DETAILED REPORT Five Speed ISUZU
Posted: Sun Jan 17, 2010 4:09 am
Five Speed ISUZU Gearbox into an Elan.
The ends did justify the means?
This is a reasonably comprehensive report on my experience of putting the Isuzu Five Speed Gearbox into my Elan because I found first hand information to assist me difficult to come by. There were many people who knew people who heard of something and someone saw something once that might have been but ? well I gave up looking and asking for help and rightly or wrongly just did it my way.
The box I used came from what in New Zealand is called a Holden Gemini SLX 1984. I live in Auckland, New Zealand so the pool of possibilities is a little smaller than some other countries.
I?m sure there are many names in many countries but the gearbox itself looked like this before I attacked it. Quite a sweet looking unit and so easy to visualise this suspended in the fork of an Elan chassis.
There are several variations that I have seen including the one below with an extended gear shift quadrant that reportedly came from an Isuzu Piazza 2.0 twin cam. Although the box and gears may be suitable the gearshift on this unit is obviously an issue.
There appears to be many generations of the box with a huge range of subtly differing ratios as well as a Diesel and a Petrol version. The Photo#3 shows the starter motor bulge in the bell housing in a position of about two o?clock when viewed from the tail whereas Photo#4 it is on the other side. I have seen a Diesel origin Gearbox which had the fuel pump on the engine using the 2 o?clock spot and therefore requiring the starter to be repositioned to the Ten o?clock location. Other different variations I have spotted appear to have a Steel Sandwich plate in the centre of the gearbox (as seen in Photo #4) in the place of the Aluminium Sandwich Plate that is in the generation of box that I used.
The correspondence I had read from as many places as I could find it covers people making up an adapter plate to mate the front of the integrated Isuzu Bell to the rear of the Ford / Lotus Block. I didn?t like this option and did it another way for several reasons. I had recently gone to great effort to make my heater work significantly better and I was reluctant to affect the Heater Hose area with the Bell of the Isuzu Box which had its starter bulge exactly in line with my heater hoses. If I were to take a bite out of the Bell to accommodate the Heater Hoses and another bite to accommodate my Starter Motor where I needed it to be I would have weakened the bell significantly structurally and visually. The adapter plate option I had read about involved cars used in Australia for racing so I presume a heater as you sprint down the back straight and into the hairpin is not a high priority. I guess the Diesel version that has its starter bulge in the ten o?clock position could suit better in the best interests of warm feet in the winter. Another reason I went in a different direction was that to cut off the Isuzu Bell meant I could retain the Lotus clutch and Slave Cylinder etc and thereby leave the Motor and Clutch 99% unchanged. In fact the only differences are that I have a 17mm inside diameter spigot bush slipped into the Flywheel instead of the usual and the clutch plate spline has been changed.
This is my Gear Box after I altered the Gear Stick in length, thickness and angle but before I cut off the bell.
And here is a shot showing the section removed and what fell out of the inside.
This is a beautiful design in the way that all the gears are mounted on the Sandwich Plate and therefore did not require to be individually removed or separated in any way. While the gearbox was split I took the opportunity to replace the input and output bearings and seals.
The cut face was Milled to exactly the same plain as the surface the bearing retainer mounted to with the exception of the two protruding mounts that Isuzu use for the Clutch pivot pin mounting positions. I reshaped the outer area of these two mounting points to 20mm diameter and 10mm proud and used them to assist in locating and mounting the Ford Bell Housing. Before any math wizard points out that I left the two protrusions exactly the same height as the plate is thick and therefore it couldn?t possible tighten down correctly I will point out that there is a paper gasket around the bearing that provides the clearance.
This is the Isuzu Input Bearing Retainer and Input Shaft / Clutch bearing support as seen in place in Photo #6.
The reverse side of the Isuzu Input Bearing Retainer and Input Shaft / Clutch bearing support.
