1971 Lotus Elan Restoration

[NTG999]

Not sure if anyone is interested? but I am about to start the restoration of my 1971 Lotus Elan Sprint, I have owned this car since the mid 80s and around 1990 I went through everything including replacing the chassis with a Lotus galvanised one, time to do the bodywork and refresh everything else at the same time.....

Totally different proposition to restoring a Clio, let me know and I will post some pictures

Attached pictures to confirm my (non robot) credibility , my first Clio was BG 182 FF sold it to buy the 172 Cup, this must have been owned by a few people on here, it has had about 100 owners!!

 

[Clio_fool]

Yes show me more of the Lotus😍.

 

[gez 172]

Definitely! Full in-depth write up, please!

 

[David Stuart]

I love the lotus elan. One of my favourite classic cars.


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[Paul172sport]

Definitely one my favourite classics.

Proper drivers classic

 

[TheEvilGiraffe]

No one cares about the Clios.. Lotus please !!

Attached pictures to confirm my (non robot) credibility

That sounds like something a robot would say...

 

[dave120]

Looks like a very clean Cup! Will look forward to seeing some progress on the Lotus.

 

[CrippsCorner]

Very cool.

 

[NTG999]

The Lotus picture I posted was about 3 years ago, very foolishly I put it under cover outside while I had another car in the garage and it suffered very badly with damp, a costly mistake
Recent picture, before first job stripping body, paint and bodywork booked for 3rd week in December

 

[Coops Mk1]

Mega, looking forward to the project

 

[imprezaworks]

Love it

 

[Scrooge]

Yep.

 

[yeecup]

awesome cars. look forward to the progress on it.

 

[Daz...]

Very cool, looking forward to this one 👍🏻

 

[italian job]

Love these, really interested to see your progress

 

[George@RTR_Parts]

Cool car, following

 

[Tighten My Nuts]

These are mad light, something like 700kgs aren't they?

Nice. I look forwartd to seeing how this progresses.

 

[NTG999]

That's correct, mine is a Sprint which has the big valve cylinder head which as standard was sold as 126BHP, this gives a power to weight ratio of approx 180BHP per tonne, slightly more than my 172 Cup 😏 Sprints also had a lower final drive ratio of 3.77 instead of 3.55 to reduce 0-60 times, 4 speed gearbox and you can redline it in 4th!
Part of my restoration/refresh is an engine rebuild, I will probably use the same L14 cams currently fitted, with some porting etc. should give a tractable and real 135BHP, racing Elans can make about 200BHP

 

[David Stuart]

That's correct, mine is a Sprint which has the big valve cylinder head which as standard was sold as 126BHP, this gives a power to weight ratio of approx 180BHP per tonne, slightly more than my 172 Cup [emoji57] Sprints also had a lower final drive ratio of 3.77 instead of 3.55 to reduce 0-60 times, 4 speed gearbox and you can redline it in 4th!
Part of my restoration/refresh is an engine rebuild, I will probably use the same L14 cams currently fitted, with some porting etc. should give a tractable and real 135BHP, racing Elans can make about 200BHP

Very cool. It’s amazing the difference gearing makes to how quick a car feels.

What carbs do these run as standard? Is it twin Webbers?


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[NTG999]

I fitted a 4.125 diff for a while, 0-60 probably less than 6 seconds, got a bit wearing after a while so reverted to 3.77

There has been different carbs fitted through the life of the Elan range, mainly Webers but also Strombergs and Dellortos, mine has twin 40DCOE Webers, in effect 1 choke per cylinder, this was the days of 5 star petrol, thrashing round country lanes = 15mpg

 

[NTG999]

Making progress, jacked up to check everything clear then 4 mates lifted body; approx 100kg and rolled out chassis

 

[NTG999]

Body loaded up, ready to be delivered for the long (and expensive) process of paint removal, grinding out cracks and re-fibreglassing

 

[Tighten My Nuts]

Now that's super-light! Those rear wishbones!

