Installing the Engine Mount Part 1 - Zenith 750 Cruzer - UL Power 350is

Here's how I installed the engine mount for the UL Power 350is on our Zenith 750 Cruzer experimental kitplane. I had to remove a tiny bit of material from the two bottom bolts to get them to fit. (Later I swapped out the nylon locknuts for steel locknuts (as you'll see in another video probably)). Stay tuned for part 2.
Kobalt angle grinder amzn.to/2YG3ABF
Standard Disclaimer: Just because we do it, doesn't mean you should. Refer to your plans.

[@mhilderbrand7693]

Zenith now has you countersink that first hole in the lower engine mount attach fittings.

[@bebo995]

Grinding bolts may change the properties of the bolts weakening them to a lower grade. Could cause a major issue down the road under stress?

[@richardfrakes1345]

Just wanted to mention that when you ground the lower left engine mount bolt you removed the cadmium corrosion protection coating; unless you corrected that but didn’t video it.

[@amtpdb1]

The issue is if he got it too hot. He could have ground it in many small steps dipping it into water to cool it in between grinding sessions. The same needs to be considered for the aluminum and the steal parts as they both are usually heat treated.

[@gumby442]

yes that camera angle gives a nice point of view. great progress...at this rate i can see first flight before October.

[@jeffandadambuildazenith6816]

Thank you!

[@alfonsopetito5498]

you should have put the bolt in from the motor mount bracket check to see at kitplane entutusisis

[@rarespaul9503]

first person perspective is awesome

[@michaelr2656]

Engine off does seem much easier ! I'd have to agree with you.

[@Al-hayat83]

Tahnks

[@HimanshuShekhar1]

Course it has to be off center to counteract the rotational torque from the single engine.

[@paulmakinson1965]

Why not use an Allen bolt. The head would be cylindrical and easier to tighten.

[@jacejk2]

dude, you are scarring me. I'm thinking of building a RV12 with a AT15 HP. The AT is supposed to compare to the Rotak 914, again totally experimental. At 130 HP, your UL Power 350is sounds like it will have extra power. Are you looking for short takeoffs or more speed? I am worried you may have weakened the Integrity of your hard points. Good Luck

[@jacejk2]

I hope you have re-thought this decision to grind the bolts. Seems to me you could avoid the grinding if you used a socket to hold that bolt from the inside instead of a wrench.

[@mikeferrel7225]

did you try taking out the small bolt first?

[@jstephenallington8431]

Since this video is from ten months ago, I'm guessing that whatever choice you have made is already done and done, but... I have couple of suggestions, one, if you can, remove the offending (floor) bolt previously installed, install the one for the engine mount, then reinstall the floor bolt. Or, two, remove the bracket AND bolts, pre-position the bolts with the heads flush in the bracket, and "fish" the bolts with the bracket back into place. Third idea, reverse the bolt/nut positions, instead of the bolt being shoved through the firewall from inside the cabin to the outside, place the nut over the hole inside the cabin, then thread the bolt into it, with the head of the bolt on the outside of the cabin, (engine compartment) side. Good luck, I'm so very looking forward to the first flight video!

[@wbhartmanii]

That offending bolt sticking up looks like it's got a washer on the head side..that would cause your small clearance issue ...you sure that little guy needed a head washer there?

[@littlewingpsc27]

Interesting that the engine mount flanges that mount on the firewall over hang the lip of a "L" channel instead of mount flush to the firewall panel. You would think that they would mount that on a flat surface. I guess since you have different engine options, there is no "common" interface to the airframe?

[@jeffandadambuildazenith6816]

Yeah. I'm pretty sure that the airframe-side mounts are all going to be the same for different engines, but the engine-side mounts change for the each engine.

[@David-pk9be]

Wobbly

[@jeffreydancinger2875]

Did you buy the engine mount from the engine company or Zenith?1st person is good.

[@jeffandadambuildazenith6816]

We bought it from Zenith. Thanks.

[@sledawgpilot]

Might try: Search Skybolt or A/C Spruce for internal wrenching bolt MS 2000 then - size. (They use an Allen wrench). Make sure to use the radiused washer with it because they have a radius under the head. Put it together with the ground bolt for now but know that that is kinda hokey. Yeah I’d worry about screwing up the heat treatment and making that bolt soft or brittle. I’m an IA.

[@poppopscarvinshop]

I'm not being mean but I think some general Mechanical Training would be a Very Good Thing for him & his Dad.

[@faainspector9699]

If you are going to grind any steel parts , take them outside the shop.........if you grind in the shop around your project , you will have all the red hot particles from grinding , melt and stick into your T-6 aluminum .........This will contaminate the metal and the little steel particles will start rusting holes into the aluminum.........the hot particles melt themselves into stainless , aluminum , and the glass in prescription glasses and windshields also........take the grinding outside , including the aluminum..........the dust from any grinding is not good for your workspace.........and wear a dust mask...

[@vongroven115]

Greetings! Sorry friends, but grinding on that bolt head gives this cautious guy goose bumps for a number of reasons, none of them professionally grounded. I would never reduce the overall mating surface of a critical attachment point that will be always under some stress load or other (up in flight, down at rest, torque while running). I would remove what appears to be the troublesome bolt temporarily, Is the bolt you just ground on repeatedly heat-treated for required hardness but now may be a magnitude more brittle or too soft for the application. With all due respect, you have numerous reasons to ditch that bolt and no good reason to roll the dice on this one. I will bet a bottle of low ash av oil that the manufacturers send you a new bolt in a heartbeat!

[@jeffandadambuildazenith6816]

Hi! Thanks for your concern. I'll keep that in mind.

[@AnthonyDigi1205]

Go pro is good