Nismo_Gizmo

Ok there is a 1991 300zx tt I am looking to buy. The guy said it needs a valve job and that only 5 cylinders are firing. He has no more information on the engine other than that. Its completely stock and he is the only owner (sounds atleast 40yrs old). My questions is does anyone know what kind of problem this is and how much it would be to fix if I did labor myself? Could I simply replace the valves, retainers, springs and guides and be safe or would i need it machined? Does anyone have information on this? I really want this car because its 4500$ and has 130k miles therefore its beautiful and in my price range!!! Please Help!

KA24Tech

First in order to diagnose the problem correctly it should have a wet and dry compression test and a cylinder leakdown test performed. This will give you an idea of the mechanical condition of the engine. If you want to rebuild the heads you will be looking at a total cost in the $2k neighborhood. If you just want to clean up the heads and replace a couple of valves, then you could probably get by on $500-$600.
Does it have a new timing belt on it? You will need one if not and if so I would check the timing marks to make sure it was installed correctly. I have redone several for people after pro shops have done a T-belt replacement incorrectly.
I bought mine with a bad engine several years ago and with $9k into just the longblock it is bullet-proof. The aftermarket support for the VG30 components is very good so which ever way you go you should be fine.

Troy

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SHIFT_Happiness
1992 S13 240SX SE Fastback KA24DE 5 spd
1993 U13 Altima SE KA24DET 5 spd
1990 Z32 300ZX VG30DETT 5 spd
Still trying to import a 1988 R31 Skyline GTS-R w/ RB20DET-R

dilly yo

Nismo

Don't kid yourself. Although Ka gave good advice, even if you do just replace the engine or rebuild it, you will be looking at ALOT more than just that price. There are going to be som many things that you should and will have to replace that you will be looking at alot more than just the engine work price. Unless your getting this car DIRT cheap I would stay away and look for another one. Also, working on this engine takes skills so unless you have a good facility and have some good skills, plan on taking TIME and do it slowly. Believe me, I've pulled this engine three times and just got done doing a complete rebuild basically by myself. Search TT.NET and learn of things that can make your job a lot easier so you will never have to go back in there in the near future. Don't try and skimp by because no sooner will you have the engine back in and you will need to pull it to fix another problem that can't be gotten to without it coming out. Key is to research research research!! Good luck.

Nismo_Gizmo

Well I bought the car.. Drove it home and am driving it now, it drives good and the valve is hardly noticable. First 2k I get is going towards those valves and from there (Exhaust, Intake/ECU, Complete Rebuild + .40 bore , wiseco pistons, eagle rods) In that order. Thanks for the info tho!

dragknt

The only car I've had a dead cylander in before was in a '97 Kia Sephia I had a few years back, and it was an easy fix, but it made the car drive lame, like it had another thousand pounds of weight, and the car had a nasty vibration, and all that... I dunno...If I were you, I'd get the valve job, yeah, but also make sure that sixth cylander starts firing again, before I look at any upgrades, especially an ECU. I don't think JWT makes ECU's for 5-cylander Z32's. =) I mean, you're probably already planning on all that...just my two cents.

dilly yo

Eagle rods and weisco pistons?!?!? Where are the bigger turbos that will present benefits with going with those upgrades? How about the injectors to supply the increased need for fuel? I think you have your priorities with this engine building screwed up. If your going to do a valve job then it would be completely stupid not to do your bottom end at this time. If you want get your bottom bored out to 88mm and then drop in the weisco, JE etc forged pistons. If you ask me there is no need for eagle rods unless your planning to be pushing crazy HP. The weak part of the VG engine is the cast pistons. Personally I would go with harder Bearings also, but this is debatable. If you have a lump some of money then get the injectors, pistons and turbos if you can. If you don't then I would not even touch the engine until yu save enough. Remember that if you get an ecu now and then upgrade your injectors, you will need to replace the ecu again. Plan your upgrades properly and save some money because you WILL need it in the future. Unless you plan on doing the Head work yourself, be prepared to spen more than 2k for all that will need to be done.

PS do a leakdown test and compression test since your car is probably not performing to anywhere near it's potential with a dead/near dead cylinder. Good luck!

KA24Tech

I agree this should be the first thing you do besides an oil change and new filters. These two tests can be very revealing and I have seen Z32s that would miss but the cause wasn't even on the top end, it was cracked ring lands. Just something to consider...

Troy

__________________
SHIFT_Happiness
1992 S13 240SX SE Fastback KA24DE 5 spd
1993 U13 Altima SE KA24DET 5 spd
1990 Z32 300ZX VG30DETT 5 spd
Still trying to import a 1988 R31 Skyline GTS-R w/ RB20DET-R

milly555

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