Lotus Marques

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The latest product news from Lotus Marques.

New and improved Lotus twin cam oil filler cap A026E0415

Monday, 09 February 2026 16:42 Product News
Does your Lotus Elan have a leaking oil filler cap?
Have you been unable to repair the original cap or find a new replacement rubber sealing washer?

Lotus Marques has solved these problems by manufacturing a faithful copy of the original cap.
This high quality alloy cap screws into an insert and is guaranteed not to leak as it has an integral oil seal located in the cap.
The original Lotus designed filler cap has a simple “twist and lock” action to secure it to the cam cover.
This is achieved by a concealed spring and two small protruding pins located inside the oil filler opening.
Also concealed in the cap is a rubber washer that originally provided a simple oil seal.
With the passage of time these caps have seen significant service and have developed various problems.
This includes - broken internal spring clips, broken cam cover locking pins and a faulty or worn rubber sealing washer.
These problems usually culminate in a poorly sealing cap and resultant oil leak.
Unfortunately these caps are difficult to repair and the original part (Lotus Part number A026E0415) is now obsolete from the Lotus Factory

Lotus twin cam oil filler cap, aluminium alloy
Photograph kindly supplied by Matthias Rode from Germany

The new designed cap is supplied with a simple threaded insert that is easily installed in the cam cover of any Lotus twin cam engine.

Be aware of alternative copies of this alloy oil filler cap that do not supply a threaded insert and rely on the steel pins to secure the original cap.
Screwing an alloy cap on to hardened steel pins is certain to shave off aluminium particles as these will fall onto the cam lobe and valve gear directly below.
These same aluminium particles will circulate in the oil and cause extensive damage to internal engine components.

TC-oil-filler-cap-and-threaded-insert
Photograph kindly supplied by Matthias Rode from Germany

Installation of the new cap
The recipient cam cover needs to have the internal locking pins removed and the oil filler opening machined to accept the insert.
The threaded insert should be a light interference fit and be installed with Loctite 620.
Once the Loctite has cured, the polished cap is simply screwed into the cam cover where it takes on the appearance of the original stainless steel item.

Lotus Marques stocks a range of oil filler caps to suit the following Lotus vehicles-
Lotus Elan S1 – S4 and Sprint
Lotus Elan +2
Lotus Europa twin cam
Ford-Lotus Cortina Mk 1, 1558cc
Ford-Lotus Cortina Mk 11, 1558cc
Lotus Elite 907, 2.0Ltr
Lotus Eclat 907, 2.0Ltr
Lotus Esprit 907, 2.0Ltr
Lotus Esprit 912, 2.2Ltr
Lotus Esprit 910, 2.2Ltr including Hci

Part numbers for the various oil filler caps to suit the vehicles above are as follows-
Early domed cap (Lotus part number 036E6018)
Three eared cap (Lotus Part number A026E0415)
912 oil filler cap (from engine # 25190) ratchet type 38.7mm (Lotus part number A912E6965F)
910 oil filler cap (prior engine # 25190) not ratchet type 38mm (Lotus part number A910E6779F)



New improved oil filler cap for early Lotus twin cam engine

Saturday, 07 February 2026 18:20 Product News
Are you looking to have an oil-tight Lotus twin can engine but the oil filler cap leaks?
There can be several reasons why an oil leaks originates from the oil filler cap and this includes the following items-

1)    Broken retaining spring clip (see photograph of faulty filler cap below)
2)    Broken, missing or loose locking pins inside cam cover
3)    Broken/faulty internal cap seal
4)    Distorted cap
5)    Distorted cam cover oil filler neck

Any of these faulty items can result in hot oil escaping and making a mess on your engine.

cam-cover-and-original-oil-filler-cap1r


The photograph below depicts two common problems associated with the early style oil filler cap.
The first and most obvious problem is the broken spring clip that is riveted to the underneath the cap.
This simple spring is responsible for engaging on two steel pins (180 degrees apart) located inside the oil filler neck at the rear of the cam cover.
The locking action of the “butterfly-like” spring appearance is brought about by the cap being rotated and the hidden pins engaging at both ends of the spring.
At the time of writing, the author has no knowledge of replacement springs being available so oil filler caps maybe repaired.

