Jump to content


Photo
- - - - -

New Problems After Gearbox Rebuild


  • Please log in to reply
13 replies to this topic

#1 Its a min

Its a min

    Mini Mad

  • Members
  • PipPipPipPip
  • 284 posts
  • Location: London

Posted 04 November 2018 - 11:22 PM

Hi everyone.

 

Following on from my last thread:

 

http://www.theminifo...ox-help-please/

 

Got the engine all back together and whilst doing so, fitted new clutch, plunger, thrust release etc. Good news is, gears now all engage fine. However, I've two new problems and hoping someone can advise/help.

 

First problem, I can't get the car to run without a little bit of choke. With the choke pulled out approx 1/4", car runs fine but as soon as I push the choke in, it struggles then cuts out. It's got a standard HS4 (without lifting pin) and I've tried enriching it but the same thing happens. As I have a Minispares stage 1 kit fitted, the carb has the supplied AAU needle, new spring and dashpot topped up with 20/50 oil. Also tried the SU oil but the same problem. Any ideas/suggestions greatly appreciated.

 

Second problem worries me a little more. After rebuilding everything, and getting it running, I have a knocking sound coming from the clutch housing. It's like a tapping sound when the car is in neutral. If the clutch pedal is depressed only slightly, it seems to stop. That said, whilst trying to tune the carb, if the engine revs are at roughly 1500, the noise disappears but as soon as I turn down the revs, the tapping starts again. I'm not sure if this could just be due to the engine hunting and erratic revs due to bad tune but again, any help/suggestions would be greatly appreciated.

 

Thanks.

 

 



#2 Spider

Spider

    Moved Into The Garage

  • Admin
  • PipPipPipPipPipPipPipPipPipPipPip
  • 13,845 posts
  • Location: NSW
  • Local Club: South Australian Moke Club

Posted 04 November 2018 - 11:38 PM

The tapping sound is possibly a bolt that's been fitted that's a little too long.

 

Have a look at your timing cover bolts and engine mount bolts, they are the usual suspects for this.



#3 nicklouse

nicklouse

    Moved Into The Garage

  • TMF+ Member
  • PipPipPipPipPipPipPipPipPipPipPip
  • 17,900 posts
  • Location: Not Yorkshire
  • Local Club: Anonyme Miniholiker

Posted 05 November 2018 - 12:25 AM

The tapping sound is possibly a bolt that's been fitted that's a little too long.

 

Have a look at your timing cover bolts and engine mount bolts, they are the usual suspects for this.

and dont forget the clutch slave ones (or clutch slave bracket if verto) or any other bolts that might just be touching the ring gear.



#4 Its a min

Its a min

    Mini Mad

  • Members
  • PipPipPipPip
  • 284 posts
  • Location: London

Posted 05 November 2018 - 12:52 AM

Cheers guys.

 

Will check the out but as I always put the bolts back from where they came after removing them i.e. remove bolts, remove bracket/component, replace bolts in their original holes, wouldn't the noise have been there all along?



#5 A-Cell

A-Cell

    Camshaft & Stage Two Head

  • Members
  • PipPipPipPipPipPipPipPip
  • 1,610 posts
  • Location: Longbridge

Posted 05 November 2018 - 10:56 AM

You say the tapping noise disappears if you press the clutch pedal or raise the engine rpm to 1500 rpm or above.
Is it coming from flywheel end?
Could be idler gear rattle.

#6 Its a min

Its a min

    Mini Mad

  • Members
  • PipPipPipPip
  • 284 posts
  • Location: London

Posted 05 November 2018 - 06:05 PM

Hi A-Cell,

 

It is coming from the flywheel end and I said 1500rpm as it wasn't tapping whilst I was setting the timing. As soon as I dropped the revs back down to roughly 800rpm, the tapping started again until the engine cut out due to the first problem i listed. As the engine revs increase (even to 90-100rpm), due to choke, idle speed screw adjustment or just moving the distributor, the tapping fades.  As for pressing the clutch pedal, I literally have to just put my foot on the pedal and as I start to press, the tapping stops.

