40 replies to this topic

[eric.sen]

Or if somebody made a mod that helps

like : FSE power boost valve

  or : new throttle body

  or : an new manifold like LCB

 

Or something else that will help

[Scott MPI]

Did you try adjusting you valve clearances? make them a bigger gap, you don't need to buy anything. 1.5 high lift rockers won't change the rpm or help your problem

If you've experienced hot engine symptoms, it's the engine leaking hot gasses through the exhaust valve before it's used all it power/heat (the exhaust valve is opening too early) making the car misfire/hesitate. We're feeling the effect of power loss, this is worse when hot becouse it leans the fuel out,

Like Hennasxi said, it will be worse if engines have been worked on

I fully rebuilt my engine, 1293 bigger valves, ported head. , new chain and pad, advanced the cam a bit etc, all things that actually made the problem worse! Why? Because it advanced the cam even more the wrong way

[bmv133]

Hi everybody,...

 

Can it be related with the fault described on page 31/73 of  https://www.uscars.b..._Bulletins.pdf,  that is. cam reluctors defaults...

 

 

On the other hand,...Scott Mpi suggests "Give the tappets a bigger Gap, say 25 thou, ( essentially changing the valve timing a bit ) " ... do you refer valve rocker clearance  ? By default, as you can check in attached file, the must be between 27 and 33 mm

 

cheers, 

Jaime

 

 

 

Attached Files

•  MiniMpiCamReluctorProblem.jpg   46.47K   8 downloads
•  ValveClearanceMPi.jpg   61.27K   15 downloads

[Scott MPI]

Yes the valve rocker clearance, this is only a test don't forget don't leave them like it, i found that when I adjusted the exhaust valves to have a bigger gap,the car drove much better, pulled better from low revs, felt like I had torque, didn't run as hot, that what got me to believe the cam timing was wrong, you could always try a different octane fuel to see if you feel a difference

If done some reading into retared timing symptoms and all seems to add up,

On light/steady throttle the car has less ignition advance so is running retarded , when you hit the throttle it will go away as the ecu advances the ignition then as you ease off the symptom will re-appear again (at any revs) couple that with an over advanced camshaft and the problem arises

If you had a carb engine it would be like running with no mechanical/vacuum advance

Well that's my therory anyway

Scott

[bmv133]

Hi Scott MPI...

 

Thanks for your explanation... it´s very interesting....

 

Furthermore, I've read mpi ecu defines at least two ranges in its maps: one under 2000-2500 rpm (city use) and one over 2000-2500 (road use) .... different ranges -> different valve timing

 

In your opinion.... could be a kent/swifttune camshatfs the solution to avoid kangaroo problem in a standard mpi ?

 

Jaime

Edited by bmv133, 05 June 2017 - 09:09 PM.

[eric.sen]

Thanks for all your help,

so the first to start :

Valve Rocker clearance : but how many mm ? 20/25:27/33  ????

[eric.sen]

Second you talk about the octane :

In France we have 95 and 98 ,

I always use 98

 

But witch is better for our problem and for the Mini in general ?

[Scott MPI]

It's not so much what fuel is best for now, its if you feel a difference in the problem, run tank fairly empty and try a few gallons of 95

Set the exhaust valves to 0.50 mm, then do a test run,

As i understanding lower octane fuel burns faster, with that and the exhaust valve open later you might feel a difference,

[Scott MPI]

Also doing some reading on here, type misfire into search at the top,

Some clues, 1 person said the only thing that made it better was to take off the 1.5 ratio rockers( the problem was still there just better)

Another person said, he had the same problem after changing the cam, but ajusted it strait away with ajutable timing kit

Both directly linked to the cam timing

[eric.sen]

OK thanks

[eric.sen]

But forum the genuine Rocker

 

Do I really have to set the valve clearance to 0.50mm ???

 

Sure ?

 

They will make the car noisier  (clik/click/click....)

[Scott MPI]

When were they last checked/adjusted?

It's only a test, you won't be leaving them like it, it will only take you a few minutes,

At one point on mine I had them at 1mm, for a test, found the car drove better, then adjusted the camshaft back a few degrees

then I reset valve clearance back to spec

[eric.sen]

Never checked since : 10 years...... or more.....

[Midas Mk1]

Should be checking tappet clearance every few thou..

Imo your chasing your tail with the 'problem', nearly every MPi does it even from new way back when (had family owned MPi's when I was younger)

[Midas Mk1]

Doesn't help with the long first gear due to the 2.7 diff ratio, rover did the mapping using a 3.2 diff, so maybe there's something in that?