1842 replies to this topic

[Petrol]

After some problems with with the gearbox build, I got it back, bought some parts and sorted it. It's 100% now.

 

Selector arm welded on. These have been known to drop off.

 

 

Fitted

 

 

Brand new, Genuine selector forks

 

 

Brand new (old stock) 3rd motion shaft with new genuine pin and springs

 

 

Brand new steel caged gear bearing. These are hard to find

 

 

2nd gear on with retainer fitted. It's not hard to do this, just a bit fiddly as you have to push the pin in to fit the retainer then rotate it to lock it.

 

 

I got some very good condition, used but genuine synchro hubs. Piston ring compressor is being used here to hold the balls and springs in.

 

 

Gears assembled. Everything should go together smooth. Nothing tight or sticking and no slop in the bearings.

 

 

Gears and layshaft fitted

 

 

X pin diff with a 3.44 CWP. Brand new RHP bearings

 

 

Shimmed up, sealant on case

 

 

Nice mod this, Magnet down the central oil pick up pipe

 

 

This is also a good mod, upgraded magnet in the sump. I bought both of these along with many other parts to build this box from retrominis. The parts they sell are top quality and everything fits.

Have to say I'm mucho impressed!

 

 

 

Bolt heads painted with Hammerite smooth

 

 

 

The gearkit is NOS Jack Knight and all the bearings are RHP brand. There are many cheap bearings about like SCH which many of the big parts retailers supply. They are cheap crap and feel rough as a bears arse when you spin them. The same goes for the gear kits, budget Chinese gear kits are not the way to go.

 

It's taken some time but progress at last.

Thanks for looking

 

Pete

 

 

 

[nicklouse]

sorry i am not a fan of those magnets in the oil flow. they just hold bits of steel until there is too much or you hit a bump that exerts a force on the clump of filings that is greater than the force of the magnet and bam there goes your pump. your bearings...

 

it is the fact it is in the flow that is the issue. the sump plug is not in the flow so there it a chance of re-catching the filings.

 

I just put a filter in that routing before the pump.

[Petrol]

sorry i am not a fan of those magnets in the oil flow. they just hold bits of steel until there is too much or you hit a bump that exerts a force on the clump of filings that is greater than the force of the magnet and bam there goes your pump. your bearings...

 

it is the fact it is in the flow that is the issue. the sump plug is not in the flow so there it a chance of re-catching the filings.

 

I just put a filter in that routing before the pump.

 

Please don't say sorry, its valuable feedback and I agree with you. It's easy to remove at this stage of the build so thanks for the heads up. I'm interested however to see how you put a filter in there.

I'll stick with just the magnet in the sump and considering the oil will be changed every 3k miles, I can't see a problem. There has been a few mods to this engine to reduce losses, the electric fuel pump being one example, it's less of a HP drain on the engine. The oil pump has been flowed and ported to make it more efficient, the galleries have been opened up to feed the main bearings and I will be using a big bore braided pipe from the oil filter to the block. The stock oil filter head will also be replaced with a billet type to again reduce pumping losses and get rid of the stock unreliable valve arrangement. 

Later Minis were run on lower viscosity oils but the gearbox was never re designed. 20w 50 is what it needs and that's what I will be using which is why it makes sence to reduce oil pumping losses as much as possible.

Every single HP counts on a 998 when the staring point is about 38.

 

I've had a lot of help and advice from Andrew at RetroMinis, his input has been invaluble to this build and I will post more of what he has done later in this thread. One of his top tips was this..... To remove the first motion shaft outer bearing, heat the casing up, then bang it on a piece of wood.

 

 

WOW!

No puller

No hassle

2 mins with a heat gun and out it came

[mini 4o]

sorry i am not a fan of those magnets in the oil flow. they just hold bits of steel until there is too much or you hit a bump that exerts a force on the clump of filings that is greater than the force of the magnet and bam there goes your pump. .

 

Hi Have to agree with nicklouse  try a better quality oil  filter  changing from 3/4 unf opens up a better range, few years back you could buy a magnet  which fitted around the filter. 

 

so how come i cant see your photos ?  

