120 replies to this topic

[MRA]

Before you go to all that trouble.... except if its leaking it really needs doing of course disconnect the the slave cylinder from the arm, now gently by hand pull it out wards as if you are trying to dis-engage the clutch, but without putting any force on it. Now grab the plunger by the 2 15/16" AF nuts and rotate it whilst observing the arm, does it move in and out ?

If so I would also say that sometimes you may also get a little crunching whilst changing from gear to gear ?

If so changing the arm and the plunger will sort out all the problems............ except the oil leak of course.

yeah i get crunching gear to gear but its completly normal its a dogbox

also i have no slave cylinder as the SH kit is full mechanicle and has already been set up correctly

Unless you have some fancy new thing I haven't yet seen you will still have a plunger and an arm ?

you wouldn't notice the crunching with a dog box, and it is not about setting it is about wear or more to the point worn out parts.....

and not all dog boxes crunch during gear changes, some snick in like silk

[1293sleeper]

i have a 3.44 diff in my 1293 and im running megajolt as its just a toy, oh well i will just have to wait to finish the engine and see how i cope

[mini93]

The plunger and arm were out not long ago in anycase and always check for wear when i remove a part.

as i said though, the clutch was fine before i swapped the transfer housing over and seeing as the only thing that could possibly be problem was the fact i didnt change the seal as i didnt have one to hand i used the old one and there for lies the oppertunity for uncorrect fittment and infact likely because i was rushing

[Cooperman]

You'll love it once it's 'on the cam' on a twisty B-road. To pull away may mean a bit of clutch slipping, especially if you have a SC CR box, but it will drive fine once set-up nicely. The 286 will pull from about 3000 rpm, and strongly from 4000 up to about 6800, with peak power at 6400.
Once set up your ignition will be fine too as you can set the static advance to enable easy starting. but with high advance at the top end.

[MRA]

One side effect of a tall gear and worse with a lairy cam is the amount of clutch dust you get with an organic plate it will require frequent cleaning sessions with some jizer or similar.

I have been running ECU's on my Mini's since the early 90's a good session on the rolling road and you get an engine that is much smoother than on a distributor, I can't speak for the electronic dizzies available as I have never used one, but an ECU is much better than a normal distributor, and the correct calibration will allow you to reap the benefits to the full.

Edited by mra-minis.co.uk, 08 November 2010 - 10:34 PM.

[Cooperman]

I helped a guy who had a 544 cam (a bit like a 286) with a SC CR box and a 3.44 diff in his rally car. It needed a clutch change after one event and I couldn't believe the amount of clutch dust in the casing. He found it so hard to pull away from rest that he asked me to take he engine out and change the diff to a 3.99, the same as I always run. No top speed, but it sure moved off the line. At 7000 rpm it's pulling about 100 mph, but it sounds like about 150!
I did some timed tests in my 'S' and 0 - 60 came up in 8.5 secs when changing at 6200 and using 1st, 2nd and 3rd, and in 7.4 secs when using 1st and 2nd only and pulling about 6800 in 2nd. Not bad for a 46 year old car.

[Flat6]

Interesting information, Flat6, however I have seen the difference between an AE piston made in the UK and the new NURAL pistons which apparently are no longer made in the UK but in Germany, I have seen a degredation in the gudgeon pin, and some of the machined surfaces are definately different, they obviously have been manufactured with different tooling, possibly different machinery even. But I will agree that the castings look like they came from the same moulding tools.

This only supports what I have been told about the location of manufacture, being in Germany now, however I agree it doesn't prove it. just supports it. but my supplier gets them direct from Federal Mogul who import them from Germany, are you also saying that these pistons are made in the UK and then shipped to Germany ?

Federal Mogul, are the holding company for Nural, AE, Payen, and a host of others.

These AE pistons haven't been manufactured in the UK for almost 20 years so don't confuse the brand change to Nural with a change of manufacturer. In many cases you'll still find AE product in the Nural box (think Marathon to Snickers), but as the AE marked stock is exhausted it will be replaced with Nural marked versions.

I'd be very interested to know why you say "the new 20659's are nowhere near the quality of the old version". Can you substantiate this in any way? Is it down to the appearance of the piston, do they measure out of spec, are they unreliable, have you had warranty claims on them? Similarly for your comments on degredation of the gudgeon pin. I'm not trying to be awkward, but would genuinely like to know the detail. Thanks.

[samsfern]

Cooperman your mini looks great i especially like the rally look. I don't really mind if the car doesn't produce much power below 3000 rpm as i usually rev my mini engine quite a bit as it needs it to keep up with modern traffic.



