14 replies to this topic

[CPC]

Hi guys

Im due to collect my first classic mini this week, im not clued up on modified engines and it's fitted with the below setup

73.5mm 11cc DISH MEGA PISTONS
SW10 Duplex timing kit
Swiftune SW10 (286) Billet Camshaft
11 ARP head studs
HIF44 carb - rebuilt and reconditioned
Stage 4 cylinder head
K&N filter
Power flow oil pump
Rebuilt and reconditioned gearbox - no expense spared
Central oil pick up 
New clutch (orange diaphragm) - clutch and flywheel balanced professionally
Facet solid state fuel pump
Custom loom from RapidFit looms and Megajolt Lite Jr ECU timing

It's currently setup with 5500rpm limit via the Megajolt.. Realistically what's a safe rpm limit for the above spec and for a road spec engine.. It runs nice how it is now but would be good to get it fine tuned and see what power it is

I think I'm going to get a pro set it up, I am based on the Norfolk/Suffolk border who do you reccomend?

Hope this makes sense

Thanks
Chris

Edited by CPC, 25 August 2014 - 08:09 PM.

[Tupers]

I would contact Swiftune for advise on their cam but seen as their site says this of their SW10 cam "with the real power from 5000rpm" I'd say you rev limit is at least 1000RPM too low.

[Tahiti Joe]

Presuming the bottom end is assembled and balanced properly, and fitted with a centre main strap as a minimum then you'll be needing a rev limit of atleast 7'000rpm, nearer 8k would be ideal. High duty cycle engine though, bottom end needs too be spot on and you can't expect it to last too long between rebuilds using them kind of revs. What final drive is in the gearbox?

[Cooperman]

I don't know what a 'stage 4 head' is as that is not a defined engineering standard. However, it looks a good specification for producing great power.

With a 286 cam the maximum power is generated at 6400 rpm, so to get the very best you need to be able to use around 6700 rpm through the gears.

The only longer-term issue is that when using such a cam to the full the rate of bore wear is relatively high and a re-bore will be necessary eventually. But with a 1380 that can be expansive as the block will need sleeving.

It might be better to fit a softer cam which will enable the larger capacity engine to produce better mid-range torque unless you are totally committed to that cam.

What is needed for quick road driving is not maximum power, but high mid-range torque. The rate of bore wear is then reduced as well.

I hope this helps.

Good luck with the car.

[CPC]

Thanks for the Info so far.

This is the bottom end spec copied from the advert if it helps
Work carried out by Rob Walker Engineering on the block:
overbore cylinder block
reface cylinder block
new cam bearings
centre main strap
regrind cracnkshaft
balance 4 cylinder crank
balance rods and pistons

Any suggestions who to use to set it up?

[Cooperman]

You won't get better work than Rob Walker does.

For that cam with a standard gearbox you need a fairly low final drive ratio in order to keep it 'on the cam'. Probably no higher than a 3.44:1, or even a 3.76:1.

Personally I think it is a bit 'over-cammed' unless it is for real competition as a 286 or equivalent does need a lot of revs to work as it should and this causes high engine wear. I run a 286 in my 'S', but I use a straight-cut close-ratio gearbox and a 3.9:1 FDR and even then it needs a lot of revs in 1st to pull away. For a road engine I far prefer a 266 or the almost identical MG Metro cam.

But, at over 6000 rpm it simply flies in all gears. I do have to re-built it regularly though with new rings and re-bores at regular intervals. Not cheap, but it's for competition.

[CPC]

Thanks, so realistically a 7000rpm limit would be safe for my engine and should it see around 100bhp? or is that optimistic?

 

The gearbox is rebuilt to standard spec so this is something that i may need to look into

[Midas Mk1]

SO much ******* in this thread. I have a sw10 and its lovely on the road.

Im running a 3.2 std box with a 4pin aswell. Perfectly fine! And... quite to some **** people say, it handled traffic on l2b, and the thistle run perfect.

 

The sw10 setup is no harder than a 2.7 mpi to drive ( I went from a 266).

Edited by Midas Mk1, 02 September 2014 - 12:27 PM.

[CPC]

It does Idle fairly well with the cam and pulls ok from low revs

[KernowCooper]

SO much ******* in this thread. I have a sw10 and its lovely on the road.

Im running a 3.2 std box with a 4pin aswell. Perfectly fine! And... quite to some **** people say, it handled traffic on l2b, and the thistle run perfect.

 

The sw10 setup is no harder than a 2.7 mpi to drive ( I went from a 266).

A lot of drivability is in the setup I have seen cars with lesser cams been described as off the cam till 2500rpm and its just poor mixture due to incorrect needle selection. Whats it like pulling away on a hill start ?

[KernowCooper]

There was a discussion here about the SW-10 v the 286 http://www.theminifo...ftune-sw10-cam/

Appears the SW10 has better torque and emissions and the spec shows different timing on the exhaust

[Mrpeanut]

SO much ******* in this thread. I have a sw10 and its lovely on the road.

Im running a 3.2 std box with a 4pin aswell. Perfectly fine! And... quite to some **** people say, it handled traffic on l2b, and the thistle run perfect.
 
The sw10 setup is no harder than a 2.7 mpi to drive ( I went from a 266).

There's a lot of difference between a car being lovely on the road and an engine set up achieving its potential.

Until recently I had a mini with a similar set up to you (286 and 3.1). It was fine pottering about in but when taken out on the lanes I had to constantly drop it into second to get it to move as it was rarely on csm. It needed a much shorter FD to do it justice. More to the point, a 266, mg metro, sw5, ac Dodd rt, Minispares evo 1 or 2, or similar can, would have suited the car much better.

I agree with Cooperman, the op proposed spec appears over cammed.

[frosty90]

If this is over cammed then mine when built is most likely going to be over cammed too!! :') but its only going to be a mess around car for driving around at weekend and down santa pod :)

[phil hill]

I've got an SW10 with 1.5 ratio rockers in a 1293cc which is primarily a track-day car, but it is still very trackable and usable on the street on twin inch and a halves and mapped ignition.  I currently have a 3.7 FD and close-ratio 'box but I think in a standard ratio 'box you could use a 3.44.  You will need a 7000rpm rev limit though as mine is still pulling like mad at the 7k hard-cut rev limiter.  

 

In my opinion the SW10 is "nicer" all round than the previous 1380cc with K276MD and 1.5 ratio rockers it replaced.  The 1.5 ratio rockers "killed" the mid range torque of this build, it was better (perceptively) with the standard ratio rockers, but perhaps the compression ratio was too low for the camin this build.

 

The builder (Rob Walker did you say ??) will advise you on things like matching compression ratio to the head and cam spec, and what FD to run.  It's all about the combination of the parts and how well it's set up rather than "you want an XX FD for that, and a Stage 27 head with a 699 cam" etc.  There is an awful lot of "myth and legend" surrounding engine builds, and everyone will have an opinion on what works best, but everyone's perception is different !!

 

 

Phil.

[CPC]

Just thought I'd update this. I had a power run done today to make sure it's running healthy and have set the rpm limit to 7000rpm.

I did not get mega power 80bhp at the wheels (est 96/98 at the flywheel?) but it's making maximum torque basically from 3000 to 5500rpm and will pull away from a stop in 2nd gear cleanly if required.. But I can fully understand the reference about gear ratios as I feel my car would really benefit from shorter gears rather than more power.

I understand that 1.5 rockers may give me more top end power, but would loose some of the healthy midrange?