3.5 install

[84E24]

Thinking about installing a 1985 - 87 3.5 into a 73' coupe and I have a couple questions.

1 - can the existing motor mounts be used as is ?

2 - I think I need to use the 3.0 oil pan for clearance ?


Anything else I need to think / plan for ahead of time ?

Thanks, Steve

 

[arnie]

Hi Steve,

Q1: yes, of course. It's still the M30 Block
Q2: I'm not sure about that. It's to long ago, that I did the conversion. Mine is also an engine of that period, a 3,5 Motronic from 85 coming from a B10 Alpina.

If you're going to keep the engine as an EFI, the intake manifold will be a problem together with the brake booster. This won't fit without changes. I modified this by shorten the flange of the booster. The latest modification to my engine was to change the intake manifold to the original one, so that it was possible to undo the mods to the brake booster.

If your conversion will be from a carburator to EFI car you will of course also need a second fuel line and electric fuel pump.

Ingo

 

[Sven]

Steve -

1. The right motor mount will need to be modified. A good welder should be able to add on a small section. No change to the left one required.

2. Yes you need the 3.0 oil pan & pump pick up.

 

[84E24]

Thanks for the input.

I currently have triple DCOE 40 that I will be using.

What type of mod will be needed to the mount ?? Does anyone have a pic ?

I would assume that the bolt pattern is the same, the only thing I can think of is the location ???

Thanks, Steve

 

[Mike Goble]

I put an '88 3.5l in my Bavaria and used the stock Bav mounts. They bolted right up. I believe that the 89 and up motors are lacking one of the bolts.

 

[Sven]

Here is a photo of my modified mount. The modification is to the part of the mount that bolts to the engine. On the newer block (in my case a 1991) the threaded boss holes for the mount are located further forward than on the old blocks. You can see the weld seam. Everything to the right is new with one new bolt hole added. The two stacked holes align and can be resused. I cut off the section to the left. I suppose you could also extend the left to reach the aft boss mounting holes. It is also possible that the 85/86 blocks are different.

Another alternative I have heard about is to get an adaptor plate from La Jolla.

 

[sreams]

Here is a photo of my modified mount. The modification is to the part of the mount that bolts to the engine. On the newer block (in my case a 1991) the threaded boss holes for the mount are located further forward than on the old blocks. You can see the weld seam. Everything to the right is new with one new bolt hole added. The two stacked holes align and can be resused. I cut off the section to the left. I suppose you could also extend the left to reach the aft boss mounting holes. It is also possible that the 85/86 blocks are different.

Another alternative I have heard about is to get an adaptor plate from La Jolla.

I don't believe this would be necessary with the '85-'87 motor the original poster wanted to use.

 

[sfdon]

And the 1988 635 engine bolts right up with no issues with the oil pan or the motor mount.
And 26 more hp.

 

[OCCoupe]

And the 1988 635 engine bolts right up with no issues with the oil pan or the motor mount.
And 26 more hp.

Bingo!