13 replies to this topic

[Aridgerunner]

At this point the block, crankshaft, con rods and pistons are at the machine shop. The engine is an MG Metro. It is being bored +.060" and will be getting Mini Spares Evolution light weight pistons with the offset shallow dish. The camshaft is Mini Spares Evolution 002. The rockers are roller rockers with 1.5 ratio. We will be running an SU HIF44 with a long center branch header. Final drive ratio will 3.2 with Mini Spares cross pin diff.

The reason I ask is that I was reading here yesterday about some other subject and in that thread the discussion turned to camshafts. And in that thread someone said that Mini Spares Evolution 002 cam "is a bit much for the street".

Our goal with this car was to have one that would give excellent performance on our back country roads, do well in autocross and and still be driveable while doing in town work as a grocery getter.

So, did we make a mistake with that Evolution 002 cam?

Once again, thanks in advance.

[nicklouse]

I would lose the 1.5 rockers  and the 001 cam would be a torquey drivable set up.

[whistler]

Standard rockers and the evo001 cam. My wife's 1330 makes almost 90 bhp and 90 ft/lbs torque with that combo. Standard MG Metro head. Use the Minispares matching distributor as well unless you can have yours curved locally.

[Aridgerunner]

I can't give up the Evolution 002 cam as I already bought it. Unless Mini Spares will take back. And then I'll be paying shipping to do that. I could put the 1.5 rockers in a box. We ran the car for years with those on the stock Metro engine and it worked fine. So I can go back to the standards if necessary because I still have those.

With all of that said I'm still hoping someone can tell me what this engine will be like as we have planned to build it.

[DeadSquare]

Sexually, that Final Drive ratio is like Granny's bathing costume compared to a Bikini 

 

Before WW2, it was not easy to make a powerful, small engined, sporty, shopping car.  Then, in 1960 they made the Mini.

 

Your engine could give 120 BHP, with a supercharger, and be great fun, if you own a Gas Station.

[Aridgerunner]

Sounds like you're thinking this car, even with the additional power, will accelerate like granny pushing her walker up hill. I sure hope not.

Edited by Aridgerunner, 12 May 2025 - 02:24 PM.

[alpder]

Seems like you're spending plenty on this engine so fitting a cam you might not be happy with because you've already handed over £100 for it doesn't feel worth it. Personally I'd put aside the pain of having spent that money, work out from scratch what cam I really wanted, and it if turned out not to be the EVO002 then I'd send it back (or sell it on) and write off the difference to experience.

 

I found that choosing a cam was a tough question: sooo many opinions and so little solid data out there. Peak power seems to be what sells cams... but in what circumstances is that a useful measure? It's only a number that you hit momentarily for a fraction of the time that you're accelerating. When I had to choose, I erred toward something with good idle characteristics and a wide flat torque profile, because I knew that would be drive-able.

Edited by alpder, 12 May 2025 - 03:21 PM.

[IronmanG]

I agree with the above having overcammed my car. Get the evo 001 and 1.3 rockers. If you really feel like you want a bit more on top end once its running stick the 1.5s on.

[Cooperman]

The bigger issue is the choice of final drive ratio.
The 002 cam has a relatively narrow power/torque band and getting it/keeping it ‘on the cam’ will be the main factor. Your overall performance will be reduced because of this.
Solution is either a 001 cam or a 3.44:1 fdr.

[Gaz66]

Sexually, that Final Drive ratio is like Granny's bathing costume compared to a Bikini

I like that one. 👍😁

[absx2]

The bigger issue is the choice of final drive ratio.
The 002 cam has a relatively narrow power/torque band and getting it/keeping it ‘on the cam’ will be the main factor. Your overall performance will be reduced because of this.
Solution is either a 001 cam or a 3.44:1 fdr.

 

Or both the 001 can and the 3.44:1  :)

[imack]

Sounds like an evo 02 is similar to a Kent 286.
I used to run a 286 with 1.5 rockers on a 1380 with a Longman GT15 cylinder head as a daily driver. I found it OK, but it won't have been everyone's cup of tea.
It really comes down to the traffic conditions and terrain you'll be driving it in.
From experience, I don't think it will cope well with a 3.2:1 final drive.
3.44:1 is as tall as I'd go with that cam.
It will also need a close ratio gear set ot it will fall off the cam every time you change gear. I had 3.44:1 fd and the 1275gt/Cooper S gear set, it really wanted closer ratios than those.
My 286 engine would pull from about 1800 rpm in top gear but not really start to get going until around 3000rpm, got stronger at 5000rpm and would hang on to well beyond 8000.
Driveability wise, it depends what you're prepared to put up with to have some fun.
Downsides - likely to be high maintenance. Regular engine refreshes, cam lobes wear out, especially with high lift rockers.

[Aridgerunner]

Imack your post is what I was looking for. While you didn't actually use an Evolution002 what you used was close in spec. However, Mini Spares does say this cam produces more power than a 286 under 5000 RPM. That might be a significant difference. When I questioned Mini Spares about the power band they said it was 1500to 6000. Which is certainly different than what you experienced.

I am rebuilding this Mini for my step son. Back when he was driving it one of his complaints was that first gear was practically useless. He wanted the 3.2 final drive to give it a little bit longer legs in first and to keep the revs down some when cruising at highway speeds. But now days this car will very rarely see interstate roads.

The intended use for this car will be occasional weekend use on nice days on country roads. The roads around here are very hilly with plenty of curves so they are great for some spirited driving. Expected annual use will probably be 1000 miles give or take some. So I doubt a rebuild will be needed for many years.

So, I guess we will proceed as planned and if the power peak is too high we can go back to the stock rockers.

With the amount of work left to be done to finish this car.I don't expect to have back on the road before next spring.

Thanks again to everyone.

Edited by Aridgerunner, 13 May 2025 - 12:09 AM.

[Ethel]

High lift rockers can be the poor man's 16 valver: they get the valves off their seats quicker to improve breathing where it's poorest. The potential downside is that'll also increase the effect of valve overlap. They also "magnify" the spring pressure on the cam lobes, so proportionally lower rated springs will do the same job instead of eating power & cam lobes. E.g. 160lb springs would hold the follower on the lobe like 200lb springs, when you make allowance for the weight reduction over sintered rockers as well.