Is our crank forged?

[Obsessionw/Boost]

Is the stock 7M crank forged. I have a feeling it isn't, but I just want to be positive. Is the 1J crank forged? I know the 2J crank is.

I have a friend attempting to run nitrous and he wants to know which are forged and whether or not a 1J or 2J crank will work in a 7M.

 

[IJ.]

Yes they're forged

Easy check is look at the parting lines Cast cranks will have a nice narrow ridge forged are usually a wide part line.

Jz are Forged and NO they won't fit a 7M.

 

[Poodles]

another trick is to tap it with a hammer...

forgings will ring, while castings won't (more like a thud)

 

[Adjuster]

The 7M crank and rods are forged.
Stock 6M and 7M cranks will fit the 7M engine block. Also been told the 5M crank fits too. (Gives you 2.8L displacement from a shorter stroke IIRC.)

6M crank and 7M crank are both for 3.0 displacement, but the 7M crank is fully counter balanced v/s partially counter balanced on the 6M crank. (If you compare the two, the 7M crank has more weights on it, has more mass as a result of that, and Toyota lowered the maximum RPM built into the ECU/TCCS.)

The early 7M engines had the 6M cranks in them, and after about 89, they went to the 7M crank, and the max RPM allowed by the computer dropped accordingly. There are reported to be some 89's out there with 6M cranks. I've also seen a few 89's with solid Pre-89 style engine mounts, and using the older style front cradle as well.

 

[gixxer750]

I own a 3/89 car with square motor mounts, 6m crank, and the ECU plugs are yellow but of the grey plug style. The car also has the higher rev limit.