Hello all, My girlfriends dad gave be a 300zx NA that sat for a for a while but got started every few months. It has some issues with running and is miss firing in at least 2 cylinders. What are some common problems to look for and to fix to get her up and running to make a daily driver. I plan to replace the plugs,wires,vaccum lines and a few other things here and there. It does have a new clutch! but i have to stay on the gas to keep her running lol. I would like to do a swap later down the road when I save up some money. I was thinking vg30tt z32 swap but I need to do some research on those motors and even this 300zx. Well thanks for any comments you may have. I really cant wait to start working on her. I will get pictures next weekend when i pick up the car.

 

step one get the fsm download for free from xenon. step two in my opinion the 86 was the best looking of the z31's. General advice attached.
Get your battery load tested. Be sure you have clean, tight corrosion free terminals on both ends of your battery cables. Be sure the ground (negative) cable goes to a bolt into the frame before going to the starter. grounding through the starter is not a reliable connection. Z's don't like low voltage. causes the electronics to act funny. it is possible to have enough amps to crank but not enough voltage to run the electronics. If you have one size fit all cheapo clamp on terminals they are a problem waiting to happen.

Clean the connectors for the maf or afm, ecu and tps. Deoxit by CAIG is probably the best connector cleaner on the market. spray with CorrosionX after cleaning and before putting together this will help prevent any further corrosion.

Replace outer tie rod ends, and ball joints. replace the bushings with poly (don't forget to lube them as directed unless you like squeaky things). New shocks. all those things will make you think you are driving a different car. doing them piece meal is a waste you won't see a great improvement until you do the complete job. Rear bushings nice too but more work and you won't notice as great an improvement. Rear shocks also because if the fronts are gone so are the rears. if car squats when you jump on the gas the rears are gone. Replacing plugs on a VG30de is somewhat of a pain. Get a plug wrench with swivel 6" extension for a start. get the wells where the plugs reside blown out really good with an air compressor they collect all manner of junk. loosen up the throttle body to make getting at #6 a lot easier. Dizzy cap and rotor. Read up on the various gizmos nissan had to making the engine idle (probably mandated by EPA). I took mine off and the engine runs great and I don't have to wonder what those things are doing. depending on mileage timing belt needs doing. If it has been sitting and still has the original after thirty years I would do it anyway. that way you get a new water pump and rad hoses car is good for another 10 years. courtesy nissan has a timing belt kit that is a good value and you get all the parts you need in one shipment. I shopped all over for my parts when I did my 86T (month ago) - saved a few bucks but not worth the aggravation. look for rust under the tool kit in the rear. Emphasize again BE sure the ground strap is grounded to the body before going to the starter starter ground is not reliable. Still getting grief from wife unit because I started driving my 85T before I got that stuff done and we got stranded on the ferry. all that comes to mind at the moment. If it wanders the road like a drunk pig get to the suspension as soon as time/money permits. When you get them running right straight and true they are a lot of fun.

 

Thank you for the comment! I now have an idea where to start this thing. i am looking forward to getting her running right. i love the body style too. It reminds me of my 89 dodge daytona i had when i was 18 lol. Im just glad these vaccum lights accually work and i dont have to do them by hand. Well i will keep up dating as i go along because im sure i am going to need a few more pointers.

 

What all would i have to do to the motor if i wanted to turbo it? Or is it easier to just do a swap? vg30et... I am curious to know if the internal block and head is as strong as the VG30ET? If so in theory, i could just throw a turbo (with all the stand alone systems and parts) on to the block and be ok in moderation. I know the vg30et can hold up to 400rwhp stock internally if I'm not mistaken or the guy was wrong that wrote it... But I'm just trying to get a understanding about the ins and outs of the car. If someone could show me a good link to read up on that has right info on it i would really appreciate the help and time. Thanks

 

I have been "goggle"ing a lot and only found one really good store to buy parts i might not beable to find in the junk yard. Are there any other things i should type into goggle? thank you!

 

swap is the easiest because you also need the turbo ecu and the correct O2 sensor. black dragon, courtesy nissan and motorsports auto. most of the basic stuff is available NAPA, OReilly etc. Don't forget to check amazon.com. You would be surprised what they have and if you sign up for prime time it is usually free shipping.

by the way ? what is a vacuum Light?

my buddy gets close to 400 on his car which is the twin of mine. Megasquirt, cam, boost controller and probably some other stuff I can't remember.

 

Thanks rogers! So if i did get all the parts the motor would hold it then... I just got all the cleaners and sprays for the big electrical cleaning tomorrow. i also grabbed some throttle body cleaner and degreaser. It has a very bad valve cover gaskets so those may be next after the radiator. It has a leak but im unsure of how bad and if a bottle of rad leak will work on it. Is it worth buying a brand new one or getting a junk yard one? i am gonna get all new hoses and replace vaccuem lines soon as well. i will get some pictures out to show everything i hope tomorrow. I cant wait to get her up and running good and strong. Is there and easy way to check the compression? Or should i take it to a shop? Thanks again and sorry for all the questions. This is my first fixer upper and i am still learning a few tricks from the older fellows.

