8 replies to this topic

[stardude]

hiya

i am unsure of what head to go for on my small bore engine project.

i was originally intending to get a 12g295 casting and have it modified to a good fast road spec.
BUT
now i am not sure wether to go down the modified 12g940 route. but that involves much more work (pocket block, block off waterway, skim block, fit smaller water pump pulley)

how much different would the worked 295 and the worked 940 be on the same engine?????

someone help me choose

i reckon they will both work out the same price to be honest.

what do you think??

cheers

adam

[Big_Adam]

12G295 seem to be semi hard to get or just out and out expensive.

12G940 (1275cc head) tend to be more plentiful in the eden like scrap yards of the internet. If you're building from the ground up, go 12g940. If you're doing a few tweaks (but all in all using a stock engine of sorts) then go 295 if you can find one.

[lrostoke]

Something Ive been considering is a 12g295, been checking out ebay for a while, and nearly always seems to be one or two on there, and recently they haven't been to pricey.
There's 3 on there now
Also worth searching for 12g202 I may be wrong but pretty much same as 12g295, from what Ive read the valve size and CC are the same.
Obviously as with anything off ebay you can never be to sure of condition

[stickycreambun]

12g202 was the 1098 head, from what I remember when I had one and a 12g295 its the same size valves as the 295 but the casting is only about as 'good' as the standard 998 head. ie. lots more shrouding of the chamber.

295 would mean less machining, if you can get a decent one.

[stardude]

it would mean less machining, but a 940 would mean more power for less money with the option of upgrading even further.

the way i am looking at it is, a 295 head would cost me around a £100, from ebay, might even turn out to be scrap unpon stripdown.

then its going to cost alot for modification.

slark and MED have quoted £600 +VAT for fast road modifications (new valves, guides, unleaded, porting, polishing etc)
and morspeed only quoted £280 to this?!?!?!?

where as, i pay £40ish to have the block pocketed and i can then buy a readily available 940 head, already modified and fit it for £200 ish

[mini7boy]

this article speaks to the issue of which head to select for small bore engines.

It is written by Graham Russell, one of the leading A-series experts in Australia.

http://www.minimania...?DisplayID=1882


there are two other articles in this three-parts series. They provide a lot of good information and flowbench/dyno results. Good stuff.

They are at:

http://www.minimania...?DisplayID=1881

http://www.minimania...on/ArticleV.cfm

Keith Calver has written an in-depth article on putting a 12G940 head on a small-bore. This article appeared in a special edition of Mini Magazine named "Mini Expert".
In it, he describes a method of using the 12G940 without pocketing the block.

Edited by mini7boy, 30 April 2009 - 05:14 PM.

[stardude]

now that is a great read!

it has realy re energised me to get this project into gear.

looks like i will be going to the 295 route then.

[MRA]

a 12G940 does NOT mean more power than a 295 on a small bore...... it's an expensive mod that a decent 295 or 202 (modded) can improve upon, with the 940 you will lose bottom end power, due to low port velocities, and at high revs you will lose power due to shrouding and buffeting of the air flow

A decent 295 will be a good all round head without the associated issues of fitting a 940 to a small block

[Nightrain]

a 12G940 does NOT mean more power than a 295 on a small bore...... it's an expensive mod that a decent 295 or 202 (modded) can improve upon, with the 940 you will lose bottom end power, due to low port velocities, and at high revs you will lose power due to shrouding and buffeting of the air flow

A decent 295 will be a good all round head without the associated issues of fitting a 940 to a small block

Someone talking sense at last, only thing I'd add. Is to make a 202 as good as the 295 would cost more than buying a 295 n the first place, unless you can do it yourself.