My Uncle is in the process of restoring a 1960 Mark-1 Atkinson 4-wheeler. It has a Gardner 5LW engine (94bhp), David Brown 5-speed box & Kirkstall worm & wheel rear axle. At some point in the past the worm & wheel housing has cracked & been welded up… First thing is to get this swaped out.
Now, having worked out the diff ratio to be 5.2:1 & assuming that top gear is straight through (ratio), at rated engine speed (1700 rpm) on the original 9.00 x 20 tyres she’s good for about 37.5 mph! Putting her on 10.00 x 20’s, which he wants to do, gets you to nearly 39mph for the same engine speed. I guess this is probably about right for the period - pre dual carriageway / motorway, etc. A slightly daft question, but what would be ‘comfortable’ engine revs’ for a Gardner at normal road speed?
So we are looking for other alternatives for improving the ‘cruise’ speed for road-runs etc. Does anybody know if there might be alternative diff ratios to increase the road speed? Secondly were there DB boxes with overdrive in top? If either of these are possible, who might have the parts to do it?
If increasing the speed is not possible, he would like to replace the welded diff housing either way.
Any advice or experience on this would be greatly appreciated! Thanks in advance, Andrew Stone.
My Uncle is in the process of restoring a 1960 Mark-1 Atkinson 4-wheeler. It has a Gardner 5LW engine (94bhp), David Brown 5-speed box & Kirkstall worm & wheel rear axle. At some point in the past the worm & wheel housing has cracked & been welded up… First thing is to get this swaped out.
Now, having worked out the diff ratio to be 5.2:1 & assuming that top gear is straight through (ratio), at rated engine speed (1700 rpm) on the original 9.00 x 20 tyres she’s good for about 37.5 mph! Putting her on 10.00 x 20’s, which he wants to do, gets you to nearly 39mph for the same engine speed. I guess this is probably about right for the period - pre dual carriageway / motorway, etc. A slightly daft question, but what would be ‘comfortable’ engine revs’ for a Gardner at normal road speed?
So we are looking for other alternatives for improving the ‘cruise’ speed for road-runs etc. Does anybody know if there might be alternative diff ratios to increase the road speed? Secondly were there DB boxes with overdrive in top? If either of these are possible, who might have the parts to do it?
If increasing the speed is not possible, he would like to replace the welded diff housing either way.
Any advice or experience on this would be greatly appreciated! Thanks in advance, Andrew Stone.
Would you consider putting an Eaton 2spd axle in as I’m sure both Atki’s and ERFs used the Eaton at that time so it would be authentic I think. I am sure that you would then be able to improve road speed considerably with the correct Diff ratio.Just my opinion for what its worth.cheers Bewick.
Before I’d got to your reply, I was thinking exactly the same thing reading the original post Dennis - this wagon sounds like it’s crying out for an Eaton 2-speeder under the back end. It won’t damage the fuel consumption (probably improve it) and it won’t be time to be going home before you get there (like it would be with the current setup)
Hello Bewick & Marky, many thanks for your replies.
We had thought about an Eaton 2-Speed, particulary when I saw the photos of of your tidy looking 4-wheeler Dennis.
There are however a couple of complications; the brakes are air-over-hydraulic with tiny little hydraulic rams operating the brake levers. If we replaced the axle complete we would need to get rid of the spring-brake actuators from the new axle & refit the old hydraulic rams - fairly major surgery, & we were not sure how the braking efficiency might end up - the lorry will have to be MOT’d.
Secondly the lorry is actually quite ‘narrow’ in the track width, the more modern axles are wider over the wheel flanges.
The plan is to keep the lorry as original as possible so if we could find an higher ratio diff, or an overdrive box, that would swap over we would be doing very well! Wondered if coaches might have had either of these?
Pebbles 74:
Hello Bewick & Marky, many thanks for your replies.
We had thought about an Eaton 2-Speed, particulary when I saw the photos of of your tidy looking 4-wheeler Dennis.
There are however a couple of complications; the brakes are air-over-hydraulic with tiny little hydraulic rams operating the brake levers. If we replaced the axle complete we would need to get rid of the spring-brake actuators from the new axle & refit the old hydraulic rams - fairly major surgery, & we were not sure how the braking efficiency might end up - the lorry will have to be MOT’d.
Secondly the lorry is actually quite ‘narrow’ in the track width, the more modern axles are wider over the wheel flanges.
The plan is to keep the lorry as original as possible so if we could find an higher ratio diff, or an overdrive box, that would swap over we would be doing very well! Wondered if coaches might have had either of these?
