22 replies to this topic

[cap'n crunch]

As far as i can tell these cams SW5-07, Kent 246 and the morspeed ph2 have very similar profiles according to http://www.theminifo...showtopic=36988

however which would you recommend?

Engine Specs

998cc or 1098cc
12g295 head
twin HS2 carbs
Stage 1 (cooper freeflow and RC40)

Ideally looking for the maximum torque

Or are there other cams that would be more suitable?

[Retro_10s]

i can't offer any real technical help with figures and charts mate, But I've driven a 1098 with an SW5 in and it was an absolute blinder. Both Mr Vizard and Kieth Calver hve praised the SW5 on the 1098 as a 'life changing' cam for the small bore variants.

With a bit of headwork I imagine it'll be a stonker.

Edited by Retro_10s, 25 March 2007 - 01:27 PM.

[Big_Adam]

The 997 cam is meant to be a little belter.

[cap'n crunch]

have you got an details/specs for the 997cc cam?

I was looking at the swiftune website and they sell a kit with 1.5 rockers, now i know there has been a big debate about what rockers should be used and how they should be matched with cam and the same goes for the springs, but do you think the 1.5 rockers would be suitable with the SW5 in a small bore engine bearing mind i am looking for torque? or should i go for 1.3 rockers?

[Big_Adam]

Nooo! 1.5.1 rockers are too much on a wee 998 engine. Too much overlap time.

[dougie_10 :D]

yer i believe that in the vizard book " how to modify your mini" it says that for a small bore engine it is best to use 1.3 rockers. 1.5 as said above gives to much overlap time

[cap'n crunch]

Nooo! 1.5.1 rockers are too much on a wee 998 engine. Too much overlap time.

overlap? i just thought it just gave higher lift so more in/out, and so therefore rockers do not effect the duration (or have i just gone off at a completely different tangent )

so 1.3 rockers are the way foward for my application then?

Edited by cap'n crunch, 25 March 2007 - 06:28 PM.

[Big_Adam]

During the overlap (when the two vlaves are open) the high ratio rockers hold the valves open too far giving too great a valve curtain area (the area between the seat and the valve) meaning a drop in hp. From vizard a 1000cc engine with 1.5 rockers can loose as much as 7hp. With a wider cam lobe you can but then you need to pic exactly the right cam or get a custom one made.

Go 1.3 rockers. BUT most stock ones are around 1.3 ratio. Well from 1.2-1.3 ratio. Thats just regular sintered steel rockers.

[stef]

i heard that with an sw5 you should stick to standard rockers?

[Retro_10s]

As adam said, if you're going to use rockers on a small bore, 1.3's are the way to go... but the steel rockers are around that anyway... so i'd say the benefit is negligable...

And yes the 997cooper cam is a belter, it's a948 if I remember correctly? available new still.

For soemthing a bit differnet....You could always use a Britsih leyland special tuning dept cam.. the good old 713, nice and pokey

Edited by Retro_10s, 25 March 2007 - 09:42 PM.

[fikus01]

i can highly recomend the kent 256 cam, just make sure u time it properly and set ur tappets to their tolerances! aint quiet but is powerfull. 246 looked a bit weedy for me, i get a lovely smooth tickover only 1100cc and with my nice big valve head and single 1.5"su carb she made 54bhp at wheels, ok its only a number and on another dyno it would make a differetn bhp number but who cares, i can race spi coopers

[cap'n crunch]

she made 54bhp at wheels

if thats 54bhp at wheels, what is that at the flywheel?


Anyway i think i will go for the SW5 with some 1.3 rockers

However is it worth paying the extra money for full roller rockers like these http://www.minispare....aspx?pid=34682

or

finding some 1.3 steel rockers (if they are available)? i know there are benefits to rollers such as reduced side loading on the valve stem and less friction however is this worth the extra £100 - £200

Also (sorry for all the questions ) what sort of springs should i get? i was looking at these as i do have a 998cooper head http://www.minisport...er-product.html

[Big_Adam]

cap,

Regular rockers are around the 1.3 mark. If push comes to shove then you can always get some off set bushes.

oh, hows the wheel packing going by the way?

[cap'n crunch]

oh, hows the wheel packing going by the way?

tis goin good i'm just waiting for the cheque to clear hopefully the courier will collect it wednesday and it may be at you door by friday if not monday

most stock ones are around 1.3 ratio. Well from 1.2-1.3 ratio

i would like to make sure they are 1.3 ratio, so i was wonderin if you can buy 1.3 steel rockers (theses perhaps but it does not say the ratio http://www.minisport...-s-product.html ) and whether is it worth payin extra to get the rollers?

Edited by cap'n crunch, 26 March 2007 - 04:10 PM.

[fikus01]

no the 54 bhp@ wheels really was 54bhp@wheels, as in just shy of 80bhp@crank, not corrected to the wheels, the dyno is older than that, not computer operated, even if its out of calibration the cars performance stil speaks for its self, as quick as an spi cooper.

the difference my head made was off the chart in my books, even the guy doing the dyno had to ask if it really was a 1098. as far as the head goes its a 12g295 head, runs 11:1 compression and has a 1.4" inlet valve(mg metro), a cooper exhasust valve and the ports are opened up as far as they go, bronze guides tapered off and the pushrod tubes round the inlets are sleved. and i have to run it on tesco 99 octane(or similar) or she starts pinking a little under load!

next time i do something to it i'll take pictures, because it really needs to be seen. only thing letting it down really is the rockers, couldnt afford anything snazzy at the time so she only has pressed steel cooper items!