M42 / M20 rubber engine mounts

[sanitroc1]

Can anyone tell me what the difference is ? . I know they are a different part number on Realoem but they look similar . Are they different heights , is it the bolt pattern or is it that the m20 ones are harder .
Thanks Steve .

[TheDutch]

318is ones are hydraulic, and much more expensive as a result.

[jmc330i]

Don't pay any attention to the pics on Realoem Steve. The pics are often different to the actual item.

[sanitroc1]

Ok thanks for the information , but if the m20b25 mounts fit or can be made to fit what would the issues be ? .
Update just been searching google images and apart from the hydraulic verses solid rubber the difference is that the m42 ( and m40 ) studs are offset by a stud width in one plane when the m20 ones are inline.
Question , does the m42 need hydraulic mounts when firms like Revshift do poly mounts part # PMM-R36.
If anyone knows why you cant fit solid rubber mounts please let me know .
I will measure m40 & m20 mounts in situ to see if there is any difference in height and if the hole and slot in the front cross member will work or if I need to get the mig and a drill out and will report back .
James did you get the new tourer moted ?
Thanks Steve

[jmc330i]

I think the M42 uses the hydraulic mounts to cut down on the transmitted vibration - one of BMs attempt at smoothing out the mighty 4pot!
I know a few people who use solid mounts, but not on everyday road cars. My white touring will be using the hydraulic mounts.

The blue touring hasn't really been touched yet! It's not looking good though, there's quite a bit of fibre glass visible around the OSR boot pocket!

[sanitroc1]

Back again , checked the heights and the m20 is 4mm less than the m40 but the m20 looks very tired so I have an excuse to buy a pair .

[Brianmoooore]

If you use M20 mounts, buy the cups for them as well.