We are still in Panama. Trump is making life in Europe very expensive. Im pulling out the 6 plugs and revert shortly.

Plugs pulled and with the pcv valve shut there is a difference in plugs 4 and 3 no more. However the initial problem is still there. If i accelerate the car in neutral and idle when warm it only reaches 6000 rpm. It struggles to go over those rpms.

First picture top to bottom 6 5 4 3 2 1

Second picture plug 4

IMHO Pull the head.

This new mechanic says the pcv valve is shut. We are making a test drive on monday again and see what happens. The car is also now driven with no thermostat.

Edited Saturday at 10:04 PM1 day by 72 Datsun 240z

Bottom line that’s not the way the engine was designed unless he thinks you had a defective thermostat.

1. I suspect that JAlex's problems may be the result of poor local fuel quality combined with local high-temp conditions. Not sure that any of us are qualified to provide proper guidance on that combination. Maybe not even Nissan.

2. It may prove difficult to find qualified tech help in Panama.

That said, I hope the new mechanic proves to be up to the task and this will end with JAlex piloting Panama's best Z on his local streets and highways.

Edited yesterday at 01:51 PM1 day by Namerow
Less words.

We are testing the car again tomorrow morning. I do notice some backfire when releasing the gas pedal maybe its due to the closing of the damaged pcv valve which permitted the oil flood of plugs 3 and 4. Car is not even reaching over 6000 rpms. A lot of misfire after getting out of traffic.

I’m personally done. If his mechanic is that good there’s really no reason to post on a topic thats well over 6 years old and pretty much has not accepted any one persons advivce nor reported back on the findings from suggestions that were given.

Car was tested and leak down test was accomplished. Drove 30 minutes with no pcv valve connected and no thermostat to avoid engine temperature rising got stucked in short traffic. Car still got some rough idle when getting out of traffic until temperature went back to normal. Parked the car and all plugs were burning ok. So this could be a vapor lock or percolation problem. Leak down and compression test got good results. Do you still think i need to take the head out? He did blocked the fuel return line as i have an airtex 8012S electric pump installed and says no need to have that line opened.

Any recommendations for quality parts:

1. 160 degrees F thermostat maybe Mishimoto brand

2. Alternator belt. Mechanic says the one installed could be sliding and i should get a tighter fit.

3. Pcv valve