Guys,
I have a DA-170 on RE-3's, running RedLine Racing Oil at 40:1. I have developed an oil leak, more of a seep than a leak coming out of the front bearing area of the motor. This engine does not have tht much time on it, about 25 gals or so. The motor is really putting out the power,no complaints there and I'm using a Mej 31x12 EVO.
The bearing feels fine, no play in it, but after every flight I take a rag and wipe that anoying few drops that smears its way back on the front shaft of the engine.
Have any of you experienced this. Does this neccesarily mean the bearing itself is going out.
I have a theory that by running pipes and hitting some high rpms during the flight that excessive pressure builds up inside the engine casing and pushing out a small amount of gas oil mixture out the the front bearing area.
What do you think? Need advice on this. I hate to send the motor back to DA if this is just a small problem thats not going to bother anything else.

Thanks in Advance,
Joe DeRenzi

Every DA I've had has done this at one point. They ran fine so it didn't bother me.

Originally Posted by as722

Every DA I've had has done this at one point. They ran fine so it didn't bother me.

Did your problem with the leak eventually get worse where you had to get it fixed, due to lack of power or just a mess?

Joe.

If oil can leak out, can an air leak develop?

Originally Posted by DeRenzi

Did your problem with the leak eventually get worse where you had to get it fixed, due to lack of power or just a mess?

Joe.

Hey Joe... Long time no see.... Hope all is well.
Since the season is just finished & you have a little time before things start to wind up again, I would suggest sending the engine in.

The front bearing is sealed and has it's own lubrication (grease) inside. Since you are seeing this coming out the front, it means that the seal is deteriorating and will eventually fail altogether. When this happens, (and hopefully you won't wait until then) if the bearing seizes in mid-air you are only inviting issues that can be solved prior to them happening. You know... way out in the back of a roller etc..

So...save yourself some repair headaches & get it done...
Say a BIG HI to Mike S for me.
Regards,
Wayne

SEND IT IN you will only pay for shipping by the sounds of it

Originally Posted by wmat7039

Hey Joe... Long time no see.... Hope all is well.
Since the season is just finished & you have a little time before things start to wind up again, I would suggest sending the engine in.

The front bearing is sealed and has it's own lubrication (grease) inside. Since you are seeing this coming out the front, it means that the seal is deteriorating and will eventually fail altogether. When this happens, (and hopefully you won't wait until then) if the bearing seizes in mid-air you are only inviting issues that can be solved prior to them happening. You know... way out in the back of a roller etc..

So...save yourself some repair headaches & get it done...
Say a BIG HI to Mike S for me.
Regards,
Wayne

Thanks for the reply Wayne, and yes its been a long time since we've talked, probably back in the sequence committee days. I'll get this fixed, but I'd sure like to know why its happening. Low time engine DA-170 on RedLine 40-1. I never had this problem with Belray Oil MC-1, but the carbon mess it made in the combustion chamber made me start out with my new 170 with Redline right from the beginning.
Now, my old 170, 3 yrs., ran on MC-1 Belray and it ran without incident. Like I said, I changed to Redline on this engine after seeing all the carbon inside the combustion port etc. Would it have anything to do with the oil itself.
I'm running on RE-3's and and a 31-12EVO and its hard to keep from barking on a roller. My question is do you think the extra rpms create excessive pressure and blow the front bearing seal out, or just a bad seal to begin with? Hope I'm making sense.
BTW, I'll say HI to Mike, we just got thru putting a DA-170 in his old RadioCraft and I helped him with the pipes and we are going to fly it soon.

10's to You,
Joe.

Originally Posted by henry b

SEND IT IN you will only pay for shipping by the sounds of it

+1. Take out the guess work and have it checked out by someone who knows this engine very well. Most likely, it just needs a new bearing. That's not too expensive.

It's impossible to build up pressure in a two stroke crankcase..Every time the piston goes down it make a little pressure, then it pushes it up through the transfer ports.....
You can get 5 or 6 lbs pressure in a tank with a one way valve in a line from the case to the tank, but that has nothing to do with the pressure on the seal on the front bearing...
Not sure if the inner front bearing in a DA is sealed, but if it is and there is oil coming out the front of the case both sealed bearings are leaking....

Another person had a very similar issue, thought he had oil leaking out of the front bearings. Turned out it was a loose header.