40 replies to this topic

[JetBLICK]

The cheaper option for the 16v head now is using a BMW motorbike k-series head. Morespeed and specialist components both do kits for them. I think the total cost of all the parts for the BMW conversion is around £2000 and it require some machine work too. Jack knight used to do one a long time ago too.

Apparently with throttle bodies the BMW 16v head will fit under a standard round nose, but not with webers. The KAD head wont fit with webers either, not sure bout throttle bodies. The arden 8 port can be made to fit under standard bonnet, if you use amal carbs, or the short weber manifold. But most people go for the longer manifold which means the carbs hang out the front.

7 ports fit nicley under the bonnet if you're after something discreet. God knows about this MED or the Elder 8 port tho, the elder aint very commen, so its hard to find info on it. And the MED one is new so you'd just have to ask them.

To be fair to MED, they know what they're doing. He probly means 10bhp more than whatever stage head you've got at the mo. But if he says 'minimum' i'm sure thats before he's fully worked the head, so there will be much more to come knowing MED. Plus if the rest of you're engine is all MED at the moment they should be very familiar with it so they will be able to get the very best out of it....

...It al just depends on what you want, but whatever way you look at it, tuning the a-series is expensive


*(unless you're handy with a dremel )

[johnnysti]

Cost really isnt the main problem. I just want the most power. I want to stay as close to the origional a series as poss. I know they didnt make 8 port or 16v ones off the production line in Oxford but what i mean is no forced induction (super charger or turbo) or honda/bike engine. Super charger is going to produce more power but means changing the compression and pistons etc and not interested in turbo anyway.

I want to really notice the difference after fitting an 8 port. Like i said, as it is now it is stunningly fast and has wiped the smile off of other drivers. Thats why i want to keep it as standard looking (bonnet wise) as poss but understand that really, the 8 port will stick out the front. Just dont want a massive silly looking bulge thing on the front on the car!!!

Also, heres what ive had done to the engine at the mo. Will it be ok for a 16v build?

The spec of the engine is as follows in all the jargon that i dont understand!!

So:

Block

Bore 73.5
C.M.S New
Face 020
O/way New
C/brgs New
Acid dip Yes
11 stud Yes

Crank

Grind Yes
Polish Yes
Ni-temp Yes
Blade yes
X/drill Yes
Wedge Yes

Rods

Bolts New
Nuts New
Lighten Yes
Polish Yes

Pistons

Type Omega
Dish 11cc

Cam

Type 285
Followers New
O/pump New

Timing

Duplex New

BRGS

Mains Comp
Ends Comp
T/W Comp

Clutch

F/wheel Steel
Plate Turbo
B/plate Steel
Balance Full
Cover Orange
Gear type Inertia
R/brg New
Bolt strap New

Head

Rally head
Valves 35.7-30.0
Guides Bronze
L/free Yes
Springs New
Port Comp
11 stud Yes
Chamber Comp

Rockers

1:5

Gearbox

Type Rod
O/put Pot
Gears s/c c/r
Drops R-BRG
Diff X-pin
BRGS New
c.p.u New
c.w.p 3.44

Shims

Primary New
Idler New
BRGS New
S/brg New




Johnny

Edited by johnnysti, 21 April 2007 - 07:43 PM.

[Sprocket]

Problem with going BMW 16v is that it entails maching the block in lots of non standard ways. It also requires, as does the KAD, valve clearance cuts in the pistons, that will require them off the rods. If your engine is built up its going to be difficult other than starting a fresh.

The BMW head flows more, unmodified, in standard form, than any offset angled big valved tunnel port, five port head that has been developed to date!!!! That means there is more room for scope modifying it.

For the results you get with the standard parts for the BMW head and mods to the block, it makes the KAD head way over priced, however, the KA head is more of a bolt on job and a nice peice of kit.

See you at Avon

Edited by Mini Sprocket, 21 April 2007 - 08:20 PM.

[Jammy]

If you want to stay as original as possible then look at the Weslake heads, as they were fitted to some of the Works cars back in the day, not sure if BMC used the Arden heads? I would definitely expect more than a 10hp increase from an 8 port head though. I once looked into sticking a Arden 8 port on the 1425 race engine I had, phoned Bill Richards up and he reckoned I'd be looking at around 180 hp and similar torque figure, this was from an engine that had about 120-130bhp with a 45 DCOE webber.

[mini93]

the KA head is more of a bolt on job and a nice peice of kit.

KA....as in ford KA??

[Sprocket]

the KA head is more of a bolt on job and a nice peice of kit.

KA....as in ford KA??

Spelling mistake ........KAD

I once looked into sticking a Arden 8 port on the 1425 race engine I had, phoned Bill Richards up and he reckoned I'd be looking at around 180 hp and similar torque figure, this was from an engine that had about 120-130bhp with a 45 DCOE webber.

In real world terms and actual figures, i doubt 180bhp is that easy to come by on an 8 valve head when KAD only achieve that on their big valve race cam head. John Kimmens achieved 168bhp on a 1380 with a standard flow BMW head with reprofiled 300 duration cams and up to 8700rpm, not exactly a road engine. The 8 port heads may be crossflow and fix the issue of siamese ports, but the valve area is still far too small for that amount of power in a normaly aspirated engine especialy on a heavy breathing 1425cc engine. This is the limmiting factor.

Now im not doubting what Bill richards might have said or that his work is anything other than top notch ( i do run one of his ex works heads) HP figures are banded around too freely these days

Oh and the weslake 8 port heads if you can find one in working order were not the best design and far from being that much better than a decent ported five porter. How ever, you are aware that old style KAD 16v head was infact the original Design of Weslake back in 1989

Edited by Mini Sprocket, 23 April 2007 - 09:27 PM.

[mini93]

aaaaah makes things clear then!! stupid ford!

[danwebster]

The KAD system still requires some specialist machining, its not a bolt on modification by any stretch of the imagination.

What you are paying for is a well developed and well thought out conversion that has been reliably producing the goods for almost 20 years, not a bastardisation of a bike head that is, as yet, unproven - ok theres one or two engines out there making good horsepower but lets see what the longevity of them is.

[Jammy]

Yea, I know what your saying MS, I would have been delighted with 180bhp, but not disappointed if it did not reach that figure. Still, I would have expected more than a 10bhp increase!

[danwebster]

I asked the question relating to the Weslake connection as I thought it seemed rather strange that a pushrod head would evolve into a dohc twin cam.....

Kad's response was as follows...

'Someone has some imagination to evolve an aluminium, direct acting, 16 valve cross flow head from an iron push rod cross flow 8 valve.

There is a Weslake connection but its more to do with persons than design since Gary Oldfield who was responsible for the KAD heads inception worked there for a number of years running the Group C Nissan engines'

Hope that clears it up.

Cheers,
Dan

[8portdave]

8 port all the way mate they are a pain to build if you havent built one before but really worth in the end