oil pressure?

A

AL_300zxtt

Forum User
.Hi this is my 1st post <img src="http://www.zclub.net/iB_html/non-cgi/emoticons/tounge.gif" border="0" valign="absmiddle" alt=':p'>
I've only had my 92 300zx tt uk spec for just over a week and after a radiator prob which looked like it had been boged by the former owner and a set of new brake pads it seems to be going fine <img src="http://www.zclub.net/iB_html/non-cgi/emoticons/smile.gif" border="0" valign="absmiddle" alt=':)'>
The only thing that dose worrie me is that the oil pressure seems a little low when the car is ticking over,when its going it seems fine, a mate says the engine may just be a little worn coz it covered 98k!
so dose this sound right or dose it spell big trouble <img src="http://www.zclub.net/iB_html/non-cgi/emoticons/wow.gif" border="0" valign="absmiddle" alt=':0'> &nbsp;<img src="http://www.zclub.net/iB_html/non-cgi/emoticons/confused.gif" border="0" valign="absmiddle" alt='???'>

BTW- it had an oil change 2k ago so the oil should be ok!

cheers 4 ur help AL <img src="http://www.zclub.net/iB_html/non-cgi/emoticons/tounge.gif" border="0" valign="absmiddle" alt=':p'>
 
Z and ZX oil pressure senders have been notoriously unreliable since day one and the Z32 is no exception. In the ideal world, the gauge should read middle or a little above at 3000rpm upwards and idle at just below quarter gauge (51-65 psi at 3000rpm and above 11 psi at idle). If in doubt, get a garage to rig up a temporary mechanical gauge to get some true readings. Or better still, fit a full-time mechanical gauge along with a boost gauge that really tells you what your boost pressure is!
 
<img src="http://www.zclub.net/iB_html/non-cgi/emoticons/smile.gif" border="0" valign="absmiddle" alt=':)'> cheers it seems 2 be reading a little higher now but i might just go 4 some after market gauges so i can keep an eye on things and put my mind at rest!!

say if it was low oil pressure what would this mean a re-build? <img src="http://www.zclub.net/iB_html/non-cgi/emoticons/wow.gif" border="0" valign="absmiddle" alt=':0'>
 
A real case of low oil pressure would indicate excessive crank bearing clearances or a worn oil pump. With the crank wear, some rumbling and knocking would not be far down the line.
Excess oil use may lead to a low oil level which in turn would lead to low and/or fluctuating oil pressure as the pump pick-up struggles to keep itself immersed.
 
I two have low oil pressure at idle under the 1/4 mark however on a cold start up the oil pressure is around 3/4 up for a little while and during normal driving it is 1/2 way marked 4.
But the thing i do not know is what my oil pressure is in psi as mine is a jap spec, can anyone tell me if all sounds ok?

Also my boost gauge is one notch from -7 on start up and idle and around one notch off +7 on full boost is this fine?

thanks all
 
Your gauge is probably differant to mine but your oil pressure sounds ok to me! i think they should idle at about 10-15psi and be around 30-90psi in normal driving but i suppose you cant tell what that is on your gauge.
As for your boost gauge on idle mine is on -14 the very left of the gauge and boosts to +14 the very right of the gauge but its been turned up to 1.0bar so i think this is about right,
as for yours only being on -7 at idle (i thought it should be on -14) and only boosting to +7 (i think std boost is about +9psi) i may be wrong so dont worry till somebody else who knows what there talking about has spoken but maybe its in saftey boost or got an air leak or something!! or it could just be that the jap gauges are differant, as i've never seen them!
 
Oil pressure gauges with "4" in the centre are reading in Kg/cm2 (how do you do superscript in this?). To convert to psi, multiply by 14.2 (approx.). Thus 4 = 56.8 psi or about 60 psi on the U.K. style gauge and "8" = 113.6 psi (120 psi on the U.K. version). 10 - 15 psi at idle would be fine, 51 - 65 psi (i.e. just to one side or the other of centre gauge) hot at 3000rpm is a good sign of a healthy engine. High oil pressure (i.e. 90psi+) will damage seals in your engine and may indicate that the pressure relief mechanism is damaged.

The boost gauge may read in psi (U.K. version) and therefore show -14 / 0 / +14. Standard boost is about 9psi, but air flow and exhaust mods will allow creep to about 10.5 psi.
The JDM boost gauge is confusingly marked up (-7 / 0 / +7) in millimetres of mercury (Hg) x 100 - a figure we are all familiar with from schoolboy science (??) <img src="http://www.zclub.net/iB_html/non-cgi/emoticons/confused.gif" border="0" valign="absmiddle" alt='???'> 700mm Hg = 13.5 psi, so +7 is roughly the same as the 14 psi of the UK gauge.

If you require accurate readings of oil pressure and manifold pressure, then I would recommend that you don't trust the standard gauges! They are a rough guide to reality.
 
Thanks to you both for your advice, i feel much better about it now, however the science behind it all is still sinking in <img src="http://www.zclub.net/iB_html/non-cgi/emoticons/confused.gif" border="0" valign="absmiddle" alt='???'> . is it possible to have uk gauges fitted or is the cars system of working things out all set up for jap gauges, therefor making it difficult to change them.
 
