RS Motorsport :: Classic Speed Restored

Since shortly after installing my Type 9 Quaife HD SC box I have had a reasonable amount of crunching when changing down from 4th to 3rd. My throttle is super stiff and I have always struggled to blip the throttle on downshifts but I don't know that just that is the cause of my issue as I do not have crunching changing any other gear combination.

Looking into the box today to see if the synchro rings have broken or are worn I can see that everything looks to be in as new condition (the best I can see anyway). I did notice that one of the blocker bars was hanging out as shown in the photo...

Blocker Bar.jpg (79.89 KiB) Viewed 11918 times

It is possible to change gears with it like that but I pushed it back in anyway but after a change from 3rd to 4th and back it pops out again. It does hesitate to change into 3rd ont he garage floor but that just be due to the gears not spinning. The input shaft nose was removed at the time allowing the input shaft to move away from the box by 5mm so maybe this is purely due to that.

Questions:
Is what I am seeing normal? This is the only blocker bar in the box that does it which makes me think something is not right. The Haynes manual I have shows there are springs (more like circlips really) holding the blocker bars in but seeing as only one bar is popping out makes me think the springs are as should be. ???

Is it time for a gearbox overhaul (after only 1000km competitive!!!!! gr gr gr) and can it be stripped with minimal tools?

Also, can somebody tell me what the purpose of the blocker bars is??? As best I can see it appears that they help push the other synchro ring out of the syncro unit so that the new gear's syncro can be engaged???

The Blocker bars are there to locate the synchro to the selector hub when it is moved towards the gear, as the synchro drags on the gear and then grips it so the hub can slide over the synchro 'dogs' on the actual gear.
Brass synchro's can do this if you're a bit of a gorilla with the gear lever. Steel synchro's fix this but they can be a pain in the arse to bed into the gear sometimes if they're the cheaper ones
My Quaife T9 boxes used to do this in 3rd gear on the back straight at QR and would literally spray the blocker bars out breaking the syncho as it went locking the gearbox in 3rd.
You're best bet is to rebuild it with new blocker bars and synchro's. but you can't fix it without dropping the cluster down and pulling the input shaft out which is a pain in the arse and just easier to do the whole thing and have a good look through the needle roller in the cluster while you're at it as a pinto is not to hard on them but my YB used to eat them

I have steel synchros on 1st and 2nd. Is it worth getting them on 3rd and 4th also? Being steel they will presumably wear the gears (or is that synchro hub) more but it isn't a high milage road car after all.

Sounds like I need to find a decent Adelaide gearbox place....anybody?

Also, I have the quaife alloy top cover with the large orange filler cap/breather. Has anybody come up with a more slimline breather for this top cover? In order to get the back of my box nigher, to straighten the tailshaft angle, I either need to remove the breather or cut a hole in the tunnel as it hits.

I had the same dilemma with my quaife top and decided cutting a hole in the floor for a stupid breather that may not be there in the future was a dumb idea. I also tried jimmying up a slimline breather but found anything short of a proper one just didn't keep the oil in.
I ended up plugging the breather hole and drilling a hole horizontally in the front of the cover and running a line to a breather bottle in the engine bay. Also made a small simple baffle on the underside of the cover. Best solution in the end, can run the box as high as you want and the hose hugs the bellhousing and can lead anywhere convenient.

The springs are only there to stop the blocker bars from floating around as the reason they shoot out and take out 4th is it's the smaller than 1st and 2nd and is thinner so when the gorilla hanging onto the stick pulls 4th it fails occasionally especially with a rose jointed shifter. On my T9's I never ran steel synchro's and the only time I had dramas was the YB doing 9500rpm in 3rd either on the dyno or down the back straight at QR. I never ever had an issue with any other synchro ever and when they flew out there would be dents in the alloy top cover.
The only way to sort out the top cover and fix the stupid breather is to weld up the hole and tap either a 1/4 or 3/8"npt fitting and run a short 90 degree fitting out to a breather tank, you also have to fit a second breather diagonally opposite at the front of the cover with a baffle underneath and as the rear one blocks up from the pick up of oil from the lower set of cluster gears. While I was at Quaife I asked them if it could be changed and they gave me a strange look. but funny enough mine was the only boxes I've seen not leak

When building the car I did mount a breather tank under the bonnet for the gearbox but could not get a 90 degree fitting under the tunnel so never used it. Your suggestions sound like the go - drilling a new fitting into the edge of the cover. Failing than I was thinking of putting a standard steel cover back on.

My crunching issues Danny are downshifting from 4th to 3rd whereas your's seem to be going up gears.

EDIT: Just a thought, what issues might I encounter if I spaced the engine crossmember down using some, say, 10mm plates between teh chassis rail and the crossmember? I guess the steering arms and TCAs will be at a different angle but is that likely to be an issue? Benefit = gearbox would fit with breather in place and lower centre of gravity.

the best option is mk1rs2000 setup
RS alloy sump lower to xmember , also allows to lower rack , better geom bumpsteer
and a std factory mk1 rs has alloy spacer blocks on g/box crossmember
thus better clearance and lower c of g

I'm running the RS alloy sump and have managed to drop the engine (and box) down almost 15mm and still have x-member clearance. So now the quaife breather fits nicely and I have maintained the engine/gearbox level. I'm now looking at the angle of the tailshaft uni's as they are quite different at rest.

I use a custom dry sump and only have around 10mm more I can drop the front :(