martinwcox Posted January 14, 2014 Share Posted January 14, 2014 I will be removing my Scorpion gearbox to fix an oil leak. I am told to make note of and mark where any shims go at the removal stage so all can go back where it should on reassembly. This is very important in regards to the 'fifth bolt' on the rear of the gearbox as this sets the 'tilt' and hence the alignment in respect to the drive shaft. Any tips / tricks from those that have done this and that a 'newbie' should be aware? TIA Martin. Quote Link to comment Share on other sites More sharing options...
sirhc Posted January 14, 2014 Share Posted January 14, 2014 Measure the distance from the top and bottom of the pulley to the fan bulkhead. It should be the same. If not, add or remove shims until it is. Quote Link to comment Share on other sites More sharing options...
timbo Posted January 14, 2014 Share Posted January 14, 2014 Martin Remember the basic principle is you're trying to make sure the pulley is aligned to the bulkhead so that the fanbelt has a straight run. It really should (!) be that simple... Tim Quote Link to comment Share on other sites More sharing options...
Richard Farrant Posted January 14, 2014 Share Posted January 14, 2014 What you should be doing is lining the centre of gearbox shaft to centre of crankshaft, this is because the Layrub type couplings do not like running out of line and can melt if incorrectly aligned. I know first hand about the alignment as when the engine mountings and Hardy Spicer propshaft were changed with the Modification to Layrub due to cranks breaking, I was doing a lot of work on CVR(T) in REME workshops. We made a pointer that slid in the end of the crank and had a fixture which we could mark off and in turn stand it against the gearbox to check the shaft centre corresponded. I cannot recollect if this aligning tool was shown in the Mod Instruction, but it was a locally produced tool, simple and effective. Quote Link to comment Share on other sites More sharing options...
sirhc Posted January 14, 2014 Share Posted January 14, 2014 As you are putting the same gearbox back in the vehicle I don't think there will be to many problems. For info, when I put the engine and gearbox in my Scimitar I borrowed a tool to line it all up. This is because the engine mounts had been removed, and on the diesel they require shimming up. There is also adjustment left and right to worry about on the engine mountings. I assume your alignment tool was something similar Richard? Chris Quote Link to comment Share on other sites More sharing options...
Richard Farrant Posted January 14, 2014 Share Posted January 14, 2014 I assume your alignment tool was something similar Richard? Chris Chris, A bit simpler than that, I recollect there is a hole in the crank end, for a spigot bush in the car I suspect, and a shaft that fitted snugly in there with a point on. The other part was a flat plate with a vertical metal bar fixed to it, this was used to mark the height, engineers blue, pointer scribed it, turn it round and align with the box. Could also be checked in the other plane. Going back over 30 years ago when we first did this! Quote Link to comment Share on other sites More sharing options...
martinwcox Posted January 14, 2014 Author Share Posted January 14, 2014 Chris / Richard - perfect, picture explains all and as usual you guys are the best! Martin Quote Link to comment Share on other sites More sharing options...
Hen Hunter Posted January 14, 2014 Share Posted January 14, 2014 Great Picture - looks like some precision is needed in aligning the engine and gearbox up - did you spirit level the gearbox to the hull and then pack the engine to match up with the gearbox or visa versa? Bruce Quote Link to comment Share on other sites More sharing options...
sirhc Posted January 14, 2014 Share Posted January 14, 2014 Bruce, Gearbox in first, then aligned the engine to match. I got laser cut shims made in different thicknesses and swapped them about to get it right . The engine had to go in and out about 3 times. Chris Quote Link to comment Share on other sites More sharing options...
Hen Hunter Posted January 14, 2014 Share Posted January 14, 2014 Are the shims just flat pieces with the bolt holes drilled in them? Quote Link to comment Share on other sites More sharing options...
timbo Posted January 15, 2014 Share Posted January 15, 2014 I am sure I have read in one of the EMERS about measuring from hull floor and sidewall to the centre of the gearbox input shaft and then to the centre of the flywheel.. All very fiddly and error prone. Tool looks much more sensible..! Quote Link to comment Share on other sites More sharing options...
Tiffy_massive Posted March 21, 2014 Share Posted March 21, 2014 unless the gearbox is new just put the same shims back in place and all should be good. Not lifted a CVR(T) gearbox in a good few years but i sem to remember that the rear mounting bolt shims are usually wedge shaped to allow adjustment. If the gearbox is new then making sure the box is correctly aligned is vital. If it is out the flexi coupling will destroy itself and you will not be able to get the quill shafts in. Quote Link to comment Share on other sites More sharing options...
robin craig Posted January 22, 2016 Share Posted January 22, 2016 So, just to revisit this subject and clarify, if doing an engine swap we need to make one of these up or are the mounts machined to a standard that will ensure correct alignment of new engine to the gearbox? Thanks in advance Robin Quote Link to comment Share on other sites More sharing options...
sirhc Posted January 22, 2016 Share Posted January 22, 2016 Hi Robin, When changing the gearbox you need to adjust the shims on the centre bolt at the back to ensure its level. On the petrol engine if the mounting at the front hasn't been disturbed you shouldn't need to adjust anything when swapping engines. On the diesel the engine mounts are shimmed to ensure it is level when the vehicle was built, if swapping engines they don't need adjusting. I have a manual somewhere that says the thickness of shims should be stamped on the mount, I'll have to dig it out. My Scimitar had all the mounts removed and I had to fit some from another vehicle, I borrowed the alignment tool and had a load of shims laser cut from different thicknesses of stainless so I could set it up properly. Chris Quote Link to comment Share on other sites More sharing options...
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