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Vitesse Gearbox - Help!


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Hi All,

so I have a Gearbox out of  a Mk 2 Bond on the bench, prefix is HC which confirms its a Vitesse 2Lt.

It is in a pretty sorry state, and my first choice would be a known good replacement, (Overdrive seems fine by the way)

So some questions for you guys who will know, If I go down the replacement route, box only, where should i be looking? internet does not really appeal

spending considerable hard earned and ending up with much as I have now.

If I go down the rebuild route then Im going to need the input shaft  machined and the mainshaft nose cleaned up, and I think I read it is possible to fit a larger than standard bush to remedy this, is that so, and can anyone point me in that direction, I'm presuming you buy the bush and do the machining to suit?

John.

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I re work a good few gearboxes and i used a MP mainshaftand input shaft up size on my Vit6  

Mike does a good job , is nr  coventry   where are you based ???

the trouble with any 'reconditioned' from main suppliers is the worldly fact that core in a useable condition is getting hard to source 

due to the box being over stressed on a 6 cyl  few survive and the parts you need are all stuffed  , its the problem of 50 yrs of use .

new old stock or remanufactured can get pricey 

Pete

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21 hours ago, john morrison said:

If I go down the rebuild route then I'm going to need the input shaft  machined and the mainshaft nose cleaned up, and I think I read it is possible to fit a larger than standard bush to remedy this, is that so, and can anyone point me in that direction, I'm presuming you buy the bush and do the machining to suit?

If the mainshaft is knackered (they usually are) and the bore in the input shaft also, it is possible to buy new mainshafts with larger tips (18mm vs 1/2") and machine out the bore of input shaft to take a needle roller with outer sleeve.  I did this on my GT6 gearbox last year.  I also had a hole drilled through the tooth root so that the meshing gears would force-feed oil to the bearing, as lubrication is a problem with these.

http://sideways-technologies.co.uk/forums/index.php?/topic/7535-nick-chriss-gt6-mk-3/page/7/#comments

Only done 500 miles so far, but so far so good.....

Nick

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22 hours ago, Nick Jones said:

If the mainshaft is knackered (they usually are) and the bore in the input shaft also, it is possible to buy new mainshafts with larger tips (18mm vs 1/2") and machine out the bore of input shaft to take a needle roller with outer sleeve.  I did this on my GT6 gearbox last year.  I also had a hole drilled through the tooth root so that the meshing gears would force-feed oil to the bearing, as lubrication is a problem with these.

http://sideways-technologies.co.uk/forums/index.php?/topic/7535-nick-chriss-gt6-mk-3/page/7/#comments

Only done 500 miles so far, but so far so good.....

Nick

If it's not a trade secret Nick can you go into exactly what you did for the gearbox mod? What size and type bearing did you use and how was it located in the input shaft? Thanks

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Yes I can see that would be problem so think a 'machined' type needle roller bearing better as these come with an oil hole already drilled in the outer race. This would have to line up with a lube hole in the input shaft but the downside with this type of bearing is their larger outside diameter...

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No secret.  I worked it out for myself but later discovered that Mike Papworth does the same thing.

It's a NK1820 18id x 26od x 20 long roller bearing, which has a hardened outer sleeve of 26mm OD.  It has no inner sleeve and is intended to run directly on the 18mm shaft tip. Note that you can also get inner sleeves so could potentially tidy up an existing mainshaft tip and fit one if it wasn't too horrible (mine was!).

This is what my tip looked like
P1180903s.jpg.a8d6e1d0308a719b03fc6c4fa44c4954.jpg

and the input shaft - I think it had been run low on oil and maybe towed a long way - loads of sparkle.....
P1180908s.jpg.8af5ce42e72c5b42d79c73821f79c45d.jpg

Which washed out looked like this. Knackered.
P1180930s.jpg.b0bb0ea90e40a1ab1192615a1df9dd45.jpg

Machined out to this (it is hard, or at least surface hard, but the machinist managed it with a suitable insert tool and didn't even damage the insert - he's good though).  Note the oil hole at the bottom, the original is obscured by the new bearing sleeve (and IMO is in the wrong place anyway).  I forget the exact details, but IIRC I think it was a light interference fit for the 26mm sleeve and 21mm deep.
P1180948s.jpg.54d179f5adc810128575449e0018cc13.jpg

OIl hole other end in tooth root where meshing will give a pumping action.
P1180924s.jpg.94e6790048a63cdcef55dce78c8a550f.jpg

New bearing fitted.
P1180922s.jpg.b318ef1561e2cef2a4c18a6f91ff27b2.jpg
You can just see part of the original oil hole at the top of the bearing (later versions such as 1850 dolly and TR7 had this lower down, feeding the middle of the bearing) and my new hole at the bottom.