Anyways, thanks again Gents, Andrew
But won’t it be worth exhausting the possibility of finding a compatible Eaton axle first as they defo used the Eaton at the time and maybe you will find one that is compatible for your motor.Com’on get shaping!! Dennis.
Pebbles 74:
Hello Bewick & Marky, many thanks for your replies.
We had thought about an Eaton 2-Speed, particulary when I saw the photos of of your tidy looking 4-wheeler Dennis.
There are however a couple of complications; the brakes are air-over-hydraulic with tiny little hydraulic rams operating the brake levers. If we replaced the axle complete we would need to get rid of the spring-brake actuators from the new axle & refit the old hydraulic rams - fairly major surgery, & we were not sure how the braking efficiency might end up - the lorry will have to be MOT’d.
Secondly the lorry is actually quite ‘narrow’ in the track width, the more modern axles are wider over the wheel flanges.
The plan is to keep the lorry as original as possible so if we could find an higher ratio diff, or an overdrive box, that would swap over we would be doing very well! Wondered if coaches might have had either of these?
Anyways, thanks again Gents, Andrew
But won’t it be worth exhausting the possibility of finding a compatible Eaton axle first as they defo used the Eaton at the time and maybe you will find one that is compatible for your motor.Com’on get shaping!! Dennis.
Pebbles 74:
Hello Bewick & Marky, many thanks for your replies.
We had thought about an Eaton 2-Speed, particulary when I saw the photos of of your tidy looking 4-wheeler Dennis.
There are however a couple of complications; the brakes are air-over-hydraulic with tiny little hydraulic rams operating the brake levers. If we replaced the axle complete we would need to get rid of the spring-brake actuators from the new axle & refit the old hydraulic rams - fairly major surgery, & we were not sure how the braking efficiency might end up - the lorry will have to be MOT’d.
Secondly the lorry is actually quite ‘narrow’ in the track width, the more modern axles are wider over the wheel flanges.
The plan is to keep the lorry as original as possible so if we could find an higher ratio diff, or an overdrive box, that would swap over we would be doing very well! Wondered if coaches might have had either of these?
Anyways, thanks again Gents, Andrew
But won’t it be worth exhausting the possibility of finding a compatible Eaton axle first as they defo used the Eaton at the time and maybe you will find one that is compatible for your motor.Com’on get shaping!! Dennis.
Or a 6-speed O/D gearbox?
Hello 240, thanks for your reply.
A 6-speed O/D does sound like a good way to go. Million Dollar question, what ratio might you get in top? Next where might there be one of these for sale?
A 6-speed O/D does sound like a good way to go. Million Dollar question, what ratio might you get in top? Next where might there be one of these for sale?
Thanks again, Andrew
Well, if a 657, or the later 6/500, 6/600 or 6A boxes would fit behind your 5LW (sorry, I couldn’t advise on that) then I think they will give you a ratio of around 0.85:1 I think they’re sometimes advertised in the classifieds of the classic mags.
Hi, I’m not sure that in 1960 Atkinsons were fitting the Eaton 2 speed, though they certainly did later, as far as I can remember, and it is a long time ago, the Eaton 2 speed of this era was limited to modest torque as fitted to Albion, Leyland Comets etc. and only in the late sixties was a version for much heavier lorry’s produced, the Gardners were Torquey if nothing else. At this time the DB overdrive box was still a 5 speeder. I can remember at least one old Atky with a coach diff which raised the speed to a giddy 40+ mph. By the way there is only one way to drive an old Gardner and this is with your foot flat on the floor, now I think of it, this applied to all the old motors in those days, another old method was to use a block ( a block of hard wood and piano wire well wrapped with insulating tape hanging behind the forks on the back of the pump. On the 5 pot beware of its habit of the engine running in reverse…Tony.
Hi, I’m not sure that in 1960 Atkinsons were fitting the Eaton 2 speed, though they certainly did later, as far as I can remember, and it is a long time ago, the Eaton 2 speed of this era was limited to modest torque as fitted to Albion, Leyland Comets etc. and only in the late sixties was a version for much heavier lorry’s produced, the Gardners were Torquey if nothing else. At this time the DB overdrive box was still a 5 speeder. I can remember at least one old Atky with a coach diff which raised the speed to a giddy 40+ mph. By the way there is only one way to drive an old Gardner and this is with your foot flat on the floor, now I think of it, this applied to all the old motors in those days, another old method was to use a block ( a block of hard wood and piano wire well wrapped with insulating tape hanging behind the forks on the back of the pump. On the 5 pot beware of its habit of the engine running in reverse…Tony. Sorry about the double post.