The other problem with this oil filler cap is the tired and distorted rubber sealing ring.
This sealing ring prevents oil escaping when the filler cap is secured in its correct position by the spring underneath.

original-oil-filler-cap2r

The solution to the original problematic oil filler cap is to design a quality replica part that has a hidden integral oil seal.
Designing a faithful replica cap with a concealed threaded insert that’s oil-tight is made possible by using Solidworks 3D CAD software.
Reproducing the original “twist and lock” filler cap (Lotus part number 036E6018) requires careful measurement to replicate the subtle dome and knurled edge around the circumference.
The 3D software model of the cap allows a threaded insert to be incorporated into the design.
This ensures the two mating parts screw together and create an oil-tight seal.

tc-oil-filler-cap-036e6018---alloy3r

These caps have been CNC machined from aluminium 6061 to produce a high quality part that is designed to last.

tc-oil-filler-cap-036e6018---alloy4r


Installation of the new cap
The recipient cam cover needs to have the internal locking pins removed and the oil filler opening machined to accept the insert.
The threaded insert should be a light interference fit and be installed with Loctite 620.
Once the Loctite has cured, the polished cap is simply screwed into the cam cover where it takes on the appearance of the original stainless steel item.

Lotus Marques stocks a range of oil filler caps to suit the following Lotus vehicles-

Lotus Elan S1 – S4 and Sprint
Lotus Elan +2
Lotus Europa twin cam
Ford-Lotus Cortina Mk 1, 1558cc
Ford-Lotus Cortina Mk 11, 1558cc
Lotus Elite 907, 2.0Ltr
Lotus Eclat 907, 2.0Ltr
Lotus Esprit 907, 2.0Ltr
Lotus Esprit 912, 2.2Ltr
Lotus Esprit 910, 2.2Ltr including Hci

Part numbers for the various oil filler caps to suit the vehicles above are as follows-

Early domed cap (Lotus part number 036E6018)
Three eared cap (Lotus Part number A026E0415)
912 oil filler cap (from engine # 25190) ratchet type 38.7mm (Lotus part number A912E6965F)
910 oil filler cap (prior engine # 25190) not ratchet type 38mm (Lotus part number A910E6779F)

Copyright © 2026 Lotus Marques

Gearbox cross member for five speed gearbox installation in a Lotus Elan or Elan 2 + 2.

Sunday, 21 September 2025 17:18 Product News
If you own a Lotus Elan or an Elan 2 + 2 with a four speed gearbox, then from experience there is a wish that that the Ford 2000E gearbox had an overdrive or fifth gear.
Whilst the ford 2000E gearbox was manufactured in a variety ratio’s it has short-comings when used for long distances on the motor-way (free-way).
A popular modification is to change out the differential with a different ratio to reduce the engine rpm at high speed.
This has a draw-back where the effective vehicle acceleration is reduced and this is quite noticeable at the “traffic-light grand-Prix”.
The simplest solution is to install a Lotus five speed gearbox as these where originally installed in the Elan 2+2 S130/5 and some the last the Elan Sprint’s that were produced.

gearbox-crossmember-5-speed1r-wm

At the time, this gearbox was a revolutionary step for the Lotus Factory to install in a road going vehicle as four speed gearboxes were the norm.
This gearbox is unusual as the internal components were sourced from a Leyland Austin Maxi vehicle with a 1750cc transverse engine.
Lotus produced their own aluminium gearbox case and re-engineered the gearbox internal shift mechanism so it ran down the side of the gearbox.
Unfortunately this arrangement does not produce the slick/positive gear change experienced with the Ford 2000E gearbox.
However it does result in a useful fifth gear (over-drive) and provides a significant drop in engine rpm at high speed.
These gearboxes still appear as second-hand units and can be successfully refurbished but spare parts are becoming scarce.
Installing one of these gearboxes requires the original bell-housing, unique clutch pressure plate and friction plate, clutch lever, release bearing assembly, unique prop-shaft and custom cross-member.
Too often the cross-member becomes damaged or lost over the passage of time.
However, this is a simple component that can be re-manufactured by laser-cutting, bending and welding.

base-plate1r

The gearbox cross-member for the five speed gearbox is distinctly different when compared to the four speed gearbox cross-member.
Both cross-members share the same rubber mounting part number 116E-6068B.
However the mounting position and fastener holes located in the chassis are different.

