K1 Diff build question

AdrianJones · #1 20-04-2013

Hi all,

Just bought a K1 today from Steve Webbs Models in Frodsham. I was building the kit and have come across a slight problem. I built both diffs together and one of them is silky smooth and the other is really notchy!

Anyone have any idea what might of caused it. I am worried that the biff balls are faulty straight out of the packet?!

Has this happened before to anyone?

Andrew Twigger · #2 20-04-2013

You'll get this feeling if the diff gear is the wrong way round. Take it apart and ensure that the gear is in the correct orientation in relation to the male outdrive. The lip on the gear fits into a groove on the male outdrive.

AdrianJones · #3 21-04-2013

Quote:

Originally Posted by Andrew Twigger

You'll get this feeling if the diff gear is the wrong way round. Take it apart and ensure that the gear is in the correct orientation in relation to the male outdrive. The lip on the gear fits into a groove on the male outdrive.

Hi,

I have tried splitting it all down and cleaning it then rebuilding (many times) to have the exact same result.

corsair · #4 21-04-2013

Quote:

Originally Posted by AdrianJones

Hi,

I have tried splitting it all down and cleaning it then rebuilding (many times) to have the exact same result.

Sand the rings and see if it helps....A 600 or 800 grit paper will do.

AdrianJones · #5 21-04-2013

Quote:

Originally Posted by corsair

Sand the rings and see if it helps....A 600 or 800 grit paper will do.

So, let me get this straight. You want me to sand my ring?

madmulc · #6 21-04-2013

have a look at this,

http://www.youtube.com/watch?v=bv3AC-Jjhbk

AdrianJones · #7 21-04-2013

Quote:

Originally Posted by madmulc

have a look at this,

http://www.youtube.com/watch?v=bv3AC-Jjhbk

Hi,

Yeh already watched this. Done exactly what he did including the Schumacher bearing blaster (racers best friend). I will have to give the sand paper idea a go!

Pascewan · #8 21-04-2013

Did you run it this way? sometimes my SV2 Diff feels notchy, after a quick run, or a few acceleration in the living room it's gone and it runs super smooth.

AdrianJones · #9 21-04-2013

Quote:

Originally Posted by Pascewan

Did you run it this way? sometimes my SV2 Diff feels notchy, after a quick run, or a few acceleration in the living room it's gone and it runs super smooth.

I have spun it up on the bench. I tried holding one wheel to engage the diff but it its still very notchey!

Andrew Twigger · #10 21-04-2013

Adrian,

When you say 'notchy', can you feel every ball as it were, or is it just quite rough? Is the notch very pronounced each time? Does it occur at a consistent frequency?

AdrianJones · #11 21-04-2013

Quote:

Originally Posted by Andrew Twigger

Adrian,

When you say 'notchy', can you feel every ball as it were, or is it just quite rough? Is the notch very pronounced each time? Does it occur at a consistent frequency?

Initially it was very frequent. After slackening it off a touch and running it on the bench it is not as noticeable but still feels very gritty. the front diff is as smooth as butter though, it just feels COMPLETELY different to the rear as if the rear diff has been run for a year.

matdodd · #12 21-04-2013

Hi Adrian
If your still having problems call in the shop and ill take a look at it for you.
Mat

budfish · #13 22-04-2013

Quote:

Originally Posted by AdrianJones

Initially it was very frequent. After slackening it off a touch and running it on the bench it is not as noticeable but still feels very gritty. the front diff is as smooth as butter though, it just feels COMPLETELY different to the rear as if the rear diff has been run for a year.

Use ceramic balls. They are more consistent with less imperfections so more chance of getting it right first time. Over tighten steel balls and flat spots will ruin the diff action. Ceramics don't flat spot

Regards

Buds

Andrew Twigger · #14 22-04-2013

The kit comes with ceramic balls.

Ceramics are smoother agreed. But they're also more brittle and slip more easily than carbide.

AdrianJones · #15 22-04-2013

Quote:

Originally Posted by matdodd

Hi Adrian
If your still having problems call in the shop and ill take a look at it for you.
Mat

Hi Matt,

I would but it will not be until next Saturday again due to work.

matdodd · #16 22-04-2013

no problem Adrian see you then

AdrianJones · #17 22-04-2013

Well I stripped it down completely and cleaned it all using bearing blaster. I used 600 grit sand paper on the metal plates with a little machine oil then re-built the entire thing back up again.

Guess what, still not smooth at all. It is just the same as it was before. The only thing I can guess that is wrong is that one of the diff balls in knackered with a manufacturing fault as its done this from day one of the cars build and it has never been run.

Sad times!

Its lucky I have a very good model shop where I bought it from who can take a look! Matt and Robin this means you guys :-)