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Mini Cooper 998 Screamer Nut And Bolt Rebuild


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#1321 Petrol

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Posted 19 November 2017 - 10:38 PM

Not much left to strip down now. This is the wiper motor.

Top cover off

 

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Remove this circlip and washer to get the arm off

 

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Circlip on the back holds the cog in place

 

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This nylon plate is how the wipers park

 

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It depresses this switch

 

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It slides out like this

 

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These two bolts hold the back plate of the motor in place

 

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With these out the main shaft of the motor can be removed

 

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Then the brushes can be removed from the aluminium housing. Two speed wipers have a 3 brush setup

 

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A good dose of wire brushing, etch primer, silver basecoat and clearcoat on the casings

 

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#1322 Petrol

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Posted 19 November 2017 - 11:21 PM

Sorry this build is a bit fragmented. That's how total rebuilds go though
 

Time to get the engine out again

 

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I'm not keen on these tab washers for the big ends as they are very soft. Although I never had a problem with the last 998 I built decided to use a bit of locktight on the threads

Bit of belt and braces

 

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I used this assembly lube on the shells because it would be stood for a long time and I need to measure the volume on top of the pistons. I will use white spirit for this.

 

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A burette is the preffered measuring tool but I don't have one. Instead I will use these 1ml syringes. They are small bore so should be reasonably accurate.

 

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The combo of a 12g295 head with modded chambers and flat top pistons will mean the head needs a big skim to get the 10:1 compression ratio I'm looking for right

 

 

 



#1323 Petrol

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Posted 20 November 2017 - 03:47 PM

To get a 10:1 CR I need 27.7cc in the chamber when the piston is at TDC.

 

Dial gauge for TDC

 

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Grease on block to form a seal

 

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Perspex with hole to inject the white spirit

 

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Bubbles can be removed by tapping the perspex

 

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Filled. It took 1.5cc

 

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Assuming 2cc in the gasket (typical figure)

 

27.7cc - 2cc - 1.5cc = 24.2cc

I need 24.2cc in the head for 10:1

 

To measure how much skimming the head needs it needs leveling both ways

 

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Then put the required volume in the chamber. In this case 24.2cc

 

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I was suprised at this point since the fluid virtually filled the chamber. I was told that the head had never been skimmed but thats obviously not the case.

 

Measured down to the liquid...... 1.2mm

 

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12g295 heads typically need about 80 thou off (about 2mm) when using flat top pistons. I had rimflow valves which are recessed fitted and the chambers opened up a bit more.

Looks like it was skimmed but more mods means it needs a bit more off.

 

 

 



#1324 Petrol

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Posted 20 November 2017 - 04:00 PM

Its possible to break through to the rocker oil feed gallery with big skims.

Its easy to measure. Thickness of head

 

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And depth of hole

 

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Plenty on this



#1325 Petrol

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Posted 21 November 2017 - 10:40 PM

 After the epic fail by Minisport grinding my crank tapered, I've taken the head to Redmans engine centre in Fleetwood. Funnily enough, they are the guys that did all the machining on my first 998 build back in “cough” 1981.

I have taken a lot of inspiration from that car in this build and improved it a bit. The engine is a very similar spec.

I also wish I'd have done more on this engine now. Things like a 4 bolt oil pump, hardened / knife edged crank, modded rods and better pistons. That said, the old 998 I built revved it's nuts off regularly without all those mods or improvements and didn't let go.

Redmans are going to fill the chambers with a burette then use a micrometer depth gauge to measure the skim. This will be accurate as the depth gauge will bridge the whole chamber and the tip can be lowered much more precisely.
 



#1326 Petrol

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Posted 24 November 2017 - 08:35 PM

I wish I'd have done more on this engine now. Things like a 4 bolt oil pump, hardened / knife edged crank, modded rods and better pistons. That said, the old 998 I built revved it's nuts off regularly without all those mods or improvements and didn't let go.

 

 

 

I'm on it. Crank and pistons are out!

 

I have spoken to a small local Mini parts supplier / specialist and explained what I'm trying to build. Things have moved on somewhat since I last built a modded Mini engine and I'm a little out of touch with current tuning techniques. I'm tired of comission based salesmen who don't fully understand what's involved but this supplier is different. I have told him what's been done so far and he's doing some calculations regarding CR ratio / cam combos  / air flow requirements and gearing.

 

He is then going to visit me to see what I have done so far and advise me the best way forwards to get this engine to sing.

That's what I call PROPER service!

More details soon!

 

 

I want the car to fit the title of this build..... 998 screamer!



#1327 cp2708

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Posted 24 November 2017 - 08:58 PM

I replaced the heater matrix with one from Minispares, it leaked after 11 months worse than the original 30 year old item. To be fair, they sent me a new one, no quibble. But I agree, I find that buying from my local motor factor gives me better parts. If you stick to QH or Delphi etc the parts seem to be a better quality. I replaced my upper and lower ball joints with local motor factor parts 4 years ago and the rubber dust shields still look like new, yet the Minispares knuckle joints are perishing and cracked. What I do find is that autoglym rubber care helps the situation a lot. I just cover all rubber parts with it when I service the car.

#1328 Petrol

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Posted 25 November 2017 - 10:01 AM

Seems like many are having problems with rubbers!

 

Console is done

 

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#1329 Marco1972

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Posted 25 November 2017 - 07:39 PM


Very smart

Nice job I like the black carbon and chrome

Mark

#1330 gadget555

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Posted 27 November 2017 - 09:54 AM

Lovely craftsmanship Pete, love the attention to detail.



#1331 Cookiez

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Posted 27 November 2017 - 12:41 PM

Looking great

 

but !!!!

 

Can you turn the USB socket 180 degrees
It would do my head in with the wording of the USB drive being upside down.



#1332 Twilton

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Posted 28 November 2017 - 09:12 PM

Very smart mini there!

 

It's going to be lovely when its on the road!



#1333 Petrol

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Posted 30 November 2017 - 11:08 PM

USB socket will be the right way round. The console needs a final buff and polish before it's fitted

 

Wiper linkage fitted with new wheel boxes

 

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Wiper motor re built

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This is going in the bin.... I need to fit a proper brake bias valve

 

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This build is not easy but I want to get it right, there are a couple of people helping me and I'm very grateful for their input... Mucho respect.

 

 

Pete 

 

 



#1334 Petrol

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Posted 01 December 2017 - 08:34 PM

Starting to assemble the dashboard. It's a bit tight at the back!

 

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Stainless wipers and a few other bits from Rimmer Bros. I wonder how long the wiper rubbers will last :lol: :D

 

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#1335 timmy850

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Posted 01 December 2017 - 11:48 PM

Your interior is coming together very nicely!

 

Who needs windscreen wipers anyway? Mine are next to useless, I'm going to try some Rain-X on mine to see if that helps






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