Manufacturing high quality components starts with being able to measure and draw in CAD software such as Solidworks 3D.
This software allows the component to be drawn up as the solid final part.
The gearbox cross-member comprises of three components which are accurately located by integral tabs and slots.
These parts start life from a flat sheet of steel, they are then laser cut, bent where required, slotted together and then carefully welded to minimise distortion.

base-plate-bridge1r

The new gearbox cross-member has a corrosive protective coating and is ready to be painted in the final colour of choice.
All the relevant fasteners and rubber mount may be supplied at additional cost if required.
Cost of the new cross-member is $150.00 excluding GST.
Pricing information is correct as of 21/9/2025 but may alter with time and currency exchange rate fluctuations.
Contact Lotus Marques This e-mail address is being protected from spambots. You need JavaScript enabled to view it This e-mail address is being protected from spambots. You need JavaScript enabled to view it for more information about new replacement parts for your Lotus vehicle project.

                                                          Copyright © 2025 Lotus Marques          

New and improved replacement clutch slave cylinder A082Q6031F

Saturday, 10 May 2025 12:33 Product News
New aluminium alloy clutch slave cylinder A082Q6031F for Lotus Esprit

The original clutch slave cylinder fitted to the Lotus Esprit S3 onwards is of a cast iron construction with a mild steel electro-plated piston.
Unfortunately this combination results in a component that has inherent design problems.
This type of cylinder may last for a while if the rubber weather seal remains intact and the hydraulic fluid is changed periodically.
Cast iron is prone to rust and it’s heavy plus has poor tensile strength. The recommended hydraulic fluid used in the clutch system is hygroscopic which this means it naturally absorbs moisture from the air. So, if you combine a cast iron cylinder with hydraulic fluid that is contaminated by moisture, it will produce rust.
Rust can be highly abrasive, so if the cylinder bore becomes corroded then it will eventually destroy the hydraulic seal on the piston.
In severe cases the internal piston can be badly corroded to the point where it will no longer move.
The solution to this problem is to design and manufacture a new cylinder that is not prone to rust.

Initial thoughts were to consider the best material to produce a strong and reliable component that would ultimately result in and extended service life.
From experience producing an aluminium casting, heat treatment, and then machining was ruled out because of potential porosity problems.
Porosity is not uncommon where small cavities or voids form within a metal casting.
These voids can vary in size and are often invisible to the naked eye.
However, they can have a significant impact on strength and durability of the finished component.
There are several causes for porosity in aluminium castings.
This includes gas trapped in the casting during solidification and moisture present in the mould material plus poor venting in the mould design.
Subsequently aluminium alloy 6061 was chosen to be CNC machined to produce a quality component that was free of porosity problems and leaking fluid.

clutch-slave-cylinder-a082q6031fr-wm

This high quality component has been designed using Solidworks 3D CAD software.

   a082q6031f 3r   Clutch slave cylinder A082Q6031F view 2

Carefully attention has been paid to the recessed stepped bore located at the rear of the slave cylinder.
This recess is a back-stop for the internal piston when it is fully retracted.
In addition to this, the recess has a bleed nipple port and an inlet pressure port that is fed from the clutch master cylinder.
The inlet pressure port has a slightly larger diameter (compared to the bleed nipple port) to ensure unrestricted fluid flow to the stainless steel piston.

Installation
It is essential the clutch slave cylinder be installed with the bleed nipple port orientated in the upward position.
This allows any trapped air to escape when the hydraulic system is bled.
Therefore the hydraulic pressure hose should be connected to the lower port to take advantage of the larger diameter connection.

This clutch slave cylinder provides a high quality solution for the Lotus Esprit S3 up to the later models S4, S4s, Sport 300 etc.

