So, I am currently doing a 2nd gen subframe swap in my GSL-SE.

I purchased second gen motor mounts and they came with the bolts that hold the mounts to the center irons. I figured these bolts would have the same thread pattern as my SE center irons but they don't seem to?

Does anyone know the thread pattern for these holes?

I put one bolt in about half way, then it stopped, the others went in like a couple threads. Now, since these are unused on the gsl-se it could be that there might be gunk in there? I tried to clean them out and it didn't improve the situation. It's possible I could be being too careful and I should just crank them in but I just can't take the chance of destroying the threads.

(the picture below isn't mine but these are the holes I am referring to)

 

As I understand it, you are using a gsl-se 13b with a FC subframe and wish to mount the SE engine into the FC cradle. I have a GSLSE 13b that is in my garage that I can check and give you depths for the screw holes in the center iron. I am at work so it will be a few hours.

 

so i looked it up for the HC Luce, and it uses the FC mount setup, which is odd because there is something that didn't, but what?

the FC stud is either 10x1.5 or 10x1.25 i don't recall, 1.25 is more likely i think

 

FC stud should be 12mm x 1.5

 

UPDATE:

I am showing my second gen ignorance big time here. Apparently FCs have the passenger side mount underneath the oil pan?! These were the BOLTS I was trying to thread into my center iron. I need to order the proper STUDS to go into the center iron. Thanks for all the replies though. Lets hope I didn't booger all my threads!

 

They are 12x1.50, just like the lug bolts. I'm using thread-in wheel studs and reversed open-ended lug nuts on mine because that is the cheapest way to get 12x1.50 nuts of any type.

Bear in mind that the FC driver side mount is not anywhere near the same bolt pattern, and it would need to be extended anyway. So you are better off just making something yourself. I tried making an FC mount work with redrilling and large washers (some holes will intersect the old ones) and I ended up plating over everything to the point where it is more or less a home fabricated mount with a cracked and shredded FC bracket inside. Kind of like a peanut M&M except it's not a peanut inside but anguish and failure.

The HB Cosmo is the engine that used the engine mount in that location. The GSL-SE intermediate housing appears to be the same one as the 12A Turbo used in the Cosmo. Or rather, Mazda stuck a 12AT intermediate and 12A 6-port end housings on 13B rotor housings and made the Super Injection, aka GSL-SE engine.

 

Thanks peejay. I think I was actually following an earlier post of yours in trying to put driver side FC motor mount in the passenger side, GSL_SE iron. Glad you mentioned the bolts don't line up because I was trying to line them up without taking the header off, so just feeling around. No wonder I got frustrated.

Ugh, I was hoping it wouldn't come to just building a custom mount but after staring at it for awhile it's clear that's the best choice.

I am quickly using up my goodwill with my "buddy with a welder".

Side note: My motor actually uses one Cosmo housing... just a fun fact. It had a weird nipple thing under the exhaust port which spewed exhaust out. No idea what it was but I jammed it full of jb-weld.