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Discussion Starter #1 (Edited)
Its been documented that Final Edition Esprits differences are the following:

-Bilstein Dampers with stiffened settings and adjustable spring platforms
-Uprated Eibach Springs
-Smart Tire system monitors temperature and pressure of each tire individually
-New unpainted Stainless steel mesh grills
-Esprit decal in rear quarter windows has an etched finish
-Stainless steel plaque with the engine builders name on the plenum
-All mesh grilles on the front valence and engine compartment are stainless steel in silver finish rather than black.
-The tow how is silver in most models (although I did see some with back tow hooks)
-Stainless steel perforated rear valance ("cheesgrater") with new rounded slots and a satin finish
-The quilted stitching on the seat backs and perforated leather on the seat bottoms and door panels
-Passenger side airbag cover is embossed with the Lotus roundel
-Elise style climate control knobs with a brushed aluminum finish
-New style shorter gear knob is finished in brushed aluminum and topped with a Lotus Badge


I've also confirmed FE Esprit ECU actually have the Sport 350 code. While doing my rebuild, I confrimed something else.

-The casting on the plennum is a little different on the FE plennums vs the others.

-The block on the later V8's is a little different from the early V8's. The casting on the later blocks have some patches in the coolant pasages around the cylinders and in the oil passages on the side near the oil pan. Although I think this change happened sometime around 2001. No one seems to know why or when the change happened. Early top, late bottom.



-FE cranks are NOT the same as other V8 cranks. The shape of the counterweights is different. JAE who has many cranks in stock has never seen a FE crank before. No one seems to know why Lotus made the change. Regular V8 on the left, FE on the right.



Is this the reason why some people say the FE V8 seems to rev smoother than others? How knows. Just thought I'd share.
 

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I am confused by what you mean by "patches in the coolant passages". What am I missing in the first pic?

The crank out of my 2001 does not look like either of those cranks from what I can tell in the pics I have. I have a pic of the casting number, C918E. Do either of those cranks have a similar number?
 

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My car sneezes
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Discussion Starter #3
I marked up my pics to show it better.

You are also right about the mid-years cranks. Those have smoother, rounder edges than the 97 crank posted above but it's still the same basic shape as the 97. The Final Editions have a totally different shape to the counterweights. All 3 version have C918 stamped on them.
 

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With regard to the casting differences in the blocks, it is likely that the "patches" do not represent a change, per se. Rather, these are areas where the casting mould was repaired or even possibly developed a minor defect (flaw) in its surface profile during later part runs ---- therefore, the later blocks may actually be imperfect (cosmetically --- not functionally) compared to the earlier blocks.

...
Is this the reason why some people say the FE V8 seems to rev smoother than others?...
Yes :)

With regard to the crank changes, without knowing the detailed measurements and just taking a visual impression, the shape modifications would have the following effects...... The total mass of the two cranks is probably identical (or very nearly so), however the profile of the counter-arms of the FRE crank (the one on the right) shifts a significant amount of mass closer to the centerline of the shaft ---- this effectively lowers the mass-moment of inertia about the rotation axis ---- and, this would definitely result in a crankshaft that is easier (takes less energy) to spin.

Incidentally, my '03 (though not an FRE version) has that same crank, as the one on the right. So, this crank made it into the engines of at least some of the later V8s, too.....and not just the FRE engines ;).

PS ---- Please get those cranks supported by (resting on) their main journals, ASAP :) Letting a flat-plane crank sit on its arms like that can impart permanent distortions. We see this often with Ferrari cranks, which are actually made from machined billets....and, thus even stronger than those more flimsy cast cranks Lotus uses :eek: !
 

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Brian Angus @ Lotus Hethel would know the exact reason for the observed design changes on those late 918 engines.

Lotus Engineering has a neat yellow LHD V8 Esprit fitted with one of 2 made 90 degree crankshafts.
 

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Shocking how such a small car company with so many challenges made so many changes every year to the Esprit.

I would guess many of the changes had to do with changing suppliers.


Sent from my iPhone using Autoguide
 

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All 3 version have C918 stamped on them.
Is there a letter after the C918? I wonder if they could reference revisions...

With regard to the crank changes, without knowing the detailed measurements and just taking a visual impression, the shape modifications would have the following effects...... The total mass of the two cranks is probably identical (or very nearly so), however the profile of the counter-arms of the FRE crank (the one on the right) shifts a significant amount of mass closer to the centerline of the shaft ---- this effectively lowers the mass-moment of inertia about the rotation axis ---- and, this would definitely result in a crankshaft that is easier (takes less energy) to spin.
Just spit balling here but wouldn't shifting mass closer to the center-line between cranks cause balance issues and defeat the purpose of the counter weights on the crank?

I would say that there were updates done for windage but they don't look radically different. Maybe just a difference in suppliers?
 

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Looking at the cranks, I'm going to say the one on the right has been lightened by removing some of the weight of the counterweights, and I'll bet the rod/piston combo has been lightened as well. Less overall rotational weight will allow the engine to rev quicker.
 

