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View Full Version : leaded or unleaded????


irishzlad
12-08-2004, 04:32 PM
anyone know if the n47 can take unleaded fuel????


thanx

Nigel Brook
12-08-2004, 04:50 PM
All Nissan heads from 1977 are for unleaded. The N47 started on the 280Z in 1977 so yours is unleaded.

qunvat
13-08-2004, 09:25 AM
....and a '78 260 ???.....Dave Jarman told me to put that expensive unleaded in....the bloke I bought it off told me to use cheapo unleaded WITH an additive....ooo dear here we go again.....

Simon.

JEZ 280ZX
13-08-2004, 10:24 AM
Hi,
One word!.....OPTIMAX!.....costs more, but is better for your engine, higher octane and you get more mpg to help offset the extra cost!
You wouldn't use cheap oil in your baby, so why use cheap petrol?....
Cheerz,
JEZ

qunvat
13-08-2004, 10:33 AM
...is that 'SHELL' ????
Si

JEZ 280ZX
13-08-2004, 10:45 AM
Hi,
Yes it's SHELL!:D ....I have been using Sainsbury's Super Unleaded occasionally, but I always prefer to use Optimax if I can, as I don't like supermarket fuel.
It's rated at 98 octane, so your engine will run ok without any adjustment and you won't get any pinking under load, which you can get with 95 unleaded.
My car will run ok on unleaded, but the performance seems reduced and the additives in Optimax are meant to clean your engine too.
Unless your car is a high mileage daily driver, then the higher cost of optimax, combined with the better mpg, shouldn't make much difference.
Cheerz,
JEZ

Mr.F
13-08-2004, 01:01 PM
Optimax is great if your engine needs the extra octane, otherwise Super unleaded is fine (the BP Ultimate is good). All heads from '77 on should be unleaded compatible, but some will need the octane advantage of Super or Optimax.

NO LRP!!!!!!!! Soon be gone anyway - good riddance!

nickknox
13-08-2004, 01:22 PM
Whats best for a 240z

irishzlad
13-08-2004, 04:55 PM
sorry!!!!! its an N42 head, not n47, please accept my apologies...


that'll still take unleaded ok yeah?

Black Bug
13-08-2004, 05:27 PM
Safest way to check is to see what the intake valve seats are made off. If they're brass or bronze (can never remember but basically goldish in colour) then the head isn't strictly suitable for unleaded. If they're steel then you're sorted.

Having said that I run my E88 head on unleaded - either optimax or BP ultimate - and it's been fine.

The attached pic is an E88 with brass seats for reference.

Cheers,
Rob

DJZ 60
13-08-2004, 07:39 PM
Yeah,cas n47 head look,s like the 'elephant man'....god I,ve got to go. just had a trunkated call............Dj'head 60.

irishzlad
13-08-2004, 08:22 PM
????? djz 60

say wot???

Nigel Brook
13-08-2004, 09:29 PM
N42 not unleaded, bronze valve seats as standard.

Mr.F
14-08-2004, 12:28 AM
All heads from '77 on should be unleaded compatible

This will include the later N42 heads.


Millers VSP provides excellent lead replacement properties AND an octane boost for non-compatible heads. Almost all heads will have had some valve / seat work by now, so impossible to know exactly what you have in a 240Z or early 260Z without strip down.

chiefbrody
31-08-2004, 07:56 PM
so wait, I am a bit fuzzy.

I have N42 head on 1979 280ZX

so is it a late N42 head and thus unleaded as per Mr F?

or are all N42 heads leaded as per Mr Brook?

or everything after 1977 unleaded as per Mr Brook also?

very confused now :rolleyes:

Nigel Brook
01-09-2004, 07:19 AM
Chiefbrody: Most N42 heads are leaded. N42 ran 1975/76. Yours being a 1979 should by rights be a N47 so I'd suggest it's been changed at some stage. Check out the valve seats to see if they are bronze or steel, chances are they've been changed to steel as the bronze seats tend to sink over the years.

pmac
01-09-2004, 10:41 PM
You all seem to be making heavy weather out of wot is a very simple subject.
IN BRITAIN the 280ZX arrived in 1979 and continued till 83.
This car had 2 engine variations. Mk 1 cars and Mk 2. Mk1 cars had a N42 head and dished pistons. Mk2 cars had P90 head with flat top pistons. ALL 280ZX cars in Britain were unleaded compatible from new. Virtually 100% of 280 engines in wot ever Zed they are now in will have been sourced from these cars.
We never had the 1975 to 77 or the 77-78 280Z in this country so there will be virtually no engines lurking around the UK from them(bar the odd import or two). so they can be discounted.
The N47 is I believe a NapsZ emissions head that ran from 1980 on some cars for export markets and it too is unleaded compatible

chiefbrody
02-09-2004, 08:40 AM
[QUOTE]Originally posted by pmac
[B]You all seem to be making heavy weather out of wot is a very simple subject.
IN BRITAIN the 280ZX arrived in 1979 and continued till 83.
This car had 2 engine variations. Mk 1 cars and Mk 2. Mk1 cars had a N42 head and dished pistons. Mk2 cars had P90 head with flat top pistons. ALL 280ZX cars in Britain were unleaded compatible from new. Virtually 100% of 280 engines in wot ever Zed they are now in will have been sourced from these cars.
We never had the 1975 to 77 or the 77-78 280Z in this country so there will be virtually no engines lurking around the UK from them(bar the odd import or two). so they can be discounted.
The N47 is I believe a NapsZ emissions head that ran from 1980 on some cars for export markets and it too is unleaded compatibleQUOTE]

well sooooory

excuse me for not being an expert on the subject after just one week of ownership :rolleyes:

JEZ 280ZX
02-09-2004, 07:31 PM
CAREFUL!.....Pmac may call round to your place with his angle grinder!:eek:
Cheerz,
JEZ:D

Mr.F
02-09-2004, 08:22 PM
It is O.K. to be confused - when unleaded fuel was introduced in the '80s, even Nissan didn't know what to advise! Their poster would have originally placed 1977 and 1978 260Zs as unleaded compatible, 280ZXs as compatible with an ignition retard (no super unleaded available originally) and Z31 Turbo as requiring leaded. The problem was clouded by the octane requirement of these different engines - in reality, for the U.K. market, all these cars are unleaded compatible, but some need an octane boost offered by Super unleaded or Shell Optimax.

Mr.F
02-09-2004, 08:23 PM
..................and none of them need or should use LRP!

chiefbrody
03-09-2004, 08:34 AM
thats good, I always use super etc anyway

theres no LRP left anywhere near me anyway. not that I ever used it. stupid stuff.

cheers

john-h
03-09-2004, 08:43 AM
I run my late 260 on super unleaded. Does this mean that it would run on standard unleaded or will it pink? Also would this affect economy? I know everyone is looking for performance but if I'm doing 300 miles at 70mph on the motorway why burn money?:)

Tony 260Z
03-09-2004, 01:08 PM
My 260 has a P90 lump in it. She definitely runs well on Optimax or Ultimate, but her fave seems to be an occasional tank of four star plus octane booster.

TL

Mr.F
03-09-2004, 07:58 PM
I run my late 260 on super unleaded. Does this mean that it would run on standard unleaded or will it pink?

In theory a standard 260Z will be happy on premium unleaded. If the head has been skimmed, the cam changed or any performance mods made, then Super would be favoured. What ignition advance are you running - this will have a bearing on the grade of fuel required also?