Cloudxs

So, I bought my first cherry red 1990 300zx na with a slight lifter knock that at first wasnt that bad or loud. There was also no oil leaks or any other problems, straight body slick top with a perfect interior. Well 3 days down the road, decide to get on it a little bit, blow off a coil plug, and the car wont start. So it takes a little while to figure out what happened, but as I did i realize the knock is louder, and sounds pretty bad.

I havent driven it past 2.5 grand after that, as this is my daily driver and I cant afford to lose it right now.

I need it to last at LEAST another week, optimum would be 3 weeks. I keep oil in it and baby the crap out of it, which I'm sure you all know is TERRIBLE owning such an obviously fun car.

With my plans like Works, and 1000 watt amp gone, I'm left to decide what to do.

Mechanic quoted me 1400$ just to fix the head. Does this sound legit?
I already read the threads on TT swap, sounds heinous and worth at least 5k, which I just dont have. That was my original plan owning a slick top to begin with...but it was supposed to be a long term goal....not immediate need.

sooo.....any advice guys? : / BTW i love the z32, its by far the funnest car ive owned. I've come from a bb2 prelude, da integra, toyota cressida, to an ae86, and this car just rocks.

Thanks anyone!

ZLover4Life

Are you certain it's lifters?

And yeah, $1400 sounds about right to pull a head and replace lifters... but if you search I've covered how to remedy lifter tick in the past. How recently was the oil changed? How does the oil pressure read?

nismo619

dont feel bad at all i thought if i changed the motoroil to royal purple5w30 that mycar would perform beter guess what lol it did , but now i have a valveknock sooooo horrable i cant go under 35 mph im changeing back to 10w30 next week " huge sigh " that royal purple cost me 50 bucks man !

KasbeKZ

here's a figure for you:

$1400 = have someone replace the lifters and hope they do it right
~$900 gets you a complete used JDM motor on your door step and you can put it in yourself and have spares from your old one.

ZLover4Life

:::sigh::: That "~$900 JDM motor" also requires a timing kit, oil pump, etc. And you will NEVER see me recommending a JDM engine unless its to replace an engine that is actually blown. There is no way to verify mileage on JDM engines and they are generally not well taken care of due to the laws in Japan.

Cloudxs

Oil is showing steady, doesn't overheat, has a pretty smooth idle until it starts bogging..just knocks like a helicopter. Its kind of strange. Im about to run some z-max and get an oil change..but i have a feeling its going to need a valve job. and as much of a fan as i am of dropping in a jdm engine, that would also cost money to put in.

So its 900$ + however generous my mechanic is.

ZLover4Life

I didn't ask if the oil pressure was steady. What's it steady at?

rtmorgan

you are running 91 octane not 87 right?

87 will make it knock like a mother fuc#er

Cloudxs

Yeah im running premium, still knocking : / I will see exactly where the oil pressure is at tonight.

napoleonzheking

i wouldn't say knock, but i would say tick. huge difference.

Cloudxs

well..shes about ready to pop. took her on the highway..came back shes ready to pop...sorry guyz. thanks for helping...now im just considering if we need to pop her or salvage her body

KasbeKZ

you can get a jdm engine with a good chance of being pretty decent at your house for $1k. do some maintenance, put it in, and you've got a working car again with lots of spares for $1300 or so.

ZLover4Life

Sounds to me like rod knock and not lifter tick... lifter tick won't really incite the kind of reaction you're having, but if you spin a bearing you're definitely gonna know it's time to do engine work. This is why my first response was "are you certain it's lifters?"

duowing

What is so special about the JDM engine? I thought around the 90s generally the US got the better engine? Why not save even more money and find a used engine here in the US?

ZLover4Life

Absof*ckinglutely nothing. They're abundant, but they're risky.

Because people are idiots and apparently don't realize that they're buying an engine having had no background on it... this is why every supplier recommends replacing everything but the internals. *I* recommend finding a used USDM engine. Or better yet, investing the time to DIY... you learn a lot about an engine (especially the VG30) from tearing into it.

KasbeKZ

agreed, nothing special about the jdm except the abundancy. it's the cheap fix. if you've got more money to put into it, the usdm would be better, and even better would be a rebuild.

zlover, all the advice i've found about rebuilding the vg has indicated that it's extremely difficult to rebuild and that many average machinists will not do it correctly having been used to other engines. however, i've heard you recommend home rebuilds a couple times now. could you put to rest these accusations that i've been hearing of the engine rebuild being so difficult? is it really as simple as using all the right tolerances and just knowing not to turn the crank?

ZLover4Life

There is nothing a professional machinist can do that an average person cannot do, given patience and a few extra tools.

You seriously need to get over this belief that the VG30DE(TT) is some exceedingly perfect machine that makes it so much more complicated on the inside than any other Japanese engine - it's not. It has tighter tolerances, variable valve timing, and turbos... that's the only way it differs from any other internal combustion engine - and there is no reason to touch the turbos, nor is there usually and reason to touch the heads. Once it's machined, assembling the lower end is as easy as orienting and compressing some rings, dropping pistons into cylinders, and torquing down bolts to the proper specifications. And then you put the rest of the components on and torque them down properly too.

KasbeKZ

ok that's good to hear. i'd look them up and show you the threads that got me so worried on tt.net if i had the energy. i've been working a **** ton lately. thanks though.

Cloudxs

someone wanted to trade me a running 2+2 + some cash on top for my blown (or very near blowing) slick top. I was highly considering this idea, but if its not going to happen engine swap is where i'm going next. I pretty much knew it was rod knock, but with enough wish and support of your "mechanically inclined friends" you can get yourself to believe its lifter tap. ~.o Now I get to find an engine.

ZLover4Life

Do not trade a slicktop for a limo unless there is a lot of cash going your way.

If you ask me, I'd take this opportunity to pick up a front clip and start the TT conversion.

snwbrderphat540

tt swap in a slick top! sexy. and if it were rod knock i'd hope he could tell the difference, the sounds resonate from completely different parts of the motor. i got lifter tick, its insane. but its because my lifters were bone dry and need to bleed from the rebuild. GL