madkaw

I have to agree with Carl, it's American greed that dictates how stuff is made. If the vendor says' make it as cheaply as possible' , that's what the Chinese manufacture will do. It's the guy ordering the product that should be setting an assuring the quality of the product.

That's funny Charles. That kind of LSD may or may not get you better handling of stuff-

Ummm- doesn't Nissan still sell those seals?

timing #'s?

Kind of weird the mn47 head gave such low CR numbers . The pistons should take effort to push up, but try some trans fluid and see what it does. How do you just find a mn47 head in the junk yard. I've been trying to run into one of those myself

SHAMELESS! If I were you I would take it to Leon. To have a Z expert in your backyard is priceless. There are many on this site that would love to have that advantage. It will save you time and money and you can enjoy your Z sooner by figuring things out early.

So you lost power after going to the 47 head? Or it had 'scary' power with which head? Don't forget the basics, a good tune is everything. Done a valve adjustment since installing the rebuilt head? Installing a 47 head you will loose compression despite being rebuilt with respect to the e31 head, so it won't run quite the same. What ignition are you running? More info is always good for troubleshooting!

Why wouldn't it?

Really no reason for your car to idle that fast in the first place, the cam is not that big. You probably have a vacuum leak as suggested. Search you tube for troubleshooting vacuum leaks

Those cam specs look like my Schneider Cam stage 2 -which should idle like normal-not 1100 rpm.

Look at the head pic of the combustion chambers. The last three cylinders I had most of the issue, but #2 fouled on me also.You can see the difference looking at the valves from a distance. The pistons had a sheen to the top of them besides also having a carbon layer-the shinier ones were 4,5,6. There were moments I had this motor running rich, but with a wideband I knew most of it's life--until lately--it ran well. I didn 't have a perpetual problem with this motor running rich or the O2 sensor would have showed that. I had some carb issues , but I always knew I had a problem right away because of the o2 and looking at my plugs. Maybe a combination of issues piling up on each other. I knew I had an issue with rockers-which effected valves, which needed to be addressed. I didn't expect to see this much build up. I didn't really poke at the crud on the valves and i haven't seen them out of the head. The head is at the machine shop now. I will say the HG showed had this crud on the fire ring edge and it wasn't hard, more oil like mixed with carbon.

They weren't stock seals, but seals that were recommended for a higher lift cam. Not enough to tell if i was.

Some pics of what I have been seeing. The cam looked good but it is still at Schneiders for evaluation. You can see the build up on the back of my valves. looks more like 100k mile engine then a 10k engine. Lots of soot everywhere. The engine builder questioned my PCV system right away. Looks like I will be replacing valves and guides minimum. I still have no cause for high oil pressure, but I haven't plastigauged bearings or examined oil pump. Right now I am cleaning all the soot off the pistons tops and examining things there.

68 threads started in less than one year

Please only use enough air to fill the system. I think I had 10psi set on my airbrush compressor. Good luck

I had some success with my 71 system by pressurizing the vent system and looking for leaks with some soapy water. Use very little pressure. I hooked up air at the vent line that is in the engine compartment .

Original radiators are good, especially a 3 row. Find a local radiator shop to flush and pressure test it. For the most part the aluminum radiator is bling and saving some weight. When i took my 3 row to a local shop that's been doing this stuff for decades said he was impressed how well that radiator flowed. You could spend the money else where.

I had a situation like this working on a coworkers car. After doing everything -----including pulling the gas tank, I gave up. Someone else had found that this girls car had mice in there chewing her wires. Car would run and then quit for no apparent reason. I guess it was a wire giving out after being loaded for a while driving- maybe a ground, not sure. My guess is module or wire issue.

So when it does die on you do you immediately check for spark? It would take a second with a screw driver or something to jump the spark plug wire. Sures sounds like ignition

Bad terninology Zed. You are right, the seal rides on the crank. It's finished surface makes me call it a bearing for some reason. Zed, I was reminded of your posts regarding the seal and what was behind it and I see your point. I wanted to tie my pressure issue and leak together, but they do seem seperate issues. I did look at all bearings as i pulled the engine apart and so far everything as far as oil passages line up perfectly. Oil passages look clear and I have blown pressurized air through them. Still have some cleaning to do, but nothing jumps out at me yet. Need to check crank passages as you have said. Also going to disect the oil pump. Plastigage the bearings... ...and I am always open to advice and suggestions.

Well the motor is completely broke down with no drama. Everything inside looked like normal wear with nothing jumping out at me. The rear main seal that has given me fits did look troubling. With the block in front of me the seal didn't look parallel to the block. It was installed at the slightest of angle. After removing the seal I noticed a mark on the bearing where the seal rode. It looked as if I put the seal on dry and the seal left a burn mark on the bearing. So I guess I did something wrong. Atleast this time I can see what I'm doing when I install the seal. The plan is to plastigage the bearing to check for oil clearance and paint the block a color other then black. Clean pistons and inspect them. Then reassemble.

I don't know Blue, I think I would talk anyone away from points, just for the reason you stated. Reliability - especially high rpm== which can equal performance. Less moving parts is always a good thing . Stronger spark helps with lean conditions where the burn rate is slower. Electronic ignition to me has always been considered a performance upgrade with respect to points. IMHO

I've run a Schneider cam with good results

.... Or what he said^

...or just go to your local parts store and get a coil made for the ZX series