Fixed Wing

I have a DA100 with 3 gallons through it using Lawn Boy Ashless 2 cycle oil and a Biela 27x10 prop. I plan to run 4-5 gallons through it before changing to Amsol and a Menz 28x10. However, I got to wondering how do you really know when you have completed a thorough break-in? I know I should experience increased power and RPM against a given prop, however, on all my other gas engines this occurred gradually over time and continued well after 5 gallons. I'm turning 6,500 RPM with the Biela 27x10 but would rather load the motor to about 6,100 RPM. The Menz 28x10 will probably be about right but I don't want to load the motor up too soon. Any tips on knowing when a motor is ready for synthetic oils and heavier prop loads?

RickP

My Feedback: (2)

DA says to burn 4 gallons with the ashless. Then switch to synthetic. I have about one more flight left of my break in fuel and then will switch to Amsoil. They reccomend this based on experience. Hey, you can't argue with success...
RickP

JB Rekit

My Feedback: (3)

thats good for seating and sealing everything but I would say around 40 - 50 flights (30 gallons) before it is 100% broken in.

I did the 5 gallon lawnboy ashless and then switched to amsoil and around the 50th flight and there were a couple of people asking me of I had switched props or anything b/c it was making a noticeable power difference. I really couldn't notice that much difference b/c I put every flight on it and it must have been a very gradual increase, but people that didn't see it everytime recognized it. I do think the uplines are a little better with it though now (not that they weren't great before).

John

sfaust

My Feedback: (11)

From what I understand, the few gallons of ashless oil is to allow the rings to seat properly. Using synthetic oils during break in lengthens the process, or prevents the rings from seating as well as they could. A few gallons of the ashless oil from the beginning helps with that process. However, the engine will gradually continue to 'break in' well after the first few gallons, and over time will just run better and develop more power. After a few seasons of use, it will be at its peak.

Flyfalcons

What I have heard from DA is if you keep using the ashless for 8-10 gallons it will speed up the break-in process and you'll get more power in the long run. I just finished my 4th gallon on my DA and am planning on feeding it 4 more gallons of ashless before going to Amsoil. If it gives me another 150 rpm then I can wait another 20 flights or so.

RickP

My Feedback: (2)

Ryan,
Where did you hear that? I heard that running ashless is not good for the motor over the long haul since it builds up carbon and is not neccessary? Perhaps I should put a call into DA?
I've got only one more flight before I switch to the 100:1 (4 gallons)
RickP

pettit

My Feedback: (23)

"...I would say around 40 - 50 flights (30 gallons)..."

Either those flights are really long, or you're running your engine really rich.

That adds up to 85 ounces of gas per flight.

Good batteries, too...

GalenB

My Feedback: (18)

DA recommends 8-10 gallons of 32:1 Lawn Boy to break in a twin cylinder engine, and half that amout for a single (DA-50).

I cannot find this recommendation on their website, but it's in the sheaf of papers that's included with the engine (the manual)... I also talked to them on the phone to learn that the DA-50 would only need half as much break in fuel as the 100/150...

Flyfalcons

8-10 gallons really isn't too long for an engine that burns 20-25 ounces per flight. DA recommends 4-5 gallons as a minimum break-in before going to synthetic, but 8-10 gallons will give it a more thorough break-in. Full scale planes use ashless oil for something like the first 50 hours of use for break-in.

sfaust

My Feedback: (11)

DA recommends the ashless for a short period during break in. Its in their documentation. I believe BME also recommends the same, as do a few others.

You are right that over the long haul, the ashless oils tend to build up carbon deposits. These can be cleaned out very easily, and does take a fair amount of time to get to this point. Overall, its not harmful to the motors, but does increase the maintenance to clean out the deposits every so often. However, the ashless oil is only recommended for a few gallons, which isn't enough to leave any carbon build up. That usually takes quite a few seasons worth of flying to get any significant build up that requires cleaning.

t_wright

My Feedback: (2)

The instructions for my DA-50 specifically calls out for Pennzoil air-cooled 2-stroke oil at 32:1 for break-in. I am getting carbon deposits like crazy on the spark plug and I'm thinking that I'm going to switch to LawnBoy ashless for the remainder of the break-in period.

Tyrone