 

valve cover a bitch to change gaskets get a long philips head and try tightening the screws. Clean the maf also but gently. are you sure the rad is leaking and not some loose hose clamps. You might be able to rent borrow a compression tester. Do that when you change plugs but not usually an issue. the z32 engine doesn't just fit in a z31 very easily.

 

ok thank you. It has 160,000 miles so i wanst to sure about the rings being good. I have read a lot about the vg30ett and i sure as hell do not want to do that! it will be a lot more money and time then what i want to spend when i can get 400hp+ for about $2000... Im really excited to clean her up and try to get her running right. I am un sure if the the hoses or the radiator its self. I plan to replace the hoses anyways so i will keep my fingers crossed thanks man for all your time. I am really greatful someone else is getting on here and helping me out.

 

get the timing belt changed or you will have a lot more to worry about than rings. get it to run reliably and the suspension proper before getting into going for horsepower. you will learn a lot about the car doing that which will be helpful when you do try to go for more power.

 

im afraid i dont have good news i got the new hoses, fixed the battery contacts, and a tune up, I added water to the radiator and as i was on the second bottle, water started pouring out of the exhaust. So i decided that i wiould try to cranker her up anyways and the rest of the water blew out of it... Any ideas what this could be? I am guessing the motor has a hole in it somewhere and its just blowing the water out through the cylinders??? i really hope im wrong!!!

 

So the only things i have come up with to explain whats wrong is a cracked block(Im not sure how) or a blown head gasket. But for it being a head gasket, i dont think it would blow out all the water out like a water gun out of the exhaust. I am hoping to take the heads off this week and look into it more... This sucks.

 

are you sure you weren't putting coolant into the oil fill hole? that would definitely do what you describe. other than that it would probably go into the crankcase not the exhaust. if your gal's dad actually started it every few months unless the block froze you shouldn't have an issue.

 

I am postitive that i did not! lol it litterally blows out though... i want to try and get the heads off today and have someone else look at it too to double check. only 3 cylinders are firing aswell and it wont stay idleing. i have to stay on the gas and it shakes the whole car.

 

so i got the passenger side head off and its doesnt look good so far. The head melted a hole from the coolant line to cyl#1. there is a little rust in cyl#3 on the inside walls. The 5th looks the best and they dont like too bad other than the rust.








i will take some pictures of the head tomorrow.

 

Alot of acorns... Looks like you have some fun work ahead of you. That rust has been on the wall for some time might look into getting that blocked freshend up.

 

are those dings in the piston top from hitting the valves? Probably had some valves hung up and then turned over the engine. Not at all good.

 

The pistons have notches for the valves not to slap the piston

 

With coolant leaking from the jacket to the exhaust, enough to rust the cylinder walls, coolant likely bled into the crankcase. Starting the motor under these conditions has probably scored the crank journals and bearings. The engine may still run, but it's running on borrowed time. I think you need to jerk the motor and consider a rebuild. Check for evidence of coolant in the oil.

 

Yes there is a lot of water in the oil. Im set on doing a swap. i found a car near me running good for 550. i just have to save up to buy it. lol thanks all of you. I didnt get a chance to take pictures of the head but it is shot. and that only one side. time to hack it all up

 

Well i got the other head off and it was the same thing as the other one. melted. the bottom end doesnt have any piston face damage but im just going to swap out the motors with the other N/A car i just bought. I am having a hot debate in my head if i want to SC it or turbo. I haven't been able to find ANY turbo cars/ parts near me. I want to turbo it but doing a SC will be unique and more than enough power. Im not racing it or anything but i am wanting to start drifting. What are your opinions on SC or Turbo? Also does anyone Live in or near Jacksonville florida? I dont see many 300zx's around me. I need some buddies

 

Thats a lot of nuts,

Congrats on the car and the project. Don't give up and take your time, between the 2 cars you should have lots of spares.


Cant come down to J-ville til summer, hope you got the engine changed and running. Like you said don't see many Z31s around, Thats why you gotta keep the faith and don't crush it.
Best of Luck,

Shogunb

 

LOL yeah he is... well i hope so too. I wont close on my house until march but i should get it done pretty quick. maybe we'll beable to take a ride together over summer!

 

I have a question. i have been looking for weeks now for turbo parts to make my (soon to be running) na to turbo... does anyone know if the parts off a vg30dett will bolt on to the vg30et? EX. manifolds?

 

Nothing will bolt on from a de/TT. People selling turbo manifolds and what not all the time on z31performance and ebay.

http://www.az-zbum.com/faqs.shtml
http://www.redz31.net/