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#1 john aston

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Posted 25 October 2011 - 18:39

I'm writing a piece which conatins a reference to the gorgeous Lotus 38 Indy car. Can somebody help me- need to know a bit more about the engine- I know it's a 4.2 Ford V8 but that's it.Production derived ? Rough power figure? Any help much appreciated.

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#2 Sisyphus

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Posted 25 October 2011 - 19:11

The twin cam, fuel injected engine in the 1965 Lotus 38 was basically a purpose built design--maybe a few dimensions were the same as the original Fairlane-based push rod engine that was used in 1963 but that would be about all. And it was running on alcohol, of course.

There is an SAE paper from the 60's that has a lot of details on this engine, including power level, which you should be able to find on their website. I'll dig out the number when I get home tonight.

#3 DOHC

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Posted 25 October 2011 - 19:28

Back in the day, the engine was rated at 495-500 bhp, running on methanol. I'll try to find sources.

#4 xj13v12

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Posted 25 October 2011 - 19:45

Back in the day, the engine was rated at 495-500 bhp, running on methanol. I'll try to find sources.

Basically the fairlane block cast in alloy, alloy heads with 4 valves per cylinder, pent chamber and magnesium timing cases and sump.
Internal dry sump pump and scavenge, Hilborn injection. Ran Autolite distributer at first and then magneto. Not sure what the Lotus had that year. They got a bit more power in qualifying by adding nitro to the fuel but too much in the race would cause failure. Used about 8,500 rpm. I can give some good reference book details when I am at work. If you want to put your email address up I can scan and send a few pages that will give all the info you need.

#5 D-Type

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Posted 25 October 2011 - 20:38

Standard warning: To keep the Viagra-vendors etc away don't put your e-mail up as itzmee@looneybin.com or whatever it is. Instead put it up as itzmee[at]looneybin.com.

#6 Bloggsworth

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Posted 25 October 2011 - 20:56

Why does everybody forget the 34 on which the 38 was based?

#7 Tim Murray

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Posted 25 October 2011 - 21:18

Hardly. The 34 was a revised version of the 29, with a 'bathtub' monocoque. The 38 was a new car with Len Terry-designed full monocoque chassis.

#8 bradbury west

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Posted 25 October 2011 - 22:14

Hardly. The 34 was a revised version of the 29, with a 'bathtub' monocoque. The 38 was a new car with Len Terry-designed full monocoque chassis. edit RL as well as being the first full monocoque Lotus single seater.


And it represented another milestone in Lotus history, since it was the first car the full design of which ACBC entrusted wholly to one person, the redoutable Len Terry, driven by the fact that ACBC knew he would be away from the office for much of the gestation period. Unfortunately many of the great uninformed regard it as a Chapman design.
I cannot offer the usual disclaimers.
Roger Lund

edit. Is there not some engine detail in the MS article on the 38 last year, or the Fergusson/DCN Lotus Indy book et al?

Edited by bradbury west, 25 October 2011 - 22:15.


#9 xj13v12

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Posted 25 October 2011 - 22:59

One of the best overviews is in Design and Development of the Indy Car by Roger Huntington. Someone may have put a cutaway drawing by Dave Kimble on that thread too.
The Ford DOHC is 255.118 c.i. displacement, 3.76" - 2.872" bore and stroke. By 1965 they had dispensed with the 8,200 rpm limit and it was now 9,200 for qualifying and 8,800 for the race. The use of nitro in qualifying trim gave 545 h.p. @ 8,200. Apparently adding 10% nitro to the mix increased power by 5% etc. Clark used 30% nitro to qualify to the horror of the Ford people. Methanol gives about 10% more power than 103 octane gasoline and all cars were running meth. There was a significant increase in economy by adding 2% toluene as well, an amazing 24% improvement!
The engine is 90 degree V8 and weighs about 400 lbs without exhausts. Using a breakerless ignition system the advance was set at a seemingly very high 47 degrees BTDC but the engines were not being used at low revs so pre-ignition was not an issue. Crankshaft timing gear drove water pump and it drove oil pump and alternator. From the crank gear there are 9 more gear drives including camshaft, inlet and exhaust gears for each bank.
I have the engine manual if you want more detail but as a more general description this covers most of it.

Edited by xj13v12, 25 October 2011 - 23:00.


