richard1

Thanks again for the information for the compression test. I will do it the proper way and will post the results in a couple of days. I am amazed that I don't have anymore smoke at all.

Thank you for the information. Is WOT means without throttle?

the engine doesn't smoke at all anymore in all conditions (deceleration or acceleration) and runs as before ...very smooth.

I am told by a hobbyist that the engine must be warmed-up at normal temperature to do a compression reading on all cylinders. Maybe I am dumb but when I reported mine above in this thread, the engine was cold and never started. Sorry if I look stupid. It seems that I am missing something or???? The other thing he told me is the carburetors needs to be at full throttle......I don't understand this one.

Nissanman, what kind of major problem could arise? The one that happened yesterday is not related to the engine but major.....the automatic transmission is slipping. I went to a transmission specialist yesterday. The converter is bad and the entire transmission needs to be redone. I will have the car back tomorrow after a $1,600.00 expense. I am impressed that the parts are so easily available for a complete transmission rebuilt. Anybody can tell me what could be the cost of a stock engine rebuilt or could I find a rebuilt one and just swap?

The results of my compression test show that my engine is showing its age no matter how much I cared over the years with good maintenance and regular oil change every 2K. #1: 135 #2: 117 #3: 120 #4: 90 #5: 100 #6: 117 The Rislone additive seems to have help a lot There is no more big blue smoke burst now at pick up after deceleration. I am surprised that there is no more smoke at all. Just a very small puff when I pull out of the drive way after the engine has idled for a long time. What do you think guys?

I installed a new PCV valve two weeks ago. The old one was good but very dirty.

Well...it seems that after 117K I will need to do something on this engine and I am not very comfortable with it in Las Vegas. The engine doesn't burn any oil at all between oil change (2K) and runs smoothly. - No smoke at cold start - No smoke at idling when at normal temperature - Burst of blue smoke at pick-up after deceleration as at a stop sign. - Problem has increased since I put Rislone Ring Seal Additive today. After all my research on the archives of this site, it seems that I have to expect valve seals problems. I will perform a compression check during the weekend but I have some questions: 1- My engine was without any problem and the car is driven on a daily basis and meticulously maintained. Is this problem can happen suddenly? 2- Is the load of the A/C running could have been part of more stress on the engine since the A/C has been rebuilt? 3- It is a 72 240Z full stock and original, never rebuilt. 4- Clean coolant in the radiator. 5- Clean oil in crankcase. Thanks for any comments you may provide.

I tried Motorsport but it is no longer available. I also need the vacuum booster hose engine side. Thanks for help. Richard

Well...short for a long story. My new Samden A/C compressor died in March after a complete refurbishing of the original system. I have a new compressor installed since last week and God Bless me that it is before the peak hot season in Vegas. It blows 50F at the outlets. Pretty good for a vintage ..original system rebuilt with R-12.

My A/C system has been completely rebuilt last January with a rebuilt compressor. When installed, it worked properly. Two weeks ago, I started the A/C and it was not blowing cold. I thought the system was leaking and I called the technician who has done the job. Yesterday, he came to check and he told me that the compressor is not giving any pressure which means it is already blown out. It is under warranty but he told me that he has had a hard time to fine one and the concern is that another rebuilt one could also be troublesome. He suggest we search for a new one. Anybody has a clue where I could find a new one? It is the kind of system where the rotary compressor is installed under the air pump.

Zup, my original 72 A/C system has recently been rebuilt after 35 year of trouble free service. It took four months to find the right rotary compressor and be sure it would fit where it is suppose to be. The technician is a certified A/C guy who has done a great job at a very reasonable price and he found the right parts as the originals. It is quite a lot of work and not for faint of hearth.....believe me. He dismantled everything including the inside components. It works nice and I refilled with R-12 under the recommendations of knowledgeable member on this Board. I suggest you do the same to avoid any modification to the original system.

I have a very slow and small coolant leak that come from under the engine on the intake manifold side when the car is parked in the garage after a couple of days. The freeze plugs are dry. Could it come from the intake manifold hoses? I cannot see any of them leaking but I tighten up the hoses that seem to deliver coolant to the manifold. They were not loose but needed some turns of the screwdriver.

I removed my hood to have it resprayed last week. I observed that one hinge is not as tight as the other. There is some play as if the rivets would be loose but they are tight. I can plat sideways with the hinge part that connect to the hood. Is there a way to fix this hinge looseness?