Suttons Tony:
Hi, I’m not sure that in 1960 Atkinsons were fitting the Eaton 2 speed, though they certainly did later, as far as I can remember, and it is a long time ago, the Eaton 2 speed of this era was limited to modest torque as fitted to Albion, Leyland Comets etc. and only in the late sixties was a version for much heavier lorry’s produced, the Gardners were Torquey if nothing else. At this time the DB overdrive box was still a 5 speeder. I can remember at least one old Atky with a coach diff which raised the speed to a giddy 40+ mph. By the way there is only one way to drive an old Gardner and this is with your foot flat on the floor, now I think of it, this applied to all the old motors in those days, another old method was to use a block ( a block of hard wood and piano wire well wrapped with insulating tape hanging behind the forks on the back of the pump. On the 5 pot beware of its habit of the engine running in reverse…Tony. Sorry about the double post.
It’s not only the 5-potters that can run backwards, Tony!
My Uncle is in the process of restoring a 1960 Mark-1 Atkinson 4-wheeler. It has a Gardner 5LW engine (94bhp), David Brown 5-speed box & Kirkstall worm & wheel rear axle. At some point in the past the worm & wheel housing has cracked & been welded up… First thing is to get this swaped out.
Now, having worked out the diff ratio to be 5.2:1 & assuming that top gear is straight through (ratio), at rated engine speed (1700 rpm) on the original 9.00 x 20 tyres she’s good for about 37.5 mph! Putting her on 10.00 x 20’s, which he wants to do, gets you to nearly 39mph for the same engine speed. I guess this is probably about right for the period - pre dual carriageway / motorway, etc. A slightly daft question, but what would be ‘comfortable’ engine revs’ for a Gardner at normal road speed?
So we are looking for other alternatives for improving the ‘cruise’ speed for road-runs etc. Does anybody know if there might be alternative diff ratios to increase the road speed? Secondly were there DB boxes with overdrive in top? If either of these are possible, who might have the parts to do it?
If increasing the speed is not possible, he would like to replace the welded diff housing either way.
Any advice or experience on this would be greatly appreciated! Thanks in advance, Andrew Stone.
Andrew drop me an email and I will put you in touch with a guy who has a 4:1 diff for a Mark 1
Suttons Tony:
Hi, I’m not sure that in 1960 Atkinsons were fitting the Eaton 2 speed, though they certainly did later, as far as I can remember, and it is a long time ago, the Eaton 2 speed of this era was limited to modest torque as fitted to Albion, Leyland Comets etc. and only in the late sixties was a version for much heavier lorry’s produced, the Gardners were Torquey if nothing else. At this time the DB overdrive box was still a 5 speeder. I can remember at least one old Atky with a coach diff which raised the speed to a giddy 40+ mph. By the way there is only one way to drive an old Gardner and this is with your foot flat on the floor, now I think of it, this applied to all the old motors in those days, another old method was to use a block ( a block of hard wood and piano wire well wrapped with insulating tape hanging behind the forks on the back of the pump. On the 5 pot beware of its habit of the engine running in reverse…Tony. Sorry about the double post.
Tony it’s over 45 years ago but i seem to remember my block of hard wood having a bent nail in the top to hang over the rack bar, or was I dreaming ?
Too many birthdays and too much diesel fumes, I get confused.com ( I do seem to remember a lot of black smoke trailing behind )
Yes Big Al, a nail would do, but us Cockney’s liked to be more cultured ! it of course had to be well wrapped in insulating tape so as not to leave marks and with the piano wire which went around the block of wood it was better positioned to create even more black stuff, and piano wire being very strong did’nt stretch much. But as a trailer mate we usually had me put the jack handle in and I did this on one of Suttons old 8 Wheeler Atky’s with a 6 LW pulling a trailer loaded with new Tomato Ketchup bottles for Heinz at Standish from Key Glass, Harlow, Plenty of smoke, a bit more speed and then the exhaust blew off. As for engines running backwards the 6 LW could do this specialy when it had had some of the above treatment and I have also had an Albion Chieftain with a 4 pot do this to me and I just chugged around the corner in reverse, the exhaust in the cab was awful but it was suffering from battery troubles and I was not sure about starting again. But the 5 LW had the reputation of going into reverse very easily and it could be very dodgy to leave it in gear without the hand brake well on as they quite happily would suddenly start either normal rotation or backwards and chug of to the nearest substantial obstruction. During Nationalisation some of the Kentish Town Trunkers who had Scammels used to have their own Trigger set ups which they would change before going up the road and then replace it with the usual one in the morning…Tony.
First thing is to get this swaped out.