1980 BMW E26 M1
Discussion
Very expensive and very rare car on road trip. Check
Travel quite quickly on road trip. Check
Doubling the mileage on said car on one road trip. Check
Richard,
I would like to award you 9.9/10 and as such winner of the internet today.
Room for improvement would be video or snap of speedo at V.Max.
Attempting Vmax on 36 year old magnesium alloys would be a little bonkers given the supposed 'life' of the wheels of 5 years, but I suspect a well fettled standard M1 would still breeze past 150 towards its 160+ Vmax.
Compared to some cars the M1's aerodynamic enhancements seem positively minimalist, especially the is-it-there-or-isn't-it front spoiler and the distinct lack of an almost mandatory 1980's a-la-mode 'wing'.
Seeing such a rare, special and now incredibly valuable motorcar at speed must be quite a thing to witness and as has been mentioned, a very special and happy memory.
Compared to some cars the M1's aerodynamic enhancements seem positively minimalist, especially the is-it-there-or-isn't-it front spoiler and the distinct lack of an almost mandatory 1980's a-la-mode 'wing'.
Seeing such a rare, special and now incredibly valuable motorcar at speed must be quite a thing to witness and as has been mentioned, a very special and happy memory.
I thought 140 was pushing it a bit on the old Magnesium alloys, but it got there so easily. I 'think', but have not experimented to find out, that the engine has had the rev limiter removed, or at least significantly raised as the internals have been very precisely balanced.
The speedo definitely under reads, according to my calculations 140 is pretty much exactly 130mph. Even if the 7,000 rpm limit is in place it should reach an indicated 175mph (actually 162 mph), if the limiter has been raised then I'd be pretty sure it would significantly exceed the maximum of 180mph on the speedo judging by the way it was pulling.
The speedo definitely under reads, according to my calculations 140 is pretty much exactly 130mph. Even if the 7,000 rpm limit is in place it should reach an indicated 175mph (actually 162 mph), if the limiter has been raised then I'd be pretty sure it would significantly exceed the maximum of 180mph on the speedo judging by the way it was pulling.
A little over 2 months after dropping the car off at Munich Legends after the Munich trip, she finally arrived home again this morning.
The main reason for leaving her at Munich Legends was to replace the suspension bushes, basically the 36 year old polyurethane had perished and they were dropping to pieces. This is what they looked like after being taken out of the wishbones
The Polyurethane was about the constancy of a wax crayon!
There are two different bushes used, 12 of one type for the front and upper rear wishbones and 8 of another for the lower rear wishbone. The front/upper rear is still available, so I could use the OEM part. The lower rear bush however is NLA. I say bush, the NLA part is more like a ball joint filled with Polyurethane. Luckily I have the technical drawing and specification of the bush, however no one I approached was willing or able to make an exact replica. Given the axis over which movement can occur, pretty much purely rotation about the axis of the bush, I decided that a simple poly bush was going to be more than adequate and definitely preferable to a deteriorating ball joint. I found a company that would make up custom poly bushes, DuraFlex, and had them manufacture a couple of sets using the highest density Polyurethane available, 90D which is pretty much rock solid!
While the suspension was apart I thought I might as well get the Bilstein shock absorbers refurbished and this is what has taken the time. While waiting I had the wishbones re-painted too, so it all looks nice and new under there now, this is the only picture I have for now, I'll take more when I take the wheels off for cleaning.
If you look closely, you'll notice that the top wishbone mounting point has been moved down. At some point in the past the suspension geometry had been set to give the lowest possible ride height. This proved to be a bit of a pain to live with, every sleeping policeman had to be negotiated with extreme care, to prevent grounding. On the Munich trip, my co-driver coined the phrase "fatty out" every time a speed bump had to be crossed. The geometry has now been set to the lowest within the factory spec range, which has meant raising it by about 20 mm.
A couple of other things were done, again while waiting. A new windscreen was fitted as the original had a small scratch and was just starting to de-laminate. The cooling system was flushed and antifreeze changed. The A/C fan was looked at and adjusted. The door lock connecting rods were lengthened by about 10mm, no idea why they were short but they were, so the pins went a bit too far into the door card when locked.
So, now I just need to remove all the temporary wrap and give her a really good clean!
The main reason for leaving her at Munich Legends was to replace the suspension bushes, basically the 36 year old polyurethane had perished and they were dropping to pieces. This is what they looked like after being taken out of the wishbones
The Polyurethane was about the constancy of a wax crayon!
There are two different bushes used, 12 of one type for the front and upper rear wishbones and 8 of another for the lower rear wishbone. The front/upper rear is still available, so I could use the OEM part. The lower rear bush however is NLA. I say bush, the NLA part is more like a ball joint filled with Polyurethane. Luckily I have the technical drawing and specification of the bush, however no one I approached was willing or able to make an exact replica. Given the axis over which movement can occur, pretty much purely rotation about the axis of the bush, I decided that a simple poly bush was going to be more than adequate and definitely preferable to a deteriorating ball joint. I found a company that would make up custom poly bushes, DuraFlex, and had them manufacture a couple of sets using the highest density Polyurethane available, 90D which is pretty much rock solid!
While the suspension was apart I thought I might as well get the Bilstein shock absorbers refurbished and this is what has taken the time. While waiting I had the wishbones re-painted too, so it all looks nice and new under there now, this is the only picture I have for now, I'll take more when I take the wheels off for cleaning.
If you look closely, you'll notice that the top wishbone mounting point has been moved down. At some point in the past the suspension geometry had been set to give the lowest possible ride height. This proved to be a bit of a pain to live with, every sleeping policeman had to be negotiated with extreme care, to prevent grounding. On the Munich trip, my co-driver coined the phrase "fatty out" every time a speed bump had to be crossed. The geometry has now been set to the lowest within the factory spec range, which has meant raising it by about 20 mm.