 

If it is the idler gear, can this be done with the engine in as I really don't..1 have the time, 2, have all the lifting equipment (HSS Hire job due to lack of space) & 3, want to take the engine out a third time.

 

Cheers.



#7 alex-95

alex-95

    I am THE CLAMP MAKER

  • TMF+ Member
  • PipPipPipPipPipPipPipPipPipPip
  • 6,017 posts
  • Location: l

Posted 05 November 2018 - 07:50 PM

You say the tapping noise disappears if you press the clutch pedal or raise the engine rpm to 1500 rpm or above.
Is it coming from flywheel end?
Could be idler gear rattle.

 

 

Hi A-Cell,

 

It is coming from the flywheel end and I said 1500rpm as it wasn't tapping whilst I was setting the timing. As soon as I dropped the revs back down to roughly 800rpm, the tapping started again until the engine cut out due to the first problem i listed. As the engine revs increase (even to 90-100rpm), due to choke, idle speed screw adjustment or just moving the distributor, the tapping fades.  As for pressing the clutch pedal, I literally have to just put my foot on the pedal and as I start to press, the tapping stops.

 

If it is the idler gear, can this be done with the engine in as I really don't..1 have the time, 2, have all the lifting equipment (HSS Hire job due to lack of space) & 3, want to take the engine out a third time.

 

Cheers.

 

It thought Idler gear rattle when I read it.

 

It's an engine out job unfortunately, one bearing in the transfer case and one in the gearbox case



#8 absx2

absx2

    One Carb Or Two?

  • Members
  • PipPipPipPipPipPipPip
  • 814 posts

Posted 05 November 2018 - 09:22 PM

I worked for a Rover garage in 1993 and nearly all the brand new minis that came off the transporter had idler gear rattle on low idle.

Apparently they chucked in whatever was available to get it close enough in the factory.

 

If your noise is due to idler gear clearance I wouldn`t say its the end of the world and once the motor is set up better you probably won`t hear it.



#9 Its a min

Its a min

    Mini Mad

  • Members
  • PipPipPipPip
  • 284 posts
  • Location: London

Posted 05 November 2018 - 10:37 PM

 

You say the tapping noise disappears if you press the clutch pedal or raise the engine rpm to 1500 rpm or above.
Is it coming from flywheel end?
Could be idler gear rattle.

 

 

Hi A-Cell,

 

It is coming from the flywheel end and I said 1500rpm as it wasn't tapping whilst I was setting the timing. As soon as I dropped the revs back down to roughly 800rpm, the tapping started again until the engine cut out due to the first problem i listed. As the engine revs increase (even to 90-100rpm), due to choke, idle speed screw adjustment or just moving the distributor, the tapping fades.  As for pressing the clutch pedal, I literally have to just put my foot on the pedal and as I start to press, the tapping stops.

 

If it is the idler gear, can this be done with the engine in as I really don't..1 have the time, 2, have all the lifting equipment (HSS Hire job due to lack of space) & 3, want to take the engine out a third time.

 

Cheers.

 

It thought Idler gear rattle when I read it.

 

It's an engine out job unfortunately, one bearing in the transfer case and one in the gearbox case

 

 

Hi alex-95,

 

I don't think it's the bearings as I checked these both times the engine was split. I'm not sure if you read my other post but the engine was taken out, gearbox rebuilt and put back in only to find there were problems with the new baulk rings i.e. seizing the gears. At this stage, the engine was running smooth with no tapping. I just couldn't get it into all gears and when tried running it in first or reverse, did a great impersonation of Skippy (for those of you old enough to remember the bush kangaroo :D ). Anyway, the engine came out again and gearbox rebuilt using two of the less worn (still within tolerance) baulk rings then put together and back into the car. It was only after this second transplant the noise appeared and as mentioned, when the car is running smooth-ish (with a little choke), the tapping is non-existent which made me think it may be due to engine hunting when choke pushed in.

 

If it is the idler gear, I would imagine (hope - fingers crossed) it's the clearance or something else but as mentioned, all the original bolts went back into their original holes.

 

It's an '89 mini so verto clutch. my understanding is that verto clutches were self centering but could it be this?



