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RV-12 Engine Mount Hardware Interference

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Hanging engine on EN-3...
Van's says no reports of this issue... what say you?

Our current plan is to reduce the diameter of the bottom washers to 1.875".

Lower Right
IMG_0273.JPG


Lower Left
IMG_0274.JPG
 
Old problem

Previously posted here with pictures. Most of us relieved the washers a bit.

There are other threads as well on this, do a search on "engine mount washer clearance". Maybe no one ever reported it to Van's.

Tony
 
Thanks, Tony!!!

Yep... this is one of the few times I didn't do a search before posting... my bad and I apologize. Hard to believe however that it's never been reported to Van's so I sent support a link to this thread.
 
Did it

I saw the prior post and could see the issue with no down side to making a recess. I made an adequate half moon recess to avoid the contact. I do not anticipate any concerns. I am surprised Vans hasn't done the fix on their end.
 
funflying said:
I saw the prior post and could see the issue with no down side to making a recess. I made an adequate half moon recess to avoid the contact. I do not anticipate any concerns. I am surprised Vans hasn't done the fix on their end.
Click to expand...

Actually Van's did take care of it a couple or three years ago.
Since that time, this hasn't been a common problem (as far as I know anyway), but since it has happened again, it has been looked at again and more details put in place to hopefully prevent it any further.
 
50-50-90 Rule

RV-12 / Do Not reduce the isolator washer size if you encounter interference with the engine mount.

Yep, the 50-50-90 rule is alive and well in my world. When given a 50-50 chance of being correct, I'm always wrong 90 percent of the time! The "shade-tree" fix for correcting the isolator washer/engine mount interference appeared to be straight forward... just reduce the washer size to 1.875". Well, I'm certainly appreciative to have the engineering staff at Van's looking over my shoulder. Here's Van's official response to my "shade-tree" solution.

"It is recommended that you do not do this.
That would make the washer smaller in diam. than is recommended by the isolator manufacturer, and Rotax.
The recommended fix would be to relieve the localized area of interference only."

Thanks Vans!
 
rvbuilder2002 said:
Actually Van's did take care of it a couple or three years ago.
Since that time, this hasn't been a common problem (as far as I know anyway), but since it has happened again, it has been looked at again and more details put in place to hopefully prevent it any further.
Click to expand...

I've just hung my engine and my bottom two mounts looked just like Ernie's photos. Also had similar interference on the top left mount. I filed half moons to get adequate clearance.
 
rgmwa said:
I've just hung my engine and my bottom two mounts looked just like Ernie's photos. Also had similar interference on the top left mount. I filed half moons to get adequate clearance.
Click to expand...

What I was trying to say... was that somewhere on the order of 300 powerplant kits have been shipped (and probably installed by now) and not everyone of them had this issue. It is very possible that the majority of them didn't (though I have no way of confirming that one way or the other)


Keep in mind.... people will always post here on VAF if they have a problem, but will rarely post if they did not.
 
RFSchaller said:
What's the big deal? Put the washers on the grinder and get on with the build!
Click to expand...

Exactly. It's no big deal. This washer interference has been known about and discussed here for a long time now. Vans know about it and the solution is simple. I certainly wasn't suprised to find some interference in my case, and didn't even think to notify Vans. Maybe I, and possibly many others, should have?
 
Whoa!!

I don't know...but my grinder is not TSO'd or approved by VAN's. Will this cause sparks with the DAR? Or will the FAA grind me down for non-corburundum? I find the whole thing kinda de-burring!
 
rgmwa said:
Exactly. It's no big deal. This washer interference has been known about and discussed here for a long time now. Vans know about it and the solution is simple. I certainly wasn't suprised to find some interference in my case, and didn't even think to notify Vans. Maybe I, and possibly many others, should have?
Click to expand...

Robert,
You seem to be implying that you know of many that have had to do this (but have not publicly mentioned it previously).

Can you fill me in on this information you have?
 
rvbuilder2002 said:
Robert,
You seem to be implying that you know of many that have had to do this (but have not publicly mentioned it previously).

Can you fill me in on this information you have?
Click to expand...

Not at all Scott. Of the three other builders that I personally know here in Western Australia, I believe one has installed his engine (not sourced from Vans) and I'm the second. Whether or not the other builder had this problem I don't know.
What I meant was that the reason Vans may not have heard many reports from other builders, is simply that they have done what I did - read about it on here the forum, saw how to deal with it and got on with the job.
However, if I hear about any other local builders having an issue, I will suggest that they let Vans know, as I will now.
Robert
 
Had same

I also had an issue with the "washers" during engine installation. I assumed it was my problem and just fixed it on the go. I guess I should have let Vans know. I didn't think it was a big deal.
 
I also had

this same problem. Just did what seemed reasonable ")" and pressed on and did not notify Vans.
 
I had one washer (lower passenger side) needing relief. I Saw the posts here about that issue before I hung the engine, so I watched for it. I ground the washer a bit, and never contacted Vans. kit 412.
 
As per my last post, I followed up and reported my interference issue to Vans, together with a photo of one of my modified washers, and this was their response:

"This is a known procedure and like you most builders will modify the washer as needed without a second thought. This is perfectly acceptable and is what is needs to be done to mount the engine.
Van's"
 
Not everything is perfect, and not everything needs to be. When a person undertakes to build an airplane that they use to transport themself and their loved ones they need to realize that their common sense and judgement must be exercised in the details of the build.
 
The manufacturing process has been further refined so that spacers and actual washers are used on the welding fixture. This will assure that the tubes can no longer be placed too close to the washers.
 
The RV-12 is getting to be a pretty refined kit. Almost makes me want to start all over again. ;)
 
re: Start all over again

Great idea rgmwa.

I'd be happy to take your project off your hands, so you can start anew. ;-)
 
120241 Had interference3

I encountered the washer interference problem when installing the engine in 120241 (143WM) in 2010. By that time the problem had already been discussed and the solution shown in photos on the Forum, so I just ground clearance in the two washers that were touching the mount and went on with it.

Wayne Moyer
120241/143WM
 
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