333 3 sync boxes - going to 4 sync 1128

[mk1rally]

Hello all,

Well had the box rebuilt last year after a spate of it dropping out of 1st whilst giving a little beans.

Tried everything outside the box and found nothing. It was stripped down and found that most of first gear was missing, well the teeth were very worn. Jim managed to source a firts gear and put it back together but although its been fine for a bit, its up to its antics once again (though not as often).

I read this was not uncommon on a well worked box (and mine is in the rally car). I get on with the lack of sync most of the time but this last weekend needed a fair few exploits into the low gear to get it out of the tight corners.

Short shifting meant it was off cam and it had to recover in second before shooting away.

So....do I try and source a NOS 1st (is anyone making them?) and do it all again or give up on the 333 and build up a nice new SCCR 1128 4 sync and be done with it?

I have had the minispare SCCR set in the 333 and loved the ratios in that so I think I will be looking at their ste.

I do also wonder if its time to put a slipper in and retire the Evolution cross pin. Its been good but I'm on it a bit more now and could take advantage of the extra grip to be honest.

Any thoughts?

[guru_1071]

if you like the ratios of the s/c kit in a three sync, have a look at the clubman kit for the four sync, as the ratios are nearly the same

3 sync

2.57
1.72
1.25
1.0

clubman

2.58
1.71
1.25
1.0

three sync outer tracks may appear again, but the tooling requirements for them are fairly horrific, they are on the 'to do' list, but a way down it, there just isnt the demand for them really.


a plate diff will certainly alter the going of your car, but dont forget to take into account the other parts required, and the sacrificial nature of the pinions - dependant on ratio and use, they are only good for maybe 1000 miles

[mk1rally]

if you like the ratios of the s/c kit in a three sync, have a look at the clubman kit for the four sync, as the ratios are nearly the same

3 sync

2.57
1.72
1.25
1.0

clubman

2.58
1.71
1.25
1.0

three sync outer tracks may appear again, but the tooling requirements for them are fairly horrific, they are on the 'to do' list, but a way down it, there just isnt the demand for them really.


a plate diff will certainly alter the going of your car, but dont forget to take into account the other parts required, and the sacrificial nature of the pinions - dependant on ratio and use, they are only good for maybe 1000 miles

Thanks for the info, I suspected the same. Those ratio's really worked with my diff and cam and It does make a real differnce off the line. Many people have commeted on how quick it is away and It's mostly to do with the thought behind the cam, gear ratio and final drive.

I'll be trying to keep it close if possible.

Have been looking at those ATB diffs too as I dont have to buy a CWP with them and that last time I drove a mini in anger with a slipper, even with a 15" wheel it was hard work. I believe the ATB are a fit and forget too??

[guru_1071]

those atb are a great, particually when you consider the saving of using a std crownwheel and not having to buy the outputs.

the only disadvantge is they need at least one wheel on the ground behaving so that the 12:1 ratio can work, otherwise they are no better than an open diff

[sandman]

When you serviced the 3 sync box - did you check and/or change the selector axels in the bottom of the box? How about the spring and ball thats holding/"locking" the selector in the right place?

If you want an LSD for any kind of serious competiton... a Plate-type diff is the only thing that will do. The ATB is ok provided you have good traction on BOTH wheels.... i.e your car must be bog stiff and the pavement smooth.

[steady eddie]

Hello all,

Well had the box rebuilt last year after a spate of it dropping out of 1st whilst giving a little beans.

Tried everything outside the box and found nothing. It was stripped down and found that most of first gear was missing, well the teeth were very worn.

Any thoughts?

Dog Box?

regards

Steady Eddie

[mk1rally]

thanks gents,

the box currently "sounds" like a dog box!!

Dogs are fine on tracks but TBH, the car is used for stage and historic rallying, i'd be battering it all the time so I'm going down the 4 sync route.

More fat to the fire yesterday, the clutch complete let go yesterday on the Tour of Cheshire. Hydrolics looks to be moving but that's no indication (both master and slave are not old) but has little resistance and is not actualting the clutch. Either the seals are not really doing much in the master or its pressure plate problems. There is no leaks (for now) I need to strip it down but it's the first time I have ever retierd in event in 20 years of competeing. I pride myself on making sure it was ready and my luck has to run out sometime!!

The bad luck came in 3's....Puncture on the way home from scruit on Friday, Clutch issue meant DNF and then the trailer had a punture on the way back!!

Never mind and another £200 out of the window when you cound fuel and maps!!

Not a great day. Its my Birthday today so I put it in the garage, swore at it (it helps!!) and I'll be on it again tomorrow to see what can be done to get it through next weekend (Borders rally which is really a great event and I was looking forward to it!), Then its all out for box work.

I not a lover of ramp diffs as you don't know which way itr wants to go when it lands, not fun!! on rough undelating stuff it makes it very hard work (even with a 15" Motolita). They should really be serviced every 1000 mile too to be in tip top condition and can really put strain on other componats (meaning potential DNF's). The open diff dosnt have that problem and I hoping that the ATB is a mix between the too, grip when I need it out of the bends and off the line but easier in the underlating stuff where the open diff is happy. We will see.

[36inter]

Happy Birthday.

Pete

[graham in aus]

Maybe the ball has broken off the end of the clutch arm?

Fits the description you give of no resistence on pedal and no cluthc actuation!

Might be an easy fix! ????