Engine mount rubbing

I have an RV6A which was completed this year and recently started flying, with about 40 hours now. The aircraft has an IO360M1B, uses the engine mount and isolators supplied with the kit, and a Hartzell constant speed prop. I hung the engine on the mounts and isolators for about two years before putting the engine and mount on the firewall. Everything looked fine. But maybe it wasn't so.
Yesterday, I was looking at the engine and the mount and the rear of the oil sump is rubbing on the engine mount tubing. The installation was done according to plans, although the isolators have different characteristics for the inside and out and may have been reversed?
I was thinking about isolators and perhaps some spacers. However, I would not have expected interference on factory built (mount and engine) components.
Any suggestions?

jay.pearlman said:

I have an RV6A which was completed this year and recently started flying, with about 40 hours now. The aircraft has an IO360M1B, uses the engine mount and isolators supplied with the kit, and a Hartzell constant speed prop. I hung the engine on the mounts and isolators for about two years before putting the engine and mount on the firewall. Everything looked fine. But maybe it wasn't so.
Yesterday, I was looking at the engine and the mount and the rear of the oil sump is rubbing on the engine mount tubing. The installation was done according to plans, although the isolators have different characteristics for the inside and out and may have been reversed?
I was thinking about isolators and perhaps some spacers. However, I would not have expected interference on factory built (mount and engine) components.
Any suggestions?

Click to expand...

The two lower mounts need an extra spacer washer next to the engine boss.

Would an 1/8 inch added here help?

az_gila said:

The two lower mounts need an extra spacer washer next to the engine boss.

Would an 1/8 inch added here help?

Click to expand...

And the lord mount halves are supposed to be reverse in orientation between the top and bottom positions (the harder durometer half is positioned so it is in compression in what ever position it is in.

I think both of these details are specified in the engine install section of the RV-6 construction manual.

Is the a way to tell which half is the harder durometer? Are they marked?

Tbone said:

Is the a way to tell which half is the harder durometer? Are they marked?

Click to expand...

The Barry ones are differentiated by a molded ring in the middle, but you still need the instructions and the part numbers printed on them to get it correct....

clarification

For the picture above, which side is the stiffer side?

Excerpt from RV install manual, and a picture of my Lord mounts. I think they are correct. Note the ring on the right side of the photo. It is on the loaded side, opposite the engine on top, against the engine on bottom.

jay.pearlman said:

For the picture above, which side is the stiffer side?

Click to expand...

In the past, the half with the rib molded into it has been the higher durometer one and should be installed on the aft side in the top positions, and the fwd side in the lower positions ( may be different now, confirm part #'s to be sure)

clearance

Thanks, everyone. Another question then is how much clearance is there between the oil sump and the engine mount tubes? This would be particularly interesting for the IO360M1B on a nose wheel aircraft.

Getting there

We ran an exercise on the interference. It looks like the engine was tight against the two tubes going from the mount ring to the nose gear cluster. My kit was delivered as a fast build at the very end of 1999. The engine mount delivered with the kit was prior to Vans selling the IO360M1B. I learned that the mount was changed for the RV-7A to allow for the engine and the new mount also fits the RV6A. So now the issue is becoming clear. It is unfortunate that either Vans did not publicize the change well or I had my head in the sand. So the advice from Vans was either live with it, get a new engine, or figure a way to use the new mount. Which would you do? The last is not straight forward because the engine moves forward about half an inch with the new mount which can now cause interference with the cowl - particularly the alternator pulley wheel.
So what are the next steps. I purchased a new mount which came today. It is necessary to buy the nose gear also as they are match drilled. I measured the current configuration and the dimensions on the new mount. I started disassembling all the hoses and wires around the engine and the mount and will work on the installation of the new mount in the next two days.
I will continue the story shortly. Thanks to all for their help and suggestions.