 

[NTG999]

Never really thought about it, but when you look at them they look like skinny broom handles!

 

[NTG999]

Engine, gearbox, propshaft and diff picked up today by JS Motorsport, at a push I could rebuild the engine myself but only to standard spec and I want a bit more, standard was 126BHP, aiming for about 140BHP ish
Engine will be the big spend, gearbox has worn synchros, propshaft needs checking for balance, diff OK but makes sense to have checked

 

[Twingo 1??]

This is going to be so rewarding when it's back together. My Hillman Avenger rally car used to do 8mpg on twin 40s until a fuel line split and it went up!

 

[massiveCoRbyn]

What sort of work is required to get 140bhp? Few four-pots sound better than a Lotus twink!

 

[NTG999]

Mainly different cams and head work, engine should be stripped and measured by the end of the week so I should get the proposal of the suggested work, I will post it up when I get it through

 

[NTG999]

Work required, basically all worn out....though it is 50 years old and has been continually thrashed

Cylinder Head
L14 cam fitted in both inlet and exhaust banks Inlet base circle .879” (std dowel fitted) Exhaust base circle .902” (2˚ dowel fitted) Shims fitted – inlet .159” .161” .154” .154” Shims fitted – exhaust .160” .147” .167” .164” Head thickness 4.608” around .020 - .025” material has previously been removed Cam bearings scored requiring replacement Excessive play in various cam follower sleeves (sleeves - tapered .0015”) Requires new cam follower sleeves and new cam followers All valve seats poorly cut and recessed in chamber All valve seats require replacement along with guides and valves Engine running L14 cams which is a good road cam At present std springs are fitted which require replacement At this point using the L14 cam; a better valve spring and retainer would be beneficial

Block
Cylinder block is at +040” 83.55mm and requires a re-bore Piston measured giving .005” piston to bore clearance Block can be bored to +060” and new pistons supplied Crankshaft is at std / std with some marking on main and big end journals Crank requires a re-grind to +010/ 010 Having re-ground crank all components will be rotationally balanced, Fly wheel requires re-facing and a new ringear fitted Clutch cover and clutch drive plate to be replaced All core plugs and oil gallery bungs to be replaced Water pump, timing chain, slipper pad, quadrant sprocket and pin to be replaced At this point a new cassette type water pump front cover should be considered. I will put this this into additional costings if required Oil pump to be stripped / inspected (the earlier castings are superior to the new ones and can be re-built accordingly) All new fasteners i.e. flywheel bolts and big end bolts to be replaced All gaskets and seals to be replaced Head gasket type dependant on final specification The engine would be fully re-built using all parts as listed below All machining / modification carried out and the unit would be dyno tested i.e. run in etc and optimised ready for turn key installation

Machining
Remove valve seats and fit new valve seats Remove valve guides, fit new Colsibro guides Selectively hone valve guides Cut valve seats as required and blend into valve throat and port Also blend into chamber and re-shape All valves lapped in and vacuum tested for efficiency Cylinder head re-faced Machine out all cam follower sleeves Fit new sleeves Machine out cam cutouts Bore and hone out follower sleeves to new cam followers Re-bore cylinder block and hone to give correct piston to bore clearance RE-grind crankshaft / polish etc and cracktest Re-face flywheel assembly Fit new ringear Carry out full rotational balance Remove broken stud from in manifold Remove broken union from thermostat housing

 

[David Stuart]

Work required, basically all worn out....though it is 50 years old and has been continually thrashed