#10 xj13v12

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Posted 25 October 2011 - 23:11

From Len Terry's book some points about the Lotus 38. He did not use his usual Terrier designation because the running gear came "off the Lotus shelf". The 38 was the first full monocoque that Lotus built so merits clear differentiation from the 34 design. The tortional stiffness was increased by around 50% over the previous bathtub type monos due to the integral top skinning (above the driver's knees and legs or from the steering wheel bulkhead through to the pedals). The car had a 3" offset to the left and a 96" wheelbase. One of the most advanced aspects of the design was the fuelling system which allowed 45-50 U.S. gallons to be taken in under 20 seconds. The very next design that Terry did was the AAR Eagle which carried over many of these design aspects.

#11 Sisyphus

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Posted 26 October 2011 - 02:37

The SAE paper I was thinking of is 640252 which should still be available. It is actually on the 1964 version of the engine. There is a fair amount of good info on the engine--torque and power curves for the Offy, the 63 pushrod Ford and the 64 twin cam. Also some simulation results for Indy which is a fairly early application of race car simulation. Even a photo of the Lotus 34 in a wind tunnel--again a pretty early application for that technology.

You can find the above paper in an SAE publication PT53 "Design of Racing and High Performance Engines" which has a number of interesting papers including one from 67 on the Ford Mark II 427 for LeMans, and the Coventry Climax engines from 61 thru 65 including the lovely little 1.5 liter flat 16.


#12 john aston

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Posted 26 October 2011 - 07:14

Thanks to all - extraordinarily helpful as ever.

#13 RobertE

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Posted 26 October 2011 - 08:13

There's a website called http://www.quadcamford.com which might offer some more information - engine users, design, development, links, etc. The usual disclaimers re. the interweb, naturally. It contains a digest, drawn from both Huntington's book and the SAE report (Scussel?) as well as Hans Tanner's book "The Racing Fords". I hope you find this useful!

Edited by RobertE, 26 October 2011 - 08:38.


#14 Bloggsworth

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Posted 26 October 2011 - 08:25

Hardly. The 34 was a revised version of the 29, with a 'bathtub' monocoque. The 38 was a new car with Len Terry-designed full monocoque chassis.


That's odd, I swear Len Terry was wandering around the workshop at Delemare Road when I was working on the 34 - He must have forgotten everything he learned from the 34 before he designed the 38 a few months later...

#15 Tim Murray

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Posted 26 October 2011 - 08:43

Terry did the detail design of the 29 based on Chapman's schemes. As Roger explained, the 38 was pretty much all his own work.

#16 Odseybod

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Posted 26 October 2011 - 09:14

The SAE paper I was thinking of is 640252 which should still be available. It is actually on the 1964 version of the engine. There is a fair amount of good info on the engine--torque and power curves for the Offy, the 63 pushrod Ford and the 64 twin cam. Also some simulation results for Indy which is a fairly early application of race car simulation. Even a photo of the Lotus 34 in a wind tunnel--again a pretty early application for that technology.

You can find the above paper in an SAE publication PT53 "Design of Racing and High Performance Engines" which has a number of interesting papers including one from 67 on the Ford Mark II 427 for LeMans, and the Coventry Climax engines from 61 thru 65 including the lovely little 1.5 liter flat 16.


Have I 'mis-remembered' or was the Indy engine also used in the original Ford GT (before it became the GT40)?

#17 D-Type

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Posted 26 October 2011 - 09:28

The SAE paper I was thinking of is 640252 which should still be available. It is actually on the 1964 version of the engine. There is a fair amount of good info on the engine--torque and power curves for the Offy, the 63 pushrod Ford and the 64 twin cam. Also some simulation results for Indy which is a fairly early application of race car simulation. Even a photo of the Lotus 34 in a wind tunnel--again a pretty early application for that technology.

You can find the above paper in an SAE publication PT53 "Design of Racing and High Performance Engines" which has a number of interesting papers including one from 67 on the Ford Mark II 427 for Le Mans, and the Coventry Climax engines from 61 thru 65 including the lovely little 1.5 liter flat 16.

I beg to disagree. Many cars were wind tunnel tested before this date.

Or was this a full-size car? In which case it would have been one of the first.

#18 JtP1

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Posted 26 October 2011 - 10:23

Have I 'mis-remembered' or was the Indy engine also used in the original Ford GT (before it became the GT40)?


Iirc, the quad cam was tried at the Le Mans test weekend, but not used in the race. In fact the Monogram GT40 kit gave you a selection of engines you could fit in the kit, the quad cam being one.


