How badly did I screw up? Forgot to reinstall a part...

Hi everyone!
Working on my first engine build, 07 Speed 3. It's taken over a year since I started pulling the engine apart. Obviously I should have done a better job keeping things organized. Quite a few parts were unfamiliar to me when the time finally came to reassemble.

Today I discovered that I forgot to install the Cover End Plate, LF1710903. For the longest time I didn't know what the thing was.

https://www.jimellismazdaparts.com/...azda-3/Cover-END-Plate/1897163/LF1710903.html

Has anyone ever had to install this after the engine and trans were already joined? Do you think I'll be able to sneak it into place without pulling things all apart again? What does this thing even do? Could my engine survive without it?

Thanks

 

That goes between starter nose and block and is near flywheel starter ring gear. It seals starter housing area between starter and block. I had mine touching slightly starter ring gear... Mine had oil soakage from engine oil leaks and is soft. When I pulled starter than transmission it was seated in block. Its in a pocket and helps seal clutch dust from clutch friction material.. OR it seals the typical oil waterfall from upper head area...like mine.
If you have starter off, I bet it can be reinstalled. Now I haven't replaced starter in car.. So let us know how it goes.

 

Yup. It just slides into place with the starter removed. Not a terrible job, but annoying that it could have been avoided. Thanks for the input.

 

dude, you know these engines pretty well! pretty impressive, how many have you built?

 

None, this is the first Mazda block build. Been working on engines for a long long time. My first was a many times rebuild of a Honda 305 back in 75, A VW bored & stroked build was first car block in 83. That one was scary...door frame would flex open on full throttle...Unibody flexing.