fbpx

 

Ok, never feel sorry for a guy with an airplane, unless it can't fly.
My engine mount is cracked on the 80 horse 912. It's an older engine, calendar wise, but only has 450 hours on the hobbs. I replaced all the rubber a couple of years ago at 250 hours and due to a series of unfortunate events, the plane sat in a maintenance hangar for 18 long unproductive months at 450 hours. I think I'll replace ALL the rubber.
I have also been chasing a leak from somewhere that as a few drips of oil on the starter. While the engine is off I want to tighten, torque check, pray over and seal anything that looks wet, loose or suspicious. What kind of clamping of fuel, oil and water lines really works without crushing rubber or metal beyond acceptable limits.
This is a 912F 80 horse from about 1990's. It runs great when I'm not breaking motor mounts, grounding straps, or CDI mounting brackets. All that in the last 300 hours. I'm not getting a warm fuzzy about reliability or safety here, is it just MY engine? I think the last 30 hours of actually smoothing out the prop angle and carb balance to perfection will go a long way, all the other damage was likely caused from vibration of worn out rubber isolators and a poorly balanced prop or so I am thinking. I know that's a lot of stuff, but I'm about to commit major surgery and I welcome real 912 experience rather than the touted experts in my AO.
  • Re: Pulling an engine off the plane.

    by » 10 years ago


    Hi,

    For coolant hose clamps at the 5 yr hose replacement, I switched to the Rotax spring clamps on all the 17mm Rotax hose .

    for the larger coolant hose 1" and whatever else size I used high quality automotive spring clamps.

    This eliminated the coolant seepage/ leak when going from + 30C to - 30C (gear driven clamps can't compensate)

    Look in the BLOG area of this forum, page 3&4, "5 year rubber replacement" it covers allot of questions you have.

    For vibration :

    1. With your new engine mount , You would use new rubber mounting cushions right.

    2. balance the carbs.

    3. A dynamic prop balance.

    These should get you smoooooth

    Thank you said by: jay white

  • Re: Pulling an engine off the plane.

    by » 10 years ago


    Yep, I ordered all new rubber isolators for the mount and new hardware for everything.
    I'm an expert at balancing the carbs and the dynamic balance will happen immediately after the new mount install.

    I'll try the spring clamps like you suggested. Thanks.

  • Re: Pulling an engine off the plane.

    by » 10 years ago


    Ok, I started taking off the parts of the engine that will allow access to the mount. The exhaust manifold, EGT Probes, Oil Temp and water temp probes. I was hoping to avoid taking off a lot of stuff to change the mount but it looks like the spider and the ignition modules are coming off as well. Im taking pics as I go and writing a manual for step by step re-assembly. Oh Goody.

  • Re: Pulling an engine off the plane.

    by » 10 years ago


    I am disconnecting the motor mount and engine as an assembly. I want to remove the mount from the engine after the whole engine is off the airframe. Can anyone suggest a good method of supporting the engine while its off the plane. Can I just set it on two by six boards at the cylinder head so I can work on it on the table, or is that too much stress on the cylinders? I have a movable engine hoist now and I want to put it down so I am not working around a suspended load.

  • Re: Pulling an engine off the plane.

    by » 10 years ago


    I got the engine off the plane. Not looking forward to reinstalling it, but I have read some of the posts on the forum and it's just another job or a homebuilder. I was astonished to unbolt the cracked engine mount and watch it fall in two pieces from the engine! I didn't think that the crack went all the way through the member. I was wrong, but I was right to ground the plane at the first sign of a crack. The new mount is more robust and has extra gussets and members.
    I will replace all hoses, and rubber. Unfortunately Rotax doesn't have a clamp that will fit my older coolant hoses. They just discovered that the size doesn't work for this application. So, I am back to gear driven clamps.
    DSC_0022.JPG (You do not have access to download this file.)

You do not have permissions to reply to this topic.