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'79 Esprit + '87 Engine = ?? Gearbox


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Hi,

I recently managed to secure myself a '79 Esprit (the good news). It didn't have an engine or gearbox (the bad news, kind of).

This is a long-term project so not too big an issue. I'm in the process of accumulating all the parts I'll need for a resto.

The obvious starting point is the engine and gearbox. I've managed to get hold of an engine.... just not the right one.

To be specific, I have an October '79 Esprit & a November '87 engine. Not for the purists but the looks of the S2 with the carb/turbo combo sounds perfect to me..... if the car had its original I wouldn't touch it but given that it doesn't this seems morally OK to me.

Harry Martens tells me the '88 US models used a Citroen gearbox & the bolt pattern on Citroen/Renault bell housings are the same, so this should be OK 

Could anyone share any experience regarding the feasibility of this with a uprated onboard Citroen box?

 

Thanks for your help with this!

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  • Gold FFM

Gearbox is dependant on hubs and braking setup.

renault = outboard brakes.

Citroen = inboard brakes.

hubs are different between the two. Renault hubs are genuine unicorn horns and priced by weight slightly more expensive than platinum.

Only here once

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I have the axles and am intending to use a period inboard box but just wasn't sure if there are interchangeability issues with the engine. 

Seems I'm all good on that front. The box I am looking at doesn't have hubs for the Citroen box so that is the starting point.

I'll try to find the hubs first.

Thanks for the heads up about the shims. I'll add it to my list!

Cheers 

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S2 Chassis design and boot floor arrangement is completely different at the rear from later models.  Also engine mountings, so it would be useful if you could find someone that has done this, to make sure no clearance issues with turbo manifolds and pipe routing etc.   Also  the positioning of the slave cylinder between NAs and Turbo turbo differs, but that's just a minor detail, of which there will be many!  

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Hi,

I had read somewhere about the chassis changes in the later Stevens cars. I think I remember them being wider?  I'll have to try to find some specifics.

In theory the gearbox should go in if it's already there in the US cars (I assume). 

Have people seen drawings for the chassis design for the respective cars? I'm seen them for other period cars but not the S2.

peteyg, I'm on the coast by Titchfield. Is there anything like a Hampshire meet?  

 

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The rear frame section is completely different as it is set up for the axles forming a suspension link.   On these models, the engine can only be removed from below.   From S3 onwards the suspension is fully linked to the chassis and the engine can only be removed from above.   But you are correct, the Citroen transmission was used in both chassis types.

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apologies for my lack of knowledge. OK, so the gearbox seems solvable. 

I guess the question is of engine mounts regardless of the rear frame. 

anyone know of if these are documented anywhere rather than me having to track down a car or friendly forum member to check?

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Maybe useful if you compare the parts books side by side, particularly for stuff like gearbox/engine mount differences.    I'm sure it will al be do-able, but there will definitely be some engineering challenges to solve, but if you are good with spanners all will be fine...   

I'm not aware of anyone that has retrofitted a turbo engine into an S2 (apart from Bell & Colville, back in the day....)

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5 hours ago, anditsoundslikebells said:

 

peteyg, I'm on the coast by Titchfield. Is there anything like a Hampshire meet?  

 

Sign up here...https://www.thelotusforums.com/forums/forum/430-topics/

I can help with lots of S2 stuff having owned mine for over 20 years but can't help much with the engine transplant you're planning.

Pete

Pete '79 S2

LEW Miss September 2009

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Welcome, Alex

The engine block mounting bosses were unchanged throughout the life of the Esprit, so an early block will work with the mountings suited to a later car chassis and vice versa. The expanded space afforded when the Turbo ( then S3 ) chassis was developed will accommodate the Turbo exhaust manifold whereas it's my belief there would be conflict if such an engine were tried in the S1/S2 chassis. The specific point of interference I'd expect concerns the left ( exhaust side ) tubular strut which ties the motor mount/trailing arm area to the aft crossbeam chassis section from which the transaxle hangers dangle on the early cars. Further concern would be for exhaust side engine mount longevity, that owing to marginality of the original design and proximity to the exhaust. On the other hand, a normally aspirated later engine should be entirely usable in any of the cars.

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  • Gold FFM

I would guess the main challenge here will be heat - The turbo cars had a lot of work to deal with cooling and extracting the additional heat of the turbo. I also think they had more heat shielding as well for this reason (I think). I would guess you will need a full width up-rated radiator (compared to an S2 one) - possible double or triple core and also some good spal or similar fans. And possibly some additional extraction fans or similar from the engine bay e.g. bilge pump style motors and fans in the ducts? The US Turbo cars had an additional cooling fan mounted on the engine cover to assist with this. Turbo cars also of course had a louvred tailgate to help with cooling as opposed to the glass one on the normally aspirated cars.

Turbo cars also had larger brakes on the front than the S2, so am guessing it would be good to upgrade the brakes a little - Lotusbits, PNM all do various upgrade kits to suit. I have a Willwood setup on my S3 from PNM which is great, much much better than standard set up. 

They also had different springs and shocks as well - I am guessing due to additional weight? so you might need to think about that too - adjustables or similar so you can get the ride height etc right. 

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