Standard head to turbo
Turbo Mini Forums

How hard/easy would it be to convert a standard 1275 head to a turbo one? Ive got a decent 1275 head with unleaded seats and it seems a shame to waste it (plus i dont want to pay silly money lol)

With the valve stems being wider is this a straightforward job to do? Whats involved? Is it litterally just a case of getting a machine shop to widen them? Then fit stainless or sodium valves?

Sorry if this sounds basic, just first turbo-charged project!

Edited by webba on 2nd Mar, 2007.

Just use as is with correct chamber sizes for your application and valve sizes to suit what you like.

Dont worry about the valve stems etc.

Us it as it is. Possibly fit some new exhaust valves. The sodium ones are overkill!

cheers for the info people. like i said its actually a good head lol. think ill fit the stainless exhaust valves

Make sure that you measure the chamber volumes so you can calculate the compression ratio you want.

Most NA heads will have been skimmed at some point and if it's a performance head this could have had quite a bit of it!!!

Every day is a school day ...........

How fast and how expensive ...... the same question...

Its a standard head, dont think its been skimmed im still toying between a 1293 or 1380 turbo so ill obviously workout the chamber volume accordingly. Im guessing a 1380 would be more of a pain?

could be yes, but depends on piston dish...

Oh yes!

A good head performs the goods...

lol good head is always a good thing.

noticed the Hypatec pistons seem far cheaper than most for 73.5mm. With 8-9cc dish. Anyone know good bad info bout em?

Edited by webba on 2nd Mar, 2007.

8-9cc wouldnt really be a lot on a 1380 turbo...

very true actually. what about on a 1293 cc?, providing there the correct pistons of course, not 73.5 lol

Edited by webba on 2nd Mar, 2007.

Ish, i prefer more in the piston than take a lot out of the head for reliabiltiy capacity for head skims etc etc.

Having run a 1380 turbo for 10 years I have some limited experience about the subject. Getting the CR down is going to be more difficult than with 1275 or 1293 engines. Especially with higher than std boost settings. And don´t fool yourself, EVERYONE will end up thinking about more boost. Sooner or later...

Cost is another issue, 1380 is more expensive to build. I haven´t checked lately but 11 cc used to be max dish size available. This means that you need BIG chambers in the head. I have cut mine 35 cc big and it needs quite a lot of sculpting.

I had the engine in bits to check things and only issues were cam and exhaust seats (again). Block and pistons were in great shape and I put them back together. Helical box was in pristine condition and will only need a quick wash, not even a disassembly. So, done carefully a 1380 will be very reliable but like I said it will cost more and require more engineering than a "normal" size engine.

Avonbar supply forged 18cc dished pistons in 73.5mm but quite expensive.
https://www.speedgenie.co.uk/avonbar/mainFrameset.html

-MINI CLUBMAN 1380 TURBO-

Has anybody looked at what dish it is possible to machine into a Mega piston??

Every day is a school day ...........

How fast and how expensive ...... the same question...

Thanks for all the info, after having a careful think, im gonna go with a 1293cc setup. Basically to keep costs down and compression issues to a minimum. Plus if i blow the engine up in the future i can still rebore the thing!

if you have the funds go for avonbar accralite forged pistons 73.5mm 18cc dish and get 28cc in the head

this will give you a cr of 8.27:1
just right

Been looking at them actually, nice but bit too pricey. Think ill stick to +20

very clever choice. As you say you can use the block several more times if it needs to be bored.