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Its been documented that Final Edition Esprits differences are the following:

-Bilstein Dampers with stiffened settings and adjustable spring platforms
-Uprated Eibach Springs
-Smart Tire system monitors temperature and pressure of each tire individually
-New unpainted Stainless steel mesh grills
-Esprit decal in rear quarter windows has an etched finish
-Stainless steel plaque with the engine builders name on the plenum
-All mesh grilles on the front valence and engine compartment are stainless steel in silver finish rather than black.
-The tow how is silver in most models (although I did see some with back tow hooks)
-Stainless steel perforated rear valance ("cheesgrater") with new rounded slots and a satin finish
-The quilted stitching on the seat backs and perforated leather on the seat bottoms and door panels
-Passenger side airbag cover is embossed with the Lotus roundel
-Elise style climate control knobs with a brushed aluminum finish
-New style shorter gear knob is finished in brushed aluminum and topped with a Lotus Badge


I've also confirmed FE Esprit ECU actually have the Sport 350 code. While doing my rebuild, I confrimed something else.

-The casting on the plennum is a little different on the FE plennums vs the others.

-The block on the later V8's is a little different from the early V8's. The casting on the later blocks have some patches in the coolant pasages around the cylinders and in the oil passages on the side near the oil pan. Although I think this change happened sometime around 2001. No one seems to know why or when the change happened. Early top, late bottom.



-FE cranks are NOT the same as other V8 cranks. The shape of the counterweights is different. JAE who has many cranks in stock has never seen a FE crank before. No one seems to know why Lotus made the change. Regular V8 on the left, FE on the right.



Is this the reason why some people say the FE V8 seems to rev smoother than others? How knows. Just thought I'd share.
I was curious about your claims via the engine block and crank, so contacted a friend who works at Lotus for his comments which are below:-

Hi Wayne,

I had a look at the pictures.



The Marks on the Block - They are marks from the casting equipment and not design changes.

They are from Chills in the Sand Castings.

The Casting Tooling gets refurbished occasionally so will be more evident on some castings.



Crankshafts.

There has been ‘minor’ crankshaft variations due to the Machining & Balancing operation over the period of Esprit V8 production.

The Forging has not changed since the start of production

There were no specific engine design changes for the Final Edition cars.

As stated above the crankshaft tooling – Forging not Casting has not changed since 1996. The Crankshaft Design (C918E0019 on Forging) has not changed over the life of the V8 Engine

Any component design variations (including blocks, heads etc.) would not have been made introduced as specific changes for any MY updates (like Final Edition) – they would have been linked to specific batches of components supplied to production schedules.

Components like crankshafts have supplier serial numbers which are recorded in the Engine Build Book. These components can be traced back to a particular supplier batch.

The crankshaft from the Final Edition in the picture looks to be from a standard C Level Forging.

That component was not produced on production tooling by our Crankshaft machinist. The source of that component is not known to us – the shape of the webs is not to our drawing.

The supplier has made the comment that the crankshaft has not been picked up correctly for machining – that can be seen from the offset of the main bearings on the picture with the 2 cranks.

Comparing the crankshafts in the picture you can see the difference in the position of the main bearings – the one on the left is central to the casting and the one on the right has the mains offset to the left which would make balancing difficult.

The crankshafts we currently have in stock are to our drawing – see attached picture.



Hope this goes some way to explain things



Cheers



Brian


So it seems your crank has been "modified" by a machine shop and your block is the same as previous 918 blocks.

Perhaps your engine suffered a spun bearing or two at some time and a PO was persuaded to "ballance" or "lighten"the crank?

Wayne
 

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Wayne,
Interesting information from your contact at Lotus. Thanks for updating, though I am a bit upset that perhaps there wasn't something else 'special' about the FE's. Doesn't really make sense to make a special crank for the FE's to improve throttle response and not mention it in press releases or the brochure.
Also, I don't suppose you'd mind posting the attached drawing, would you? Facinating stuff.
Derik
 

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Wayne,
Interesting information from your contact at Lotus. Thanks for updating, though I am a bit upset that perhaps there wasn't something else 'special' about the FE's. Doesn't really make sense to make a special crank for the FE's to improve throttle response and not mention it in press releases or the brochure.
Also, I don't suppose you'd mind posting the attached drawing, would you? Facinating stuff.
Derik
Hi Derik,
It was an image sent of the current 918 crankshaft offered by Lotus ASO that was produced to the factory drawing.
Wayne

 

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There is only 1 listing in the Parts Catalog for a V8 crankshaft (C918E0019F). No variation from year to year or FE-exclusive part is listed.
 

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So Gonzo, how did you end up with this crank? Do you really someone changed it out before you got the car?
 

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My car sneezes
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Discussion Starter #18
Very interesting info Wayne, that's what I suspected when it came to the block. Unfortunately I think he's off when it comes to the cranks. The pics I posted were from Kirk's cars (who can forget Lotuson74). Both his 97 and 04 are currently taken apart and the cranks were pictured. My crank looked just like Kirk's '04 crank and Finnerty said his '03 non-FE also looked like the '04 crank posted above. I highly doubt we all have "modified" cranks. There's something else Lotus isnt saying.

Although 04Esprit is right, there is only one part number for a V8 crank.
 
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