ok i just bought a 1990 300zx

there is a slight knocking comming from the left side of the engine...
i used a stethicsope<<i think i spelled that wrong>>> and its definatle comming from inside the head...
i talked to a mechanic.
and he suspecs something to sdo with the cam shaft...
i said any ideas?

he said that nissan put shims on the camshaft that can wear over time creating a knocking sound..
is this true?

and second... im taking the intake manifold off and the valve coover off to get to the cam shaft to scope out the situation...
but here is the PROBLEM...
i cant seam to get the manifold off...
i have takes so many tubes, throttle cables, 6 magnitos, fuel lines, vacume tubes...ect

taken the bolts that hold it onto the block...

its Lose i can move it back and forth and up and down but there seams to be something holding it from comming compleetle off...

i need pictures or a detailed something...to help me get this damn thing off...so i can finally get somewhere... any help will be appreciated

wait for wes (zedex) to get on here...he can probably give you a detailed explanation on how to get it off...

everyone says there are hoses and wires in the back that always get caught...

1990's are notorious for valvetrain problems that nissan fixed in 91'...i never heard anything about cam shims that get worn out. :dunno:

try to find some used low mileage heads from a 92-95 in a local wrecking yard or on ebay, that will probably save you a lot of money. because if you can get the upper plenum off, you can get the heads off and replace themn yourself. this will save you a huge labor bill...

oh man, i took the intake manifold off a few weeks ago, and just to let you know, it is a complete bi**h. took me forever to do it. there is quite a few hoses in the back you can't really see that hold it down. one of them i just riped off and didn't even know about it. i will go and find the link i used to help me take it off.

-Jared

Great...hope you find it...im in a bind...i have to get this fucking thing street ready ASAP

Ok... You've got the curse my friend, but here is the procedure to remove the upper plenum.

-Remove the battery completely before this procedure (rememeber, you have to remove the passenger side cowl before you do this)
-Remove the Throttle Cord Cover. 4 Hex bolts
-Remove the 8 Main Support bolts, these may be down there with Loctite, but they will come up with some force.
-There are two EGR (Exhaust Gas Recirculation) Arms that snake undernieth each side of the plenum. Look about 2" Back from the Throttle Bodies, and it should only be 2 10mm bolts on each side.
-Detach the Throttle Cords
-Remove the fuel lines from the Fuel Presure Regulator, make sure that you plug these off with a clamp of somekind, but a center punch in the end should do the trick.
-Remove the 6 coil packs.
-MAKE SURE, that you tag off the EFI (Electronic Fuel Injection) plugs that lead to each cylinder. DO NOT GET THESE MIXED UP! And chances are, you'll have to replace these as well. Most of the hosing and connectors on a '90s engine are pretty worn out.
-Just go ahead and slice the vaccum hoses on the bottom of the plenum, because chances are they are dry rotted, and are going to need replacing anyways. I would go ahead and buy the Stillen vaccum line kit... Its like $33.95, and it has every line you'll need.

Well that should do it... That and a little force should get the job done. The fun part is, reassembly :D

-Wes

sorry, i can't find that link. but yeah, do as wes sad and just cut the flippin vacuum hoses, i removed them all and it was a huge bitch. reassembly was actually pretty easy with some lube to get all the tubes back connected. disassembly was a lot harder than reassembly.

-Jared

Some cars use a bucket and shim assembly to control valve lash.

Z32s have hydraulic lash adjusters.

I don't know what shims he could be talking about.

Check the oil level? The hydraulic adjusters will tick if they aren't getting the proper oil pressure.

oil level is good...no lifter tick...
just a knock
175k miles on engine

Broke... Didnt you have a 'slight' knock in your engine? Right before the piston shot through the crank case? :lol:

Be careful dude... I wouldnt suggest beating on the thing.

-Wes

i got the stupid thing off YEAH...
ok next problem...the knock
or more of a tap from the lifters
a little more of a metal sound of a lifter thats not getting enough oil...
but the oil lvl is perfect...
the mechanic said that the wear on the cam is abnormal

mabey i should get some other heads like he ^^^^^^ said...

any body in the market to sell some 92-95 nonturbo heads?...
or mabey a price range that i can shoot for? are we talking a few grand for a seat of heads cams and all?

and the cams are non-adjustable? err the valves?...the valve lash i guess its called...?

or mabey a price range that i can shoot for? are we talking a few grand for a seat of heads cams and all?

check on ebay and go to twinturbo.net 's classified section. if you can find a used set, they shouldn't be that expensive. maybe $400 or so. if it comes down to spending more than a grand, i would just buy a new motor. JDM importers usually sell N/A motors for just a tad over $1000...

or another thing you could do, it sounds like you can do the engine bay labor yourself so you could take the heads to a machine shop and have them work their magic and then replace what needs replaced...and machine what needs machined. then you will have a almost brand new set of heads...

The valve train on a 90-96 VG30 engine uses hydralic lifters. If you changes the cams with reground cams with smaller base circles then they make shims for that. Or you can use cams that are welded up and have the same base circle as stock cams and don't have to use shims. Now if you use solid lifter cams like my racer you have to measure and install shims for proper clearence.
If you have a noisy lifter time to replace it or install a new set.

Doesn't the Z32 have a distinctive 'tick' anyway?

there is the usual injector tick....
but this sound is distinktive...its not suopst to sound like that

a little more of a metal sound of a lifter thats not getting enough oil...
but the oil lvl is perfect...
the mechanic said that the wear on the cam is abnormal


Could be clogged. There is a pair of small holes on the side of the adjuster that flow into it. If they get clogged (as a high mileage engine with higher than usual blow by might get) then the oil can't make the adjuster "pop" up again after it is pushed down by the cam. And then you'll have a small gap inbetween them until the cam lobe comes around again and hits it, making a tapping sound. If you already have everything apart, try cleaning the adjusters (don't mix them up, make sure then go back into the original hole) and see if the tap goes away, that would be alot cheaper than getting another set of heads or a new engine.

hey broke..u wanna explain this-^^^ process a little more in depth, or give us a link

yeah a link or an explanation or a location of an
adjuster? i got the p[lenum and the valve comers off ...

can i get a link of that Stillen vaccum line kit?

i found a set of 1993 heads off of a 300zx non turbo convertable...
they should fir on my 1990 300zx non TT right?

i found a set of 1993 heads off of a 300zx non turbo convertable...
they should fir on my 1990 300zx non TT right?

they should...might want to confirm with a Z specialist or someone on here will br able to confirm.

how many miles are on the heads??? and how much does the seller want for them???

The'll work great and it would be a good time to rebuild them and save some problems later down the road.
And if your planing on doing some major upgrades later on, install some TT valves.

Brought for your consideration, One left (drivers side) and one right side (pasinger) cylinder head. Engine ran fine. No smoke or oil consumption noticed. I would not have a problem just slapping this head on, BUT, my suggestion is that you have your local machine shop go over it. Gasket surfaces were not cleaned, I felt this add an extra layer of protection during transit. Good luck and happy bidding!


You asked:
"what year 300zx is this off of and how many miles has this head been through?"

Hi, thanks for asking. The head is off a 1992 300ZX, it had approximately 80,000 miles. Cam seals were changed and have about 3,000 miles. Kid was driving at highway speed and it dropped out of gear. Crankshaft was damaged making heads available.



bid and won
50 bucks apiece pluss 60 bucks shipping

think it was worth it...?

yep...you got a great deal!!!

i would do what he said and have a machine shop go over them to make them perfect once again. shouldnt hardly cost anything for you to have a machien shop go over them and well worth whatever you pay. good luck!!!