Engine Alinement 1977 J Model

[flyingwhiskey]

I would like to determine the alinement of my engine to the airframe. There must be some spec's out there. I have contacted Mooney a few diferent time they don't seem to want to give me the info. first thing anyone say's in change your lord mounts then you may have to shim the bottom mounts for the spinner to fit the cowl. That's not right!!!! there shoud be spec's they say for example level the aircraft then the engine should be 3 % down or up something like that. I have new Lord mounts & I have shimed the lower mounts still low.

[jetdriven]

the spinner shoud be perfecly centered in the cowl. For our new engine mounts it took two 1/8" shims on the bottom, and one 1/8" shim on the left bottom as well for the right thrust.

[garytex]

What if one questions one's cowl alignment, say for example if one has an aftermarket cowl. I have wondered about this myself.  There is quite a bit of thrust vectoring going on with some models of ac with something like 2 or 3 degrees up or down, and about 1-2 side to side to counteract P, etc..   Mooneys fly so straight that I bet there has been some tweaking done.

Gary

[garytex]

Say Byron

Are you in the air yet?  Hows that new motor?  I always get that "well Ican't possibly hook up this fine new motor with this obviously won't go to tbo hose, control, wire terminal or whatever" disease, that wastes more time than one would imagine.  Hope it's not biting you too bad.

Gary

[jetdriven]

Yes, it has 8 hours on it. Pretty much everything forward of the firewall was replaced. Well, the starter was reused, thats about it.

Some observations:

-the new engine runs quite a bit hotter than the old one. The dearly departed engine would run 360 CHT at 15 or 20  LOP at cruise. At 1500' leaned to a straight 10 GPH it would run 330 CHT.  WOT full rich sea level 330 CHT. This new one is 360 full rich full throttle, 330 in cruise with cowl flaps open, and with cowl flaps closed goes up to 380 and keeps climbing.  They tell me it is because the rigs are still seting. it better be.

The airplane is slower now. I expected that going to 20 degrees timing.  But not this much. The airplane would indicate 183 MPH on a 80 degree day at 1000'.  Bumping the timing up to 25 degrees gave us about 188-190 MPH IAS.  One cold day (32 degrees) it indicated 195.

The new engine does not like LOP as well. The GAMI spread was 0.8 GPH...far too great to be useful. When #2 was peaking, #3 was already 40 LOP. Removing the injectors, cleaning in acetone and then Hoppes #9 cleaner, and rearranging #2 and #3 for each other, brings it down to a 0.2 GAMI spread.  The old one had a zero spread.

Right now, the fastest IAS I have seen during the break in is 173 MPH.  This is substantially slower.  This is a pretty big disappointment, but I have been told to expect a few MPH back after the rings are fully seated.

The new engine is light years smoother than the old one. Being a factory engine the flywheel is drilled to balance it. That and the prop getting refinished and static balanced makes for a smooth running engine.

I am still optimistic after the engine is fully broken in we can get out speed back with the 25 degrees timing, but requires some serious cash to do it. That electroair is nearly three grand. But a 5-knot slower airplane with a 1/2 GPH fuel flow higher than before, and Slick mags,  costs an extra 500-1,000$ a year to operate 200 hours, so there is an economical reason to do it still.

 

 

[rbridges]

there's an article about aligning your engine.  It does seem to be a little on the experimenting side.  Here's a link to it.  I ended up adding new mounts.  After a few months, I needed the thinner shims on the bottom.

 

http://www.donmaxwell.com/publications/MAPA_TEXT/Alining%20Engine%20Using%20Shims/ALIGNING_YOUR_ENGINE.HTM

[garytex]

Byron

Thanks for the update.

It's been just the Tiniest Little Bit hot lately, that is probably lowering IAS some. I saw 100df at 1000 feet yesterday afternoon.  CHT's will come down after the rings seat.  Could the leading edge of the prop profile have been slightly tweaked by dressing at OH?  Let things settle a while, and let it cool off some before you reach a conclusion.  I have been disappointed with a freshly OH'D engine in the middle of summer that was magically reborn in October with 50 hours on it and OAT's 30df cooler.

Rob

Isn't that a wonderfully well done "how to" from Maxwell?  Thanks for sharing it.   All good, he suggests aligning the engine before the SWTA cowl.  I wonder if that was done on mine.  I've got a little droop.  Is the engine off, or the cowl?  There is a little wiggle room in the cowl, and a reference to something solid would be nice.