27 replies to this topic

[mini7boy]

Crikey - such a fuss! I would hope the '286' is a better cam - it's a much newer design and they would hardly go backwards. My experience is mostly with the genuine 544 - I only mentioned '286' as being the nearest modern equivalent, because genuine 544s are probably thin on the ground now - and I honestly can't believe the power difference will be at all noticeable between the 544 and the '286'.

Roy, I hate to seem like a lawyer and prolong this matter, but you are doing the OP a disservice when you assert that the 544 and 286 have the same timing and performance.

They simply don't.

In your first posting, you stated "the old BMC 544 (or some of it's many copies) is an excellent cam - with 286 timing ".
That's a lot different than your new statement that "I only mentioned '286' as being the nearest modern equivalent".

If the 286 and 544 actually had same timing, then Cooperman's posting with cam specs for both cams would not have indicated otherwise. I pointed out the differences in one of my earlier posts.

Furthermore, if you read Vizard, he states(on pages 298-299 of his 3rd edition)

"You'll notice that the cam(286) and valve train combination went on to produce significantly more power than the regular 544 profile."

He even has a graph of dyno results showing the 286 with 1.5s, the 544 with 1.5s and the 544 with 1.25 rockers.

The dyno graph only covers the 3000-7000 range, except for the 286 which it shows to 7250.

In that graph, the 286 with 1.5s compared with the 544 with 1.5s shows superior torque from 3000 and up. It shows between 5 and 15 horsepower more for the 286 between 5500-7000.

Admittedly, the 286s advantage is most sizable at the higher RPMs, but it produces lesser amounts of increased torque from 3000 and up.

I think most people could feel the difference of 10-15 horsepower, if not 5 horsepower.

In posting this, I just want the OP to know that the 286 is the significantly superior cam here. They are not at all equivalent.

Some people will fault me for going to such great lengths to ensure that the OP got the correct information,
but as the warning above says "Don't give out incorrect advice - if you don't know the answer, don't post!"

[Boothy]

Mini7boy does that mean that the 286 is the cam to go for with 1.5s and will i see a increase in power or torque?

Thanks Jack

Edited by Boothy, 04 October 2009 - 08:01 PM.

[Calver ST]

The limitation of a cams' performance will be the cylinder head spec where one is tested against the other on a decent cylinder head. If the head is not that good, you can throw any sports/rally/race profile at it and it will not rrealistically improve performance other than ceratin specific characteristics (the sportier the profile the lumpier the engine wil lrun low down andthe peakier/narrow the power band will be). Where the standard MG Mtero head is concerned there will be negiligible differemnce in performance. In fact the 544/643 with standard rockers may well out-perform the 286 with 1.5s... and at less cost.

[Nightrain]

The limitation of a cams' performance will be the cylinder head spec where one is tested against the other on a decent cylinder head. If the head is not that good, you can throw any sports/rally/race profile at it and it will not rrealistically improve performance other than ceratin specific characteristics (the sportier the profile the lumpier the engine wil lrun low down andthe peakier/narrow the power band will be). Where the standard MG Mtero head is concerned there will be negiligible differemnce in performance. In fact the 544/643 with standard rockers may well out-perform the 286 with 1.5s... and at less cost.

After previous post by you, couldn't let this go laughing my ass off

Edited by Nightrain, 05 October 2009 - 09:39 AM.

[998dave]

After previous post by you, couldn't let this go laughing my ass off

Nightrain,

I don't see the point of this post? Can we stick to useful and factual discussion, mini7boy and bmcecosse had at least been discussing, albeit it in a heated manner.

I'd hate to see another topic go down the lines of people just arguing and name calling again!

Dave

[tuktuk]

i liked the 286 in my 1330... only problem was the idle

[mini7boy]

Mini7boy does that mean that the 286 is the cam to go for with 1.5s and will i see a increase in power or torque?

Thanks Jack

Hi Boothy, I tried to submit this reply last night(my time), but the Mini Forum hosed up and disappeared before I could submit it. Luckily I sensed a forum problem and saved it off.


Boothy,

you will definitely see an increase in power and torque, but it may be at a cost that you won't like paying.

the 286 w/1.5s is a very popular setup, but I think Vizard said something to the effect of "the 286 is about the hottest cam that can be used, comfortably, on the street"

People disagree about just how hot a cam is suitable for street use. It depends, partly, on your driving style and habits. There are those who want a cam that is just slightly better
than the original cam their engine came with. Others, the Boy Racer types, have to have a cam that doesn't perform well below about 3,000. These are both extreme tastes,
but each one of us has different preferences when it comes to the drivability of an engine. You are doing the right thing by asking around to get opinions from which you can choose,
but I would suggest that you try to drive the cars of friends or acquaintances so that you can get a good feel for what you like as far as drivability is concerned.

