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The Lotus slant 4 two litre engine in racing


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#1 mariner

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Posted 20 November 2020 - 15:31

One of the few pleasures of covid lockdown is reading my collection of Motor and Autocar magazines from the 60's/70's when they had technical editors like Charles Bulmer and Anthony Curtis who could do really in-depth articles .

 

Today I found Anthony Curtis's description of the then new Lotus two litre slant-four engine. 

 

He describes how Lotus used the Vauxhall slant 4 block to speed development while their own cast alloy block was designed. That mixed engine was the LV240 as fitted to the Lotus 62 which won a lot of Club races albeit with John Miles driving it .

 

Then the later all Lotus alloy block engine became big rally winner in the Lotus Sunbeam.

 

However I don't think it ever had much success as racing engine until the much later Espirit turbo engines - I can only think of the Novamotor engines which were done for the Texaco Star F2 cars.

 

As I remember it those engines were no very good and the cars never showed any real promise despite the team and drivers ?

 

Apart from the Lotus 62 and the Texaco Stars were there any other naturally aspirated lotus two litre engines used in acing ?

 

 



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#2 RS2000

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Posted 20 November 2020 - 19:53

Someone who rallied a Sunbeam Lotus told me that engine's alloy block seemed as heavy as an iron block.



#3 Gary Jarlson

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Posted 21 November 2020 - 04:20

Renowned engine builder Chuck Willis, who did my Cosworth BD motors, told me about the time someone brought him one of those  "Lotus things" with the hopes of making it into a "racing engine." It seems that when he just tried to hone the cylinders, the block would distort. He made a stabilizing plate but that was not the complete solution. Years later, I ran into a racer in the Seattle area who was using that very same engine. "We can never get consistent measurements during rebuilds. It's just hope and pray," he said.



#4 john aston

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Posted 21 November 2020 - 07:25

Surprisingly perhaps , because by most accounts  it was a pretty horrid car in period , one still sees the occasional Jensen Healey competing in Historic racing . Its problems , apart from the uninspiring styling , were invariably engine related. How we have progressed - here was a sporty overhead cam 16valve which gave 140 bhp - not much more than your niece's 1 litre Fiesta 'three'  in 2020... 


Edited by john aston, 21 November 2020 - 07:25.


#5 Odseybod

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Posted 21 November 2020 - 10:11

But the J-H seemed to handle pretty well - at least, based on a ride back to London from Silverstone in "Motor"'s long-term test car, conducted by a certain T. Dron in the wet. Of course, that impression may have been at least partly due to the driver ...


Edited by Odseybod, 21 November 2020 - 10:11.


#6 RCH

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Posted 21 November 2020 - 11:09

Someone who rallied a Sunbeam Lotus told me that engine's alloy block seemed as heavy as an iron block.

 

Going a little off topic, that original Vauxhall block was a heavy old thing. Tough though, mine did 30 plus miles, ten stage miles at least, with no water having blown a core plug. Hammered in a new core plug, filled with water and it was good to go. 



#7 mariner

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Posted 21 November 2020 - 11:47

Surprisingly perhaps , because by most accounts  it was a pretty horrid car in period , one still sees the occasional Jensen Healey competing in Historic racing . Its problems , apart from the uninspiring styling , were invariably engine related. How we have progressed - here was a sporty overhead cam 16valve which gave 140 bhp - not much more than your niece's 1 litre Fiesta 'three'  in 2020... 

 

Yes, progress in engines has been steady and relentless.

 

Back in the 80's we marvelled at the Cosworth Sierra 2 litre 16 valve turbo giving 200 bhp in high performance road car and 145 mph. 

 

today my very ordinary 2 litre 4 cylinder turbo Mondeo has 240 bhp - 20% more, way better fuel economy and its claimed 149 mph top speed despite its huge size. The Lotus 2 litre engine was up to 301 bhp in final S4 Sport form by 1993.

m

 

The  highest bhp/litre "regular"  road engine is the MB 2 litre turbo , it churns out 400 bhp with reliabilty. To put that in perspective if it had two extra cylinders it would have 600 bhp - same as most Le Mans cars!

 

Of course there is down side. Engine tuning in world of spec. racing and fuel limits means less work for engine tuners . I suspect its the Historics that keep many in business?


Edited by mariner, 21 November 2020 - 11:49.


#8 BRG

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Posted 21 November 2020 - 11:57

I have always been a little unsure about the relationship between these Vauxhall and Lotus engines.  The LV220 had its genesis as the Vauxhall motor used in such exotica as the Bedford CF van and the Viva GT.  Did the LV use the Vauxhall crank and rods, even after replacing the iron block?  I was told that these were really tough parts, good for a lot more power. 

 

In parallel, there was the Vauxhall Chevette HS and HSR which used a similar DOHC 16 valve engine also based on the slant four base.  There was a problem in rallying when DTV were found to be using the Vauxhall head in their Gp4 rally cars and had to change to a Vauxhall head.  Presumably the road car (homologation special) used a Vauxhall head, but the rally team used the Lotus one to save time and effort developing it?  What block did this engine use?  The iron one or an alloy one, and if so was that the Lotus block?



#9 Myhinpaa

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Posted 21 November 2020 - 14:52

I have always been a little unsure about the relationship between these Vauxhall and Lotus engines.  The LV220 had its genesis as the Vauxhall motor used in such exotica as the Bedford CF van and the Viva GT.  Did the LV use the Vauxhall crank and rods, even after replacing the iron block?  I was told that these were really tough parts, good for a lot more power. 

