Welcome to our BMW E30 based Marlin Sportster Build Site,
we hope you will find this documentation interesting and helpful.
The site has grown massively since its inception in 2005, I hope to one day soon improve the navigation as it's a bit overwhelming to start with. The main areas of interest to builders will be:
The rolling chassis build
Bodywork Fitting
SVA Issues
Final Assembly
If you would like read about the build in date order then have a look at his page.
It took 2.5 years to build the car and pass SVA and a lot longer to get to where it is now! To see the Sportster out on the road have a look at one of the videos here.
During 2008 we rebuilt the BMW engine from 2.5 to a 2.8 creating an M20B28 stroker engine. It uses the crankshaft from the later BMW M52B28 and the conrods from the M20B20. Not much more work is needed other than a clean up, slotting those bits together and a crank spacer. To read about the engine build click here (very picture heavy!)
Finally in March 2009 it was painted, a full set of images is here.
To read the whole build from the start click here.
08/04/2007
Wiring, and a few small things
Lots of wiring done under the bonnet :
Bumpers bolted in - the nut is welded to the top so the bumper can be taken out from the bottom. There is also a bolt in the side to stabilise it.
Additional bracket added to the striker pin plate to make it stronger. Its bolted at the bottom and held to the striker plate with a rivnut - this should serve well in pulling the bottom of the fiberglass tub into place on the passenger side.
Bumpers bolted in - the nut is welded to the top so the bumper can be taken out from the bottom. There is also a bolt in the side to stabilise it.
Additional bracket added to the striker pin plate to make it stronger. Its bolted at the bottom and held to the striker plate with a rivnut - this should serve well in pulling the bottom of the fiberglass tub into place on the passenger side.
06/04/2007
Bumpers
Bumper holes!
Rather than taking the recommend route and blindly drilling holes for the bumpers in the back and then fitting the tub around it we fitted the tub and then did the bumpers. Drawback, the mounting holes for the tub are now slightly wrong - not to bad can fill those up and move them as needed.
On the + side the bumper holes are now pretty much spot on.
In order order to located the exact position of the holes we inserted a felt marker in each bumper mounting hole, put masking tape on the inside of the tub. Mounted the tub then marked out the approx position of the holes with the markers. Took the tub off and had a look. The passenger side (shock horror!) was too far up and the driver side about right. So taking the height of the driver side as the default - which is approx 25mm up from flat of the area where the fog / reverse lights are mounted. The centre to centre between the bumper mounts is 930mm so we measure 25mm up and 930mm between the two centres. The estimate from the marker was only 4mm too closer together.
To double check all the measurements we drilled a small pilot hole from the back at the marked location, making sure the drill ran parallel to the mount hole. The tub was then refitted and a visual check made through the pilot holes to make sure then were in the correct place. They looked like they were correct so we took a hole saw and cut out the final size holes, again making sure the drill ran parallel to the mounting holes. After drilling the first hole - due to it not being straight on - I though it was a full hole size out. Turns out it just my eyes and the fact that the hole is not straight on! Stuck a bumper through the hole lift the back of the tub a bit and it went right in! Repeat for hole number 2 :) Very happy these are now sitting right it was one of those things we were not looking forward to.
Spent more time on the front of the tub on the passenger side trying to get it to fit better after the bumpers were installed. Took quite a bit of material off the bottom to bring it down. Its now sitting much better but still needs some work. You may also notice the colour sample (formerly part of an E39 M5 diffuser) pretty sure this will be the cars colour, but what is it? So far the top suggestion is LeMans blue as that was a standard colour on the M5.
Max inspects our progress and checks on the cars colour scheme options:
Finally, does anyone know what colour this is?
Rather than taking the recommend route and blindly drilling holes for the bumpers in the back and then fitting the tub around it we fitted the tub and then did the bumpers. Drawback, the mounting holes for the tub are now slightly wrong - not to bad can fill those up and move them as needed.
On the + side the bumper holes are now pretty much spot on.
In order order to located the exact position of the holes we inserted a felt marker in each bumper mounting hole, put masking tape on the inside of the tub. Mounted the tub then marked out the approx position of the holes with the markers. Took the tub off and had a look. The passenger side (shock horror!) was too far up and the driver side about right. So taking the height of the driver side as the default - which is approx 25mm up from flat of the area where the fog / reverse lights are mounted. The centre to centre between the bumper mounts is 930mm so we measure 25mm up and 930mm between the two centres. The estimate from the marker was only 4mm too closer together.
To double check all the measurements we drilled a small pilot hole from the back at the marked location, making sure the drill ran parallel to the mount hole. The tub was then refitted and a visual check made through the pilot holes to make sure then were in the correct place. They looked like they were correct so we took a hole saw and cut out the final size holes, again making sure the drill ran parallel to the mounting holes. After drilling the first hole - due to it not being straight on - I though it was a full hole size out. Turns out it just my eyes and the fact that the hole is not straight on! Stuck a bumper through the hole lift the back of the tub a bit and it went right in! Repeat for hole number 2 :) Very happy these are now sitting right it was one of those things we were not looking forward to.
