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MX5 engine mounts in a Locost
jnooge - 5/4/22 at 08:36 PM

Hi all,

Firstly, what on earth have I done to myself!?

I'm currently in the process of getting my 1.6L MX5 MK2 engine into my Locost (she's called Lola).

To accommodate various points, I need to fabricate new engine mount brackets.

Basically, my question to the community is can I have the rubber engine mount bush at a 90-degree angle screwed directly into the engine? Or do you think that I should make a bracket to go at 45 degrees to the engine? I hope this makes sense.

I hope to hear from someone soon.

Lola and I would be really grateful.

Cheers.

J


Rallychris - 5/4/22 at 10:15 PM

Can’t you use the standard Mazda brackets mounted to the engine that put the rubber mounts at approx 45 degrees? The same mounts put directly into the engine would not work as they will be in shear rather than compression and likely fail very quickly. Also it won’t help mounting bracket strength (to chassis) or vibration in the car if you deviate greatly from the OEM position and orientation.

[Edited on 5/4/22 by Rallychris]


jnooge - 5/4/22 at 10:53 PM

quote:
Originally posted by Rallychris
Can’t you use the standard Mazda brackets mounted to the engine that put the rubber mounts at approx 45 degrees? The same mounts put directly into the engine would not work as they will be in shear rather than compression and likely fail very quickly. Also it won’t help mounting bracket strength (to chassis) or vibration in the car if you deviate greatly from the OEM position and orientation.

[Edited on 5/4/22 by Rallychris]


Unfortunately, the brackets won't fit in the engine bay. So, I will have to fabricate my own.

Thanks for getting back to me though!


ianhurley20 - 6/4/22 at 07:50 AM

Not sure what you are calling a locost - mine was a Haynes Roadster and I used the standard engine mounts and fabricated some 45 degree pick up points on the chassis. I also offset the engine slightly to the nearside to give the clutch clearance against the chassis. When I fitted the mounts I put the bonnet on then jacked the engine up as high as it would go before tack welding the mounts to the chassis rails. Ended up with 5 mm clearance between cam cover and bonnet and no need to cut and shorten the sump


Slimy38 - 6/4/22 at 09:55 AM

The original brackets are mounted vertically, so there's no reason why a fabricated version can't use the same holes. But as mentioned you'll still need the engine mount to be in compression rather than shear. Standard tintops with vertical mounts still have sufficient metal to ensure the mount is in compression.

This is what I did to reuse the brackets;

http://slimyroadster.blogspot.com/2020/06/engine-mount-progress-2.html

That puts the mounting directly on to the standard rails of a Haynes roadster.


nick205 - 6/4/22 at 02:04 PM

MK Indy engine mounts were 45° steel with a rubber block in compression between mount and chassis.
Circled in this image.

MK supplied the steel engine mounts. 50mm box section with flat plates welded either end. The engine end plate bolted directly to the engine mount points on the engine block.



[Edited on 6/4/22 by nick205]