I have an early 240Z (VIN around 7,000 or so) that has an E88 head. Does anyone know when Nissan made the change over from the E31 to the E88?

Thanks.

Koreavet

Koreavet---

Not real sure as to when Nissan made the change from E31 to E88. However, given your relatively low vin # (and assuming they match your block) and your quite sure the E88 in question is the original, I would say you have the "good" E88. It's identical in every way to the E31 with exception to casting. It's actually superior to the E31 strength wise. E31s are prone to cracking between valve seats. Most likely due to there use in high performance applications.

I run an E31 but I have an early E88 as a back up since these heads are reaching their thirty-fifth birthday. Check out this post:

E31 & E88 Cylinder Heads

contributed by: Carl Beck, IZCC # 260

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Note: The question of, "which head do I have and how can I tell them apart", comes up often in any discussion of the E31 and E88 heads for the L Series Engines. I know these are not the best pictures of the combustion chambers - but they are better than nothing - and are intended to support any discussion of this subject...

The E31 head was used on the 1970 and 1971 Model Year Z's. There are at least two E88 heads. One was used on the 1972 Model Year Z's and the other was used on the 1973 240Z and the 1974 260Z. For performance applications the 1972 E88 is considered a better design, thus yeilding better flow than the later E88's.

You can spot the E31 and early E88 heads because they have a distinct notched area just to one side of the spark plug hole. The later E88's lack this notched area and are smooth on both sides.

These pictures illustrate the differences between Early and Late E88 cylinder heads. Photo's from www.Zhome.com

Ok bambi, I see this but what does it mean? What difference does this make?

I'm not an expert on the heads, but the compression is lower on the late E88 head. The racers favor the early heads (E31 and early E88) and claim that they "flow better" than the late E88. I do know that there was a significant decrease in HP fro the 72 model Z's to the 73 models. Largely due the head change and to the switch to Flat-top carburetors, I believe.

Sorry I can't provide more information or be more specific.

Lone Star Z-----I believe the "notch" (found on the E31 and early E88 heads) is designed to ideally "position" the fuel and air mixture to the electrode tip of the spark plug. As well as increasing the compression.----Jerry