Ratfink

Time to play.

Finally got a hold of an E31 head locally. Little more than I wanted to spend for a used head. I pulled it off an engine that had a rod cap come loose, and the result was an exhaust valve kissing the piston, and bending it. Valve is not stuck, but I can see light through to seat when it's all the way closed.

I can't seem to find much info on the E31 on a L26 combo. But, I know it's been done.

Only question I have is, how big can I go with the valves before there is any problem?

I think I can get valves locally from ArizonaZcar.com.

But, they have two sizes. They say they are for the N42 style head, and are longer. Will they work in an E31??

Intake
44 mm $16.00 each
46 mm $19.00 each

Exhaust
35 mm $16.00 each
38 mm $16.00 each

Measured the valves in the head and I come up with a 42in, 33ex.
Same size as whats in the E88 head I'm running now.

From what I understand, the cam in the head has more lift, but less duration than the E88 on the L26 engine.

Is that right?

veyenyl

Cool. I wish I kept mine in case I ever wanted to build a nostalgic racer. They're hard to find unmolested.

Use the 280 valves. If it's the stock 260 block you have to notch it or overbore it it clear the intake valve.

ASA240z

The Head Info Page for Datsun In line Six
Cylinders.

From http://www.bandmzcars.com/headinfopage.html

To start, I have been collecting heads for years, and have came across many web sites that had
misleading information about the L series heads. I have decided to make my own conclusions about the
info about the different heads that will bolt onto a L series.

The heads that will bolt onto a L series block, that are accessible, include the following, starting with the
earliest to the latest:

E30= This head came on Japanese Domestic Market (JDM) cars only. It was available on the 2.0 L
series engine. This head has 37cc chambers, and SMALL intake ports. The valves are also small in
diameter. Bronze seats as well. This head would be a screaming High Compression head if someone
would take the time and put the bigger valves and do a decent port job on it as well. This head also does
have a high quench design as well.

E31= This head is available on all 240z's up to about the month of 10/70. There were about 10,000 of
these heads made. This head has 42cc chambers and is also a high quench design as well, much like the
E30, except this head has the 35mm Intake Ports and the larger valves. E31's had bronze seats as well.

E88= There are actually 3 variations of the E88. The first variation is of which it is the EXACT same
head as the E31, except it has the E88 casting code.

The second is which it has the large open chamber to where it is a 47 cc chamber now, and not the 42.

The third is where it has the open 47cc chambers and also has the large Ex valve inserted, the 260z's got
these, and to where the bore had to be notched to accept the larger valve.

N42= This head came on all 75-76 and EARLY 77 cars. It has the 47cc chamber, and this head is a
fully open head. This head was used on a fully dished piston, to where no quench was used. It has the
largest of the valves much like all 280's did. 44mm intake and 38mm ex. This is the last of the L heads
that came with bronze seats. This head has Square ex ports, and has the Injector notches as well.

N47= This head came on all mid 77 through the 1980 z cars. It has the same exact characteristics as the
N42 except that it has the cast in ex liners. These liners were cast in place, for the reason that when the
motor is running, these liners get so hot that they glow red hot, and with that you get the advantages of
them burning off the hydrocarbons that are left over in the exhaust charge. This is the first head to have
hardened seats put in all of the valves.

P79= This head is a Good head. This head came on all 81-83 NA cars. This head has the Ex liners cast
in as well, but the chamber is a HIGH quench design. The chambers are 53cc's. This head when used
with a Flat top block will yield a HIGH quench design, and will reduce detonation.

P90= This head is also a good head, as it has the same exact characteristics as the P79, except that it has
the non-linered square port ex ports. This head is wildly used for NA setups also, to where most shave
.08" off of the deck, and then insert the 75-80 valves to take up the valve lash, and then put cam tower
shims to make up the timing chain slack.

P90A= There are actually two variations of the P90A. One is the solid lifter style to where it is exactly
like the P90. The second is also exactly like the P90, except it has Hydraulic lifters.