A couple of other things were done, again while waiting. A new windscreen was fitted as the original had a small scratch and was just starting to de-laminate. The cooling system was flushed and antifreeze changed. The A/C fan was looked at and adjusted. The door lock connecting rods were lengthened by about 10mm, no idea why they were short but they were, so the pins went a bit too far into the door card when locked.
So, now I just need to remove all the temporary wrap and give her a really good clean!
Not driven it far since the refresh, just about 5 miles to fill up with fuel where I was approached by a guy in a M235i saying he'd never seen one on the road and could he take some pictures. I'd say it feels a bit tighter, but not that much different to be honest. Although the polyurethane in the bushes was shot, I think it's main purpose was to keep dirt out of the joints. I'm sure after a year or so those rear ball joints in particular would be seriously worn. I did have to navigate some speed bumps, no hint of grounding out and far less stressful than it used to be!
Another small job that needed tackling was the rear view mirror.
There were two problems, first the design has a mirror and a piece of glass at a slightly different angle, the reflection from glass being used in dipped mode. This means that there is a gap between the two and over the years the internal surfaces had become dirty just like the driving lights. It's not so bad during the day, but at night with lights behind it creates a lot of glare.
Having spoken to someone while in Munich, they said it was an easy job to take apart and clean. I was a little nervous because the mirror is no longer available, the housing is made from 36 year old plastic that gets baked in the sun and is clipped together and the mirror has always been rather loose on it's swivel mounting. That's the second problem, I've always suspected that there is probably some sort of plastic clamp inside that's cracked, so it still holds it firmly enough so it does not move while driving, but it's just a bit floppy. If I take it to pieces will it just fall apart in my hands!
So I warmed up the housing by placing my trusty fan heater in the car and went about opening it up. Actually the plastic was very flexible and I could take it apart with just my fingers, the outer surround is just held in place with 4 barbed clips. Sure enough, just as anticipated, the clamp for the swivel mount was cracked
So, first question, try to fix it or leave it as is? It looks as though the clamp piece, which is part of the dipping mechanism, is just held in place with 4 clips. Should I un-clip them and risk not being able to put it together again or not? In the end I chickened out! Due to the soft nature of the plastic I think it would be near impossible to mend the cracked piece. I decided to use a more Heath Robinson fix, cable ties!
It's now a little more solid and should not get any worse.
Here are the mirror and covering glass removed from the housing
Both the interior surface of the glass and the mirror were quite grimy, difficult to see in the picture above, but after wiping a small section on the glass and mirror you can see how dirty they were
All put back together again
There were two problems, first the design has a mirror and a piece of glass at a slightly different angle, the reflection from glass being used in dipped mode. This means that there is a gap between the two and over the years the internal surfaces had become dirty just like the driving lights. It's not so bad during the day, but at night with lights behind it creates a lot of glare.
Having spoken to someone while in Munich, they said it was an easy job to take apart and clean. I was a little nervous because the mirror is no longer available, the housing is made from 36 year old plastic that gets baked in the sun and is clipped together and the mirror has always been rather loose on it's swivel mounting. That's the second problem, I've always suspected that there is probably some sort of plastic clamp inside that's cracked, so it still holds it firmly enough so it does not move while driving, but it's just a bit floppy. If I take it to pieces will it just fall apart in my hands!
So I warmed up the housing by placing my trusty fan heater in the car and went about opening it up. Actually the plastic was very flexible and I could take it apart with just my fingers, the outer surround is just held in place with 4 barbed clips. Sure enough, just as anticipated, the clamp for the swivel mount was cracked
So, first question, try to fix it or leave it as is? It looks as though the clamp piece, which is part of the dipping mechanism, is just held in place with 4 clips. Should I un-clip them and risk not being able to put it together again or not? In the end I chickened out! Due to the soft nature of the plastic I think it would be near impossible to mend the cracked piece. I decided to use a more Heath Robinson fix, cable ties!
It's now a little more solid and should not get any worse.
Here are the mirror and covering glass removed from the housing
Both the interior surface of the glass and the mirror were quite grimy, difficult to see in the picture above, but after wiping a small section on the glass and mirror you can see how dirty they were
All put back together again
gforceg said:
Really interesting to read this, as always.
I would have thought the cracked piece would be a perfect candidate for a 3D printed replacement if unavailable elsewhere.
Yes, I would imagine so. That's what I was going to investigate. I think the problem may be the material type, but I'm no expert on 3D printing. The material would have to be strong enough to hold the ball tightly, but flexible enough for the dip toggle at the bottom of the mirror, it's all one piece with a plastic hinge between the main block and the toggle.I would have thought the cracked piece would be a perfect candidate for a 3D printed replacement if unavailable elsewhere.
Love reading about your keeping such a great BMW on the road. My own first thought for the 'repair' was cable ties and I see no reason why that shouldn't hold for a good few years. I wonder what their thinking was, for placing the mirror behind glass like that? I assume it's a design that remains unique to the M1?
Some months ago being the oaf that I am I broke the glove box handle on my E12. A similar scenario as far as breakages are concerned. I effected a solid repair buy firstly supergluing the pieces together then using a very small drill bit to drill directly from once broken piece the the other. Once drilled I took the drill bit and snapped it to length to fill the hole that bridged the two pieces. Once coated with super glue I slid the drill bit back into the hole to provide the strength and rigidity required.
My misses has been functionally testing it buy slamming it ever since...still hasn't broke
.
Just an idea if it's suitable.
My misses has been functionally testing it buy slamming it ever since...still hasn't broke
. Just an idea if it's suitable.
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