25 replies to this topic

[miniman92]

Hi Everyone.

Thought it was about time I started a project thread seeing as everything regarding this build will be getting under way shorlty, so.......

Originally my mini had a fast road 998 engine including 276 cam, fully worked 12g295 head, close ratio box, sc drops etc but it eventually the engine started to smoke and had loads of blowby. After looking at how much it would roughly cost to re-build my 998 I decided to go down the 1275 route due to the fact that I'd get more power for my money. Whilst I loved my 998 it was really lacking in the way of torque and it had to be tonked to get it anywhere and I wanted a motor with more torque for the roads, hence........ bring on the 1310cc build!

This is my mini it will be going in to.......



Ok, so the engine spec should be somewhere along the lines of:


Cylinder Head:

12G940 "stage 3" spec head (11 stud)
35.7mm intake and 29.4mm exhaust plasma nitrated valves (single collar retention)
180lb double valve springs and bronze valve guides
Fully Gas flowed (keeping the intake ports a sensible size to aid low down torque)
Hardened Valve seats suitable for unleaded fuel

Minisport 1.3 ratio roller tipped rockers

Engine Block:

1310cc A+ Plus Block (Drilled for 11 stud)
Crank re-ground 10thou on mains and 10 thou on big ends, crack tested and dynamically balanced
Centre Main Strap
A+ rods, crack tested and size and alignment checked, individually balanced end over end
AE 21253 +40 High Compression pistons, individually balanced and fitted to rods
Quality Glacier shell bearings and thrust washers

AC Dodd RS+ 270 duration cam and minispares follwers (similar to the Kent 276 and PH3)
Steel Backed oil pump
Minispares Lightened Duplex Timing Gears

Gearbox:

Rebuilt A+ gearbox with 3.44 final drive
Rebuilt diff with Guessworks Molybdenum competition diff pin and planet gears
Guessworks Central Oil Pick-up Pipe

Here is the doner engine; A 46k miles Sprite A+ Unit









The Block and Crank should be back sometime this week.

Ash

Edited by miniman92, 21 January 2012 - 02:23 PM.

[miniman92]

My ACD-RS+ was delivered today.......... thanks ML Motorsport!

[miniman92]

Rang Minisport today and my block, pistons and crank are ready to collect......... I went for the half engine kit in the end as it worked out cheaper:



I know Minisport get some bad press but they are only an hour or so from me and i'm willing to give them the benefit of the doubt. There are a few people in my club with minisport based engines and they seem to be happy enough.

At the end of the day I'll give everything a good checking over including the piston to bore clearances and ring end gaps etc and if it's not right then the whole lot will just go back....... fingers crossed everything will be fine! Never had any issues with Minisport in the past so we shall see!

Also forgot to put up a few pictures of my gearbox being re-built:



Diff being re-built and crownwheel replaced with a 3.44



New planet Gears



Layshaft was in great nick



All done thanks to my mate Ben from my club, cheers mate! ....... just needs a good wash out now.

Edited by miniman92, 25 January 2012 - 03:50 PM.

[newnham500]

looks cool man, not to put a downer on it but i read a post about a half engine kit from mini sport, i would read it. sick mini though

[miniman92]

Ive read it newnham, which is why I'll be making sure everything is A1 i.e. the piston to bore clearance and ring end gaps.

On the plus side, the reason I went for 1310 capacity is because minisport were out of +20 pistons so they said they would bore the block to 1310cc for no extra charge...... at least this way they will have to set the machine up! I think half the problem is that they set the machines up to bore to 1293 and 1380 and use the same settings each time without regard for piston skirt measurements i.e. they dont bore the cylinders to match the pistons. With my +40" pistons they will have to!

Ash

[newnham500]

good man, well hope it all goes well. have fun, mini

Edited by newnham500, 25 January 2012 - 04:13 PM.

[miniman92]

Time for an update....

Got the engine kit back from minisport on friday. Haven't really had much time to do anything with it as I was busy all weekend and then in uni all this week but fingers crossed Im going to get it all cleaned up this weekend ready to start building it on monday.

I forgot to tell minisport not to fit the oil gallery plugs so I've managed to remove those ready for cleaning. Whilst the block has been cleaned in a hot tank I want to be sure the block is 100% clean before starting the build. Ive bought 4 litres of paraffin and Im borrowing an air compressor from a friend, so hopefully should get it all cleaned this weekend.

Also checked my ring end gaps, they are all between 14 and 15 thou which is about bang on for a 1310 using the 21253 ring pack. (Thanks Pete for the second opinion.)

Anyway, here are a few piccies:

The Block

[PhilipGCaldwell]

mmmm, beautiful block!Top looking clubby mate, one of many at Missiles!
Keep the updates coming

[1380roadmini]

looks great, keep the updates coming

[miniman92]

Thanks Phil, we are definitely partial to a clubby or two in the missiles lol. I'm really pleased with the quality of minisport's work, I payed a reasonable price as well, much cheaper than getting it all done at a machine shop and buying the bearings and pistons separately.

I'll try and get some more pictures up tomorrow, my photobucket account was playing up last night for some reason.

[miniman92]

Spent yesterday cleaning the engine block and crank ready for assembly. Washed all of the oil ways through with paraffin and then shot compressed air in to everywhere and anywhere I could get it to make sure I got rid of all the swarf..... one nice clean block:





Did the same treatment with the crank:





In whent the main bearings:



And then on whent the crank along with the standard size thrust bearings and centre main strap:




One I'd tightened down the centre main I then moved on to check the crank end float using my dti:




Woops........... nearly 8 thou crank end float, and I wanted about 3 thou!

Got on the phone to minisport yesterday to say that I had been given the wrong sized thrusts with the crank, so they said they would send me out a pair of .005" oversized thrusts to put on one side to bring the end float down to .003".. I couldnt believe it when the post man came to the door with them this morning.......... now thats service!

So I fitted the oversized thrusts to one side of the crank, tightened everything down and put my dti on the nose of the crank and found that there was now no crank end float at all! Stripped everything down again and measured the oversized thrusts against the standard ones to find that they were more like .008" oversized not .005".

So now ive got to find some thrusts that will give me the correct end float, not sure if I should buy a full set of .003" oversized thrusts and go from there!

Ash

[racingenglishcars]

Sand them down

[RawlinsGTR]

I'm gonna ask this question for my own intelligence, since I've been searching around on Google and can't really find an answer.

How is it you chose 0.003" thou to be your desired end float? Is that just the basic standard, or do you choose the amount of end float based on other variables?

I'm busy trying to learn loads of stuff about engine building, so was just wondering :)

Your build looks really clean and tidy, and I LOVE your Clubman.

Simon.

Edited by Dog., 07 February 2012 - 04:29 PM.

[miniman92]

Thanks Simon. Only reason I stated that I wanted an end float of .003" is that on a fresh build it is considered that an end float of between .002" and .004" is required, hence me stating .003" thou. However I have heard that some people use an end float as much as .007" on high revving engines to aid oil retention between the thrust face of the crank and bearing surface. I suppose to a degree it is just personal preference. My theory is that by the time a heavy duty clutch diaphragm is fitted and the engine run in, the end float will soon increase, so the closer to .002" the better I think.

Racingenglishcars, I was thinking of sanding them with 800 wet and dry however I am just worried about not being able to achieve a uniform finish without any taper which I presume is hard to do by hand?

Ash

Edited by miniman92, 07 February 2012 - 06:24 PM.

[RawlinsGTR]

Great answer, thanks. :)