9 replies to this topic

[interhacker5]

while driving along the car is totally fine but when you come to a junction or have to stop for any reason, on pressing the clutch the engine starts to stall and the revs bounce around 200 - 1100rpm and the engine will eventually stall if i don't pull out the choke (to raise the revs as can't use accelerator because of breaking) eventual as the engine warms up it does get better but the revs will still bounce around, if left to tick over it will have no problem, it is a MG1300 lightened balanced fly wheel & usually has a K&N but have replaced with standard air box to try and cure the problem as it has only started to do it as it has got cold any help is appreciated
Thanks
DAZ!!!
Just a Few Pics

[Bluemini]

By the sounds of it, your car keeps stalling because of the fly wheel. Fly wheels are the weight they came out of the factory for a reason - to keep the engine turning over. When you decrease the speed of the engine quickly with a lightened fly wheel, it loses momentum because its not heavy enough, this causing the engine to stall. When you press the clutch it puts extra force on the fly wheel causing extra drag, and helping it stall.

These type of fly wheels are ok on the road, but you have to remember that they are designed for race applications, where the engine isnt going to be dropped below 3000 rpm, so there is no chance of it stalling.

If you want a production lightened fly wheel, the best sort to go for are the early (A series) type, these are also manualy adjustable for when the cluct wears. Because they dont have all the extra bits on them that the later (A+) metro fly wheels have for adjusting themselve they are a few pounds lighter - a noticable difference if you pick the 2 up one in each hand, and once fitted you'll find the engine revs more freely and is bags of fun too!!

On a more serous note though, if you do change to this type of fly wheel and the problem continus it points towards a bit of a problem. What you'll probably find is that the thrust bearings are worn. These are the bearing shims that go between the crank and block on the centre journal and stop side to side movement of the crank. If these are left to wear too much, it will lead to a damaged crank and block which will need ditching. To check if it is this, get a long flat bar and put it in between the crank pully and timing chain cover, and see if you can get any major side to side movement in the cank. Check the Haynes manual for the stated figure of end flaot in the crank, if yours is more than stated, then I would look at getting them replaced. This is an engine out and strip down job tho I'm afraid.

But I should think it's just because your running a lightened fly wheel that you having problems.

Good luck...

[Wil_h]

I agree with some of the above. I don't think that a lightened flywheel alone would cause your problem, if you had a full race type cam with a large overlap then maybe.

However, I think worn thrust bearings is likely, especially if it only happens when you put your foot on the clutch. What happens if you just knock it out of gear when slowing down/stopping without pressing the clutch?

And finally, ever heard of heal and toe? A invaluable technique needed for mini driving.

Cheers

Wil

[interhacker5]

The cars been fine over the summer and it has only started doing it since its gotten cold, it does still stall when you take it out of gear, the fly wheel is a minisport lighten balanced pre verto, machined from a original factory item and ive had no problem with it in the past untill now, the car does have all the right thrust bearings and the right length arm and slave cylinder,

After posting the first message i found a site Ime.co.uk that sugested it was a weak mixture mad worse by the waxstat in the float bowl and too thick oil in the dashpot - that gets thicker in the cold slowing the return of the needle after release of the pedal

As for the heal toe I drive like that anyway as ive been racing minis for 4 years but it stalls too quick to catch it in time

Chears
Daz

I'll let u know how the mixture thing works out.

[Bluemini]

In that case, I recon the best thing you can do is either take the carb off and give it a service, or what I would do, take it off and stick a metro 1 3/4" HIF on there. You'll get a power gain and they are much more reliable too.

[interhacker5]

i ve serviced the carb which is already a metro 1 3/4" found nothing wrong with it but i have found that if i turn the choke off as soon as ive started the engine it doesn't do it as bad

Daz

[Bluemini]

Another thought... I have jus done this to mine today and it made a vast improvement on tickover characteristics... Have you tried changing the dashpot damper spring for a slightly softer one? If the spring is too hard, as was mine, the piston drops too fast, thus starving the engine of fuel...

[HUBBA.HUBBA]

Post revival alert!

I suspect my piston dropping too quickly and starving fuel, but i think i already had a soft spring what would be the best damper oil for this situation?

[KernowCooper]

As 10yrs have past I suspect this has been sorted or scrapped

[HUBBA.HUBBA]

As 10yrs have past I suspect this has been sorted or scrapped

I was asking a question, not giving an answer. You never know, someone out there can help me.