Lister-Blackstone G2 gearbox transplant.

[RLWP]

Well, the rocker is on the right on an HA

 

Does that help?

 

Richard

[MoominPapa]

Well, the rocker is on the right on an HA

 

Does that help?

 

Richard

What direction does it rotate? The FR is anti-clock, looking forward and the rocker is on the left.

 

MP.

[RLWP]

Clockwise looking forward, rocker on the right

 

Richard

[MoominPapa]

Clockwise looking forward, rocker on the right

 

Richard

It all fits! You can see from my pictures that the holes to mount the rocker pedestal on the other side are drilled and tapped into the casing. The FR was available in reverse rotation. The number of components that need to be changed to make it go the other way is amazingly small.

 

MP.

[MoominPapa]

Another question for the experienced.

 

How do I get the small bearing at the front of the bug reduction gear to slide into the the hole in the rear housing when I'm assembling the reduction box halves together? I'm severely hampered by having to do this with the reduction box already mounted on the engine (there's too little clearance to install the reduction box in one piece). Every time I offer the back half up, the bearing jams in the housing and I can't get it any further. This happens before there's enough thread exposed on the studs to use them as pullers, should that be deemed safe.

 

MP.

[RLWP]

Persistence

 

I assume you are talking about getting the inner race (on the main shaft) into the bearing held in the housing?

 

You are putting together a matched pair? You cannot swap the inner race to another bearing

 

Richard

Edited February 25, 2015 by RLWP

[MoominPapa]

Persistence

 

I assume you are talking about getting the inner race (on the main shaft) into the bearing held in the housing?

 

You are putting together a matched pair? You cannot swap the inner race to another bearing

 

Richard

No, I'm talking about the bearing in the output shaft at the front, ie the one away from the output flange, the last thing to assembled on the stub shaft before the big bolt. The bearing is all installed on the shaft fine, and as the two halves of the reduction box go together, the outer race of the bearing needs to slide into a machined recess in the half of the reduction box closest to the main box. As I do that, it jams.

 

 

Cheers,

 

MP.

 

 

ETA, the roller bearing is a matched pair, and is not giving a problem.

Edited February 25, 2015 by MoominPapa

[Timleech]

Are you certain that the bearing is actually starting to enter the housing?

The weight of the gear will be making it drop out of line, you'll need to counteract that in whatever way you can improvise.

It shouldn't really just slide in, should be tight enough to stop the outer race spinning in the housing.

If you're sure it has entered, a few judicious taps with a hide mallet on the output coupling ought to set it on its way. Obviously, check for burrs on/in the housing beforehand.

 

 

Edit - don't go giving it heavy treatment with a hard hammmer, this is likely to marr the bearing race surfaces, leading to premature failure.

 

Tim

Edited February 25, 2015 by Timleech

[MoominPapa]

Are you certain that the bearing is actually starting to enter the housing?

The weight of the gear will be making it drop out of line, you'll need to counteract that in whatever way you can improvise.

It shouldn't really just slide in, should be tight enough to stop the outer race spinning in the housing.

If you're sure it has entered, a few judicious taps with a hide mallet on the output coupling ought to set it on its way. Obviously, check for burrs on/in the housing beforehand.

 

Tim

I'm pretty sure that it's starting to enter the housing, since once it stops moving, it takes a bit of leverage to remove it again - exactly at you'd expect if the race was a little cock-eyed in the housing, and jammed. I foolishly didn't check that the bearing fitted easily before installing it on the shaft, since this is a different bearing than was originally fitted.

 

I had the same problem getting the other bearing into the housing, but once a got it straight, it slid in fine.

 

A possible strategy would be to loosen the ring of bolts holding the round retainer of the big bearing, that would allow me to get casing back far enough to get some bolts on the casing-half studs and pull it together that way. That would be transmitting force across both bearing races, and I worry that forcing the awkward bearing when it's not straight will ust jam it irretrievably.

 

 

MP.

[bizzard]

I'm pretty sure that it's starting to enter the housing, since once it stops moving, it takes a bit of leverage to remove it again - exactly at you'd expect if the race was a little cock-eyed in the housing, and jammed. I foolishly didn't check that the bearing fitted easily before installing it on the shaft, since this is a different bearing than was originally fitted.

 

I had the same problem getting the other bearing into the housing, but once a got it straight, it slid in fine.

 

A possible strategy would be to loosen the ring of bolts holding the round retainer of the big bearing, that would allow me to get casing back far enough to get some bolts on the casing-half studs and pull it together that way. That would be transmitting force across both bearing races, and I worry that forcing the awkward bearing when it's not straight will ust jam it irretrievably.

 

 

MP.

I take it the outer track for that bearing is in the reduction box casing and your trying to enter that roller bearing into it. If so, those rollers will be slightly loose in the cage and the lower ones will have dropped a little and are probably baulking up on the outer tracks edge. A thin elastic band around the rollers will keep them snug on their inner track whilst entering. The elastic band will disintegrate and disappear.