#19 Tony Matthews

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Posted 26 October 2011 - 10:46

I seem to remember that someone was selling complete sets of drawings for the engine some time ago. I was tempted...

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#20 Odseybod

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Posted 26 October 2011 - 11:10

Iirc, the quad cam was tried at the Le Mans test weekend, but not used in the race. In fact the Monogram GT40 kit gave you a selection of engines you could fit in the kit, the quad cam being one.


Thanks, that kit is probably one of the reasons I half-remembered it (and also hearing it at those Le Mans Test Days - diisappointingly non-V8-like to a callow youth captivated by rumbling Galaxies, etc).

Edited by Odseybod, 26 October 2011 - 11:11.


#21 Sisyphus

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Posted 26 October 2011 - 19:52

I beg to disagree. Many cars were wind tunnel tested before this date.

Or was this a full-size car? In which case it would have been one of the first.


Yes, it is a photo of the actual Lotus in the tunnel. Either the 29 or the 34--hard to tell which in the low res photo.

I know that cars have been put in wind tunnels going way back in special circumstances--LSR cars, for example. But it wasn't routinely done in road racing or Indy in the 60's, I don't believe. More common in the 60's was taping wool tufts on the car and taking photos of the car on course.

But when Ford came in at Indy and LeMans, they definitely upped the ante in using things like wind tunnels and computers and data acquisition systems to develop their race cars. And, of course, GM did a tremedous amount of chassis and handling development working with Jim Hall on his cars.

I do wonder how much useful information was obtained on those early wind tunnel tests. Proper rolling roads in the tunnels to get the tire aerodynamics correct didn't come until years later.

On the other hand, the race cars of the 60's were far more attractive than today's, in my opinion, so maybe what they did learn was put to good use...

#22 xj13v12

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Posted 26 October 2011 - 20:13

Thanks, that kit is probably one of the reasons I half-remembered it (and also hearing it at those Le Mans Test Days - diisappointingly non-V8-like to a callow youth captivated by rumbling Galaxies, etc).


At least 2 Ford GTs were fitted with the Indy Ford which was originally going to power the car but that decision was changed. Jim Toensing did one for his own car and then Edsel Ford saw it and asked for his own GT to be fitted with the engine.

#23 Steve Sobieralski

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Posted 28 October 2011 - 13:24

While the twin cam V8 was mentioned in Ford's early press releases regarding the GT40, that is apparently as far as it went:

"Plans to fit the dohc unit under development for the 1964 Indianapolis programme in later cars was overtaken by a policy change and this pure racing unit was seen only in later private conversions." (Ford GT, An Anglo American Supercar Classic by David Hodges)

"...delays in the development of the DOHC engine resulted in no Ford GT ever running with one." (Ford, The Dust and the Glory by Leo Levine)

Most of the other major books on the Ford GT (Spain, Legate, Allen and Jones, Ludvigsen) do not even mention the engine. Early cars were fitted with the aluminum block pushrod Indy engine, then came the 289 and, of course the 427.

The model kit mentioned was originally released by IMC (Industro Motive Corporation) in 1965 or 1966. It did include three engine options, one of which was the DOHC engine and represented the earliest version of the car (original nose, wire wheels). It was later modified and released as the MkII and then again as the GT40 production version. It was later reboxed by Union and Testors, but I don't believe it was ever released by Monogram.

Steve Sobieralski

#24 xj13v12

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Posted 29 October 2011 - 00:34

While the twin cam V8 was mentioned in Ford's early press releases regarding the GT40, that is apparently as far as it went:

"Plans to fit the dohc unit under development for the 1964 Indianapolis programme in later cars was overtaken by a policy change and this pure racing unit was seen only in later private conversions." (Ford GT, An Anglo American Supercar Classic by David Hodges)

"...delays in the development of the DOHC engine resulted in no Ford GT ever running with one." (Ford, The Dust and the Glory by Leo Levine)

Most of the other major books on the Ford GT (Spain, Legate, Allen and Jones, Ludvigsen) do not even mention the engine. Early cars were fitted with the aluminum block pushrod Indy engine, then came the 289 and, of course the 427.

The model kit mentioned was originally released by IMC (Industro Motive Corporation) in 1965 or 1966. It did include three engine options, one of which was the DOHC engine and represented the earliest version of the car (original nose, wire wheels). It was later modified and released as the MkII and then again as the GT40 production version. It was later reboxed by Union and Testors, but I don't believe it was ever released by Monogram.

