Unleaded Fuel in 260Z

[oldmates260z]

I am running a stock original L26 in 1975 260Z 2+2. It has been run with fuel additive however I have been told that all Jap alloy heads can use unleaded without the additive.

Does anyone know if you need it?

[C.A.R.]

You don't need the additive.

 

The alloy heads already have the hardened valve seats in them for the factory. :wink:

[ZD44TT]

You don't need the additive.

 

The alloy heads already have the hardened valve seats in them for the factory. :wink:

 

BP ultimate all the way :lol:

[luke_mcmahon85]

From the Datsun Z Garage....

 

 

The E88 came on the 1971-73 240s and '74 260s, in 2 versions, small valve on the 240 and large valve on the 260. It's chambers are the same cc size as later N42 and 47 heads. Despite what some older books say, I can't see why the E88 would have any performance advantage over any other head.

 

The larger valve N42 came on the 1975-76 280Z. 280Zs didn't use a catalytic converter until 1977, so the head came with softer bronze valve seats for use with leaded gas. Many people like these for performance because of it's square exhaust ports. And as a easy mod, putting it on a flattop L28 motor puts compression in the mid 10's.

 

The N47 came on the '77-80 280Z(X). It has diamond-shaped exhaust ports with emission liners, which some feel reduce flow. Starting in 1977 Nissan heads came with steel seats for use with unleaded gas. Like the N42, putting it on a flattop L28 motor puts compression in the mid 10's

[zedrally]

Problem here is that your quoting US statistics. for instance we (OZ) never got a 280Z, let alone cat converters (thank god).

 

It's easy to be mis-lead on Z history/models when most information is

HLS orientated...

 

FWIW

 

 

MOM

[nat0_240_chevZ]

look the us stats are always gonna guide you the wrong way, US had much tougher emissions even back then.

 

in my experience (4 z cars), never had a problem using unleaded. even running 10.85:1 comp on an l24 n42 shaved 2.25mm. ran fine i was able to advance the timing slightly for better pickup and only pingged on load below 1.8k-2krpm in 3rd gear and above.

 

dont worry yourself with the additives.

cost youll pay couldnt be worth more than getting the head reconned with hardened valve seats......see my point.

 

is the car on gas by any chance???

if so youll be fine if the have already been done.

 

whats the casting # on the side of the head between 1 & 2 spark plug???

 

just out of curiosity.

 

nato

[oldmates260z]

Thanks guys for all the feedback, I'll go without the additive as I agree that if I burn out a valve it will be a good excuse to do the head up.

 

I bought it in Albury and drove it home to Brisbane and used all the oil it had in it! I am guessing its a true Datsun and I am loosing it through the valve stems. Throttle off down hill and out comes the blue smoke when I hit the gas!

 

No its not on gas.

 

I will check the casting number on the weekend

[Mr Camouflage]

I'll guess its an E88

[oldmates260z]

E88, you were right

 

Cheers