Cylinder Head
L14 cam fitted in both inlet and exhaust banks Inlet base circle .879” (std dowel fitted) Exhaust base circle .902” (2˚ dowel fitted) Shims fitted – inlet .159” .161” .154” .154” Shims fitted – exhaust .160” .147” .167” .164” Head thickness 4.608” around .020 - .025” material has previously been removed Cam bearings scored requiring replacement Excessive play in various cam follower sleeves (sleeves - tapered .0015”) Requires new cam follower sleeves and new cam followers All valve seats poorly cut and recessed in chamber All valve seats require replacement along with guides and valves Engine running L14 cams which is a good road cam At present std springs are fitted which require replacement At this point using the L14 cam; a better valve spring and retainer would be beneficial

Block
Cylinder block is at +040” 83.55mm and requires a re-bore Piston measured giving .005” piston to bore clearance Block can be bored to +060” and new pistons supplied Crankshaft is at std / std with some marking on main and big end journals Crank requires a re-grind to +010/ 010 Having re-ground crank all components will be rotationally balanced, Fly wheel requires re-facing and a new ringear fitted Clutch cover and clutch drive plate to be replaced All core plugs and oil gallery bungs to be replaced Water pump, timing chain, slipper pad, quadrant sprocket and pin to be replaced At this point a new cassette type water pump front cover should be considered. I will put this this into additional costings if required Oil pump to be stripped / inspected (the earlier castings are superior to the new ones and can be re-built accordingly) All new fasteners i.e. flywheel bolts and big end bolts to be replaced All gaskets and seals to be replaced Head gasket type dependant on final specification The engine would be fully re-built using all parts as listed below All machining / modification carried out and the unit would be dyno tested i.e. run in etc and optimised ready for turn key installation

Machining
Remove valve seats and fit new valve seats Remove valve guides, fit new Colsibro guides Selectively hone valve guides Cut valve seats as required and blend into valve throat and port Also blend into chamber and re-shape All valves lapped in and vacuum tested for efficiency Cylinder head re-faced Machine out all cam follower sleeves Fit new sleeves Machine out cam cutouts Bore and hone out follower sleeves to new cam followers Re-bore cylinder block and hone to give correct piston to bore clearance RE-grind crankshaft / polish etc and cracktest Re-face flywheel assembly Fit new ringear Carry out full rotational balance Remove broken stud from in manifold Remove broken union from thermostat housing

Exciting. I love old classic engine rebuild. And we have defiantly lost something with the stage tuning / boost and timing maps on modern cars.

I got the machining done locally but build my minis engine at home. It’s super interesting and very satisfying work. But you need the time and patience so you don’t end up rushing and forgetting stuff.

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[NTG999]

Exciting. I love old classic engine rebuild. And we have defiantly lost something with the stage tuning / boost and timing maps on modern cars.

Very true, tuning with laptops is a different world

 

[NTG999]

Chassis stripped and pressure washed, though it's galvanised and still in good shape I'm going to have it powder coated to freshen it up

 

[NTG999]

Went to see work in progress on the body, all paint pretty much stripped off, only one area where evidence of slight accident damage at the front which will be sorted

 

[Kev@KAM]

Chassis stripped and pressure washed, though it's galvanised and still in good shape I'm going to have it powder coated to freshen it up
View attachment 1519695

I'd personally look at other specialised underbody paints rather than powder coating as once damaged or cracked powder coating can let in water behind it.
There are lots of heavy duty anti rust paints that will be far superior. I really like the Buzzweld range but there are others.

 

[NTG999]

Hi, if the chassis was bare steel I would definitely use a specialised coatings, I did consider them. My thought process is under the powder coating it is still galvanised and I am only doing it for cosmetic rather than protection reasons, luckily the car is kept in a warm garage (central heating boiler in there) and unlikely to be out in the rain

 

[NTG999]

Some gratuitous engine pics

 

[NTG999]

Chassis back from powdercoaters, very pleased with result, assembly time 😁 different proposition to working on my Clio

 

[David Stuart]

I take it you can build it into a rolling chassis and then get a few helpers just to lift the body on?


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[NTG999]

That's right, chassis can be completely built up, carbs have to off though to slot the body back on, bare body is 2 man lift