Escalon, You are right......this Honda motor is not OEM. So I am not stock anymore and you are true. Lets say that it is a little " improvement "

Carl, I really appreciate your long posts with all this information. Your suggestion is pretty much the same as my friend told me: don't expect miracles. Quite frankly, for all these years, the A/C has been fine but certainly no to our modern standard. I don't expect it to be better but at least operational and giving some " fresh cold air " during the hot days. There is one subject I would like to explore further from your comment. If the R 12 molecules are larger, you explained that it is more appropriate for a rubber hose system. Am I right? If so, I believe that I am better to stay with R 12. Furthermore, the compressor is the exact same as the original as the new evaporator and " valve " ( my apology to miss the right part description ). The " radiator " ( sorry again ) in front is the same and has not been replaced and is the only part not removed in this refurbishing of this A/C system. Again , all hoses are new. I still believe that my best option is still R 12. Do you agree?

In the last three months, a friend of mine who is a MB A/C technician has rebuilt my original after market 72 A/C. It took time because finding a compressor replacement was not easy ( the rotary one ) and everything has been replaced including all hoses. In the next few weeks, I have to decide if it will run R 12 or R 134a. I have the Honda motor blower that is stronger than the original Nissan. In summer here we are close to 117 F. He believes that I can go with R134a because I will not see any difference, the system still having rubber hoses that absorb heat no matter I have installed insulation on all of them. Some savy members here to give me advise?

Thanks, you were right. The wires were inverted.

My son is an engineer and do the maintenance of the Z. Some years ago, I mentioned to him that the best would be to go with electronic ignition and he told me it was out of question. He is not under the hood every week and to set up new points take him less than ten minutes with all the adjustments and timing ( he has a trick ). The only other point sets that I found are the Standard Blue Streak as mentioned above but the problem is they wear very fast because the " blade " is plastic instead of fiber on the regular Standard Brand ( red box ). I also prefer to keep it stock as it has been at the time because mine is bone stock down to the hubcaps and it is the way I like it. Now, I will buy " many Standard red Boxes points sets ". My car run smooth with them and I will keep a stock of them.

I have more and more problems to find good ignition points sets for my 240z and I discovered today that the MotorSport product is the exact same garbage as a local import resaler here. The exact same design that makes your car fire on four cylinders instead of six or don't even start. Both are manufactured in Taiwan with different boxes but exactly the same wrong design about fit and the fiber brush location. Today, I went to a NAPA store and I bought the STANDARD brand, JTP2 point set (dual points). My car now flies instead of having a hard time to pick up. When BOSH points were available, I have never had a problem with my ignition system. I have back order points from Motorsport but I will cancel my order and/or send them back. All the other products as the condensors are OK and made in Japan. Stay away of the Taiwan stuff.

There not just one but TWO fuse holders to this S""T and both were blown. The car is fully original and both fuse holders have 20 amps. The console and glove box have to be removed to work properly, at least on mine because they were hidden under the original radio. Now, everything is OK but my blower motor (Honda) is not as strong on the third speed (which is supposed to be close to double the original Nissan) and my A/C will not blow as it is supposed to be with the Honda motor. I disconnected the wires at the blower motor and I am not sure if it may be not the problem. These fuse holders are so hard to reach that I don't want to have to change them again. The Honda motor has a + and a - black electrical connection. Which one of each of my wires go in? Is it possible that I just inverted the wires and the motor is not performing at the full speed it was doing before?

there is a fuse holder ( modern two pin type ) in between the A/C compressor and the fuse box. It is a red wire. This one just seems to give power to the A/C compressor and is coming from the 20A fuse in the fuse box ( A/C Air ). Is there another fuse that could be under the console and do I have to remove the console to check or is it under the dashboard or on top of the glove box? I can see an " online " fuse on the wiring diagram but I cannot locate where it is.

My heater motor doesn't blow air at all when I turn the heater switch on. I checked the fuse box and they are all OK. The connections at the blower are OK. What else may I look at?

There is no coolant mixed with the transmission oil nor in the crankcase and the bottom of the radiator is dry. A real mystery.

Living in Vegas maybe paradise for some but for a museum quality piece as a 72 with original paint, summer time is a killer if you have not a garage and covered parking space at work if you use your car on a regular basis. It is not anymore museum quality since I drive it on a regular basis but it is fully stock down to the hubcaps, radio, exhaust and all the original stuff of the time in perfect shape including the dashboard cover. I bought it at 32K and is now at 101k. It has been troublefree with extremely and sometimes excessive maintenance schedule. In the last three years I drive regularly about four times a week, troubleshoot every problem on the spot and fix it with my library but also with the advise of the very knowledgeable members of this forum. So, no winter on the blocks here but the original A/C still on the R-12 must be kept in perfect condition for our harsh season.