15 replies to this topic

[smurfomatic]

Over the last few days I've noticed a strange vibration-like noise at certain rpm (roughly 2k in 3rd and 3k in 4th) - only happens when driving so difficult to see what's going on. This occurs at part throttle, ease off slightly or accelerate a little and it goes away.

 

Apologies for the quality of this recording, but you can hear it at roughly 10-11 seconds and 16-22 seconds:

 

https://drive.google...iew?usp=sharing

 

Any suggestions? I've tried checking if anything obvious is loose in the engine bay, but can't really think what to check next.

[smurfomatic]

A few things that may (or may not) help:

 

Mini Marcos, based (as far as I can tell) on a Mk 2 Mini but built in 1980

998 with HS4 carb

Remote chanage gearbox, rebuilt & new clutch from Guessworks 6 months ago

[Spider]

It could be a broken engine mount.

[smurfomatic]

Thanks Moke, will investigate at some point over the next few days - if it ever stops raining here!

[smurfomatic]

Is there likely to be a steering related cause for this? Only asking as I just went to leave for work and something major has gone wrong, steering is all over the place.

There hasn't been any kind of vibration through the steering wheel so might be a coincidence.

[smurfomatic]

Only got the car back yesterday (garage couldn't source a Mk2 steering column so had to modify a newer one) but noise is still there.

 

Engine mounts & stabilisers look fine to me, though I did notice the manifold clamp wasn't bolted to the engine - will give it a run tomorrow and see how it sounds.

[smurfomatic]

Well, adding the bolt on the manifold clamp hasn't got rid of the noise. Does anyone have any further suggestions?

[Spider]

What engine does it have and has it got any modifications?

 

These can be curly to work out via a keyboard and computer screen.

[smurfomatic]

It's tricky to work out from inside the car too! with it only happening at around 30mph in 3rd and 55-60mph in 4th it's a bit difficult to pin down.

 

Standard (as far as I can tell) 998 - possibly from a Mk2 Mini as that seems to be the age of a lot of the donor parts

Single HS4 carb (recently had a new jet, not that this should be causing the noise!)

4 synchro remote box, John at Guessworks rebuilt it in November as the case was damaged by a failed idler gear bearing

 

May have to take the guy from the local Mini garage for a run in it, to try and get his opinion.

[smurfomatic]

Sorry, just to add:

 

Clutch & flywheel replaced at same time as gearbox rebuild

New Accuspark electronic dizzy & leads about a month ago

New brake shoes all round at the same time as dizzy

[smurfomatic]

So, finally got time for the guys at the local Mini garage to take a look. Left it with them yesterday morning, they looked it over but couldn't replicate the noise. Took one of them for a drive and managed to show him what was happening. they reckon it's the idler gear, which would be a surprise as it's only six months since John at Guessworks completely rebuilt the gearbox...

[Spider]

Sadly, the audio in your recording isn't the best, however I could hear something that could be an Idler Gear werring away, though, other than a noise these don't normally make a vibration.

 

Might be worth going to a shop who does Minis and getting another opinion.

[Northernpower]

So, finally got time for the guys at the local Mini garage to take a look. Left it with them yesterday morning, they looked it over but couldn't replicate the noise. Took one of them for a drive and managed to show him what was happening. they reckon it's the idler gear, which would be a surprise as it's only six months since John at Guessworks completely rebuilt the gearbox...

When you say John rebuilt the gearbox, did he set up the idler gear clearance in the transfer case as well?

[smurfomatic]

When you say John rebuilt the gearbox, did he set up the idler gear clearance in the transfer case as well?

 

He had to move everything into a new casing as the old one was damaged, so I assume he will have set up all the clearances.

[Northernpower]

 

When you say John rebuilt the gearbox, did he set up the idler gear clearance in the transfer case as well?

 

He had to move everything into a new casing as the old one was damaged, so I assume he will have set up all the clearances.

 

I understand he built the box but who assembled the transfer case?