Conical Engine Mount issue

N941WR · #1 08-28-2006, 11:34 AM

This morning I got motivated and hung my engine. Something that should have taken about 10 minutes took three hours and I'm still not finished.

Any suggestions are appreciated.

The conical mounts were installed per the instructions; engine mount, large washer, cone, engine, cone, two large washers, and castle nut. The problem is the washer and nut are about 1/32" away from the rocker arm push tube on #4 cylider and any engine vibration will cause it to touch.

In fact, I had to pull the #4 cylinder out a little bit to get the 2nd large (AN970-8) washer in place.

Have any of the rest of you had any of these issues? If so, how did you resolve it?

Thanks for the help!

Mike S · #2 08-28-2006, 12:11 PM

Just a guess here, but can you put the bolt in the other way? Bolt heads usually offer more clearance than nuts do.

Mike

pierre smith · #3 08-28-2006, 02:24 PM

Bill,
Our engine has already sagged a good quarter of an inch and we need to add a big washer behind the lower engine mount tabs to raise the prop and spinner. We originally mounted the spinner equidistant from the cowl all the way around. In retrospect, it would have been better to mount the engine with the top of the spinner flush with the top of the cowl. Within the first 75 to 100 hours as the rubber mounts "set" and the engine sags a little it will be centered on the front cowl circle.
Cheers,

dwilson · #4 08-28-2006, 02:54 PM

I had the same problem. Ordered the conical mount 0-320 from Bart at aerosport power. Ordered the engine mounting pillows and hardware from Vans.

Put the two together with almost NO clearence between bolt head and pushrod tube #4.

Called Bart and Vans. Bart had the answer.

Use 3/8' inch bolt for that mount instead of the 1/2" bolts supplied by Vans. Bart sent me some spacers to fill out the hole from 3/8 to 1/2.
Bart strength of the 3/8" was more than enough for this application.

Hope to fly it by end of Oct. If you hear of an RV9A falling out of the sky around then because an engine mount bolt broke you will know there really was an issue!!!!

Good luck

Duane Wilson

N941WR · #5 08-28-2006, 03:45 PM

Quote:

Originally Posted by Mike S

Just a guess here, but can you put the bolt in the other way? Bolt heads usually offer more clearance than nuts do.

Mike

Mike, that won't work as the washer will still bash the tube and that only removes a little of the head. - Thanks

Quote:

Originally Posted by pierre smith

Bill,
Our engine has already sagged a good quarter of an inch and we need to add a big washer behind the lower engine mount tabs to raise the prop and spinner. We originally mounted the spinner equidistant from the cowl all the way around. In retrospect, it would have been better to mount the engine with the top of the spinner flush with the top of the cowl. Within the first 75 to 100 hours as the rubber mounts "set" and the engine sags a little it will be centered on the front cowl circle.
Cheers,

Pierre, I've heard this before but that first engine start will most likely trash the tube, it is that close. (Sorry, can't post a piture, I've hit my ISP limit for now.)

Quote:

Originally Posted by dwilson

I had the same problem. Ordered the conical mount 0-320 from Bart at aerosport power. Ordered the engine mounting pillows and hardware from Vans.

Put the two together with almost NO clearence between bolt head and pushrod tube #4.

Called Bart and Vans. Bart had the answer.

Use 3/8' inch bolt for that mount instead of the 1/2" bolts supplied by Vans. Bart sent me some spacers to fill out the hole from 3/8 to 1/2.
Bart strength of the 3/8" was more than enough for this application.

Hope to fly it by end of Oct. If you hear of an RV9A falling out of the sky around then because an engine mount bolt broke you will know there really was an issue!!!!

Good luck

Duane Wilson

Duane, Thanks for the tip! I sent a picture to Van's this morning and I'm waiting for their reply. I agree, 3/8" is more than enough for this application. I'll wait to hear what Van's has to say and then will give them a call.

BTW, were your top two bolts difficult to install in the mount? The bottom two went right in but the top two had to be drawn through with the nut and a bunch of washers.

dwilson · #6 08-28-2006, 04:12 PM

Bill,
I had to ream all of the holes in the mounting tubes that came from Vans. I went out and bought a 1/2" reamer to do the job. After that they slid through real nice!!!

Duane

N941WR · #7 08-28-2006, 07:44 PM

Quote:

Originally Posted by Mike S

Just a guess here, but can you put the bolt in the other way? Bolt heads usually offer more clearance than nuts do.

Mike

Mike, it looks like you win. Van's recommended turning the bolt around and removing one of the two large washers. Just sent them a picture of the new installation and am waiting to hear their reply.

Surprisingly, or not surprisingly, they are watching this thread to see what others might have done.

Do any of you have an O-290 powered Tri-Pacer? If so, could you take a picture of the upper left engine mount from the front and back and sent them to me? That would be a great help!

Thanks!