So I was contemplating swaps and just would like to get an idea of what are some common problems on the 1jz? i have only heard of rod knocks anything else? i dont expect much being it is built from toyota but i would like some input

 

It all depends on the condition of the motor when you do buy it and what kind of preventative maintenance you do before putting the motor in. I say if youre going to do a swap go with a 2jz

 

my 1jz has no signs of rod knock and i've been pretty hard on the car.

Valve stem seals is a common

 

Check the crank pulley for signs of dry rotting in the dampener rubber.(1jz and 2jz). Ive heard stories of crank walk (1jz)but never actually saw anyone who had that issue.....

 

rod knock on a 1j? never seen it before unless its a tuning error or owner error

 

i am really familiar with the 2jz set up and motor and all its just freaking expensive for the swap i guess ill just have to continue to wait for that right moment. im just getting eager to do more to my car.

 

Maybe the weak stock twins when pushed past 18psi? Leaking ECU capacitors? Not many significant things I can think of.

Both motors:

Valve cover gasket leaks.
Crank pulley as someone mentioned.
Cracked coils.
Valve stems as mentioned as well, but I think most owners just ignore it.

I've seen a crank walked 2JZ before and many owners on the forums post about it. It probably applies to 1JZ as well just haven't heard or seen one yet. Disable the clutch switch.