Material – aluminium alloy 6061, CNC machined
7/8 inch bore with stepped recess at rear of piston
7/8 inch high quality internal hydraulic rubber seal
Quality external rubber dust/weather seal
Stainless steel piston that will not rust
Bleed nipple port has a 3/8UNF female thread
High pressure hose port has a 3/8UNF female thread
Note - Please check thread detail prior to ordering as a 7/16UNF adapter may be required to accomodate the high pressure hose fitting
Mild steel/zinc plated bleed nipple with dust seal supplied as standard
Optional stainless steel bleed nipple is available at $8.00 extra
Clutch slave cylinder assembly comes with a 12 month warranty

This aluminium alloy clutch slave cylinder comes fully assembled and is ready for immediate installation
The price is AUS $195.00 each (excluding GST)

To complement the clutch slave cylinder installation, Lotus Marques offers a stainless steel braided clutch hose that eliminates “Red hose syndrome” that might be experienced on a hot day.
Clutch hose, master to slave cylinder braided and fittings RHD, part number B082J4088J-braided @ AUS $ 223.75 each (excluding GST)
Pricing information is correct as of 9/5/2025 but may alter with time and currency exchange rate fluctuations.

Lotus Marques supports local industry by manufacturing these clutch slave cylinders in Australia.

Trade inquires are also welcome - please call (03) 9761-1903 to discuss your requirements
Please note carefully, pricing above does not included postage and packing.

Shipping from Australia to UK, USA, New Zealand, anywhere worldwide!
Contact Lotus Marques now for postal or courier shipping costs.

Speedo gear housing 105E17269

Wednesday, 12 February 2025 17:57 Product News
New and improved 105E17269 speedometer gear housing with integral oil seal

If you own a Lotus Elan, Elan 2+2 or any other vehicle fitted with a Ford 2000E gearbox and you have experienced a slight leak from the speedometer gear housing,
then there is a solution. This solution has been driven by observing this problem operating a Lotus only workshop and requests from several Lotus owners.
Solving this annoying leak has involved working around existing components to design and manufacture an inexpensive component that is “plug and play”.

The first step in this process is to understand why the speedometer housing leaks.
The original aluminium housing was produced by using a die-cast process followed by machining of the features and critical dimensions.
This aluminium die-cast process is often used by the automotive industry (including Ford) to create complex aluminium components that need a minimal amount of machining.

gearbox-speedo-gear-housing1r
Photograph kindly supplied by Duy Bui from Queensland

The above photograph shows gearbox oil escaping from around the speedometer gear driven shaft and dribbling down the extension housing casing.
This oil leak is usually hidden by the threaded aluminium pedestal that is clamped in position covering the end of the driven gear shaft.
This hidden oil leak is caused by hot oil escaping between worn speedometer gear driven shaft and the internal supporting bore.
The speedometer gear shaft has a contra-rotating spiral groove cut into the length of the shaft in an attempt to move oil back into the gearbox extension housing.
Such an arrangement can be likened to the historical Archimedes-principle seal.
Today, this simple arrangement is known as a “Windback Seal” and relies on a very small clearance between the rotating shaft and supporting body.
This type of seal was common on older engines until the 1960’s when engines operated at lower revs and lower oil pressure.
One notable Classic Car to use them at both ends of the crankshaft was the W.O. Bentleys.
The clearance between the crankshaft and the housing had to be precise to prevent oil leaks.
This required an experienced machinist to achieve this degree of accuracy when align boring freshly white metalled main bearings.
(thanks to Rowley Errington for providing Windback information)

Whilst this “Windback Seal” arrangement appears to be a simple and cost effective solution to retain oil in the gearbox, it does have an inherent design flaw.
This seal is only effective whilst minimal clearances are maintained.
So as normal wear gradually increases the shaft clearance, the oil scavenging action along the shaft decreases allowing oil to escape.
A simple solution to this is to design a replacement housing that incorporates a double lip seal.
Examining the top section of the driven gear shaft reveals there is a plain section that does not have a continuation of the spiral groove.
This plain cylindrical section is ideally suited to run in contact with a double lip seal that will prevent oil escaping along the driven shaft.

     speedo-gear-housing-front1r     speedo-gear-housing-rear1r

The solution is to design the new speedometer gear housing in Solidworks CAD software where it’s possible to view a 3D model that includes a double lip seal.
This important process allows dimensional checks to be made and to consider the final component assembly process.

gearbox-speedo-gear-housing--cable
Photograph kindly supplied by Duy Bui from Queensland

These housings have been CNC machined from 6061 aluminium alloy and have a tumbled finish to ensure there are no sharp edges.
To assist in the installation process, some silicon lubricant and a cotton bud are included in every parts order.
Please lubricate the seal, speedometer gear shaft, plus housing body and sealing O-ring prior to installing the assembly in the gearbox extension housing.

speedo-gear-housing--pedestals1r

Other components that are available from Lotus Marques to complement the speedometer housing installation in a Lotus Elan or Elan 2+2 are as follows-
1)    New housing complete with double lip seal and O-ring
2)    Right-angle gear drive for speedometer cable
3)    Aluminium pedestal 7/8UNF x 18tpi
4)    Aluminium pedestal 3/4UNF x 26tpi

NOTE – Please measure relevant threads carefully before ordering a new pedestal.

