Stepnose 105 gearbox woes

Author
Discussion

fergus

Original Poster:

6,430 posts

275 months

Friday 17th April 2015
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A well known specialist used another well known gearbox specialist to rebuild the gearbox on my GT Junior last year.

However, although several new bearings were used and better spec synchros, the box still whines excessively and even when warm, the shift quality is not great. It doesn't baulk or graunch, but doesn't go into gear particularly well.

I'd be grateful for recommendations for someone to take a look at the gearbox (i.e. take it apart). The gearbox issues make me think twice about taking the car out as it's not particularly enjoyable to drive.

Recommendations for rolling road tuning would also be welcome.

What mods (if any) can easily be done to the little 1300 to make it more peppy? I already have a 123 dizzy (not mapped on a rolling road), along with a lightweight flywheel...

george123

459 posts

182 months

Friday 17th April 2015
quotequote all
fergus said:
A well known specialist used another well known gearbox specialist to rebuild the gearbox on my GT Junior last year.

However, although several new bearings were used and better spec synchros, the box still whines excessively and even when warm, the shift quality is not great. It doesn't baulk or graunch, but doesn't go into gear particularly well.

I'd be grateful for recommendations for someone to take a look at the gearbox (i.e. take it apart). The gearbox issues make me think twice about taking the car out as it's not particularly enjoyable to drive.

Recommendations for rolling road tuning would also be welcome.

What mods (if any) can easily be done to the little 1300 to make it more peppy? I already have a 123 dizzy (not mapped on a rolling road), along with a lightweight flywheel...
can't help on the gearbox but if you're anywhere near the South Central area, then I'd recommend Tom Airey tuning near Winchester. his set up is essentially a large garage with a rolling road but he's a carb expert - must be in his 70s and been doing it for 40 odd years. He tuned my '76 Spider 2000 and it runs beautifully & is now putting out 138bhp. Not cheap...cost me around £300 for 2.5 hrs incl. 4 iridium plugs, however finding people like him is getting harder. I'd try this before thinking about any mechanical changes, a proper set up maybe all you need.

Alfa101

64 posts

139 months

Saturday 18th April 2015
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I'm told that using Redline 75/90 NS oil in the alfa boxes improves them. I'm about to try that with one of mine. It might be worth a try before you take the box out. Cloverleaf transmissions in Cumbria have a strong reputation.

Jonathan

fergus

Original Poster:

6,430 posts

275 months

Monday 20th April 2015
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Alfa101 said:
I'm told that using Redline 75/90 NS oil in the alfa boxes improves them. I'm about to try that with one of mine. It might be worth a try before you take the box out. Cloverleaf transmissions in Cumbria have a strong reputation.
Thanks. CL trans did the original work....

RicksAlfas

13,394 posts

244 months

Monday 20th April 2015
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fergus said:
It doesn't baulk or graunch, but doesn't go into gear particularly well.
Could it be something like the clutch, or simply a badly fitted rubber gaiter on the lever?
I'd give Charlie a ring and chat it through before you start taking it all apart.

Just a thought - did you have the flywheel lightened before the gearbox rebuild, or as part of it?
If it's been skimmed rather than notched, it might be too thin for the clutch to work properly?

James B

1,302 posts

244 months

Monday 20th April 2015
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If it's of any interest at all I have an OS Giken ratio'd box for the 105 available. I was going to use it in my racer but have opted to rebuild the box that was in the car. The box is at Alfaholics.

I can also ask them who it is that's rebuilding my box at the moment I case that is of assistance?

fergus

Original Poster:

6,430 posts

275 months

Tuesday 21st April 2015
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RicksAlfas said:
fergus said:
It doesn't baulk or graunch, but doesn't go into gear particularly well.
Could it be something like the clutch, or simply a badly fitted rubber gaiter on the lever?
I'd give Charlie a ring and chat it through before you start taking it all apart.

Just a thought - did you have the flywheel lightened before the gearbox rebuild, or as part of it?
If it's been skimmed rather than notched, it might be too thin for the clutch to work properly?
I had one of Alfaholics' lightweight flywheels fitted along with a new Sachs clutch.

Double de-clutching has it straight into gear, making me think that the oil may be too slippery for the synchros to grip properly. I'll try redline 75w90 NS and see if that helps. Will also call Charlie. Thanks

jamieandthemagic

619 posts

192 months

Thursday 23rd April 2015
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I can really really recommend Peter Baldwin at wilsher garages, for old school carb only tuning on a rolling road.

ToothbrushMan

1,770 posts

125 months

Saturday 2nd May 2015
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did the 75/90 oil help?

fergus

Original Poster:

6,430 posts

275 months

Sunday 3rd May 2015
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ToothbrushMan said:
did the 75/90 oil help?
Not got round to changing it yet. Having some bathrooms done, so the Alfa has slipped down the priority list a bit!

Need to take it somewhere to get the 123 dizzy and webers setup though, as my first car, a Vauxhall Astra 1300S felt quicker....

Will get the redline NS oil and see how it goes. How easy is the box to fill on the 105?