Sierra cast alu engine mounts

[voucht]

Rather than buying 30x30 box section tube, and removing my "book" engine boxes, I have tried to "copy" the cast aluminium engine mount wit 25x25 tubes. I could adjust their vertical position on the 5mm plate attached to the engine in order to get rid of the 15mm extension cylinder I did in the first place. I will cap the end of the tubes to close them.

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It fits perfectly, I have the right height and the clearance I needed between the steering column and the water outlet. For now, the elements are just tacked together, and before fully welding them I wanted your opinion. Will it be strong enough?

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I will also add 2 plated, on top and on the bottom, to "close" and brace the triangle. The bolt is just here to hold them together, and will be removed after I weld the plates. It will be a water drain as I don't want any water to be stuck in between the two plates.

CustomEngineMounts03.jpg

Please tell me what you think, is it OK, shall I fully weld and put the plates on top. If you confirm it is OK, I'll do the right mount in the same way.

Thank you very much in advance.

[jps]

I'd think that bottom plate is too thin, I'll be doing mine out of 6mm plate...

[K4KEV]

btm plate DEFO too thin......agree a minimum of 6mm plate

[jps]

I'm also going to use some 40mm box section which is 4mm wall I think. not sure if your box section is thick enough, also it's not welded all round, can you not construct it in such a way that you weld around the whole end of the box section rather than just one side?

[voucht]

Thank you for the replies.
I changed the bottom plate to a 6mm (actually 5.5mm!) plat.I also made it longer, and it looks stronger now. Thanks for the tip.

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I also cut another top plate which will cover the full length of the mount. I think it makes more sense.

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JPS, I totally understand you last point, that makes sense. This was my first idea too, but while drawing, I discover that it would give a "pointy head" to the triangle, and the contact surface with the bottom plate would be to small. But now, with this longer and thicker bottom plate, it would be definitely a better option. But honestly, if you guys think that this version is OK and will be string enough, I'll leave it like that. Just let me know!

Thank you for your inputs.

[flyerncle]

Possibley too late but I placed the mounting plates where the rubbers go on the chassis legs, and the angle of the load is more acceptable instead of being 90 deg/ vertical on the plate close to the engine.

[voucht]

Originally Posted by flyerncle

Possibley too late but I placed the mounting plates where the rubbers go on the chassis legs, and the angle of the load is more acceptable instead of being 90 deg/ vertical on the plate close to the engine.

Thank you Paul.
Yes, I know. The best thing would have been to do a custom engine mount as described in the book (alternative engine mounts), without using the boxes made with the "EM plates". I totally agree that angled legs would have been better. But I made the "boxes" and they are fully welded to the chassis, because I didn't expect I would have clearance issues between the water outlet and the steering column. I really didn't want to remove them, that is the reason why I "copied" the original cast mounts, and just adjust the height to solve the clearance problem.

The engine mounts are now finished. They look like that.

CustomEngineMounts04.jpg

I braced the right one with triangular plates on top. The bottom plate (6mm) is fully welded on the full length of the tubes making the "skeleton" of the mount.

CustomEngineMounts05.jpg

No bracing on the right mounts, but two plates, fully welded to the tubes, on top and at the bottom.

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I hope they are going to be strong enough. To me, they do look strong enough, but again, I'm not a specialist. What do you guys think of the final mounts?

Any comment is still welcome.

Thanks a lot.