Building a 3.1 litre stroker motor for your Z: Introduction

Contributed By: Lee Cobb & Eric Chapman, IZCC #4604

Introduction
by Lee Cobb

Boy! This sounds like a great idea.

I am one of a rare breed, I have owned my Z since it was new. It celebrated its 23rd birthday this year. For those of you mathematically challenged its a 1973 240Z. Ever since I bought the car, the factory Hitachi carburetors coupled with the crude attempt at exhausts emissions kept the car from really performing.

About a year ago I attended our monthly Z car club meeting. During this meeting one of our member brought a diesel Maxima crank shaft. This crank was a work of art! The edges had been knifed and polished. The total weight had been reduced by 26%. I though to myself wow! I bet this make his Maxima really haul butt! Then it was explained to me that this crank would also fit into a 280-Z, improving the stroke and horsepower over the stock specs. The club member was Eric Chapman. Eric runs Z-Quip, a machine shop in Newnan GA. Z-Quip builds one-off parts for Z cars. During this same meeting another club member (Steve McCarley) mentioned he had built an engine using this same technology. Steve mentioned that a person with reasonable mechanical skills and approx. $3,000 could build such an engine. Boy! This sounds like a great idea. Steve outlined the basic concept of a 3 liter engine.

As I listened, visions of racing at the front of the Indy 500 started to run through my mind. After all $3,000 is a lot of money. Little did I know. As Steve proceeded with his information dump, I was frantically writing down ever syllable that came out of his mouth. During this information dump, Steve would say, ìsince you're doing this you really should upgrade to this and that. So, by the end of the meeting, I had gone from not knowing what a 3 liter was, to spending $3,000 to build one, to upgrading to this and that. As near as I can tell somewhere between yes I can spend $3,000, and driving home I spent an additional $2,500 on upgrades.

During this article I hope to share with you the ups and downs of building a 3 liter stroker engine. I am not an expert. The technical part of this article will be handled by Eric Chapman. Between the two of us, you should have a good idea whether or not you want to tackle such a project. Eric and I have broken the process down into several parts:

Introduction
Getting Started
The Machine Shop
Engine Assembly
Cranking & Debugging