GEO Modifications
Home Project Logs Project Pictures My Experiences Hover Videos Hoverware

Discoverer Project
Modification I made to the GEO Engine

This page shows you the modifications I made to the stock GEO motor.  My goal was to have the simplest engine setup possible so I would be able to make repairs or adjustments away form home or even on the water.

I started by pulling a 1 litre engine from a 1993 GEO Metro.  The odometer showed only 33k miles but I suspect that it was actually 133k.  It's been really hard to tell for sure because the engine seems tight, doesn't smoke, has plenty of power and generally is in good overall condition.  It has had it's little problems like a leaking oil pan gasket and rear main seal that needed replacement.

I have ended up with a very simple, easy to connect and easy to adjust engine setup.  The ignition system only needs a 12VDC and a  ground wire, the timing works off the engine vacuum, the carb has one mixture screw and and idle adjusmtment.  As you follow the pictures I will try and give you descriptions about each specific item I changed on the engine.  If you need any details about setting up a simplified GEO send me an email.

I had to remove the tailpipe from the exhaust manifold so I could adapt a SS flex pipe to it.  I used a 1.75" ID to 2" OD adapter to get form the manifold to the flex pipe.

 

Then I used a 2" inlet/outlet "Cherry Bomb" glasspack muffler to help keep it quiet.  It actually does quite a good job.

 

I removed the EGR valve completely to save a little weight and covered the passages in the intake manifold with an aluminum that plate I made.

 

I removed the original distributor which required the use of the ECM and replaced it with a 1991 distributor with the self contained electronic ignition system and vacuum advance module.

 

I also removed the original fuel injector carb because it also required the ECM.

 

I bought a VW Beetle replacement carb since those engines were very close to the same size as the GEO.  I had to make a special adapter to mount it to the intake manifold.

 

I had to make two aluminum plates to use to mount the starter.

 

I also bypassed the PCV and just ran a breather hose form the valve cover to the fitting on the bottom of the air cleaner.

 

I decided to try a larger carb and see if it would give me a little more HP at the lower rpms and maybe a slightly higher max engine rpm too.  It's a Holley 200 cfm carb, the size used on some VW Beetle engine upgrades years ago.  If it gives me the extra power I want without eating to much fuel I'll keep it.  Now I need to build another adapter to mount it to the intake manifold.

 

I took two aluminum pipes and cut them down the side so they can be welded together.  Then I'll build a new top and bottom plate so I can mount it to the intake manifold.  I'm glad we work with aluminum down at the shop!


 

Here are the three pieces of the new adapter, before and after welding.  I currently have epoxy setting up in all the inside seams.  After it's setup I will sand and polish the inside completely.

I still have to look at how the throttle linkage will attach after the engine is back on as it is slightly different than the VW carb.


 

The carb and adapter are finally mounted. I also had to change the throttle cable (not shown here). It is a 3/32" SS wire inside a vinyl coated metal jacket.

Initial run-up on the trailer was great. The engine started right up, there's no hesitation, rpm comes up very fast and the power seems to very good.

 
       
[Home] [Project Logs] [Project Pictures] [My Experiences] [Hover Videos] [Hoverware]