11 replies to this topic

[carts60]

I'v been toying with the idea of tuning my engine for ages now, but have never had the money or time, but with my 21'st coming up soon, im banking on getting some decent moolar which could set things in motion eventually.

Currently, the car (91 cooper carb) got a totally 1275 standard engine with an HIF44 carb. I thought i had the makings of a stage 1 kit from the previous owner but, taking a look at the exhaust manifold its all rusty to im guessing the only change thats been made is a new inlet manifold.

Im totally clueless when it comes to the actual mechanics of an engine and how everythings put together and works, but im keen to learn and fancy taking the engine out and doing the mods myself - if you think il be able to given the right tools and advice.

I'm going to set the budget at £1k give or take.

Here's what iv been thinking of doing - please tell me whether they're good things to do, or whether there are better alternatives

1)Minisport Pro Flow LCB Exhaust Manifold attached to my current link pipe and 1.75" maniflow exhaust (currently off the car, but is that the best size bore for a 1275?) - £60
2)K&N or similar air filter for HIF44 - £50
3)Kent 266/ Swiftune SW10/ Piper 270 Cam (Which is best for torque and an everyday driver??) - £190
4)Mini Sport 1.5:1 Alloy Roller Tip Rockers - £170

Thats so far the best part of £500, and with the other £500 i could:
a) Get my head reconned, ported and polished to say Mini Speed Stage 4 (36x29mm Valves) for £510
b) Do other bits such as
1)Electronic Ignition Kit - £105 (Would a new distributor be needed??)
2)Kent Duplex Vernier Timing Gear & Chain Set - £140
3)Mini Speed Billet Ultralight Steel Flywheel - £120
4)Drilled & Grooved Discs with Green Stuff Pads - £100

So they're my plans and ideas. Obviously its going to go on a rolling road post fiddling to get it set up right.

If iv chosen something that could be replaced with something better, or mised out any alternative mods which could be made, just let me know.

What do you all think??

[carts60]

Anybody got any ideas??

I only ask because im going to Southern Mini Days tomorrow and was planning on buying a fair bit of the gear. I dont want to go getting stuff i shouldnt or would be better waiting to get.

[wile e coyote]

An opinion is to do it in stages - sort a full stage 1 kit - decent exhaust, filter (a replacement element rather than cone being my preference) & manifolding, cam - if on a budget the old MG metro ones - effectively a 266 cam can be picked up relatively inexpensively - for road use the 276 is probably as "hot" as you need (theres always the SW5 too), duplex chain always useful and relatively cheap (no need for super vernier jobbies) - slap a decent head on there, fit electronic ignition and get it rolling roaded... a few judicious purchases and a bit of luck could bring this in at (assuming you do all the fitting yourself) about 5 - 600. Could spend the rest improving the handling still more..... just my 2p worth...

[carts60]

With reference to the cams - are they all pretty much same and same alike? I hear people talking about 'lumpiness' and 'hotness' but i dont really follow their meanings. I understand they change the torque and bhp curves, but are they the same just called different things or is one preferential to the other in terms of general drivability?

[carts60]

Having looked at a load of reviews, i think im going to get the Swift Tune SW5-07 cam because i like low-mid range torque and rarely drive the revs over 5000 which is when the SW-10 gives its real power. I think the 266 will be ineffective at changing the engines characteristics as its too mild and i havent read anything about the Piper cam.

Is it worth doing anything else with the engines internals whilst im fitting the cam??

[Ethel]

Factory manifolds are cast iron, the after market ones are fabricated in steel tube. See if there are any welds on it (fabricated) or cast in numbers. Get a good head on it as the first priority.

Swapping a cam is really an engine strip job. That would put your car off the road for a wee while and cost a bit in gaskets etc so it would make sense to only tackle it when you're in a position to make the most of the opportunity - new oil pump, shell bearings, gearbox rebuild...

Sourcing an engine 'n box to build up at your leisure then drop in would make it more enjoyable

[carts60]

Well if its only sensible do a whole engine rebuild when the engines apart, then im going to be waiting a long time.

I only really want to modifiy the current engine because i wont have to modify the logbook and tell the DVLA about engine swaps.

It also devalues the car upon resale if it doesnt have the standard engine, as well as my insurance company saying they wont insure me for having an un-original engine.

The SW5-07 High Lift Kit (the one i was planning to get, saving money on 1.5 roller rockers, duplex timing kit etc etc) has an oil pump included, so that would be changed.

I was planning on taking then engine apart at uni and taking a month or so to fiddle and mod it before getting it back on the road and put on the rollers.

Good idea or not??

[Cooperman]

Factory manifolds are cast iron, the after market ones are fabricated in steel tube. See if there are any welds on it (fabricated) or cast in numbers. Get a good head on it as the first priority.

Swapping a cam is really an engine strip job. That would put your car off the road for a wee while and cost a bit in gaskets etc so it would make sense to only tackle it when you're in a position to make the most of the opportunity - new oil pump, shell bearings, gearbox rebuild...