Whilst the amount oil gradually lost via the speedometer gear housing may not be consider to be serious, over time and regular use the gearbox oil may reach a very low level where damage occurs. Therefore it is recommended that oil leak be checked and at the same time the oil level in the gearbox be checked.


A special mention to Classic Ford car owners, if you own a Ford Cortina or Escort fitted with a 2000E gearbox then this speedometer gear housing will fit your vehicle.

New housing complete with double lip seal and O-ring @ $60.00 excluding GST
Weight including new O-ring, double lip seal and lubricant is 42 grams

To request more information or to order parts please contact Lotus Marques by email This e-mail address is being protected from spambots. You need JavaScript enabled to view it

Please note carefully, pricing above does not included postage and packing.
Pricing information is correct as of 8/2/2025 but may alter with time and currency exchange rate fluctuations.
Shipping from Australia to UK, USA, New Zealand, anywhere worldwide!
Contact Lotus Marques now for postal or courier shipping costs.

Lotus Twin Cam timing chain tensioner bracket 026E0012

Saturday, 30 November 2024 13:51 Product News
This timing chain tensioner bracket has been fully CNC machined from high tensile steel alloy 4140 and is suitable for a Lotus twin cam engine built on a Ford 701M cylinder block.
The steel bracket is a direct replacement for the original bronze component (part number 026E0012).
The timing chain bracket shown below has a small rectangular protruding pad.
The sprung loaded tensioner piston applies pressure to the pad located at the end of the bracket which in turn tensions the timing chain via the attached sprocket.

Lotus twin cam timing chain tensioner bracket for 701M block

For large capacity Lotus twin cam engines built on a Ford 711M tall cylinder block, the overall length of the tensioner bracket has been extended.
This guarantees the tensioner piston is going to make contact with the pad when the cylinder head is installed on a taller cylinder block.
Note – installing a Lotus twin cam cylinder head on a tall block results in moving the tension bracket pad upwards by 6mm or 12mm and away from the tensioner piston.

Lotus twin cam timing chain tensioner bracket for 711M block

These high quality components have been carefully designed to provide additional strength and reliability for street and race applications.
A simple bronze bush is installed in the bracket to ensure the pivot pin has a low friction bearing surface that is lubricated with engine oil.

Tensioner-bracket-shown-in-SolidWorks-CAD-wire-frame

These brackets are zinc plated and passivated to provide long term corrosion protection.

Vehicle application details - to suit Ford Lotus twin cam 1558cc, 8 valves
Model Production dates
Ford Lotus Cortina Mk1 1963 to 1966
Ford Lotus Cortina MK2 1967 to 1970
Lotus Elan 1962 to 1974
Lotus Elan 2+2 1968 to 1974
Lotus Europa Twin Cam 1968 to 1974
Lotus and Caterham 7 1973 to 1974

Tensioner bracket 701M or 711M @ $165.00 excluding GST
Tensioner plunger, 026E0010 - standard length $29.50 excluding GST
Tensioner plunger, 026E0010 - extra long @ $29.50 excluding GST
Adjuster screw, 026E0391- standard length @ $9.70 excluding GST
Adjuster screw, 026E0391- extra long @ $12.00 excluding GST
Tensioner sprocket assembly, 026E0707 @ $66.00 excluding GST
Tensioner sprocket pin, 026E0013 @ $27.50 excluding GST
Tensioner pivot pin, 026E0011 $27.50 excluding GST
Timing chain guide, A026E0014 $32.00 excluding GST

Please note carefully, pricing above does not included postage and packing.
Pricing information is correct as of 25/11/2024 but may alter with time and currency exchange rate fluctuations.
Shipping from Australia to UK, USA, New Zealand, anywhere worldwide!
Contact Lotus Marques now for postal or courier shipping costs.

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