Hybrid in S-series

From GM Wiki

In this set of articles, I will be explaining what I did in my build for my 1985 GMC S-15 Jimmy. Other S-series trucks of the 1st generation ('82 to '93), originally equipped with a 2.8 will be a similar process.

Contents 1 Overview & disclaimer 2 Getting started 3 The recipient 4 The Plan 5 Prepping the truck 5.1 Fuel tank 5.2 Battery Relocation 6 Building the Hybrid 6.1 Block Prep 6.2 Crankshaft 6.3 Connecting Rods 6.4 Pistons 6.5 cam 6.6 Heads 6.7 Intake 6.8 Headers 7 Swapping it in 7.1 Intake piping & Intercooler

Overview & disclaimer

This is for informational purposes, and not to be used as a step by step guide, but rather a loose idea of what I did.

This is more than just a swap or just a build, you have to have the skills and desire to build an engine, from oil pan to intake, and the skills to swap it in place. If you are uncomfortable with the actual hybrid build, a machin shop could do this step for you, though it's not an overly difficult process to do, just takes some care and planning.

I will be laying most things out in chronilogical order and why it may seem that some steps are not in order, due to the fact that I had to drive this truck everyday, as it was really my only means of transportation.

I found the more difficult part the external parts, the parts needed to make the engine fit in the chassis.

Getting started

First you need to decide the goals and priorities of the build and swap.

For my build, I wanted to use it as a test bed for future projects I had in mind, this was also to be reliable to serve as my daily driver and impress a few people around.

The recipient

The truck in a 1985 GMC S-15 Jimmy 2WD. I had originally bought it with the intent to do as everyone selse does when they hop these trucks up and drop a SBC in place of the tried 2.8, but as gas prices rose and my parts were sitting there I had a brainstorm of an idea, and that was to build a hybrid 660 with the parts I had laying around.

The Plan

The plan was to build the engine and get it ready before taking the truck apart, I knew I would be able to pull off assembly of the engine itself before pulling the truck apart, but other parts like the headers and hoses, wiring etc, would need to be test fit. Fortunatly the 660 has very similar dimentions through it's 3 generations, so I was able to measure off certain points on the engine in the truck, and then build from that, being quite sure there would be enough clearance.

I wanted to test some theories and ideas I had, I also wanted to dive in to a turbocharged vehicle, like building a hybrid back when it was almost unheard of and thenswapping into a vehicle that had up until then never been known to have such a swap done wasn't hard enough on it's own.

Prepping the truck

To get the truck ready, I had to figure out where everything was going to be, turbo placement, hose routing, wire routing, etc. The truck as it was originally built was a carburated vehicle, that utilized a mechanical pump attached to the driver side of the block.

Fuel tank

As "luck" would have it, my original fuel tank developed a leak shortly after I was done the body work and actually got the truck on the road, well same day I got it on the road actually, as it was the first time I had filled it since I bought it.

So I did a little reasearch that night, and found that there was a larger tank offered, so I bought one from the Local Wreckers (thanks Brent), and then tried to find straps, well they all get cut at the wreckers and the only ones that you can buy new are the upper straps, I ordered these as the parts place couldn't tell me which straps these were, they came in, they were the upper straps, figured it wouldn't hurt to change them anyway, so I bought them.

I decided that I would make my own lower straps, out of some strapping that I bought from Home Depot, you'd be surprised what can be found there. They were pieces of metal 1/8" x 1.5" x 42" If I remember right. I had to drill holes in the ends and bend them to fit around the contours of the tank, to support it.

Battery Relocation

I also decided that I would move the battery to the driver side, so that there could be more space on the passenger side, for the turbocharger and air filter, along with intercooler piping.

I made a battery tray from 1/8" x 1" angle iron, some flat stock and some bar stock.

You will also notice in the second picture, the ford starter solenoid that I used to simplify wiring and also aleviate any possiblity of an hot start problems.

Building the Hybrid

I looked at all of my parts I had around and decided I needed a RWD block, 2.8, 3.1 or 3.4, ideally I would have liked a 3.4L block from the '93 to '95 F-body, but the prices were a bit higher than I was willing to pay. A friend of mine had a friend that had a 2.8 that was an '86 S-series.

Block Prep

As it turned out this engine was already rebuilt and bored .030" over. I had origanally planned to use stock pistons pirated from a 3100, but a new plan had to be made. I measured and it seemed to be only .020" over, which was just my mistake. I ordered some .030" over pistons, thinking that I could then bore out an extra .010", but it wasn't to be.

I will mention at this step, about the slight modification to the timing cover, that requires that the tab at the top that sits above the top of the block to be removed to clear the thermostat housing on the FWD intake.

Crankshaft

I used a stock crankshaft from an early '90s 3.1, I don't know the exact year, since the engine was not in a car when I received it. Casting 981

Connecting Rods

I used the stock 2.8 rods that came with the block.

Pistons

I was going to order the 3100 hypereutectic replacments, and in hind site wish I had, but when it came to pluking down a few hundred dollars on a budget build, I decided to go the safe route and order 3.1 pistons that would give me an SCR (Static Compression Ratio) of 8.9:1, as opposed to the 9.5:1 of the '95 3100.

I had the block hot tanked, and inspected, honed, and then I paited it, paint is not nessisary, but I like a black block, so I masked it off and went to town with some engine paint in spray bombs.

I used new cam bearings, ordered a high volume oil pump, new gaskets, etc.

cam

The cam is a GM Parts Performance Camshaft P/N

Heads

The set of heads I used were from a 1995 Buick Skylark, so these were the "small port design". The bolted onto the block without issue.

Intake

The intake is from the same source as the heads. All I had to do was place the thermostat housing at the front of the engine.

Some pictures of the hybrid as a long block:

[[1]]

Headers

In this step I had to make headers from scratch. There were no aftermarket offereings that would be usefull for my goals, with the turbocharger, there were no factory manifolds that would even fit the chassis and work well with these heads. The decission to build from scratch was the obvious choice here.

I started with some 1/4" flanges (Yeah a little thin, but never had a problem), and a box of bends that I purchased through where I worked at the time.

I came up with a system that looped from the driver side under the bellhousing and back up to the passenger header, to the turbo.

[[2]]

I am working on a new set-up and will update this once I get that far, to show a different idea in the same truck.

Swapping it in

Intake piping & Intercooler

Well to get the compressed air from the turbo to the intake you need some piping, this can be as creative as you want or as rudmentary as will work. You will probably also want an intercooler of some sort in there.

When it comes to this step I like to start with the intercooler, mounting it in place where it will be or as close to as possible. First you must choose the type.

You might want a water to air intercooler, this type uses water or coolant as a cooling medium for the compressed intake charge.

For a street application I prefer air to air, as it is simpler to install, less parts and virtually no maintenace needed. Most air to air intercoolers are mounted behind the grill or front bumper where air will flow through the IC core and help pull heat out of the compressed intake charge.

In my case I chose an IC from a Mitsubishi Starion, that I had traded a few years earlier to use on a different project that no longer existed. I mounted this IC on some L-brackets using the ICs mounting tabs. It was a decent fit for my Jimmy, in front of the rad. Unfortunatly it was a bit close to the rad and eventually wore a hole in one of the tubes in my rad. So make sure you have adequate space between these components.

--Six Shooter 01:09, 9 December 2006 (EST)