#10 Its a min

Its a min

    Mini Mad

  • Members
  • PipPipPipPip
  • 284 posts
  • Location: London

Posted 05 November 2018 - 10:43 PM

I worked for a Rover garage in 1993 and nearly all the brand new minis that came off the transporter had idler gear rattle on low idle.

Apparently they chucked in whatever was available to get it close enough in the factory.

 

If your noise is due to idler gear clearance I wouldn`t say its the end of the world and once the motor is set up better you probably won`t hear it.

 

Hi absx2,

 

Thanks for the post.

 

That's what I was hoping/thinking. Once I manage to get the carb sorted, I'm hoping (fingers crossed) with the engine running smooth, the tapping will reveal itself as being due to a labouring, badly tuned/timed engine. Probably won't be able to get to look at it until the weekend but will see. I'll pull the clutch cover off and investigate.

 

Is there anything else I should look out for?

 

Hopefully it won't be another engine out job.



#11 Bat

Bat

    One Carb Or Two?

  • Members
  • PipPipPipPipPipPipPip
  • 903 posts
  • Location: Bermingum

Posted 06 November 2018 - 01:31 PM

Hi,

I ran a 1380 for years with a rattling idler gear, due mostly to the lumpy idle speed.

I did eventually pull the engine to replace the gearbox input bearing which had failed due to age/load inflicted. I wouldn't be rushing to pull the engine out at the moment.

Cheers  :proud:



#12 GraemeC

GraemeC

    Crazy About Mini's

  • TMF+ Member
  • PipPipPipPipPipPipPipPipPipPip
  • 7,302 posts
  • Location: Carnforth

Posted 06 November 2018 - 04:07 PM

I don’t think it is idler rattle if the slightest touch on the clutch stops it.

When it is doing it just try holding the throwout adjustment nuts - it could be something as simple as the clutch plunger rattling in the bore of the wok or the release bearing just catching

#13 Its a min

Its a min

    Mini Mad

  • Members
  • PipPipPipPip
  • 284 posts
  • Location: London

Posted 06 November 2018 - 06:05 PM

Hi,

I ran a 1380 for years with a rattling idler gear, due mostly to the lumpy idle speed.

I did eventually pull the engine to replace the gearbox input bearing which had failed due to age/load inflicted. I wouldn't be rushing to pull the engine out at the moment.

Cheers  :proud:

 

 

I don’t think it is idler rattle if the slightest touch on the clutch stops it.

When it is doing it just try holding the throwout adjustment nuts - it could be something as simple as the clutch plunger rattling in the bore of the wok or the release bearing just catching

 

Cheers guys,

 

All good info for when I start investigating.

 

Anymore suggestions welcome.



#14 A-Cell

A-Cell

    Camshaft & Stage Two Head

  • Members
  • PipPipPipPipPipPipPipPip
  • 1,610 posts
  • Location: Longbridge

Posted 06 November 2018 - 07:05 PM

Hi A-Cell,
 
It is coming from the flywheel end and I said 1500rpm as it wasn't tapping whilst I was setting the timing. As soon as I dropped the revs back down to roughly 800rpm, the tapping started again until the engine cut out due to the first problem i listed. As the engine revs increase (even to 90-100rpm), due to choke, idle speed screw adjustment or just moving the distributor, the tapping fades.  As for pressing the clutch pedal, I literally have to just put my foot on the pedal and as I start to press, the tapping stops.
 
If it is the idler gear, can this be done with the engine in as I really don't..1 have the time, 2, have all the lifting equipment (HSS Hire job due to lack of space) & 3, want to take the engine out a third time.
 
Cheers.


The idler gear rattle is a common mini proble. Itbis not caused by the the idler bearings. If the shimming of the gear (lateral) is too loose and therefore the amount of play too large then the idler gear 'chatters'.
It's not really a serious problem, more a characteristic of the Mini!

Just run the car for a bit. The recommended 850 rpm idle (in reality specified to minimise emissions at idle ) is too low. Try Running it with an idle between 1000 and 1200 rpm and this will minimise the chatter and hence the rattle noise. Less of a machine gun effect to more of a buzz!




1 user(s) are reading this topic

0 members, 1 guests, 0 anonymous users