Just finished replacing the heads on my 96 4Runner 3.4L 4X4 Manual with 230k miles. The left one was cracked. I ended up replacing both with a set from a totaled 02 4Runner with 76K.

The heads were poorly shipped and the cam bearings were all thrown in a baggy together and severely gouged. So I used the bearings from my old heads. I was hesitant and I hope this isn't a huge problem (opinions?). I also had to use my cams for the same reason. There was one obviously bent valve that I replaced. All the others appeared to be good, I didn't bother to pull them and really check. I checked for cracks and warping, looked good.

I finished putting it all together last weekend, but went to start it and got no combustion. Its turning over, getting spark, and fuel. Started diagnosing with the FSM and didn't get too far except to check resistance in the ECM and make sure all connections were good, which they were. Tried swapping ignitor, fuses, and ECM with a running 98 4Runner, no luck. Then I checked compression... don't really know why I hadn't right off the bat. Got 120 consistently from the left side... and 60 or less on the right side

Thoughts?

All I can think are the exhaust valves are all bad?

 

I'm wishing I had just left the original right side head on.

 

I am not sure but could the cam be in the wrong position on that side when you put the timing belt back on?

 

I was going to guess a timing problem, but your compression is in the toilet so something else is bad in there. Sorry, but you'll have to take it all apart again.

 

I thought it might be the timing on that cam, but I know I did that right. I'm thinking the valves are bad because I did not check them completely. I guess thats what I'm doing this weekend.

 

Im not sure but if the timing is off on that cam couldn't it be that the valves aren't closing at the right time and thats why there is low compression? What are the odds of all the valves being bad on that head especially with these being non interference motors?