E88 Head

[stuart barrie]

I have looked at previous posts regarding heads, valve size and camshafts
there are early & late E88 heads fitted to the 240z engine but how can I tell the difrence.

 

[zedhead260]

An external spray bar oils the cam in the early head.

The later heads have an internally oiled (hollow) cam with outlet holes on the lobes.

I think valve sizes are the same for both.

 

[stuart barrie]

Thanks for that I have the spray bar type

 

[Carl Beck]

Hi Stuart:
Actually... the E88's fitted to the late production 1971 and 1972 model L24's were both very good heads. The very early one's had the same combustion chamber shape and size as the earlier E31's. The second E88 head found on the 1972 model year Z's had the same shape combustion chamber, only it was a couple cc's larger.

The "emissions" E88 head came on the 73 model year 240Z's here in the US at least (also on the 74 L26). It has a different combustion chamber shape/design... intended to reduce emissions, but at the cost of performance.

I'm not sure what heads you received on Euro models of the 260Z's after 1974. All our L series engines in the Z's had oil spray bars up until about the L28's from 77 forward as I recall. (we didn't get internally oiled cam's on any E88 heads).

Regardless of the oiling set up.. it's the combustion chamber design and size that matters to you from a performance perspective. The "good" E88 has the same combustion chamber design (shape) as the earlier E31's. They both have a built up area around, or notched out area around the spark plug hole (depending on how you look at it), the emissions head has a smooth even area around the spark plug.

See: http://zhome.com/ZCMnL/tech/E31andE88Heads.htm

FWIW,
Carl



Carl Beck
Clearwater, FL USA
http://ZHome.com
Z Club #260
IZCC #260
ZCAR #260

 

[stuart barrie]

It would apere that I have A 1972 head with notch on my march 1973 car.
Next Question what is the recomended amount to skim of.

 

[Carl Beck]

How much you can mill the head depends on a couple factors. If you plan to run the car on the street, on pump gas... HIGH TEST 92+ octane (combined R&M).. then you really don't want to get the compression much above 9.0 or 9.5:1 (leaves a little margin for error or future milling if needed).

You would have the larger 280Z valves installed and un-shrouded and that would increase the total cc's of the combustion chambers... Mild porting and port matching is cost effective.. extensive polishing doesn't buy much for a street engine... At any rate once the valves are changed.. the machine shop can measure the combustion chamber volume.. and from there you can calculate how much can be milled.

Of course before you spend any money on any of this - you want a good machine shop to check the head for cracks (especially around the exhaust valves).

Most heads that have been off the engine for a while will have a slight warp when measured.. many machine shops will mill the head to make it flat again.. some very good head shops will heat the head and bolt it down to a block to take the warp out...

At any rate, for a street engine, I wouldn't mill the head any more than necessary.

FWIW,
Carl


Carl Beck
Clearwater, FL USA
http://ZHome.com
beck@becksystems.com
Z Club #260
IZCC #260
ZCAR #260