BME 110 Mounting Dimensions

[AHP]

Can someone provide me with the BME 110's mounting dimension? The engine is on its way and is being mounted in a H9 33% Cap.

[KrisW]

Center-Center of the mounting holes is approximately 3 1/8", in the X and Y axes.

Overall length, firewall to prop hub, is approximately 6"

Overall width is about 10 3/8".

Propellor hub center hole is 7/16", and the two anti-rotation studs are on the same bolt circle as the SMALL 3W pattern used in the 80-100cc engines. Newer hubs come with a 6-bolt pattern already in place. The retaining nut and stud are 8mm x 1.5 thread.

Be sure to use a full-coverage firewall/spacer system, where the entire ring mount is supported on a solid piece of wood or metal. Attempting to mount the engine with standoffs that only contact the mount at the mounting holes WILL result in a broken mounting ring.

For firewall setup, drill four 1/4" holes on the 3 1/8" pattern, then use 10-32 bolts with T-nuts (blind nuts) on the back of the firewall. This will allow a slight amount of "mismatch fit" for the bolts to easily slide into the mount, since the mounting holes are not exactly 3 1/8" (actually, it's closer to 3 3/32", but it's a metric value that is very difficult to transpose to SAE measurements). Once the firewall is compressed by the mounting ring, it will never move or slip.

Be sure to double check the motor mounting bolts after a few flights to make sure they are tight.

Other things to check on the engine:

Red loctite the carburetor throttle plate screw. They can sometimes loosen, and though the staking of the screw will prevent it from totally backing out, the throttle blade will flop around, damaging it and the carburetor bore. It's best to just make sure it can never loosen before you start the engine.

The throttle arm is drilled for 1/16" holes. They will have to be enlarged if you use a clevis or ball link. Not enlarging them will result in a broken throttle arm.

Use 50:1 petroleum based gas-oil mix for break-in. I, personally, recommend 8-10 gallons of beak-in mix. Then, switch to 100:1 Amsoil Sabre, mixed at 80:1 if it is hot conditions, or 100:1 in cooler times (such as late Fall to Early Spring..)

Recommended props: I've successfully broken in the BME110's on the Mejzlik 28-10. Using a Menz-style 27-10 will allow the engine to rev more freely, but will also be much noisier.

Be sure to use GOOD baffling for adequate cooling. It's also a good idea to not do a lot of torque rolling until the engine is properly broken in.

To ensure against prop slippage. . you MUST use the anti-rotation pins. A personal technique I use is to apply Thick CA between the prop and spinner backplate, and bolt it in place till the CA cures, then remove the "assembly" and balance the spinner and prop as a unit. This really helps a lot to alleviate any problems with prop slippage. The prop and backplate can be disassembled with a simple "knock" against something solid, if you need to change props.

Best of luck with your new 110. . They are great little engines.

[LookNatU2]

Could't have said it better KrisW...lol

[AHP]

Excellent! Thanks Kris!

[KrisW]

Since you are putting the 110 on a H9 Cap, you might consider the Vess 27-a prop in lieu of a Menz style 27-10. It's a good pulling prop that spools quickly, and is moderately quieter than the MEnz 27-10.

I "advise" (since BME says 87 octane) to run the engine on 89 octane if you are using standard in-cowl mufflers, and 92-93 octane gas if you bolt canister mufflers or a tuned exhaust system to the engine. Raising the octane will not hurt the engine or drop your power, but it will definitely help avoid any problems with detonation or pre-ignition.

If you need any further assistance or have questions, PM me off thread and I'll give you wnatever answers I can.

[bodywerks]

I got 3.041" if you want a tight fit, not that the other way isn't suitable.