 

In parallel, there was the Vauxhall Chevette HS and HSR which used a similar DOHC 16 valve engine also based on the slant four base.  There was a problem in rallying when DTV were found to be using the Vauxhall head in their Gp4 rally cars and had to change to a Vauxhall head.  Presumably the road car (homologation special) used a Vauxhall head, but the rally team used the Lotus one to save time and effort developing it?  What block did this engine use?  The iron one or an alloy one, and if so was that the Lotus block?

 

Blydenstein never used an alloy Lotus block in any of their cars, as far as I know. The first car to use the Lotus head was Old Nail from the '72 season onwards.

That was by then a 2.2 litre from a 2 litre block in 8 valve configuration, after the 16 valve conversion it was gradually enlarged up to 2.6 litre capacity.

The car used a Tecalemit Jackson fuel injection system both before and after the the Lotus head conversion.

 

The debacle over the use of the Lotus head on the early Chevette HS was due to a rule change for '78. Before then alternative cylinder heads could be homologated

for use on the original type block in Gp.2/4, providing there were available at least 100 kits. Such did we get a 24-valve Stratos, 16 valve Corolla/Celica, BRM Avenger etc.

The Chevette was homologated with reference to the Vauxhall head (meant for the HP Firenza) but from the beginning it used the Lotus head on a Vauxhall cast iron block.

 

So when the '78 season started Vauxhall continued to us the Lotus head due to the non-availability of the base homologated head. This did slide a bit and they got away with

it on quite a few rallies, Sweden, Mintex, Circuit etc. Allegedly Ford with the help of Graham Robson in an article in Autocar drove this issue to the attention of the FIA.

He visited Shepreth before writing that article and was welcomed and shown around the workshops by Bill Blydenstein and Gerry Johnstone. 

 

So at scrutineering in Portugal the proverbial hit the fan proper. A very few heads had been produced by Vauxhall before, but GM being the way it is/was it would take a long time

to get the correct heads in production, Jensen Healey did a few too. But after Portugal it was Cosworth who was chosen for the main batch, there wasn't much choice with the very limited amount of time available, and the quality required. Vauxhall/WBB could not put the whole rally programme on halt for a variety of reasons.

 

There might have been some privateer Firenza and Chevette specials for hillclimbs and sprints using the whole Lotus engine but there's no info of any official WBB built cars. (?)

 

Lotus had three different cars they used to test their prototype, (iron block first) 16 valve engine in, a Victor FD VX4/90, a Viva HB GT and eventually a Bedford CF!

The latter was the car they used to road test the first alloy block version, allegedly. There might be some more details in Tony Rudd's book, "It Was Fun"

 

Source : http://www.lotusespr...evelopment.html

 

Vauxhall never experienced the same problem as the Talbot team did with seized cranks etc. During certain times it was a big problem, it was not totally unknown for the engine to

seize over night in parc fermé even! Russell Brookes experienced this at least once and had to push the car out to where they could get a tow rope to a service van/chase car. 

Then towing it down the road to see  if they could free up the engine again.... When Russell first tried to let out the clutch the rear wheels locked up!

 

Not sure if they got that engine going again at all on that event. They (Phil Davidson) must have got over this problem somehow, the engine proved reliable (enough) eventually.



#10 mariner

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Posted 21 November 2020 - 14:55

In his article Anthony Curtis mentions that the Vauxhall iron block was very strong as was the iron crank. Supposedly the  block would take 9,000 rpm ( not sure how GM knew that?). Lotus used the Vauxhall iron crank in early production at least.

 

It's interesting if the alloy block was weak because it followed DFV practice in having a very substantial alloy lower main bearing cap ladder for strength.

 

Novamotor claimed 275 bhp for their ace version of the Louts engine. As Lotus got 240 bhp quite quickly for the type 62 this doesn't seem unlkely but I guess by then BMW had raised the F2 bar to about 300 bhp .



#11 Myhinpaa

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Posted 21 November 2020 - 15:53

The Chevette HS rally engines did tolerate 9000 rpm, but it did shorten the life expectancy of the block if taken to that regularly. 

What usually happened with that block was that the centre main bearing web cracked and the oil pressure dropped to half, it was on borrowed time then.

 

Normally a rev limiter was fitted which was set at 8500, it was possible to disconnect quite easy however...

I guess the drivers would know how to get to the reset button for the tell tale needle, or he had a loyal mechanic to do it. (Sworn to secrecy)

 

The Lotus seemed to have problems with cylinder liners in the early days too (mentioned in the article above) but that was sorted out.

Not sure if the problems the block gave was due to design or production, heat treatment to relive stresses after the casting process is extremely critical.

Especially with an alloy block, if not done properly the material will continue to "move" and make main bearing and cylinder bores/liners etc. go oval.

 

Henri Toivonen's engine seized on the road section after SS19 on the '81 RAC : https://youtu.be/2ZOZhxp9dn4?t=737 (Exact reason not known though)



#12 RS2000

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Posted 22 November 2020 - 15:45

Probably from running upside down for a bit, judging by the state of the roof when I stood alongside it in the depths of Kielder!



#13 RS2000

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Posted 22 November 2020 - 20:43

Someone else with a Sunbeam Lotus I hill climbed against was selling CF van 2.3 blocks as (the same) Chevette blocks and making a profit. He was a Ford dealer....