8 replies to this topic

[John H]

righto!

my 93 spi cooper has an annoying habit of when you let off the throttle the car seems to start to back off then all of a sudden surges on for a split second.

any ideas what could be causing this?

also i think i have started to settle upon a specification for my rebuild.
looking for comments if possible.

+20 thou overbore using 21253 Pistons
Regrind, Balance and Polish Crank
Balance Rods
Centre Main Strap
Recondition Current ST3 Calver Head and work chambers to approx 23cc to give sensible CPR and allow use of normal 95ron unleaded
Duplex Timing Gear & appropriate offset key
New Followers
Kent MD274 Injection Cam
Standard Sintered Rockers
Lighten & balance std flywheel
enlarge throttle body to 44mm
Port inlet manifold
rebuilt box with 3.44 diff with central pick-up & uprated diff pin
maniflow lcb with lambda takeoff in y piece
twin box maniflow CAT back system
De-CAT Pipe
k&n induction kit

Edited by minimadmotorman, 29 November 2007 - 09:11 AM.

[duncancallum]

hi your spec is a little higher than mine

mines as follows:
+20 thou overbore using 21253 Pistons
Regrind, Balance and Polish Crank
Balance Rods
Centre Main Strap
MG Metro Head
Duplex VernierTiming Gear
New Followers
Kent MD274 Injection Cam
Standard Sintered Rockers
rebuilt box with 3.2 diff(standard SPi)central oil pick up comp diff pin
maniflow lcb with lambda takeoff in y piece
twin box maniflow CAT back system
k&n induction kit
Decat pipe

Its a Very nice engine not had it rolling roaded but it will do 107 and still pull that was mesured on sat nav on a private road

it is far more lively than standard and makes a brill every day runner

[duncancallum]

oh turn the ignittion on pump the throttle pedle 10 times to reajust the stepper on the idle control valve n see if that helps

[Sprocket]

oh turn the ignittion on pump the throttle pedle 10 times to reajust the stepper on the idle control valve n see if that helps

Rubbish!!

Where did you hear that

[John H]

hiya sprocket,

can you suggest anything to check with regards to the surging problem? i suspect there is no thermostat in the engine at the moment as it runs cold when your driving a warms to normal when your standing, could this be the cause?

Although i do now have a larger problem as the thrust bearing on the clutch has just gone

also as you seem to be the messiah when it comes to SPI what is your opinion on my proposed specification?

is it likely i would need to change the injector or would the standard one about manage this spec?

oh and duncan i have borrowed some ideas now from your spec too.

Edited by minimadmotorman, 28 November 2007 - 11:16 AM.

[duncancallum]

if you have the ignition on and pump the throttle then stop you can hear the motor adjust up

not sure where i heard it

[nev_payne]

oh turn the ignittion on pump the throttle pedle 10 times to reajust the stepper on the idle control valve n see if that helps

Rubbish!!

Where did you hear that

No offence Sporcket but I do this to my MPI when it decides to have a revving fit in the morning and it does work. It resets the throttle body sensors' Min/Max angle setting (or what ever the term is). Helps especially when changing the idle.

[DaveRob]

Just a point here.......... no thermostat in an A series engine is not a good thing. It screws up the coolant flow around the head and can lead to some cylinders running hotter than others. Then cracks appear and gaskets burst. Then tears and work ensue. Standard disclaimer applies and tin hat at the ready.............

[John H]

i only purchased the car recently and have only driven it about 5 times. it is my intention to replace the thermostat if there is one present or not.

i would never run a car without one.