easy w114 swap, ?

[donlawson84]

found a cheap 380sl with low miles and was wondering.....
How similar are the w107 and w114 subframes and engine bay clearances? besides plumbing and eletrical, will the 3.8 v8 bolt up to existing motor mounts? will the trans fit in my w114 trans tunnel with no modifications?

[alabbasi]

Subframes are the same. Should be feasible and has been done before.

[Idle]

Originally Posted by donlawson84

found a cheap 380sl with low miles and was wondering.....
How similar are the w107 and w114 subframes and engine bay clearances? besides plumbing and eletrical, will the 3.8 v8 bolt up to existing motor mounts? will the trans fit in my w114 trans tunnel with no modifications?

Do some research on the early 107 subframes cracking. This is a real thing that you don't see in the 114's because the 114's are not subjected to the higher weights and horsepower the 107's see.

This is not the end of the world and fixes are available. It is just something to deal with, if it has not already been dealt with by a previous owner, while you are in there.

A popular upgrade is a subframe from a later model 107. They come better built from the factory and pop up on Ebay all the time. Going to Ebay and searching for one of these is a good way to see what I am talking about.

[JimFreeh]

Originally Posted by Idle

Do some research on the early 107 subframes cracking. This is a real thing that you don't see in the 114's because the 114's are not subjected to the higher weights and horsepower the 107's see.

This is not the end of the world and fixes are available. It is just something to deal with, if it has not already been dealt with by a previous owner, while you are in there.

A popular upgrade is a subframe from a later model 107. They come better built from the factory and pop up on Ebay all the time. Going to Ebay and searching for one of these is a good way to see what I am talking about.

Subframes are the same with one exception: You will need to drill access holes to get to the W107 engine mount. Good thing is that the position is already stamped... The 85 and earlier W107 is the suspect one. The 86 and up 560SL had the factory reinforced subframe. The issue is the lower control arm rearmost mount, it can tear from the subframe.

I used a W114 subframe when I replaced the broken one in my 84 280SL. The MB kit for the subframe was around $100. It consists of gussets that you weld at the suspect mount to reinforce it.

If I were to install a V-8 (M116/M117) I'd make the above mods, and figure out which trans mount frame piece to use. The rest should be pretty easy..... yeah....

Jim

[Idle]

Originally Posted by JimFreeh

Subframes are the same with one exception: You will need to drill access holes to get to the W107 engine mount. Good thing is that the position is already stamped... The 85 and earlier W107 is the suspect one. The 86 and up 560SL had the factory reinforced subframe. The issue is the lower control arm rearmost mount, it can tear from the subframe.

I used a W114 subframe when I replaced the broken one in my 84 280SL. The MB kit for the subframe was around $100. It consists of gussets that you weld at the suspect mount to reinforce it.

If I were to install a V-8 (M116/M117) I'd make the above mods, and figure out which trans mount frame piece to use. The rest should be pretty easy..... yeah....

Jim

That's handy info to have. Someday someone will be searching for this info and find it here in an easy to understand write up.

[donlawson84]

Thanks for all your input, will be considering all options when i start making moves on the swap. (probably after Christmas) will have a post on the build