That said, I think it's best to err on the side of having too little cam. At least then it will be driveable, if not entirely satisfying. However, if you err on the side of a cam that is too aggressive
for your tastes, you are stuck with a car that is a pain to drive and you'll be wishing for the day when you can change the cam for something better suited to you.

I have read of people running 649s on the street, but my race car, and many others, were once run with 649s. However, most people consider a 649 too aggressive for road use.
I knew a guy who worked for a well-known American Mini parts vendor and most of his driving was on freeways. He ran a 649 on the road and said that it was OK for his mostly freeway
use, but very few people would be happy with a 649 on the road.

So, you have to decide what you are comfortable with. Personally, a 286 is hotter than I would run on the road. The enjoyment of a really agressive engine that must always
be kept within its useful RPM range is often diminished in everyday stop and go traffic. Remember, though, that the 286 and many other cams were actually designed to be run
with 1.5 rockers. If you run one of such cams without the 1.5s, the cam will not operate at its best.

I suggest you have a look at the ML Motorsports forum: http://www.mlmotorsport.com/forum/

This particular forum has a lot of common sense written about cams and less of the Boy Racer nonsense. You may have to register to use this forum, but it is free of charge
like most other forums. One of the frequent contributors to the ML forum is AC Dodd who likes to build sensible engines that provide more pleasurable driving instead
of pubtalk. He has extensive experience running Mini engines on the rollers and is a legitimate expert.

I put together this thread some time back that has some good links to check out that may help you. http://www.theminifo...howtopic=133599

Edited by mini7boy, 05 October 2009 - 05:06 PM.

[Cooperman]

Sorry Boothy,
This thread is not really giving you an answer to your question which was what cam would be good for a road-going, presumably not a competition, Mini with a 1275 engine.
The sensible answer was, and despite all the above agro still is, an MG Metro or a Kent 266. With a small amount of cylinder head improvement it will be smooth to drive, will not be 'horrible and cammy' in traffic and won't need the clutch slipping to maintain the revs to pull away as it would with, say, a 286 or hotter.
You will like the response and driveability and smooth delivery of good torque followed by a reasonable level of upper-end power up to about 6000rpm.

Peter

[Boothy]

Thankyou mini7boy and cooperman you have been the most helpful i think i will go for the 286 with 1.5s.

Thanks Jack

[mini7boy]

You're welcome, Boothy,

I'm glad to help when I can.

in addition to the earlier FAQ link I gave you, I meant to give you this one also.

it points to individual threads on cam selection in those forums that may help you.

As I said, AC Dodd takes the approach of building and tuning engines for drivability, not pub points.

check it out. I think you will find it useful.

http://www.theminifo...t=#entry1560733

some of the titles of threads linked to are:

Camshaft selection made a little less difficult

Recommended road cams

Topic: List of Camshaft Id's & timing figures


Topic: Bhp & Torque

Edited by mini7boy, 05 October 2009 - 08:47 PM.

[mini7boy]

Boothy,

I just now noticed that you also asked about roller tipped rockers.

For road use they are a complete waste of money because they do nothing to raise power(unless they are 1.5 and you have std. ratio rockers) because they only reduce valve guide wear.

If you decide you MUST have 1.5 rockers, Mini Spares makes a nice set of forged 1.5 rockers, without roller tips, at a pretty reasonable price compared with roller tipped rockers.

The Mini Spares units are: http://www.minispare....BLY 1.5 HI LI...

for comparison, these are probably near the cheapest 1.5 roller tipped rockers from MSC: http://www.minispare....BLY 1.5 ROLLE...

As an aside, you have to be careful buying roller rockers because there are a lot of crappy ones out there.
Some of them have problems with the rollers failing in use.

Titan probably makes the best roller rockers, but they are expensive compared with most others.

Edited by mini7boy, 06 October 2009 - 01:48 AM.

[Calver ST]

I'd just like to apologise for the attrocious spelling in my posting... way too much of a hurry to spell check it having dipped in to this topic whilst downing a cup of coffee... I will try harder in future. And, for pities sake, quit the aggressive chat guys. Oh - and can't the moderators do an IP address check or some such to finally underline that I am NOT Mini7boy?

As for the 286/1.5 rockers in an otherwsie standard engine - it's gonna be a nasty, lumpy thing low down with no real benefit at the top end. The standard MG cam is quite good but the valve clearances need setting at 0.014" inet and 0.017" exhaust to smooth it out at idle and give better mid-range. As has been mentioned - a Piper 270 or Kent 266 wiuld be a better choice.

Edited by Calver ST, 06 October 2009 - 06:54 AM.

[CharlieBrown]

This topic has been close until people can post in it without bickering.