Steve Sobieralski


Chassis P/1027 was later fitted with the Ford DOHC and on display at the Cunningham Museum until it closed. You are quite right though. A few of the earliest cars 103, 104 started life with the pushrod version of the Indy 4.2 litre engine. The press release of April 4 1964 said "...and the Ford 4.2 litre 350 BHP Indianapolis engine is mounted amidships directly behind the driver. ....Although the 4.2 litre push rod Indianapolis engine is being used in the car at present, provision has been made for the new twin over head camshaft V8 Indianapolis engine to be incorporated later in the year." It never happened but 2 cars were converted by later owners.

#25 john aston

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Posted 27 November 2011 - 07:50

One further query- I recall seeing -and hearing!- a 38 at the Goodwood Revival on 2000(?) . Not the same car which Clasic Team Lotus restored which was the Indy winning car. Any detail on background of the non CTL car ?

#26 arttidesco

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Posted 28 November 2011 - 02:17

Apologies if this has appeared else where in TNF but was looking up Alban Scheiber on Google just now and found this pic of Jim Clark Hill Climbing at Bergrennen Ollon-Villars in 1965 in what appears to be the Indy Winning Lotus 38, news to me hope it might be of interest.

#27 hlfuzzball

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Posted 28 November 2011 - 06:39

Quote:

At least 2 Ford GTs were fitted with the Indy Ford which was originally going to power the car but that decision was changed. Jim Toensing did one for his own car and then Edsel Ford saw it and asked for his own GT to be fitted with the engine.



Dean Jeffries also installed a Ford DOHC in his GT-40 Roadster.

#28 bradbury west

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Posted 28 November 2011 - 07:22

One further query- I recall seeing -and hearing!- a 38 at the Goodwood Revival on 2000(?) . Not the same car which Clasic Team Lotus restored which was the Indy winning car. Any detail on background of the non CTL car ?


John, the programme lists it as 38/3 owned by James Jaeger from USA, driven to 7th by Johns in '65 and 2nd by JC in '66
Roger Lund

#29 Andrew Kitson

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Posted 28 November 2011 - 08:58

Apologies if this has appeared else where in TNF but was looking up Alban Scheiber on Google just now and found this pic of Jim Clark Hill Climbing at Bergrennen Ollon-Villars in 1965 in what appears to be the Indy Winning Lotus 38, news to me hope it might be of interest.

This 38 was changed to have symmetrical suspension for the hillclimb, but it was not Jimmy's Indy winning car, that went straight to Ford after the win. Jack Sears shook down the car at Silverstone once it was in symmetrical spec, one of his rare single seater outings. He told me that just doing those 5 laps, it was by far the fastest thing he ever drove. Once that was done he stepped into the type 40...then had his bad crash at Abbey which put him in hospital and ended his racing career.


#30 arttidesco

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Posted 28 November 2011 - 09:05

This 38 was changed to have symmetrical suspension for the hillclimb, but it was not Jimmy's Indy winning car, that went straight to Ford after the win. Jack Sears shook down the car at Silverstone once it was in symmetrical spec, one of his rare single seater outings. He told me that just doing those 5 laps, it was by far the fastest thing he ever drove. Once that was done he stepped into the type 40...then had his bad crash at Abbey which put him in hospital and ended his racing career.


Thanks for the clarification Andrew :up:

#31 B Squared

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Posted 29 November 2011 - 13:30

One further query- I recall seeing -and hearing!- a 38 at the Goodwood Revival on 2000(?) . Not the same car which Clasic Team Lotus restored which was the Indy winning car. Any detail on background of the non CTL car ?



John, the programme lists it as 38/3 owned by James Jaeger from USA, driven to 7th by Johns in '65 and 2nd by JC in '66
Roger Lund


If of further interest, see post #'s 98 & 111 in the attached thread for photos of this car taken in Indianapolis.

http://forums.autosp...w...80&start=80

#32 Allen Brown

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Posted 29 November 2011 - 13:39

Some info here in case you haven't seen it:

http://www.oldracingcars.com/lotus/38/

#33 B Squared

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Posted 01 December 2011 - 11:04

Some additional photos of the Jaeger car at Goodwood, courtesy of Aaron Lewis. Appears to be Franchitti at the wheel. Friend and Indy Car restoration specialist Walter Goodwin stands near the cockpit in the first photo.

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