Actually with a 296 it won't produce much useable power below about 4000+ rpm (look up the cam profiles and graphs on the Kent Cams website).
You are certyainly going to have to drop the diff ratio, so your top speed and cruising speed will be lower than, say, a 1380 with a 266 or 276 diff because of the need for lower gearing. So, you will probably need to be cruising at around 5500 rpm which, on say a 3.76 diff will be around 85 mph. To keep up with modern traffic, if that traffic is going relatively quickly, you will need to use 3rd gear a lot and 6500 to 7000 rpm to get it onto the cam. It will give of its best, assuming a really good head, at between 5500 rpm and 7200 rpm. At below 5000 rpm the acceleration will not be very good, but that's why you have a high overlap cam to give real serious top-end power for the track. With my 'S' I cruise at around 4200 rpm if I use it on the road in order to keep engine wear as low as possible and that is a cruise speed of about 60 mph in top.

i normally cruise at about 65 mph, which is 4k, im quite happy sitting at that speed, itll still accelerate well from that speed/rpm.. I did go down the country lane bits to work this morning, and i wasnt going slow, most of the time the revs were over 5k. I dont think mines too bad in traffic, but then again ive never really driven a standard mini. I dont have to rev the nuts off it everywhere, just doesnt have a great deal of power off the cam, but i can drive it sensibly if i want. I really dont understand why people say a car with a high lift/duration cam will not be useable in modern traffic, its just a bit different to normal and youll soon get used to it.

Edited by samsfern, 09 November 2010 - 12:48 PM.

[1977 Loud_Mini]

I think since most on here are using the 3.76 and 3.9 diff ratios then i will possibly go for the 3.76 as 4000rpm seems quite respectable at 60mph. Does anyone know roughly what 0-60 times would be with the 3.76, anything like coopermans times? The 286 cam pulls from lower rpm's so that would have an advantage over the 296SP.
Cooperman, How hard was it for the person running a 3.44 diff in his rally car to pull away then? Did it need massive clutch slip to get moving?

[Cooperman]

It was a while ago, but I did get to road-test the car before we lowered the diff ratio and, from memory, 1st gear seemed to go on forever. It did need quite a bit of 'slipping' to get off the line and as it was required to accelerate it had to be held at over 4000 rpm whilst the clutch was engaged, so you could smell the clutch burning. That was with a comp diaphragm and a higher-performance organic plate. With the 3.9 it was the same as mine is now and that's more-or-less OK except in traffic or when starting off up hill. With my b286 it won't run cleanly below just over 3000 when hot and even then it won't take any sort of high throttle opening without what I call 'lumping' along with fuel being thrown back through the carbs due to the high-overlap on the 286. This is when the intake mixture velocity is too slow to achieve the necessary inertial ramming. I had a 649 on a 1071 'S' and that would not really run below about 3800. That cam was changed for a 286 after a couple of rallies as it was too easy to come 'off the cam' and lose time on stages.
The problem is that we are dealing with a 51 year old basic design annd you can't have something for nothing in performance terms. For racing, it's peak power that is important, so cams like the 298 and above have been developed for that application. For rallying, where some road mileage is involved, a slightly softer cam is needed like the 286. Sometimes, when competing I fell that maybe I would be better off with a 276, especially when I come into a tightening corner a bit too quick and it falls off just when I need a big dose of torque. For a road engine, and I'm speaking personally, I would never go more than a 266 as that is such a lovely all-round cam. Otherws may well be prepared for the downside of a really hot cam on the road, but I find it wearing and tiresome, especially on a journey of any distance. It's just so noisy and wearing on the engine to have to use so many revs to just keepup with modern traffic. A 266 will enable easy running with moderns, especially with an over-bored engine where higher torque is the big benefit rather thn top-end power.

[1977 Loud_Mini]

Thanks for the help, i wouldn't want to be slipping the clutch at 4000rpm often otherwise clutches would need to be changed very frequently, so will have to opt for the 3.76 diff as this ratio will suit me better as it will have the acceleration i want and still keep a bit of the top end speed cruising.
Basically i would ideally like to keep up with my brothers 1.4 metro GTI 16v and a video of a mini on youtube with the 296SP cam and 3.76 diff has enough acceleration to slightly beat it so seems good to me.

[samsfern]

mine will keep up with a friends saxo vts, wiped the grin off his face.

Edited by samsfern, 09 November 2010 - 08:06 PM.

[1977 Loud_Mini]

i found out mine will keep up with a saxo vts, the other night, wiped the grin off their faces, lol

Seriously! thats what i wanted to hear, my mate has a vtr and may possibly get a vts so its nice to be able to keep up for once

[samsfern]

that is using ridiculous revs and with no sympathy for the engine, lol,

mine is however using a lot more fuel than it use to, which is another thing you need to think about.

Edited by samsfern, 09 November 2010 - 08:13 PM.

[1977 Loud_Mini]

that is using ridiculous revs and with no sympathy for the engine, lol,

mine is however using a lot more fuel than it use to, which is another thing you need to think about.

I can imagine at those revs that more fuel is being used. So i take it yours is basically run in now then. Have you tried a 0-60 time and what speed did you keep up with the vts to?