Spent more time on the front of the tub on the passenger side trying to get it to fit better after the bumpers were installed. Took quite a bit of material off the bottom to bring it down. Its now sitting much better but still needs some work. You may also notice the colour sample (formerly part of an E39 M5 diffuser) pretty sure this will be the cars colour, but what is it? So far the top suggestion is LeMans blue as that was a standard colour on the M5.
Max inspects our progress and checks on the cars colour scheme options:
Finally, does anyone know what colour this is?
04/04/2007
Bonnet panels
Did a lot of prep work on the bonnet side panels today. Did some initial cuts on the metal today to start fitting the panels in. Also spent a lot of time on the passenger side re fitting the door and adjusting it. For some reason the passenger side causes more trouble than the driver side!
29/03/2007
Little things
Got these a while ago, conrods from an M20B20 - 130mm center to center. 5mm shorter than the standard M20B25 and will mate well with the M52 crank!
Spent too much time on eBay and ended up with a model of an Alfa Romeo 2300 Monza 1932 which very clear shows some of the styling inspiration of the Marlin line up!
Spent too much time on eBay and ended up with a model of an Alfa Romeo 2300 Monza 1932 which very clear shows some of the styling inspiration of the Marlin line up!
27/03/2007
Thar be 'oles in that dash!
25/03/2007
Dash
Time has come to spend hours and hours debating where to put the gauges! After many, many permutations using prints outs and bluetak here's the results:
Dash masked and all the hole centre marked from the graph paper used to precisely layout the dials
The next question, how to cut the holes in the ali without needing to spend a good £50-£60 on the correct hole punching tools for the job!
Dash masked and all the hole centre marked from the graph paper used to precisely layout the dials
The next question, how to cut the holes in the ali without needing to spend a good £50-£60 on the correct hole punching tools for the job!
19/03/2007
A few changes to the site!
We've add a new preview function to all images on the site, it's now no longer necessary to download large images to get a closer look at each one.
Just click the thumbnail or the "preview" button. You'll get a short loading animation and the image will appear. If you want to download a full size one like before click "Full Size" button or the "Right Click Save As here to download full size" link in the preview.
Just click the thumbnail or the "preview" button. You'll get a short loading animation and the image will appear. If you want to download a full size one like before click "Full Size" button or the "Right Click Save As here to download full size" link in the preview.
17/03/2007
Wires, bodywork and parts
Wiring
We've made excellent progress with the wiring, pretty much everything is in place now ready to go!
Bodywork
Rear lights are in and the tank filler hole is drilled. The wings are not the same, the left one is longer than the right one. Makes for an interesting task lining up the lights. Rear view is nearly done, the real lights still need to go in (rather than the reflectors) the fog lights need to go on. As do the number plate lights!
Also started removing the flash lines from the tub, what a PITA job!
Finally a bit of future tuning news:
This is a crank from a BMW M52B28 engine, with a spacer at the front end this will drop right into the M20 block. Combined with 130mm conrods from a M20B20 and the pistons from the M20B25 this will result in a 2.8 ltr stroker engine. The parts been put in the box ready for rebuilding the engine at some point in the future.
14/03/2007
New gallery section
New gallery section - Other peoples pictures
These are various pictures taken by other people that I've found on the net. Please contact me if you would like any of these removed, or a credit added.
These are various pictures taken by other people that I've found on the net. Please contact me if you would like any of these removed, or a credit added.
11/03/2007
Mixture Adjust and a bit of fun!
A final round of engine tuning! Decided to set the idle mixture today as the engine was very obviously running rich. Got the gunson gastester out and it verified the rich running by showing 3.5% CO. After a bit of tweaking of the idle mixture control on the AFM we got this down to around 1.2-1.3%. It's not going to be 100% and it can be fine tuned at the MOT test before SVA.
Wasn't in the mood for much else after the fuel pipe off the tank started spewing petrol all over the place. Replaced the cloth covered stuff with some 3/4" rubber pipe I had in the parts bin. This was a tighter fit and also found a more suitably sized hose clip. Figures crossed it will be fine now!
As it was such a nice day it seemed like the perfect time to take the car for a little spin (on the driveway at least!)
Me driving the first round (mixture not adjusted) and Richard driving second after the adjustment (but the neighbours had returned so he had to be a bit more careful not to take out their car!)
Click to download the test drive video (12Mb)
Wasn't in the mood for much else after the fuel pipe off the tank started spewing petrol all over the place. Replaced the cloth covered stuff with some 3/4" rubber pipe I had in the parts bin. This was a tighter fit and also found a more suitably sized hose clip. Figures crossed it will be fine now!
As it was such a nice day it seemed like the perfect time to take the car for a little spin (on the driveway at least!)
Me driving the first round (mixture not adjusted) and Richard driving second after the adjustment (but the neighbours had returned so he had to be a bit more careful not to take out their car!)
Click to download the test drive video (12Mb)