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Thank you Julian, The rear casting is now off with no problems and I will take it to a TIG welder next week. Too much mass for my Mapp gas!
The front horns were moving nicely, but only because of the input shaft movement. I shall reapply myself to that end and carry on with the full job.Great Adam,
As Bill has said, the input / main shaft Spiggot bearing is very important, it should be moving on both internal and external surfaces but should have minimal play. The club have them in stock I believe, T8 and G9 use the same bearing.
Regards,
JulianVery happy to report that the gearbox is all apart and appears to be in excellent condition. No broken teeth, bronze bush fitting well, no blockages in the oil hole feeds to this and no apparent bearing wear. I guess it was well restored before my tenure! On the instructions of the previous owner, I have always filled with gear oil, perhaps this has been helpful. On dismantling I noticed that only jointing compound, no gasket, was used on the bearing holder and front/rear casting faces. Red hematite was used, I would use Blue Hylomar unless there are any other suggestions?
Well done Adam !
I am sure Blue Hymolar is fine or a very good quality silicone ?
If you dont have a magnet in the drain plug now would be a good time to fit one ?Regarding sealant, I quite like Wellseal and there is quite a good debate on the web at http://www.model-engineer.co.uk/forums/postings.asp?th=99081 I agree with the sentiments here.
I keep most types of sealants to hand, including the wonderful loctite pipe sealer but if in doubt, it’s Wellseal for me. I like to wear thin surgical gloves when I use it and spread it around with thin plant label sticks which can be found in pound shops.
Thanks for your useful advice Julian.
Colin
I believe they’ve changed the chemical compound of Wellseal within the last few years. I used it on my engine rebuild in 2104 and it failed completely. I’ve the photos to prove it. An expensive episode and I seem to remember the reason given for changing it was to do with EU regulations on some of the ingredients. No idea if that’s true.
Anyway, the comments on the model engineer debate seem to refer to older applications and I have also had great results with it in the past. Nothing’s as good as it used to be. However…..I shan’t be using it again. Fingers burnt etc.
These days I have more faith in modern products even if they are harder to clean up and messier to apply.
I rather feel that I am making a mountain out of a molehill! All going well until I nipped up the bearings and spacer on the input shaft as tight as I could with the castellated nut. The internal spacer washer is now catching on the layshaft gear. I am pretty sure this was assembled with the cup facing inwards, away from the roller bearing. Am I right?
I presume that I couldn’t over tighten the castellated nut thus not leaving the washer loose? I am asking the questions before I consider turning the washer round (would prefer not to dismantle again unnecessarily), or “dress” the washer edge away from the gear. Thanks to all for your help and comments.Adam, according to my notes the domed washer should be facing away from the bearing – i.e. with the cup facing inwards. At least, that is how it was on my gearbox ! This is presumably to throw excessive oil away from the bearing.
Is the layshaft assembled correctly – or didnt you remove it ?Bill, thanks for that. It was my feeling as well. The layshaft was removed and is now assembled correctly after a second attempt. Having carefully observed my photo I still managed to get the herringbone the wrong way round but this is pretty obvious on reassembly of the main gears. I think some gentle re-modelling of the cup washer, which was not in “as new” condition will resolve the issue. I didn’t want to do that if it was the wrong way round anyway. It may be there was a little play, previously, which kept it free. I do have a C spanner for the castellated nut which means I can tighten it well.
Well there has been a bit of a pause and a few interruptions and away days! Gearbox is now in and nicely lined up. Final job to reconnect propshaft and guess what? The UJ is hitting the cross member. If I raise the rear of the box I shall be out of line with the engine. Raise the engine, I don’t think so. Let the new fabric couplings take the strain, best not I would have thought. Probably need to raise the rear around 1/4″ at least. Any suggestions?
Are you sure the gearbox is correctly lined up ?
What did you alter that could possibly have affected the position of the gearbox ?
How did you line the gearbox up ? Did you double check this before you put the shaft and fabric coupling on ? I found that it was also best to take the clutch off to make absolutely certain everything was in line.
Julian M. posted some help on the Forum some time ago about correctly lining everything up
I will check later and see how close my UJ is to the cross member on my car- in case this helps.As I had new fabric couplings, I realigned the gearbox height and position with the couplings. As I haven’t changed anything at the clutch engine end it didn’t seem necessary to go to great lengths in checking alignment with the crankshaft. Wrong again, perhaps, but the original mounting heights would not let the couplings line up. I wonder whether the engine mountings may have softened and “sagged” over the years. These are pretty expensive and I wonder if they can be replaced with the engine supported but in situ?
I have checked and there is in fact only 2mm clearance with the cross member at the widest point of the UJ on my car.
However I have original engine mountings and this affects it. I intend to replace these one day but it is a very difficult job – almost an engine out !
If you are absolutely certain that the gearbox is correctly aligned maybe you could raise the rear engine mountings fractionally and then realign the gearbox. This may give you enough clearance – after all the engine may not be level anyway !Not a model I’m familiar with, so excuse if this is daft. But is it possible the new fabric joints are thicker? Would fractional movement of the gearbox forward resolve this issue? Possible that the new coupling dimensions may differ slightly, or that retightening of the nuts will make a difference?
LaurenceThanks Lawrence. Yes they are a little thicker but I don’t think this affects the situation. I am hoping to get back to it soon, and will look at it all with refreshed eyes!
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