RV7 IO-360 M1B Engine Mount Query

Hello

I have the IO-360 M1B as supplied by Vans with the matching firewall forward kit and I am currently bolting up the engine to the mount. On the bottom 2 isolators and mounting lugs they are not sitting flat as the oil sump casting sticks out past the flat engine mounting face as you can see in the photo attached.

In my firewall forward kit I received the 4x isolator kits which each included a large flat washer which is under the head of all 4 bolts and mounts, and then separately with the engine mounting bolts in the Vans kit there were 2 slightly smaller diameter large washers included, as you can see in the second photo.

My thoughts are that I could use these 2 washers on the front side of the BOTTOM isolators to space the engine mounting lugs out and clear the sump casting .. but I am conscious I could be adding up-thrust by doing so.

What are you guys doing with this?

https://ibb.co/thRTB6L
https://ibb.co/zmmfjR7

Thanks,
Jonathan

I did not use the Hutchinson isolators. Check the instructions closely as (with the isolators I used) the washers are placed differently on the top and bottom positions.

From your picture it looks like the engine flange and the mount are parallel or pretty close, but the isolator looks angled. Is the isolator just not correctly seated in the mount? Maybe take the weight off and try to reposition?

I I remember going through the same issue when I built my 6, I had to use one next to the sump casting, I didn?t get he isolation mounts from Vans for this project since I went with the Lord mounts , ,, upon checking in the shop I did get my bolt kit from Vans and I?m looking at eight washers in total , maybe you are short A couple of the large washers that would allow you to put washers on each side of the isolator

Engine isolator & washers - See Dwg 46A

Look at Van's RV7 drawing package - dwg 46A which is specifically for nose draggers but has a good picture of the Typical Installation of Dynafocual mounting parts. Of particular interest should be note 3 which says "Washers provide clearance for rubber mount to fit over step in engine case".

I used this exact stack-up on my RV7 tail dragger with IO360 M1B & it works great... your Hutchinson isolators are likely similar...

AZSteve053 said:

Look at Van's RV7 drawing package - dwg 46A which is specifically for nose draggers but has a good picture of the Typical Installation of Dynafocual mounting parts. Of particular interest should be note 3 which says "Washers provide clearance for rubber mount to fit over step in engine case".

I used this exact stack-up on my RV7 tail dragger with IO360 M1B & it works great... your Hutchinson isolators are likely similar...

Click to expand...

Perfect, Thank you! Yes that looks exactly like what I need to do and it mentions it in Note 3 on dwg 46A too ... bottom only.

Thanks,
Jonathan

Happy to Help

Glad to help a fellow builder anytime
Steve

+1 for what AZSteve said. We just mung our M1B a couple of weeks ago and followed the guidance on DWG 46A very carefully, especially the difference in washer between the upper and lower mounts. The extra washer on the bottom mounts seems there specifically to avoid the problem you had. And it corresponds to using longer bolts on the bottom.

Washers?

Where can I buy the engine mount washers as called out DWG46A? I am installing an 0-360, but the engine mount washers Aircraft Spruce sells only go up to the 0-320. The washers are described as VIP50074-11 or J-221861 washers.

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