7 replies to this topic

[Nietro]

Hi again everyone,

 

Apologies in advance for the following essay but it kind of needs to be a long winded explanation. I'm still not happy with how my 1999 Japanese Domestic Market (JDM) Mini 40 Cooper is running. Please note the JDM part of the description is very important later on.

 

After a bit of a victory with fixing my O2 sensor cct in my ECU my bad running has returned with perfect idle, hesitation on acceleration with occasional backfiring thru the injection unit and a real lack of power.  After talking to a local mechanic who used to work on classic minis (now refuses to work on them) he suggested bad spark timing or possibly my timing chain had skipped a tooth, as the spark timing is ECU/Sensor controlled and I have confirmed it all works I decided to have a look at the cam timing and can now confirm that it is set up dot to dot with next to no stretch on the simplex chain and very little wear on the tensioner.  It makes me think that it must of been relatively newish when I bought the car 4 or so years ago.  

 

While there and I was easily able to turn over the motor in a controlled manner I took out the crank sensor so I could watch the reluctor ring and see what its doing.  Now as the mini has a SPI injection system I was expecting there to be two gaps in the splines 180 degrees apart at TDC and BDC. I actually have an MPI reluctor ring that has a gap then the next two are there then another gap and then on the other side of the flywheel theres a gap, next three are there and then another gap. So I started thinking that I have an incorrect flywheel but couldn't work out why the engine even ran at all.  

 

Then I read somewhere that the JDM mini of that era was a MPI motor fitted with an SPI injection system and uses a different ECU to UK models and that would kind explain why it different to what I was expecting but still works.  

 

A bit more research/reading I came across a picture that Sprocket had produced many years ago that showed a MPI flywheel with TDC shown and then the gaps at 30,60,210 and 250 degrees. Now the problem is that my gaps are at 60,90,240 and 280 degrees making me think that the wrong clutch as been fitted and has retarded the reluctor ring by about 30 degrees.  I remembered that I could advance the spark timng under adaptive values when using MemsFCR (limited to 9 degrees unfortunately) and when I did this it became a different car and drove as well as it ever has since I have had it. The ECU was doing its thing with about 14 degrees advance and I had pit another 9 on in the back ground and so I believe it sort of confirmed I'm correct about the clutch being the incorrect one and I'm leaving a lot of performance off the table as the car is still quite retarded with its spark timing.  If I remove that 9 degrees of advanvce I put in the vcar runs rubbish again. 

 

I think I have an AP pressure plate instead of a Valeo pressure plate which when I look at a side by side comparison picture looks like it would retard the reluctor ring by about 30 degrees.

 

Does this make sense to you gurus? And would I be correct in thinking this kit is the correct clutch from mini spares. 

 

https://www.minispar...c/GCK152MS.aspx

 

If you made it this far thanks for reading and any advice would be greatly appreciated.

 

 

Attached Files

•  mpi flywheel.jpg   77.45K   1 downloads
•  pressure plates.jpeg   39.49K   0 downloads

[viz139]

The JDM SPi does use a MPi flywheel. What you are describing sounds correct.  A similar thing was done on my brothers MPi and it ran very underpowered untill we switched the pressure plate 

[Nietro]

thanks viz139 guess I know what the next job on my baby is going to be. Not looking forward to it, so much stuff to remove thats in the way.

[Nietro]

Think I found why the timing is out.  The flywheel bolt wasn't even tight and looks like it was never locked.

 

 

Attached Files

•  boss.jpg   68.67K   2 downloads
•  washer.jpg   51.15K   3 downloads

[mini-mad-mark]

Bummer - worried for the state of your crank....looks like it's got a bit warm and might be hard work getting the flywheel off, even when you do the taper might be a bit knackered?

 

Good luck!

[viz139]

Not good

[Nietro]

Currently waiting on a flywheel puller and then will start working on getting the flywheel off.  Hopefully paitence, time, torque, heat, shock and the occasional bit of swearing will get it apart.  Never done this before, looks like I got a doozey to cut my teeth on. 

[Nietro]

Just thought I would finish off the thread.  Car is alll fixed.  After ordering and waiting on a flywheel puller I stressed and stressed about how stuck the flywheel would be.  Spent longer making sure the puller was perfectly aligned than it actually took for the flywheel to come off.  Crank taper wasn't too pretty most of the imperfection appeared to be from the flywheel boss itself.  Made a mock up of the taper then pressed it against the crank taper in the reverse direction and proceeded to remove all of the raised sections and after 4 or so hours got the crank taper looking pretty good.  Used a tip from the forums on using grinding paste and lapping the flywheel/boss to the crank and was very surprised on how good it looked afterwards.  Cleaned it all up and did a dry test fit and was very happy when after pressing it on by hand and a little twist to get the slots lined up I couldnt remove it without attaching the puller again and giving it a little pressure.  To me this indicated that the tapers were well and truely matched and would hold tight when assembled properly.  Managed to do all this with the motor still in the car, which I'm very happy about.  my back isn't happy but I am.

 

Everthing is back together now and the car is the best its ever been since I have had it.  So thanks for the tips and advice, I'm now off to go and enjoy my little girl.

Attached Files

•  20190425_104100.jpg   89.69K   1 downloads

Edited by Nietro, 14 November 2024 - 11:45 AM.