1911 parts are not drop in. They ALL must be checked and fitted for proper function. And you Llama is not a true 1911. I would be more properly described as a 1911 inspired design or a first cousin to a 1911.
Now to your issue. Fire control parts have a very narrow range of acceptable dimensions and that range is defined by the specific combination of parts on any given frame. You new sear is different from the old one. Either the nose length is shorter relative to the old one or the foot of the sear that is engaged by the thumb safety is dimensioned differently, preventing the safety from blocking sear rotation. You will have to replace the thumb safety or have the blocking surface built up with weld and refit.

 

Thank you for the response.
I am looking for a drawing that will show me these mating/engaging surfaces so i can better understand where to modify whichever part is not engaging the other.

 

 

Thanks to all, especially Creeper!
That is what I needed to see. The old sear is back in the gun now and will stay in until I decide what to do.
I fit a Beaver Tail Grip safety to the gun last week and found out that the pin on the safety that holds the GS in place is too large in diameter to fit into the grip safety. I had to open up that hole in the GS. not having the correct reamer for that I used a drill bit and buggered it up pretty bad, so I did not finish fitting the GS.
I have a Springfield RO that I can take apart and mic the pins. I will check and see if I can source a new safety for the Llama, GunParts has some stuff in stock? Or maybe try to source a new Llama sear, depends on how it compares to the RO?

Thanks again to all!

 

Sarco is another potential source of inexpensive 1911 surplus and "first cousin to a 1911" foreign parts that you might find useful.

Have fun getting it all to work... "frankenguns" are nothing if not entertaining.