11 replies to this topic

[Bevan]

Hello peeps.

I have been thinking about more performance upgrades for my mini and I would like to get the block boared. I have tried doing some research on this but cant find a great deal. I understand there are 3 different boars, +20, +40, +60. (correct me if im wrong)
What CC would these give out in the end, and do I need to uprate anything else to cope with this? new cylinder head? (I take it I will be needing new pistons?)
Will I need to be taking the block out or will a place like minisport be able to do it while it is still in the car?

Also, how do you go abouts claiming the work you have done? Does the DVLA need to know that the CC has increased? Will this be a performance mod to claim on insurance or will it fall under a bigger engine catagory?

Many thanks in advance.

[Bungle]

i think engine size goes from 1275-1293-1330-1380

and just send your log book back to the DVLA with the engine capacity change and the same with the insurance

the engine needs to come out split from the gear box and completely dismantled

[alexcrosse]

lots of different bored, 1293, 1310, 1330, 1380, 1400 and more. Then strokes too, stroked 1380 1425 1430 1600 etc.

U will want to change the cam if you have the engine out n ur looking for more performance. Cylinder head you can do later, no need for strengthening with an 11 stud if ur stayin 1380 n under and aiming for 90bhp ish.

your going to be taking your entire engine to bits and rebuilding it unless u pay someone else to do it all, everything needs to be like new when re assembled which means complete strip. You will want a turbo clutch in it.

Ring up insurance and tell them what you have done. Cant say Lbft or BHP or anything because its completely dependant on spec. A 1380 can range between 80bhp and 200+ dependant on induction, cylinder head etc.

[Jammy]

Bore.

Common engine sizes.

[alexcrosse]

Bore.

Common engine sizes.

i managed to resist that one jammy, lol

[Bevan]

Some nice info on that link, thank you. So doing an overboar pretty much means a whole new engine? Also, I have heard if you do a +60 its the last life the engine will ever have? (if you damage the walls somehow)

[Jammy]

Boar:


Bore:


A rebore means new pistons and new piston rings. To acheive certain engine sizes though you may need to get a custom crank or regrind the crank.

On large bore engines +60 offset bored is about as large as you can go, and yes, generally if the bore then wears down you can't bore the engine out anymore. Traditionally people have just scrapped the block because replacements have been in plentiful supply, but large bore blocks in particular now are getting in short supply, and so I think it'll become more popular to liner a block to give it a new lease of life.

For small bore blocks its possible to bore then out +80.

[miniboo]

engine sizes: http://www.theminifo...?showtopic=8736

[Bungle]

[Sprocket]

On large bore engines +60 offset bored is about as large as you can go, and yes, generally if the bore then wears down you can't bore the engine out anymore. Traditionally people have just scrapped the block because replacements have been in plentiful supply, but large bore blocks in particular now are getting in short supply, and so I think it'll become more popular to liner a block to give it a new lease of life.

if the +60 bore is 'offset' when done, there is no reason why you cant fit 73mm or even 73.5mm pistons later

Incidently +20, +40, +60 are classed as re bore as its a standard bore sizing. 73mm, 73.5mm, and 74mm are clased as Overbore as they are non standard and 'over' the normal bore sizes.

[alexcrosse]

oui, as sprocket sayes, if you go +60 offset you can then go 1380 and 1400 afterwards. Mines bored out to 73.5mm and i could go 74mm after. i think i might actually.... *adds to mini wishlist*

[THE STIG]