[MoominPapa]

I take it the outer track for that bearing is in the reduction box casing and your trying to enter that roller bearing into it. If so, those rollers will be slightly loose in the cage and the lower ones will have dropped a little and are probably baulking up on the outer tracks edge. A thin elastic band around the rollers will keep them snug on their inner track whilst entering. The elastic band will disintegrate and disappear.

Sadly, not so. The end bearing on the gearboc shaft is just like that, but the end bearing on the output shaft, which is the one I'm having problems with, is a ball race. It's installed on the end of the shaft and as the complete assembly of the backplate, shaft, gear and bearings is pushed in, the outer race of the bearing has to slide into a machined recess in the other half of the case.

 

Mp.

[bizzard]

Sadly, not so. The end bearing on the gearboc shaft is just like that, but the end bearing on the output shaft, which is the one I'm having problems with, is a ball race. It's installed on the end of the shaft and as the complete assembly of the backplate, shaft, gear and bearings is pushed in, the outer race of the bearing has to slide into a machined recess in the other half of the case.

 

Mp.

Ok, got ya.

[MoominPapa]

OK, it's done. For future reference, this is what I did.

 

1) Loosen the ring of 6 nuts holding the cover over the big bearing.

2) Unscrew all the studs holding the two halves together as far as you dare.

3) Put the two halves of the reduction box together, there'll be a big gap, but the studs now protrude enough to get nuts on.

4) Tighten the those nuts slowly and evenly, keep checking that everything is free to rotate.

5) When the bearing cover is pushed out to the six nuts, tighten those down slowly and evenly. Keep checking everything is free. This pushes the bearing into place. When you've tightened the nuts, loosen them off again, and tighten the casing nuts down more.

6) Repeat until everything is tight.

 

This procedure made some of the sort of groaning noises you get pushing a bearing into a housing, but it never bound up, and I never had to use much torque on the nuts, so I don't think I've overstressed anything. Getting is apart again might be fun, of course.

 

 

MP.

[Timleech]

OK, it's done. For future reference, this is what I did.

 

1) Loosen the ring of 6 nuts holding the cover over the big bearing.

2) Unscrew all the studs holding the two halves together as far as you dare.

3) Put the two halves of the reduction box together, there'll be a big gap, but the studs now protrude enough to get nuts on.

4) Tighten the those nuts slowly and evenly, keep checking that everything is free to rotate.

5) When the bearing cover is pushed out to the six nuts, tighten those down slowly and evenly. Keep checking everything is free. This pushes the bearing into place. When you've tightened the nuts, loosen them off again, and tighten the casing nuts down more.

6) Repeat until everything is tight.

 

This procedure made some of the sort of groaning noises you get pushing a bearing into a housing, but it never bound up, and I never had to use much torque on the nuts, so I don't think I've overstressed anything. Getting is apart again might be fun, of course.

 

 

MP.

 

There should be some tapped holes on the edge of the rear casting, between the stud holes, for drawing screws.

 

Tim

[MoominPapa]

There should be some tapped holes on the edge of the rear casting, between the stud holes, for drawing screws.

I couldn't see any. There are a couple of dowels.

 

It's all back together and had preliminary testing. All seems to work and we've stirred up the water in the marina. The loud bearing rumble has gone and in forward it sounds great. Reverse wines like mad, like it always does with these boxes. The only slightly concerning thing is in neutral, the straight-cut reverse cogs can still heard, which I don't recall with the old box.

 

 

Thanks to all who assisted this gearbox newbie, especially Richard and Tim.

 

MP.

[madcat]

Thanks Moomin Papa for an interesting thread and good illustrations . These sort of topics are One of the good things about this forum

[MoominPapa]

A finished picture, for Madcat.

 

MP.

 

 

[madcat]

Thanks , greenie for an excellent topic with good photos. A good companion to Richards posting on the innards of the Blackstone box .

[RLWP]

Thanks , greenie for an excellent topic with good photos. A good companion to Richards posting on the innards of the Blackstone box .

 

I must get around to doing the 3G clutch one

 

Richard

[MoominPapa]

Melaleuca moved under her own power for the first time with the new gearbox today. Just up to the lock, where the Fens winds pinned us to the side for a while, and back again. There were a couple of false starts when it was clear that the reverse brake-band was slipping and not much reverse was to be had. It does need to be quite tightly adjusted. I'm still getting used to the different noises that this box makes, which seem to be much healthier than the loud bearing rumble the old one generated. Tomorrow I may even tempt fate and glue the carpet down in the back cabin.

 

MP.

 

 

 

[madcat]

No don't glue the carpet back down , that's just going to tempt the fates too much

[RLWP]

The proper method is to leave the carpet unglued until you eventually trip over it. Then you can glue it down

 

Richard