And now I have come to the end of the maximum allowable attachments so I will attempt to add part 2 in the next section. Bare with me while I negotiate the system.
The ends did justify the means?
This is a reasonably comprehensive report on my experience of putting the Isuzu Five Speed Gearbox into my Elan because I found first hand information to assist me difficult to come by. There were many people who knew people who heard of something and someone saw something once that might have been but ? well I gave up looking and asking for help and rightly or wrongly just did it my way.
The box I used came from what in New Zealand is called a Holden Gemini SLX 1984. I live in Auckland, New Zealand so the pool of possibilities is a little smaller than some other countries.
I?m sure there are many names in many countries but the gearbox itself looked like this before I attacked it. Quite a sweet looking unit and so easy to visualise this suspended in the fork of an Elan chassis.
There are several variations that I have seen including the one below with an extended gear shift quadrant that reportedly came from an Isuzu Piazza 2.0 twin cam. Although the box and gears may be suitable the gearshift on this unit is obviously an issue.
There appears to be many generations of the box with a huge range of subtly differing ratios as well as a Diesel and a Petrol version. The Photo#3 shows the starter motor bulge in the bell housing in a position of about two o?clock when viewed from the tail whereas Photo#4 it is on the other side. I have seen a Diesel origin Gearbox which had the fuel pump on the engine using the 2 o?clock spot and therefore requiring the starter to be repositioned to the Ten o?clock location. Other different variations I have spotted appear to have a Steel Sandwich plate in the centre of the gearbox (as seen in Photo #4) in the place of the Aluminium Sandwich Plate that is in the generation of box that I used.
The correspondence I had read from as many places as I could find it covers people making up an adapter plate to mate the front of the integrated Isuzu Bell to the rear of the Ford / Lotus Block. I didn?t like this option and did it another way for several reasons. I had recently gone to great effort to make my heater work significantly better and I was reluctant to affect the Heater Hose area with the Bell of the Isuzu Box which had its starter bulge exactly in line with my heater hoses. If I were to take a bite out of the Bell to accommodate the Heater Hoses and another bite to accommodate my Starter Motor where I needed it to be I would have weakened the bell significantly structurally and visually. The adapter plate option I had read about involved cars used in Australia for racing so I presume a heater as you sprint down the back straight and into the hairpin is not a high priority. I guess the Diesel version that has its starter bulge in the ten o?clock position could suit better in the best interests of warm feet in the winter. Another reason I went in a different direction was that to cut off the Isuzu Bell meant I could retain the Lotus clutch and Slave Cylinder etc and thereby leave the Motor and Clutch 99% unchanged. In fact the only differences are that I have a 17mm inside diameter spigot bush slipped into the Flywheel instead of the usual and the clutch plate spline has been changed.
This is my Gear Box after I altered the Gear Stick in length, thickness and angle but before I cut off the bell.
And here is a shot showing the section removed and what fell out of the inside.
This is a beautiful design in the way that all the gears are mounted on the Sandwich Plate and therefore did not require to be individually removed or separated in any way. While the gearbox was split I took the opportunity to replace the input and output bearings and seals.
The cut face was Milled to exactly the same plain as the surface the bearing retainer mounted to with the exception of the two protruding mounts that Isuzu use for the Clutch pivot pin mounting positions. I reshaped the outer area of these two mounting points to 20mm diameter and 10mm proud and used them to assist in locating and mounting the Ford Bell Housing. Before any math wizard points out that I left the two protrusions exactly the same height as the plate is thick and therefore it couldn?t possible tighten down correctly I will point out that there is a paper gasket around the bearing that provides the clearance.
This is the Isuzu Input Bearing Retainer and Input Shaft / Clutch bearing support as seen in place in Photo #6.
The reverse side of the Isuzu Input Bearing Retainer and Input Shaft / Clutch bearing support.
And now I have come to the end of the maximum allowable attachments so I will attempt to add part 2 in the next section. Bare with me while I negotiate the system.