1991 Cooper Mainstream Project

The Home of any non Mini projects & discussion.
mini_surfari
Posts: 620
Joined: Fri Jun 25, 2010 10:26 am
Location: South West

Re: 1991 Cooper Mainstream Project

Post by mini_surfari »

Thanks for the comments, progress is a little slow, but going in the right direction. The main issue is not 'over restoring' the car, it is supposed to be a nice tidy Mini, that you would happily drive in any weather.

So we collected the engine parts back from Slark, they're currently boxed up awaiting assembly until all the dirty body work is done though.

Mean while ....

New heritage valance and closing panels, so its actually the right shape.

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Crusty tabs replaced

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Battery box look a little thing one end, so repaired that

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All the obsolete holes were welded up in the wings/ bulkhead

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And we blew in the floor repairs, before putting sound deadening down.

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And also managed to pick up the proper minilites with the bolt holes inline with the spokes!

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coopersean
Posts: 164
Joined: Thu Feb 03, 2011 10:41 pm
Location: Derbyshire

Re: 1991 Cooper Mainstream Project

Post by coopersean »

Great project, and really enjoying the progress so far!

One quick question - is your car a very early mainstream, as most were fitted with the later style of wheel with the bolt holes inbetween the spokes, unlike the the RSP, 30 and Racing Flames?
mini_surfari
Posts: 620
Joined: Fri Jun 25, 2010 10:26 am
Location: South West

Re: 1991 Cooper Mainstream Project

Post by mini_surfari »

coopersean wrote: Sun Jan 15, 2023 6:41 pm Great project, and really enjoying the progress so far!

One quick question - is your car a very early mainstream, as most were fitted with the later style of wheel with the bolt holes inbetween the spokes, unlike the the RSP, 30 and Racing Flames?
Thanks Sean, I'm unsure of the build date, but registered in June 91. So I'd guess it was built not long before.

An early photo of the car shows it with these type wheels that's why we've gone for them, as do all the brochures, I can only assume it was a 'use what's on the shelf?'. It also had white bonnet stripes, and too aux lamps. So believe it had the Italian Job pack from factory (should've also had the plastic boot tray). This is all just from reading online mind :lol:

Chances of finding some Rover Aux lamps seems slim though.

Cheers, Oli
alexm
Posts: 185
Joined: Mon Jul 05, 2010 6:12 pm
Location: Surrey

Re: 1991 Cooper Mainstream Project

Post by alexm »

Really glad I ventured into the 'Other interesting vehicles of projects' section of the forum. Watching this with interest.

My 2nd mini was a BRG mainstream Cooper. Loved it.
Grant 111
Posts: 34
Joined: Thu Feb 26, 2015 7:48 pm
Location: Wiltshire

Re: 1991 Cooper Mainstream Project

Post by Grant 111 »

Nice work as always oli!
Glad to see this one being saved My mum had one as a daily driver.
CooperTune
Posts: 1032
Joined: Sun Sep 22, 2013 1:47 pm
Location: Coastal VA USA

Re: 1991 Cooper Mainstream Project

Post by CooperTune »

I'm also busy working on a 1990 Mainstream Cooper. Having owned and worked on minis since 1968 you would think I'd have seen it all by now. Being a fairly low mileage car everything untouched is in great condition. Yes, all rubber is dry and cracking. Otherwise I'm seeing poor repairs the likes of which I can hardly imagine. Who welds lug nuts to the sub frame as a droop stop? I'll discard the front sub and replace with a freshly powder coated unit complete with S racer Red springs, Hi Los, and on car adjustable suspension. Some where along the way the air box was replaced with a a K&N cone filter. I have read Cooper offered a twin carb kit to upgrade. I would like to see the information on what was included. Running a compression test I came up with 180/150/175/180. When I have a chance I'll pull the valve cover and check for a valve clearance closing up. Failing that I'll run a leak test to determine the issue. If it is just a valve I'll port the head and repair any other issue. I have a set of HIF38s but have suffered with the linkage. I also have a set of HS4s ready to go. Over time the cat and the cast LCB have gone missing. It does have a SS DTM system. Steve (CTR)
mini_surfari
Posts: 620
Joined: Fri Jun 25, 2010 10:26 am
Location: South West

Re: 1991 Cooper Mainstream Project

Post by mini_surfari »

Thanks for the comments guys, it is coming together slowly. Although in some ways, trying not to over restore the car seems to take longer than just hacking everything out and starting a fresh.

Steve sounds like a good project you've got on the go, heres a link I've been using for reference http://mainstreamcooper.co.uk/default.a ... ndexid1761

We've managed to source, the correct dash, steering wheel, air box, rubber surround for the rad, only things we need now are a gearknob, electric fan, and spot lights I believe.
CooperTune
Posts: 1032
Joined: Sun Sep 22, 2013 1:47 pm
Location: Coastal VA USA

Re: 1991 Cooper Mainstream Project

Post by CooperTune »

Thanks for your reply, I do have some questions you may be able to answer. My 90 Mainstream while low mileage was converted to a Sport Pac look along the way. I'm concerned about the diff pin and wonder about the first and third motion ball bearings. I do a lot of transmission work. This is about the right period when the plastic spacers break up allowing shaft to run off center till something breaks. Have you taken a look at your gear box?
Pulling valve cover last night exhaust valve #2 is a little tighter than it should be. Did these have hard seats from factory? Thanks Steve (CTR)
mini_surfari
Posts: 620
Joined: Fri Jun 25, 2010 10:26 am
Location: South West

Re: 1991 Cooper Mainstream Project

Post by mini_surfari »

Steve, I've not yet looked at the gearbox, I think we'll finish the body, running gear, short engine, then box last to be honest. Yes should've had hardened seats from factory, 1989 was the introduction I believe.

underside all painted. Kept some of the battle scars!

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Onwards with more sanding and priming now!
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