Bit of a long one this – sorry – but I thought it would be interesting (to some) and I need some guidance.
I am rebuilding a 1973 Lotus Europa Twin Cam Special.
One of the many questionable designs of the Europa is the cast aluminium rear axle housings, see picture “Arrangement” - “Example Install” - “Actual Housing”
Many enthusiasts "re-engineer" this area, at considerable expense, but the car did 73,000 miles with this arrangement, and I want to rebuild the car, not improve it.
What happens is that due to a lack of attention, the bearings (SKF 6206) fail and spin in the housings; many bodges prevail for this and in my case, one of the previous owners “dimpled” (for want of a better term), the bearing seat faces in an attempt to provide an interference fit for the bearings. (In all fairness it may have done as this is what I found after removing the bearings.) See “The Problem”
Some people use one of the many Loctite products but, being a bit “old school” – well just old tbh – I want to repair them properly and sleeve them.
Note: You can buy just about anything for a Europa, (except the ashtray… “yes” seriously – they are just unobtainable and if one turns up, three figures prices have been asked), you can buy new aluminium axle housings, (£230 + VAT ea), but I don’t have that spending power.
I don’t have a super equipped workshop, (I would love a Colchester Bantam and a small Bridgeport – but for the amount of time I would actually use them, I simply can’t justify the cost), but I do have a small EMCO lathe, (albeit a bit of a toy by engineers standards), and with this I reckon I can line bore these housings and fit sleeves. See “Got This”
I have been thinking around this issue for some 12 months, (on and off obviously), and the final piece of the jigsaw came together when I finally found some round square bit holders being sold in Canada !!! (I could not find these anywhere in the UK – I bought 2, one ¼” and one 3/8” for square bits) See Round square bit holders 1,2,& 3,
I have made a mock up in wood, (don’t laugh; I just wanted to “see” the idea). See Mock Up 1 & 2. The “boring bar” is represented by a piece of plastic pipe. In reality the support bracket bolted to the T slots on the cross slide will be 12mm plate and the boring bar 40mm.
Without boring you all – the pictures hopefully tell the story.
There are machine shops where I live, but I have been quoted more than the cost of buying new ones to sleeve these…. Also, I don’t have TIG equipment, (I do have a small solid state MMA machine which has proved to be superb…but not for this !!), so building up the housings and thereafter machining, is not an option.
So – reckon this will work? Or am I missing something?
I am rebuilding a 1973 Lotus Europa Twin Cam Special.
One of the many questionable designs of the Europa is the cast aluminium rear axle housings, see picture “Arrangement” - “Example Install” - “Actual Housing”
Many enthusiasts "re-engineer" this area, at considerable expense, but the car did 73,000 miles with this arrangement, and I want to rebuild the car, not improve it.
What happens is that due to a lack of attention, the bearings (SKF 6206) fail and spin in the housings; many bodges prevail for this and in my case, one of the previous owners “dimpled” (for want of a better term), the bearing seat faces in an attempt to provide an interference fit for the bearings. (In all fairness it may have done as this is what I found after removing the bearings.) See “The Problem”
Some people use one of the many Loctite products but, being a bit “old school” – well just old tbh – I want to repair them properly and sleeve them.
Note: You can buy just about anything for a Europa, (except the ashtray… “yes” seriously – they are just unobtainable and if one turns up, three figures prices have been asked), you can buy new aluminium axle housings, (£230 + VAT ea), but I don’t have that spending power.
I don’t have a super equipped workshop, (I would love a Colchester Bantam and a small Bridgeport – but for the amount of time I would actually use them, I simply can’t justify the cost), but I do have a small EMCO lathe, (albeit a bit of a toy by engineers standards), and with this I reckon I can line bore these housings and fit sleeves. See “Got This”
I have been thinking around this issue for some 12 months, (on and off obviously), and the final piece of the jigsaw came together when I finally found some round square bit holders being sold in Canada !!! (I could not find these anywhere in the UK – I bought 2, one ¼” and one 3/8” for square bits) See Round square bit holders 1,2,& 3,
I have made a mock up in wood, (don’t laugh; I just wanted to “see” the idea). See Mock Up 1 & 2. The “boring bar” is represented by a piece of plastic pipe. In reality the support bracket bolted to the T slots on the cross slide will be 12mm plate and the boring bar 40mm.
Without boring you all – the pictures hopefully tell the story.
There are machine shops where I live, but I have been quoted more than the cost of buying new ones to sleeve these…. Also, I don’t have TIG equipment, (I do have a small solid state MMA machine which has proved to be superb…but not for this !!), so building up the housings and thereafter machining, is not an option.
So – reckon this will work? Or am I missing something?