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iain1967s wrote: ↑Mon Apr 20, 2020 1:22 am Thanks to Roland for the metal dipstick & tube - they are quite hard to find these days, and I really didn’t want to use the later nylon type tube.

It would actually be the other way round, the metal tube superseded the nylon one, this happened in 65. So you have the correct one for your engine.

Not too much progress this week, but the stranded package from the UK finally arrived so I was able to fit and gap the primary gear. Also the MG Midget metalastic damper (same part number as Cooper S) from Canada, so the crankshaft pulley and front mounting bracket are now on.

Last remaining job before I start working on the top end, is to fit the primary oil seal. I’ve seen a lot of discussion recently about the (lack of) quality of primary seals, so not sure yet which one to use. Might just buy all 3 and see what they look like side by side... 13H2934, 13H2934MS and LUF10005.

Oh, and I need to source a suitable flywheel/clutch assembly.

hi very often the new seals are old and hard and there fore do not seal properly i have found that by going to a bearing /seal seller that the seals can be better as not as old
cheers roger

Picked up this Mk3 ‘S’ 940 head from eBay UK. Bit of an effort to get it over to the USA due to the covid lockdown, ended up using a courier company to pick it up from Mum’s house and forward it via DHL.

Now that it’s finally here, I can strip it down and take a good look at the ports. The ad said it was fairly heavily worked, and indeed it appears to have been ported quite extensively - mostly on the inlets. No tuners marks stamped into the casting that I can spot.

I blocked off the waterways on the face using gorilla tape, and filled it up with boiling water to see if there were any leaks. Bone dry in all the ports after 15 minutes so looks like at least it isn’t porous like the 163 head I had issues with a while back.

Anyway I’ll pipette the chambers to see what the capacity is, and then work out if the compression ratio will work for my engine.

Why did I not buy this 30+ years ago?

All those hours spent struggling with masking tape to get the damn primary oil seal in without ripping the lip on the gear splines, and this tool does it perfectly in about 30 seconds.

Amazon came through with the 5/8-16 plug tap, so I was able to drill out and re-cut the thread for the bypass hose and then fit a new spigot, with thread sealant since it’s now a parallel thread not a taper.

Cleaned the head up generally with CLR, and ground the valves in today. Also, scraped off a layer of rust to reveal the original
“S 12G1805” stamp behind the thermostat. Shame it’ll be covered up again with a coat of primer and paint very soon.

Now that the valves are back in, I can measure the chamber volume. You can see the combustion chambers are quite roughly finished - someone has definitely been in here with a die grinder.

Feels like I am getting closer to the end now. Just need to put the clutch/flywheel together and fit the head.

Since I won’t be able to install it in the car until lockdown is over, am thinking of fitting a starter motor and turning it over on the bench, so I can check the oil pressure, compression and maybe do a leak-down test.

To that end, I’ve just ordered up one of Nippycars reproduction Mk1 oil cooler kits. The original Petroflex hoses on my car are well past their best anyway.

Approx 22cc chamber volume, but it leaked a little bit past the grease while I was refilling the 10cc syringe for the 3rd time...

Probably should have used something a bit more sturdy than a CD jewel case for the flat plate

Anyway, I’ll call that close enough to the factory Cooper S spec [21.4cc] so whoever skimmed it went through the effort of grinding the chambers back to standard.

All dressed up, and nowhere to go...

Torqued to 48/24 LbFt, with an eBay set of 12G1221 rockers

Need to set the valve clearances, then clutch and flywheel next.

I decided that building up the clutch release assembly would be an ideal ‘home school’ learning experience for my 7yo daughter...

So I printed out the relevant page from the Haynes manual, then gave her a pile of Mini Spares bags and took a step back.

Have to say, she did a pretty good job. The only bit I had to help her out with was bending and clipping off the split pin ends.

To complete the build, an original ‘S’ two part flywheel came courtesy of Nick at min-e-bitz, to which I fitted a new Borg&Beck blue spring diaphragm and clutch plate.

Also, a British Leyland NOS top-hat style release bearing, because I don’t trust the modern heavy-duty types - ever since I had one push the center of the race straight through into the flywheel.

An original Lucas dizzy is rebuilt by Martin the distributor doctor, and curved for modern fuel.

