12 replies to this topic

[hughzy69]

Hi guys just after a nosey into people's 1330 set ups, with the power they have if possible.

My 1330 build is almost complete and this is the set up:
1:5:1 roller rockers
Stage 3 slarke race head, 35.7 inlet and 31mm exhaust.
AE pistons all balanced to reground crank.
S/C drop gears
3.1 diff
Hif 44 carb or the Yamaha R6 bike carbs I modified.
Turbo clutch.

[RonH]

Hi Hughzy69,
can't help on the spec but would be very interested in how yours performs when it's done:
I have most of the bits to do a 1330 with kent 266 cam, 1.5:1 rockers, twin dellorto 40s, stage 3 head (35/31s) LCB wtit single box 2" pipe.
Not got as far as a comperssion ratio yet as it's all bits int he garage at the moment, but it's nice to dream.

Good luck with yours

[scotty_18]

I'm going for a similar set up..
But I'm going for a Kent 286 cam and I'm debating on the straight cut drops.
In hoping for 100 horses but well see :)

[Cooperman]

I went out in my 1310 'S' today. Put my ear plugs in as I have SC drops which I wish I had never fitted - they just sound horrible. I have about 115 bhp and need the SC drops for rallying, but still wish I had stayed with helical drops.
286 cam is what I have, but you need a low final drive as the power is high up the rev range. A 286 needs to rev to 6700 rpm to get best results power-wise.

[jamiestevenbell]

What cam you running? If its a 286 you should be close to 100bhp mark

[Jordie]

one of my first builds was a 1330cc with 286 cam. went like the stink.

only took it out to go turbo

[hughzy69]

Yeah I went for the crane vp3c cam with the 1:5:1 rollers, so should be around a 286. Just itching to see what Bhp it will have!

[scotty_18]

What final drive would be best cooperman?

[tom1234177]

I've got a very similar spec, 276 cam but with a 3.4 fd, mines still running in so no rollers just yet but will be getting it done soon, as I want the advance curve setting for my new electronic dizzy

Edited by tom1234177, 20 June 2012 - 09:45 AM.

[hughzy69]

I have the standard 3.1 dif

[Cooperman]

Regarding cams and diffs there are a few things to remember. With a 'hotter' cam one might assume that it is being fitted in order that the increased power is going to be used. Thus with, fir example, a 286 the best power will be between about 5400 and 6700 rpm with peak at 6400 rpm. It is necessary to build an engine that can sustain those revs without blowing up.
To keep an engine at those revs so that when you change up at 6700-ish the engine is still right 'on-the-cam' and a close ratio gearbox is usually necessary to achieve this. But, a close ratio gear set has a very high 1st gear which in turn means a lower final drive ratio is needed to pull away without having to mega clutch slipping.
A 3.44 diff is about as high as you can realistically go with a SC CR box and a 286 cam which can be very 'lumpy' below about 2800 when the engine is warm.
A 3.44 will give around 16.5 mph/1000 rpm in top gear so 70 mph is about 4200 rpm.
It's all a trade off of max power against driveability and flexibility which is why so many go for the Kent 266/MG Metro cam option (they are very similar) as that cam will pull a standard gearbox with a 3.1 final drive and still give good power up to around 90 bhp plus a sensible cruise at meduim revs.
To take as an example my 1310 cc Cooper 'S'. It has a 286, 1.5:1 rockers, 11.2:1 C.R., twin H4 carbs, etc, etc. Everything is balanced and lightened and it has around 115 bhp. But I have to run a 3.9:1 final drive which means that at 70 mph in top I'm pulling 5000 rpm. However, 0 - 60 has been measured at 7.3 seconds on dry tarmac.
For a road 1275 I would always recommend a 266 cam with about 10.5:1 CR, 35.6 mm inlet & 30.5 mm exhausts, custom distributor, decent carburation (I like twin HS4 or equivalent, but others prefer a big single carb) and a very careful and thorough build. That way you get a really smooth engine which will run well right through the rev range and will npull strongly from around 3000 rpm, pull away from 2000 rpm and rev to just over 6000 rpm. Gear ratios can be standard and diff can be 3.1 or 3.2. Also the engine will last much longer between rebuilds. With an engine using, say, a 286 and running regularly at up to 6700 rpm with cruising at 5000 rpm+ there will be a need to rebuild quite often, maybe every 10,000 miles.
I hope that explains the issues.
A

[Guess-Works.com]

My old 1330, which was retired almost 4 years ago not long after the attached sequence, due to diminishing compression which was already apparent before.

17.2 second quarter mile, last recorded 83(ish)bhp at the wheels about 6:20 in

A series, standard crank, rods and 21253 pistons, cooper S head,
296 scatter cam
Ultralight flywheel
GT helical box and drops with X-pin and 3.4 final drive...
HIF44 12oz spring BBC needle

but would still do mid to late 30's mpg on a long run, and less than 10 if you put your foot down....

[1275GTS]

My 1330 which was built by Southam Mini & Metro centre consists of the following.
Fully lightened and balanced bottom end including lightened flywheel which uprated grey clutch, twin HS6 carbs, piper 285 cam, 1.5 rockers, 11 stud cooper s head with unleaded conversion bigger valves and some port work. The gearbox is a 1275GT close ratio box and 1275 GT final drive with centre pick up. The engine was fully set up by Southam on their rolling road and it achieved 85 bhp at the wheels. It is a great engine and pulls from 1200rpm no problem in 4th but really starts to go over 2500rpm up 6000rpm. Its not to bad in traffic but the clutch can become a bit tiresome. Also I fitted an uprated radiator to help with cooling, its runs a standard plastic fan with a kenlowe electric fan if it gets too hot. The temp rarley rises above half way except when stuck in really heavy traffic. I also replaced all my coolant hoses just for safe measure.
Too sum my engine up, it provides good performance for a mini without being a pig to drive.