Thanks for the idea. I will have it seen by a mechanic having known the problem.

Thanks and God bless
Luka

First for 1200rallycar: it will pul as low as 2500 but not full throttle, it needs to be at about 4k for that. The 39mm flatslides are a touch big for the mild state of tune. It's happy abpve 4500 RPM's.

Dave it's pretty likely the syncro is gone, it just seemed odd that it was fine prior to disassembly. Of course as the bits of third went twirling round the box at 7000 RPM's they could have damaged other things. The fact that it goes into gear at lower speeds is probaly a case of having more time to match the RPM's.

Tom

Rallytwit, I would suggest that the energizing lugs are not working correctly or that there is some wear on the hub splines. I wouldn't mind betting that the spring that retains the three lugs has come off one of the lugs.

Luka, it sounds like you might have a broken synchro on the 2nd gear. it will cause those symptoms






On Tom's problem, I don't know what could cause it to be baulky downshifting at speeds above 20mph.


> below about 20 MPH it goes into 2nd without issue

Could it be a broken/missing clip/ring on the synchro?

Anyone with know how of Datsun 1200 gearbox issues, i am not able to shift to Gear 2 its like grinding sound and doesn't engage, i have to use gear one then jump to three. anyone to help. thanks luka - kenya

i always thought what you described is a synchro issue, though sounds like you've done more with gearboxes than i have.

you have no power at 3500rpm? i always found in rally that holding third gear as much as possible is much faster than down-shifting to second. though second often results in wheel spin in dirt, you are essentially eliminating two gear shifts (down to second and back up again)

it's off topic but surely you can have an engine setup with power lower than 3500rpm, my pet hate is spectating rallies, too many cars running twin webers/dellortoes bogging down in the corners as they have zero power at low revs (go the SU's!)

Well after installing the new 3rd gear and cluster gear (replacing damaged 3rd) , I didn't like how 1st 2nd engaged.....I even took the tail cone off to double check. Well all the gears engaged and seemed fine on the quick test up and down the cul de sac.
Well once on track yesterday it quickly became apparent some thing isn't right. Upshifting from 1st to 2nd is fine, up and back 4th between 3rd is no problem what so ever. For turns 5,9, 15 & 18 I need 2nd. Regardless of what I do it clunks/crunches into 2nd; I tried double declutching, slow deliberate shifts, revving the motor higher and sliding it into 2nd..............all with the same result. (I can carry 3rd but it does drop to 3500, which doesn't help the lap times)

When the gearbox was apart all of the syncros where in excellent shape. It doesn't jump out of gear or anything like that. Also below about 20 MPH it goes into 2nd without issue The one and only thing I do notice is the 3rd 4th shift has a nice click click to it where as the 1st 2nd side feels a little vague. This wasn't an issue before the box was taken apart clearly something is out of adjustment...........so before I pull the box back out if anyone has dealt with this I'm wondering if there is an adjustment for the shift rod, detent balls or whatever that cure this let me know. Realistically I know I'm going to be pulling a gearbox but it doesn't hurt to ask.

Tom