8 replies to this topic

[lippo]

 Quick Q - when I accelerate and take my foot of the pedal, the engine feels like it shunts, or kicks back. It can do the same when I press the accelerator. It doesn't do it if I feather the throttle. It feels like there's a bit of slack somewhere.

 

 I have 3 engine steadies so I don't think it's that. Nothing is hitting the engine bay/exhaust either. What could it be? Timing chain, clutch? I do remember my old mini's used to suffer with this as well.

 

 I'm sure someone knows what this is.

[nicklouse]

If you are sure the engine is not moving?

 

check for a broken subframe.

check for play in the diff.

[mab01uk]

Also check the rod or remote gear lever rear rubber mounts are ok. Sometimes they can look ok but when engine moves under load the rubber has actually detached/split  from the metal part of the mounting(s).

Rod change has two large 'cotton reel' type mounts in the centre tunnel behind the gear lever. The earlier remote change has a single large rubber mount.

 

Engine steady bar bushes can also seem ok but inside the rubber bush has worn, same with the steady bar(s) low down on the subframe to gearbox on rod change Minis. The metal bracket on the subframe weld can also crack.

[lippo]

 Thanks both, subframe seems good as are the mounts but I will check them again. I rebuilt the gear stick housing last year and renewed the cotton reels, so they should be good still. I've renewed the engine steady bushes and have a brand new tasty engine steady from S-Can which is solid.

 

 It feels like it's something to do with the gearbox/flywheel possibly? It'll do it when I'm accelerating normally, not just when giving it the beans. It feels very 'mechanical'. It doesn't affect the drive, nothing is slipping etc, it just gives the car a jolt. Wouldn't be clutch as it only does it when in gear.

 

 I'll check the diff when I work out how to do that. Any other suggestions are more than welcome.

Edited by lippo, 02 June 2026 - 05:06 PM.

[Quinlan minor]

Jack the car up and put axle stands securely in place.

Select first gear and rock each front wheel, in turn, to check for slop in the drivetrain.

Edited by Quinlan minor, 02 June 2026 - 06:45 PM.

[lippo]

Jack the car up and put axle stands securely in place.

Select first gear and rock each front wheel, in turn, to check for slop in the drivetrain.

 Thanks, if there's slop, what does that indicate?

 

 It happens in all gears too.

[nicklouse]

Also pull the starter and check the flywheel is not loose.

[Cooperman]

It sounds like a worn diff-pin to me.

Easy to fix - once the engine and gearbox are out of the car!

[Quinlan minor]

 

Jack the car up and put axle stands securely in place.

Select first gear and rock each front wheel, in turn, to check for slop in the drivetrain.

 Thanks, if there's slop, what does that indicate?

 

 It happens in all gears too.

 

That the "shunt" is in the drive train, or not.

 

You're not checking first gear, you're locking the gearbox. In fourth gear, it'd be easier to turn the engine over with the wheel.