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Scammell Pioneer Restoration


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Question for those of you with more experience of these things than me.

Dad and I just put the two halves of the box together, i put the finest smear of sealant around the join before putting it together and doing the bolts up, and now then output shaft is quite stiff to turn. Everything turned beautifully when it was open, and the input shaft is still as free as it was before. I can't believe that we've compressed one of the bearings! - have we? We did pour a load of the correct oil over everything before putting it together, and it is in one of its neutral positions, so i wonder if the output shaft is still coupled to the majority of the gears inside and its just oil resistance.

Thoughts please.

 

Thanks, Richard

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Remember it is a constant mesh box so you are turning a lot of gears with cold oil on them, new oil seals as well? it will drag much more in any neutral except between 1st and 2nd, (when only the output dog clutch is engaged) and it has yet to settle in.

 

 

Had a similar thing with my gearbox, it did not turn very freely at first, it dragged slightly in one place like an oval brake drum. I was worried about this as I had put some bearing retainer in to stop the bearing outers turning, and thought this might have set too quickly before I'd tightened the box together and squeezed a bearing.

 

But a bearing would be tight all the time, not intermittent, so it must have been a miss matched gear or spline, it would only have to be a couple of thou or so out.

 

I drilled a flat bar to fit the flanges with a long bolt through the end and used this to turn the gearbox, from both ends, gave it a vigorous wizz up every time I passed it. it freed up a lot after a while doing that, but was not absolutely perfect, me being too picky I suspect.

 

When I first drove it I imagined that I could hear this but it soon went away and the box is very quiet, or else I've gone completely deaf!

Edited by gritineye
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  • 2 weeks later...

Finally got the stiff gearbox sorted. Took the spider out to allow all the selectors to move, which they all did happily except the one on the output shaft dog. When we tried withdrawing the selector shaft it was very tight and took considerable effort while all the others moved freely. When it was eventually removed, the dog was happy to move and the stiffness in the shafts was gone. We couldn't find any bend in the selector rod or any out of perpendicularity in the selector fork, but replaced both with the ones from the original box, and now everything is spot on. Got the front mount on and the rear cover / support, all the external pipework and the handbrake bracket, so i'm happy.

Now to crack on with all the other bits next weekend.

Just like to add many thanks to Bernard and Richard Farrant for their help and advice.

 

Richard

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  • 4 months later...
  • 1 month later...

Gearbox finally finished

 

P1010392.jpg

 

P1010393.jpg

 

Also finally got the drop arm off the steering box with help from fellow HMVFer Hippotastic, and stripped the rest of the box down, cleaned up and started reassembly. Photo below shows the cork seal i made for the rocker shaft in position.

 

P1010391.jpg

 

Unfortunatly one of the thrust washers that the cam follower bears against was totally u/s so i'm having a new one made by a friend. Strangly the other one was almost as new.

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I'm making a stainless exhaust silencer for our Scammell, and i'm wondering if anyone can explain the rather peculiar design of the original. Take a look at my photo below, i've cut the cylinder of the original circumfrencially and theres another cylinder inside about 1/2" smaller. The inner one is flanged on the ends and appears to be just be a tight fit on the inside of the ends. Can anyone suggest a reason for the two skins? Do i need to copy this in my stainless version?

 

P1010396.jpg

 

Cheers, Richard

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Possibly just a means of insulating the hotter inner part to avoid accidental burns. Gardner's had a similar specification for dry marine exhausts where the space between the skins was used to draw air out of the engine room, and help to cool the whole assembly, so the idea may have come from them.

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  • 2 weeks later...
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  • 3 weeks later...

When we had our 6Lw bottom end done I seem to recall the white metal shells were going to be problematic. I think we managed to get a set of later 180 gardner rods which accept the later type shells.

I think you can get white metal shells "re-metalled" but there is a lot of engineers blue and scraping in to do with white metal.

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Cheer up, I've seen worse. It doesn't look like the crank journals are badly grooved, so you can probably build up the white-metal enough to take a re-grind. Modern alloys are a bit tougher and more tolerant than some older ones and I don't suppose you'll be doing enough mileage to fill them with debris. I imagine with your machining skills you could keep the cost down to a bearable level.

 

Not knowing the marque, I guess under-size shells are either thin on the ground or very expensive?

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Thanks all for your input. I've spoken to a few white metallers including Terry Formhall who was vey friendly and helpful, but its sooooo expensive, way out of our budget, so after a few words of encouragement from Philb were going to tackle it ourselves.

When you sit down and look at it, its not really a complex procedure just alot of work, hence why its so expensive, and its this side of the hobby that i really enjoy.

 

Standby for updates, Richard

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  • 4 weeks later...

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