Hope this is useful.

Nick

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13 hours ago, Pete Lewis said:

i fitted a cased  needle roller for a 1/2"   repair it lasted 2 years , failed due to lubrication failure , as could not make oil holes in the needle case 

it was a light press fit .

pete

Yep, lubrication is key.  Rollers don't need alot of lube, but they do need some.  Seems like they ought to get lots, but they are in the eye of the storm, as it were.  The oil gets centrifuged away when the engine is running.

Originals with 1/2" tip had the oil hole drilled from here.......
P1180928s.jpg.7cc58f98418f3a80ad9a9255807b27d6.jpg

.....at an angle, to here.  No real reason for it to go where it is needed - gets centrifuged away.
P1180906s.jpg.dc288311a1e3dcf18fb787d0d9047b30.jpg

Later ones start at the same place but go straight.....
P1180925s.jpg.72f09dd668b8fc79cd9b9144f38f247f.jpg
Coming out mid-roller.  Some chance of this working, but centrifugal forces are still against you.  This is a single rail Dolly 1850 part.  Someone (I forget who now) told me that the late Sprint and Stag boxes had the oil hole drilled in the gear so oil was reliably forced into the bearing and it improved their life considerably.  Thought it worth a punt.

Left field alternative (not sure I'd try it behind a six though)

P1150215s.jpg.c81535f33a3b8936c009f52a4f046db0.jpg
slightly damaged mainshaft tip turned down to be parallel again,  Fitted with an oilite bush - interference fit on the tip (fit after synchro hub!!), running fit inside the input shaft.  Was possible because the mainshaft tip was only lightly damaged and the input shaft bore was ok.  You could also (maybe should) use a PB bush with a spiral oil groove on the OD - would be stronger.  So far this has lasted 6,700 miles behind an injected 1300 in my sons Spitfire, which is already 6k more than many were predicting.  Was cheap and easy.

Nick

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nick thats shows the options well,

mine had the mid way oiler, i dremel'd a groove down the outside of the needle case to get some idea of oil to the back of the assy , it lasted 2 years and i fitted the MP 18mm kit later sold her so no idea how well its lasted 

Pete

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Thanks Nick, thats exactly what I was thinking but using one of these and a centre drilled oil feed. I might go fo a 16mm long bearing as the mainshaft tip will only be 19mm. Were there any difficulties drilling the oil hole?

nkl.jpg

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My existing oil hole runs from the space between the synchro engage teeth and the main gear and is angled to come out the rear. The new hole will have to be completely separate and it'll be hard but I want to drill from a trough in about the middle of the main gear directly in to meet up with that bearing oil hole...

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Id want t,no why the tip mangled up,

lube aint always the problemo, esp if yer oil levels kept topped up,

most ar,nt

the crank spigot if worn is a real culprit for  tip wear, break,n

And, if ye wer t,get a recon exchnage, ye most likely loose yer deposit,cos box is kaput

 

 

I got some  re done  GT OD boxes wid mods,  ready t,go oot,

as ye well no.

I told Ye an R,  I would still help oot,  even though I was Disavowed.

but  obviously would rather eat Humble Pie than ask locally,  after   Disavowing , Me.

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6 hours ago, GT6M said:

Id want t,no why the tip mangled up,

lube aint always the problemo, esp if yer oil levels kept topped up,

most ar,nt

the crank spigot if worn is a real culprit for  tip wear, break,n

Agree that the crank pilot bush can be part of the problem, as can a distorted engine backplate.  Main problem is the tip bearing size is too damn small for forces involved and lube is marginal, even when oil levels are correct.

Nick

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  • 3 weeks later...

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