Gearbox problem

[Charlynsane]

Hello guys

some more problems with my new engine, the gearbox doesn't seem to work properly

We built it with the following species

-22G1128
-ST 4 sync S/C gearbox
-KAD pinion housing
-MED S/C drop gear
-MED Ultralight flywheels





I checked the gearbox extension, everything is ok and greased, I set the clutch arm properly, master and slave cylinder are ok

I was wondering if the KAD pinion support hold properly this fork? as the standard pinion housing have. big flat surface



inside it's very close but we slightly modified the pinion housing for clearance



Thank you for your help guys

The gears are hard to engage even with a shut off engine, and the 2nd gears scratch if you don't make an heel and toe.

[imack]

I've been running the KAD pinion support housing for a few years in a 22G1128 box with no issues.
I know what you mean by the KAD housing being hollow instead of flat where the speed change claw is supported but it hasn't caused me any problems.
Have you definitely got adequate clearance between the speed change 'claw' and the KAD housing? I had to cut and grind away quite a lot of one of the webs on the KAD housing.
Also ground some material from the underside of the selector rod that passes above the bearing in the KAD housing.

[Charlynsane]

Hello I mack

Yes we trimmed the KAD support instead of trim the shaft

Kad lauched a new version for remote, that why I was wondering if it could cause any problem to maintain the claw against the gearbox housing

[LuisM]

The gears are hard to engage even with a shut off engine, and the 2nd gears scratch if you don't make an heel and toe.

2nd gear crunching: sorry if this may sound a silly question.... but do you have the inner piece of the 1st/2nd selector hub fitted properly ? the side which has a small ridge around the mainshaft hole must face the pinion side. Otherwise.. 2nd will always crunch

cheers
Luis

[Charlynsane]

Hello Luis

I didn't make the engine by my self, I guess yes because it's a really experienced engine builder that make the engine.

I was thinking of a problem with the clutch as well, maybe a too tight primary gear?

[LuisM]

I was thinking of a problem with the clutch as well, maybe a too tight primary gear?

that leads to crunchy gears, but not only 2nd gear,
If the primary gear is starting to "grab" on the crank, the engine when engaged in 1st with clutch depressed should drop revs and try to stall .

[imack]

Primary, idler gear or clutch issues will cause gear selection problems with the engine running, but they're not going to cause the difficult selection mentioned with the engine off. It sounds like there is a separate possible 2nd gear issue too.

[Fanfaniracing]

Did you check the primary and idler is running free when you put the engine on top of the gearbox?

In certain cases you should not fit a Gasket between engine and box.

That's why i always prefit everything to check clearance and free gears.

Building a remote box takes time if you want to do it right...

[bwaminispeed]

On the 1st/2nd speed hub, as well as the three detent balls and springs for the outer gear ring, there is also, a plunger and spring detent for the hub itself on the mainshaft.......

This is something, that, I believe many people are not even aware of. It has a very specific orientation upon assembly.......If this is not done correctly (or, if the plunger is missing altogether) can cause symptoms like these, and, quite often, much worse.....

[LuisM]

On the 1st/2nd speed hub, as well as the three detent balls and springs for the outer gear ring, there is also, a plunger and spring detent for the hub itself on the mainshaft.......

i'm not familiar with 3 Sync gearboxes, but i believe you should be referring to 3 sync boxes ? as in a 4 Sync none of the synchro hubs has detent plunger.

[Charlynsane]

Hello guys

I made some more tests this afternoon

I lift the car and the wheels are turning, even you push the clutch pedal, so something is wrong..

The only thing I made since I restart the car is to replace my orange diaphragm with a blue one.

I have some pictures of the gearbox rebuild if that could help

A thing that help is to accelerate juste before to engage a gear, if you do that there is no gearbox scratch

[Lakeland997]

It sounds like the clutch is not releasing fully or the primary gear is sticking.
You can check this by removing the starter motor and while someone holds down the clutch, see if you can rotate the primary gear with a screwdriver.

[Charlynsane]

Hello

The engine is in the car so not easy to do at the moment

Does the KAD pinion support make gear selection harder?

[imack]

The KAD pinion support housing should not make the gear change harder unless the speed change 'claw' has inadequate clearance and is fouling the housing or the shift rod above the support bearing is fouling the housing.
I wonder if KAD's 'new' remote shift pinion support is an all new casting of if they are modifying the housing for you before you receive it.

[Charlynsane]

As you can see Imack we made some clearance,

The only thing that I was wondering is if the KAD pinion support housing maintain well the claw as it's not flat as the standard pinion housing

[imack]

The only real difference I can see is that my 'claw' appears to be sitting higher in the selector forks than yours is.

[Dearg1275]

Looking at your photo there seems to be contact here

A73DC512-0362-4F9B-9043-14C34A40A990.jpeg

Perhaps this is forcing the claws down against the selector rods. Whether that’s the problem ?

D

[imack]

Is the steel plate sitting flush with the gearbox case in the circled area?

[Charlynsane]

Hello

I think it sit properly but for example the original pinion housing have a big surface area to sit flush properly the claw



Do you experienced iMack?, but if you slightly push the throttle you can easily engage gears

[imack]

This is your area of concern isn't it.
It concerned me too but it's not caused me any issues although it's not ideal, if memory serves me correctly the claw actually bridges the recess in the KAD housing. There shouldn't be any force being applied to the claw during gear shifts as it only follows the gear selector, in fact I'm not actually sure what its purpose is.
No problem with gear selection on my box.