[hhhh]

Regarding a filter before the pump: doesn't that run the risk of obstructing the flow and causing cavitation due to the increased restriction?

[Retroman]

I'll have to disagree with Nick and Mini 40

 

A magnetic trap can and does stop shrapnel going through the pump, generally about 1/4 of whats on the sump plug.

 

The way I look at it is any metal in the oil is going through anyway so a magnet will help stop it, in the flow or not.

 

Maybe use the Gold plug in the trap as they are seriously strong and would be better

 

I used to run with a speaker magnet on the bottom of the main filter too.

[warning634]

Absolutely stunning build, read through it while I was at work a few days ago ?

Your attention to detail is crazy!!! Keep up the great work.

Talking about magnets, you used to be able to get a magnet trap that fitted in between the oil filter and the housing. It came with an longer oil tube, you removed the standard one from the housing, screwed in the longer tube, fit the oil trap then the filter.

Cheers kev

[Petrol]

I'm not getting hung up about magnets. More to the point of saving the engine, I've fitted this

 

 

The valve springs are not terribly over rated to keep hp losses to a minimum. I don't know at what revs valve bounce will occur so this could save the engine from letting go. The last thing you want is a leg out of bed!

 

I wont be needing this

 

 

So I made a blanking plate

 

 

Its easier to make it out of carbon than steel so why not.

 

I need some idler gear shims and a speedo drive from Guessworks to get the speedo as accurate as I can then the gearbox will be done.

 

 

I've had a lot of help from Andrew at Retrominis on this build. The guy really know his stuff. I'm using a 12g295 modded head which will need skimming quite a bit. These are his calculations for the skim-

 

I did the dynamic calc from the closing point of the inlet;

 

LCA + 1/2 duration -180 = closing point

103 + 134 -180 = 57 deg ABDC aiming for timed straight up

 

p313 fig11-6   cylinder volume correction figure 0.83

 

257cc per pot X 0.83 = 213.7

 

p310 fig sb11.2  97 ron fuel 77deg  8.2 Dynamic comp ratio (DCR)

 

  213.7 /7.2 + 0.6 for accuracy gives chamber vol of 27.4cc

 

So to check this;

27.4 - 1.2 -2.7 = 23.5

257.5 + 23.5 shared by 23.5 = 11.96:1

 

Perfect when checked p228 fig9.43 it works out exact for a 268 duration cam

 

So the static comp will be 12:1 giving a DCR of 8.8 so we need 23.5cc in the head

 

 

 

 

 

 

 

 

I'll be running it on V-Power

 

Pete

 

 

[Petrol]

Help please. I assume this washer is for the bolt that goes through the dowel to bolt the engine to the gearbox. Where abouts does it fit?

 

 

 

 

Thanks in advance

Pete

[1330RG]

As always this build is so vlean and never fails to impress! Sorry cant help on the washer as im away from the garage and the mini atm ? criminal i know.

[alex-95]

Yep that’s for the block to gearbox. The angled part fits against the ack of the block, the bolt goes down through the dowel and the flat of the bolt fits into the flat of the washer. It’s sort of locked in by the flat and angle against the block.

[Petrol]

Thanks very much. Progress is good now.

 

Windage tray

 

 

Setting the idler gear end float

 

 

Box onto engine

 

Pete

 

 

 

 

[pete l]

What does that tray in the gearbox do ?

[Retroman]

Its whats known as a windage tray, as it reduces the windage (drag) on the engine

 

They stop the all the gears throwing oil up into the rotating crankshaft assembly

 

The oil flying round in the crankcase causes drag on the crankshaft which reduces output

 

Its one reason why some engines are 'dry sumped' its another small power gain

 

If you gain 1 1/2 hp on a 40 hp engine its 3.75%...I feel a tesco slogan coming on hhahah

 

20 years before you could buy the trays I hand made them, found one recently I made from a door skin !! its not pretty

 

Oil scrappers have similar gains, but never seen it done in a Mini.

[jamesquintin]

Never heard of these before, let alone one for a mini.

Is it worth adding one during a rebuild? I'm restoring my Cooper 'S', so it woul dbe nice to try and get to the magical 90Bhp... (was 84 at last dyno run)

Q