'71 240-Z no suction from one carb

[Ttiger]

I was driving my '71 Z and when I came to a stop and tried to start up, it died. I got it started again and continued. While climbing a hill I was losing power and finally the car died. It would not start and I had it towed home.

After a few hours I tried to start it and it would only run with the choke pulled. I checked the carbs and using my hand, found the front one sucking much more than the rear. However when I put my Uni-Syn on them they were pretty closely synched up.

The plugs for #4-5-6 looked decent although #6 had a small bit of oil on it.

Compression was all over the map:

1-145

2-150

3-82

4-159

5-37

6-65

#5 and #6 would cause low compression and therefore low suctiuon from the carb. The valve adjustment was OK and I did not see anything broken when I pulled the valve cover off.

Aside from a complete tear-down, any other ideas? The car was running great before this happened.

[mayitin]

These are some ideas not cures ok. Torque the head again. Perhaps add a little bit of oil on the low cylinders and check compression see if it changes, some times the valves do not close all the way. vacumm leacks. I wish I was a mechanic to give you good advice I know is depressing specially when everything was working fine.