Just waiting on a repro oil cooler and Petroflex hoses ordered from Nippycars, then I’ll be able to spin it over on a spare starter motor and check the compression and leak-down.

While I wait for the oil cooler, figured I would clean up this rather tired rocker cover. Used a Dremmel and a round file to grind out two semi-circles for the extra S studs, then dollied out the dents and generally got it back to correct shape.

Soaked in CLR and wire brushed / 120 grit within an inch of its life to get the deep rust out, then Rusoleum self etch primer, filler primer, block sanding, first guide coat, wet flatted, and two top coats of Moss engine enamel.

New decals on their way from MiniSpares, and maybe one of Mk1’s new BMC ST plates too

Repro oil cooler kit arrived from Nippycars, and very nice it is too. The hoses are very close to the original Petroflex, but the sheathing is quite a bit thinner and it wrinkles easily so some care is required on the tight bends.

I primed the oil pump and pre-filled the cooler, then cranked the engine over [plugs out] for a few seconds. I guess the oil pump must be working because it’s pissing 20/50 out the side of the Purolator canister...

It got me worrying that the filter canister was over pressuring and maybe the oil is not getting through the filter and circulating around the engine, so I pulled the filter head off the block and checked that oil ran back out of the gallery, and that the filter bypass ball bearing/spring was free to move.

While I was at it, I changed the canister rubber sealing gasket/ring to the thickest of the three supplied in the box by Minispares, then screwed it down good and tight.

I had put an $8 foot pump [100psi] gauge on the oil takeoff but it read zero. Maybe it was bad? So I removed the gauge and spun the engine again. Out comes a torrent of oil, great... but now I have both a basement floor and a work bench covered in 20/50

The good news is that after all that, the gauge is registering 60psi during cold cranking so that’s good enough for now. I can tweak the pressure release valve once it’s in the car and running.

hi well it was good that it happened in the shed and not while zipping down the motor way like mine did a long time ago all oil out in no time at all quickest oil change i ever had
lucky that the tool box was in car and spare oil so disconnected oil cooler and fill up and of we went hope nobody hit that oil but next time past no sign of trouble
cheers roger mcnab

AndyPen wrote: ↑Wed Apr 01, 2020 9:20 am Hope the basement steps aren't all that steep... and that you have a strong buddy

Due to the lockdown, I had to get creative to do it single handed...

Rigged up an A-frame using some heavy duty dexian and a 4x2 as a cross brace, then used a four-wheel pulley to slowly winch it up a wooden ramp and out the door onto a dolly.

It just about fits into the boot of my Gen3 MINI, so at least getting it up to the lockup where my mini is garaged will be easier - last time I had a Gen2 and it wouldn’t fit through the hatchback, so me and a mate had to push it half a mile uphill on the dolly!

Love the ingenuity there! This has been a great build thread to watch.

Not a Mini related quarantine project but I thought you lot might get a kick out of it.

It’s only a little Suzuki 125 commuter bike but I wanted to get more time on the English Wheel so I’ve been making an aluminium mudguard, headlight surround, fuel tank, seat/tail unit & side panels.

hi
well it is good to see that some one else has bikes as well as minis i have 3 yamaha projects in the shed with the mini and last night bought a crank shaft assembly for a triumph T100c bike on a whim now i have to pay for it to come from america to oz another bike to play with it is a start all i need is all the rest
cheers roger

Tupers wrote: ↑Wed Jun 10, 2020 8:40 pmIt’s only a little Suzuki 125 commuter bike

Looks like a GP125? Can't be too many of those left these days. My first motor transport was a Yamaha RS100, very similar design to the GP - I lost control on a roundabout and slid under the front of an HGV - fortunately passed my car driving test the same afternoon, and bought my first Mini a few days layer.

Funnily enough I was looking around eBay etc. recently to see if there are any RS100's up for sale still, as maybe a future project... but I don't think they had 2 strokes that late over here in the USA.

iain1967s wrote: ↑Fri Jun 12, 2020 2:16 am Looks like a GP125?

It’s just a ‘90s GN125 unfortunately, no fun 2 stroke noises for me.

It has been a good opportunity to use the English wheel though.