The senders are the same and the gauges are transferable. Indeed, if you were to have an alternative colour dial set made up, you could specify the more user friendly U.K. markings. I have this on my own JDM NA Z32 for the oil pressure gauge.
 
Hi Guys I'm a newcomer.
Call me Swanie or if you prefer Deon.

I imported myself a 1990 t/t 2x2 and i'm now in the process of registering it on the road, however i have driven it a few times. I drove it back from Southampton and to the MOT test centre today. For the first time i noticed when the motor is hot the rev needle drops and rises approx 1000 rpm, and from time to time the motor misses a bit, but on high revs she kicks back in onto all 6 cylinders... could it be a starvation of petrol due to a dirty petrol filter or dead spark plugs. Any advice will be appreciated.

Many thanks
Swanie
 
As a freshly imported car, you should check all aspects of normal servicing like fuel filter, oil filter (and oil&#33<img src="http://www.zclub.net/iB_html/non-cgi/emoticons/wink.gif" border="0" valign="absmiddle" alt=';)'> and air filter as a matter of course. Also, if no evidence of cam belt change and mileage coming up to or in excess of 50K, then cam belt change and spark plugs would be in order.

A fuel filter change is a cheap trial to see if the misfire is cured. A fuel pressure check might be in order to ensure the regulator is behaving properly. Air leaks somewhere on the plenum / manifold would give similar symptoms. Try a few tests to eliminate these aspects and then post again for further diagnosis if required......
 
Hi Thanks for the advice
I have found a leak on the exhaust just before the cats, on a joint, but the problem is how do i get in under the car??? i'm no platipuss!!!! Could you recommend a garage close to Twickenham area that does not charge an arm and a leg just to have a look, and to have my car serviced. &nbsp;Or is it something i can do myself as there is no service history with the car anyway... although the fan belts look brand new and i have not yet checked the cam belt. &nbsp;<img src="http://www.zclub.net/iB_html/non-cgi/emoticons/sad.gif" border="0" valign="absmiddle" alt=':('>
 
Welcome ,,swanie,,,Back your car up on some halford (eg) car ramps that will get the back end up ,then using a trolley jack you can jack up the sides one at a time , use a bit of wood so not to harm the car or use the car jack supplied and jack up on the toughen sill points .That gets the car up enough to slide under NOTE:- USE AXLE STANDS BEFORE GOING UNDER CAR,BE SAFE!!!!!,,,, then you can establish whats blowing .My import had the same problem , i ended up getting a moded exhaust, spk to mike(mfeeny) or ken at "zxs" to get your spares ......before you make expensive discisions.

As for servicing,whats your milage?,,,,, you can do most of it your self ,using the manuals as a guide , and you can always ask questions on here,,,,,give it a go &nbsp;,,,,other than that ,"Gio " lives near Heathrow ,he might know of some one ,give him a try!
 
Thanks for the advice John
<img src="http://www.zclub.net/iB_html/non-cgi/emoticons/smile.gif" border="0" valign="absmiddle" alt=':)'>
I'll have a look at halfords for the ramps, my car has done 55k i'm hoping the guy in japan would have had the cam belt done not to long ago. <img src="http://www.zclub.net/iB_html/non-cgi/emoticons/confused.gif" border="0" valign="absmiddle" alt='???'> I'm also very luky that the rear boxes are brand new. From what i can see the car had a scrape underneath, i asume it could have happen at the port when they offloaded it, could be the reason for the blowing pipe <img src="http://www.zclub.net/iB_html/non-cgi/emoticons/mad.gif" border="0" valign="absmiddle" alt=':angry:'> &nbsp;Excuse my spelling i'm South African my English are not to good
 
Hi guys <img src="http://www.zclub.net/iB_html/non-cgi/emoticons/sad.gif" border="0" valign="absmiddle" alt=':('>
I had the small hole in my exhaust fixed and the revs are still fluctuating up and down, <img src="http://www.zclub.net/iB_html/non-cgi/emoticons/confused.gif" border="0" valign="absmiddle" alt='???'>, I just let her idle till the temparature was up to normal. I did not take her for a spin &nbsp;as she's not registered yet, i'm waiting for my registration papers. &nbsp;Where could i get the fuel pump checked &nbsp; <img src="http://www.zclub.net/iB_html/non-cgi/emoticons/confused.gif" border="0" valign="absmiddle" alt='???'>
 
Hey swanie, welcome to the wonderful wacky world of Zed-ownership. &nbsp;<img src="http://www.zclub.net/iB_html/non-cgi/emoticons/smile.gif" border="0" valign="absmiddle" alt=':)'>

The guy I use is Steve at Lucas Garage in Datchet (between Slough and Windsor). (01753) 520403.

If you don't have proof that the timing belt has been changed, bite the bullet and get it done. A broken one would cost ouch ouch ouch in damage - the risk just isn't worth it.

HTH - Gio
 
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