needle valve settings..Whose factory ? Walbro ? Walbro carbs come from Walbro with the needles open somewhere around 1 1/2 turns open..If the company that uses them doesn't run each engine there is no way that setting can be right...Simply learning how to adjust your own carb will go a long way..
I am a VERY small retailer..Every engine is run and set with a prop of the size usually run with that engine...Due to the altitude here (7000 feet) this setting will usually be too lean everywhere else, so the carbs are opened up slightly to compensate..Sometimes it's right, sometimes not...Adjusting a carb is something the user should be able to do himself...
My .02...
I have no idea what the problem with the BME is, and this is in NO WAY a reflection on ANYONE, just a general observation...
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Old 07-15-2003, 03:03 AM
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John Murdoch
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RCE... You're absolutely correct. I know, given the time, I'll get my motor running like it did when it was new....
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Old 07-16-2003, 06:59 PM
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Wow. This is painful.
Diablo: Kris is right. I was having all the same problems you mentioned. Ducting appears to be very important, mine seems to run cooler with a ducted cowl that without a cowl - go figure. Its very important to make sure the air runs over the tops of the cylinders and has a large exit - 3 to 1 inlet to exit isnt enough, it needs closer to 4 to 1. I started with no ducting, and overheated rapidly, then ducted about 1/4 inch above the bottom of the jugs and got good results but still a tad warm, moved the ducting up to 1/2 inch above the bottom of the jugs and that seems to be the right spot. Also, I tried an NX26x10, a MenzS26x10, a Mezjlik 26x10 and 26x10n, best pull came from the Mezjlik 26x10 turning about 6500rpm, the coolest run was with the 26x10n at 6800rpm, but it doesnt have quite the vertical, and rips very easily in the air and I have noise issues to contend with.
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Old 07-16-2003, 07:17 PM
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Just out of curiousity what is the max acceptable temp for a bme102?
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Old 07-16-2003, 11:40 PM
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It almost sounds like a fuel system problem, especially if it seems to consistantly have a problem so many minutes into a flight. Things I would check for are a split in the clunk line which allows the engine to suck air after the fuel level drops to a certain point; clunk fell off or is touching the back of the fuel tank; vent tube touching the top of the fuel tank. If the plane has a fueling device/valve it would be highly suspect. If the diaphram(sp) has been vented make sure the tubing is not melted from touching a cylinder.

It might be worth mounting it on the bench and running it. If it shows no signs of a problem after 6 minutes then the problem is in the airplane (airflow, fuel system, etc)

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Old 07-17-2003, 12:57 AM
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Guys....I have flown nothing but BME for the last 5 years and never have ducted my cowl for cooling my engines......and have never had an over heating problem.....lived in Georgia the last 3 years and just moved to Florida so its hot. I truley believe that if people would stop tweaking the heck out of them to to get every last RPM they wouldn't need to be concerned about cooling. At the same time I do believe certain installations and cowl design obviously can affect cooling so I can see it as an issue in some cases.

Also during this time I have run nothing but Amsoil.....100:1 1st then the 50:1 the last 2 years and prefer the 50:1. I will never ever use lawnboy again for break-in either....I did that a few years ago on a BME100 and it carboned up stuck rings and I had to send it back....whcih led me to think about the problems I used to have with my Quadra and Brisons. I run Amsoil right from the get go set rich and my last 2 engines have come on beautifully for power.

As to a motor running a certain amount of time and then quitting.....well that has nothing to do with the motor itself....it wouldn't take any more than a minute for a problem to show up, if that. As someone said in an earlier post you can usually side with user error....and if a user is too hard headed and usually not as smart as they think they end up with problems. My guess is that its an ignition issue....I have had cases on some singles in the past where after a while it would start missing in the air badly and come down hot. After cooling it would run fine on the ground...then I'd take off and in a few minutes the same problem. Each time I would send in an ignition CH would replace the leads and my problems were solved. Seems the materials in the leads can and do break down over time and when they get hot the insulating characteristics worsen and the problem shows up. It doesn't take much to picture that exact scenario showing up after a certain amount of minutes each time.

Perry
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Old 07-17-2003, 01:32 AM
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Hey Perry, Ted (the prop guy) here.
Again...not my motor, but we've tried all the logical things.
Swapped ignitions from another BME that didn't have a problem.
That didn't fix it. Switched gas/oil to Mobil 1 MX2T (32:1) that works fine in my ZDZ and 3W-100. BME ran a little better but still sagged 6 minutes into flight. Took the cowl completely off. Engine ran much cooler (200F instead of 260F), but still sagged before 10 minutes of flying. Set the high needle 1/4 turn richer on the ground (also tried 1/8 turn richer), and the engine just ran without power in the air (no vertical).

I will bet a dollar to a donut that it is a mechanical problem or a fuel delivery problem. The engine does not turn over as freely by hand as other twins (tight bearing?, twisted crank?) and the nose of the crank is wet with oil (likely bad crank seal) - not a lot of oil, but I don't like to see any oil.

This is not a BME bash. The owner has a BME-76 that runs great.

Len, good thoughts on the fuel tank. If the tank isn't vented properly it could just get leaner and leaner through a flight. We'll check the fuel system out.
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Old 07-17-2003, 01:51 AM
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Hey there Ted! Got any 27x10's in stock? only kidding at the moment.

Ok now I traced it back to the BME102 post...thought someone else was having a problem with a 50 too that refuses user error.

Yeah your non EVO 102 probably needs to have the front seal replaced. And its probably a 3 bearing version...which I think they all are now but that was one of the 1st. My non-EVO 102 turns a 27x10 Menz S (from you) at 6100...last I flew it. My EVO was about the same maybe 100 rpm stronger but haven't tached it down here in Florida yet. That motor should turn the 26x10 S at 6500....Daves was screaming last year at 6600/6700 up there in Chicagoland.

Now that I understand your issue more, just call Keith and send it on in.

Perry
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