cheezmonta

For the price of having the block punched out, sleeved and honed you could just buy a VG33 and have it shipped to your front door for much less.

Run the ECU codes. My money is on a bad Cylinder head temp sensor. Those things are well known to be the cause of MANY a bad running Z31.

This sounds like a bad 02 sensor to me. My 89' Z31 did the same thing. It seemed to run good till it warmed up then it started to sputter and lack power. I ran the ECU and everything came back fine but was not. I ended up changing the 02 and the prob went away. It couldn't hurt to change the 02 anyway. Look at it as preventative maintenance.

The lifters aren't the cause of the valves floating but are a contributing factor. Those little things have to move pretty quick up and down to open the valves and at higher rpm's they don't do thier job very well. With a nice set of lighter solid lifters, rollers, or something it is less mass that has to be moved and will let the motor rev higher, safer. The JWT and Ferrea springs are both a bit stiffer than the OEM's (15-20%). Ferrea doesn't actually make springs for the Z31 but they do carry valve springs in the same dimentions as the Z31. If you call them or a Ferrea dealer with the specs they can find something that will work for your application.

I have been searching the forums here, on Z31.com, Z driver, and 300ZX club. There is no info on solid lifters for the Z31 300ZX motor!? I have found them for the Z32 motor or VG30DE(TT). Just not for the Z31. I am trying to redo the valvetrain to handle prolonged high rpm with a bit more reliability. And to raise the limits I can rev. without fear of catastrophic valve float. The limit of the stock Z31 valvetrain is about 7200rpm. I'd like to raise that to at LEAST 7500rpm without problems. To do this I need to address a few issues: 1- The heavy and sloppy hydrolic lifters. 2- The weak stock valvesprings. 3- The camshafts. 4- The solid un-adjustable rockers. Now the valvesprings are easy enough. JWT and Ferrea make a set of performance springs for use with a performance high-lift cam. The rockers are not a major concern as they are very strong and not prone to wearing out easliy. However the Nismo rockers are adjustable, but I am not about to spend $900 on a set of rockers just to eliminate a bit of valve clatter. Which leaves me with the lifters.... The OEM lifters are about $26 a piece, so for the same $300+ I'd rather buy a set of solid lifters. Unfortuanatly no one makes them so I might have to have them made. They are just flat tapet hydro lifters. If anyone has found another lifter for a different motor that I could even possibly find a way of working. What would it be? Maybe a set of roller lifters? At this point I'm open to any suggestions... In need of some assistance with some R&D here. Thanks for any help!

I need these measurments to see if they would fit. This is a crappily made diagram of my NA axle. I'll need the Dia. and length of the input. I have the "A" arms for both type of boltup to the hub so no problems there. Hope this pic works. Thanks

I have a NISMO 2-way VLSD installed in my car right now and have run into a bit of a problem. The LSD was installed in my 89' (Z31) N/A R200, replacing the open diff. There is about a mm of freeplay in the input when they are installed. I nabbed a turbo axle from my friend to see if that would work but it is the same diff. input as the stock ones on the car. The axle was from an auto turbo. May be differant from the other turbo axles, I'm not sure. I need some insite as I've been racking my brain on this one for a week. Are the MT turbo axles input shaft bigger than the N/A. What about the Shiro axles? Would a set of these work better since they are from a VLSD stock?