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240z swap question


sirtimeless

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It will bolt on, but I believe that the stock valves on the E88 are smaller than what is needed for the L28. I know that if you want to use an E31 head you have to have larger valves installed. Some of the E88's may have come on the L26 and have bigger valves. Do a search for oversized valves and I suspect you will find your answer.

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That's fine, I just did my notorious "fixing up a stock setup and not looking into upgrades first" deal again. So i have a redone head with only 300 miles on it :P Would like to not have to junk the money spent.

Any more information into this would be fantastic, I am new to my Z and have all winter to finish her up.

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This engine parts calculator will give you some ideas. The numbers seem to be mostly correct. You can look at any FSM's Engine Mechanical chapter to check things like valve size, although apparently there were several E88 head versions so you might have to do some digging to get combustion chamber volume. Don't forget that there are two basic types of "L28", those with dished pistons and those with flat-tops. Z L28's and ZX L28's (US market).

Engine Design Utility

p.s L28 Late would be flat-tops, and L28 Early and Turbo would be dished. 1.25 is a good estimate for gasket height.

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  • 2 weeks later...

You should do some checking on the E88 head. There are 4 different versions of the E88. Its really had to find accurate information about them on the net and the Nissan parts manual/fishe aint much help either.

1. The first E88 is pretty much identical to the E31 and came out somewhere around june 71 in the series II 240Z. It also had 42.4cc and the 33mm exhaust and 42mm inlet valves.

2. The second (I think series III, october 71 onwards) had minor port runner improvements and still had 42.4cc chambers.

3. This head was modified again with emmision chambers somewhere at the start of the series IV around August 72. This increased the chamber capacity, but I dont have any accurate information on that.

4. The last version got the bigger 35mm exhaust valve and emmision chambers. It came out on the 260Z. The bigger 44mm inlet valve would have to wait till the L28.

This head has a larger chamber and was only in the US market. I have seen 47.8cc quoted in a Nissan manual, but Im not sure if that is with the later L26 which had the dished pistons. Maybe someone here has more reliable figures on this head...

All these heads are designed for flat top pistons. The last was used on the L26 with flat tops pistons and dished 7.01cc pistons from June 74.

If the L28 is running dished pistons, that will add 10.9cc to the chamber and bring the early heads up to the P79 range which had 53.5cc.

If anyone sees any mistakes, please feel free to correct me.

Chas

Edited by EuroDat
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All heads swap and fit between all the years, as long as you use the head gasket intended for the block not the head. The concern is chamber and piston volumes as mentioned.

The one issue that may prevent you from selecting one head over another is your choice of fuel delivery. All heads are drilled with the 8mm holes to bolt on the SU manifolds, but only the N42, N47, P79and P90 heads have the 10mm threaded holes for the Fuel injection manifolds. These heads also have the notches cut out of intake ports for fuel injection knozzles.

So if you have FI, and want to use an E88 head, you're in for some fun!

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As Chas said, you need to do some homework. Figure out what head you have-exactly-WHY?

...because

a 73 e-88 head on dish pistoned L28 block gets you 8:1 compression-yuk

a early e88/31 head with flatops gets you 10:1-yummy

A late model block would be ideal, or something with flat tops, hell, even a L24 or 26

Here is a link;

L6 heads; pics and descriptions - L-Series - HybridZ

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This does have dished pistons, and i plan going with a carb setup. I currently have a 390 holley on my l24 which is a bit over kill. My hopes is to move the head over, I'll just have to do some digging as to which e88 head it actually is.

Worse case, i do have the head that came with the 280 block. I could always clean it up and use that in a pinch, all though I would rather not rebuild another head.

Edited by sirtimeless
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