Sourcing an engine 'n box to build up at your leisure then drop in would make it more enjoyable

I think you'll find the 1990 - 1 Cooper 1275 had an alloy inlet manifold as standard together with double down pipes. In fact it's quite a good set-up as standard. All that needs doing is to get a flapwheel and remove the casting 'flash' to get better inlet flow. With a 1.75" ID RC40 twin-box exhaust system it is very good without going to the expense of an LCB.
The head and cam are the key to improvement once the exhaust is sorted. The MG Metro cam or the Kent 266 (almost identical) would be my choice. A re-worked MG Metro head with 35.6 mm inlet valves and with 30.5 mm exhaust valves, gas-flowed but without spending a fortune on those expensive ones is fine for a road car.
Offset roller rockers give very little improvement except for a slight bhp improvement right at the top end, like over about 5500 rpm, (although they do reduce valve guide wear), so save your money for the cam.
If you an afford it, a re-bore to 1330 cc, that's +0.060", with Hepolite 21253 pistons and a compression ratio set to about 10.4:1.
The carb itself can be gas-flowed and as it's an HIF44 as standard you have a advantage already.
What you need to do is to buy a copy of Vizard's book 'Tuning the A-Series Engine'. Read and digest the contents, then decide what you want to do within your budget. For c.£1000 you should be able to build a really good road engine including a re-bore and a new cam plus an improved head so long as you do most of the building yourself. We are all here to help and advise if you get a bit stuck during the building phase. A lot of people spend a lot of money on things they think they need whereas what is really needed is a good head and cam plus an accurate build and assembly. That's what makes for a 'nice-to-drive' and quick Mini.

[carts60]

Cooperman - that is an excellent reply.

However, i'v just spent 80 bob on a maniflow 'stage 2' LCB at Southern Mini Days so thats going to be going on now regardless. - i was told it was essentially the best money can buy?

I'v got a 1.75" Maniflow back box sitting in the garrage so would that be decent enough to put on instead of the extra £50 for the two box system?

Would the Sw5 be better than the 266 because it has more low down torque rather than at the high end of the rev scale?
Reason i ask is because blurb about the 266 reads "Brilliant all round performance road cam. Smooth idle, pulls from around 1,200 RPM. Small gain in low end, big increase in med and top end. Unbeatable for genuine fast road use. Rev band 1,200 to 6,500/7,000 rpm"

With the biggest difference from 5k revs upwards, its not really my cup of tea because i very rarely rev the engine above 5k.

Out of interest, how much is a rebore of that kind of scale??
I would be interested in doing it because is clearly the best way to get more performance, but my old man's words about how much it cost him back in the day lead me to believe its not at all cheap and would be blowing half of my budget immediately (£500 ish) without even getting the pistons, head modded and all the other bits too.

Any suggestions for whos a good person to go to to get the carb & head worked, ported, polished and flowed??

I have to admit i already have the Vizard book but i just find its quite heavy going and i get confused by the tech and numbers - which is why i prefer asking in the forum because you can ask for everything in lehmans terms.

Thanks for all you're help and advice

[twrminisport]

No point putting any of that on without a full rolling road set up and tune. Bank on 2-3 hours to do this properly with the sort of mods your talking at most places about £55-£75 an hour so set aside £150-£200 for this. Itll be well worth the money

[Cooperman]

I build and have built a lot of engines for Minis over the last 49 years (yes, really). I've always liked Kent cams because you get what you pay for and Kent are open and helpful in terms of cam specifications. The 266 is a great road cam with strong mid-range and good driveability in both 998 and 1275 units. The 277 always seems to perform in club rally type engines and for fast road and track day units which are also used on the road and in traffic. The 286 is my personal favourite and I use it in a lot of 'quick' engines for rallying, although it can be a bit 'lumpy' for road use.
To be honest, I've never used an SW5 or SW10, although I'm sure they are good. Stick with what you know works is what I do and that is really the Kent product. Whatever other cam you get you can't get 286 top end with 266 bottom end, no matter what some may claim or what 'number' they give it.
The cost of a re-bore will vary from mahine shop to machine shop. However, for a bore and hone to the next size up, expect to pay around £100, plus the cost of having the block faced smooth, say £25. Pistons (say Hepolite 21253, 'cause they are very good) will add around £140. If the crank needs a re-grind add about £80.
There will be other amounts for bearings, thrusts, oil pump, cam followers, timing chain, cam, etc, etc. If you want me to cost it all out, PM me and I'll do a parts and machining budget for you assuming that you do the actual build.
I hope this helps.

[carts60]

No point putting any of that on without a full rolling road set up and tune. Bank on 2-3 hours to do this properly with the sort of mods your talking at most places about £55-£75 an hour so set aside £150-£200 for this. Itll be well worth the money

Yeah, iv already planned on getting it rolling roaded. First, the rest of the stage 1 kit is going to go on the car which i bought today, and il get it set up properly after that for me to drive daily, and to get me to uni in late september.

Then il take the engine out at uni as i dont really use the car at uni unless im coming home, and fit all the mods before rolling roading it again.

Thanks for all your advice Cooperman. You really know what you're talking about. I think il cost it up myself in the next few days, then wait til the birthday and see how much money i actually have to play with before i need to add funding of my own.

Im fairly sure im going to have a crack with the SW5. Purely because from what iv read it sounds like a torquey cam low to mid range with little to offer over 5.5k or so, which i rarely push the engine to anyway, and that Swiftune offer a camshaft kit including cam followers, oil pump, and alloy vernier duplex chain for £250, which saves about £50 on what i priced the individual components at if buying them separately.

But before i go ahead and gte parts for the serious part of the build, il see what its going to do to my insurance and whether the 21'st pays out well. If its reasonable on both counts im definitely going ahead with the build.

Time will tell...