(Ron Laymon)

Denny Hulme caresses his Repco Brabham ‘RB740’ V8 in the Mosport pits during the Canadian GP weekend, August 1967…

As well he should too, it was this engine which powered his Brabham BT24 to victory in that years drivers championship. Mind, you that statement is not entirely correct as Denny used the ’66 engine, ‘RB620’ early in the season as Jack raced the 740, that engine was only used by the Kiwi after Jack deemed it available and raceworthy to him.

In the meantime Denny scored 4th in South Africa and won at Monaco using RB620 V8’s- those results won Denny the title really, Jack was 6th and failed to finish in the same two races. Denny’s 51 points took the title from Jack’s 46 points and Jim Clark with 41.

Clark from Hill during the 1967 British Grand Prix at Silverstone, Lotus 49 one-two for a while at least, GH retired with engine failure on lap 64 to end a dismal weekend, he crashed after suspension failure on Saturday. Clark won from Hulme’s BT24 and Chris Amon’s Ferrari 312 (Sutton)

Clark’s 4 wins shaded Jack and Denny with two apiece in the epochal Lotus 49 Ford Cosworth. Any design which is competitive over four seasons, inclusive of drivers and manufacturers title wins (Hill in 1968 and Rindt in 1970) is ‘up there’ in the pantheon of great GP cars. The 49’s first win was Clark’s victory at Zandvoort in ’67 upon the cars debut, its last the result of Jochen Rindt’s stunning tiger drive at Monaco in 1970- at his friend Jack Brabham’s expense, the great Aussie pressured into a famous last lap error by the storming Austrian.

Without doubt the Lotus 49 was the car of 1967, its always said it would have won the title with more reliability that it did not have as a brand new car.

But that simple analysis fails to give credit to the Aussies.

The Brabham BT24 was a ‘brand-spankers’ design as well. Tauranac says that it was only his second ‘clean sheet’ GP design, his first was the BT3 Climax which raced from mid-1962. The GeePee Brabhams which followed were evolutions of that design.

Love these close-up shots. Its Denny’s BT24 and RB740 engine the cam cover of which has been removed to give us a better look. The cars spaceframe chassis is clear- small car for the era. Based on Tauranac’s BT23 F2 design the engine was tightly proportioned and economical of fuel so the package around could also be tight. From the bottom you can see the distinctive ribs of the 700 block below the top suspension radius rod. To its right is an ally tank held in place by a rubber bungy cord, a fuel collector which picks up from the two, one each side, fuel tanks. SOHC, 2 valve V8, circa 330 bhp in period. Cams chain driven. Note the rail carrying coolant behind and above the camshaft. Fuel injection is the ubiquitous, excellent Lucas product, to the left is the top of the Bosch twin-point distributor. In the centre of the Vee is a hornets nest of carefully fabricated exhausts- wonderful examples of tube bending art. Ferrari fitted 12 within the Vee of its engine in a trend common at the time. The idea was to get the pipes outta the breeze and away from suspension members. What a wonderful bit of kit it is (Laymon)

The ‘RB740’ SOHC, 2 valve, ‘between the Vee’ exhaust engine was also a new design. Both the Repco designed, Commonwealth Aircraft Corporation cast ‘700 Series’ block and the ’40 Series’ heads (the heads were cast by Kevin Drage at Clisby Industries in Adelaide) were new. They were completely different to RB620, albeit the 700 block could and was bolted to 20 Series heads and ancillaries when 620’s were rebuilt and its modified Oldsmobile F85 block cast aside as no longer fit for purpose.

Jack and Repco ‘blooded’ or tested the head design in the early 1967 Tasman races but the block was not ready then- the 2.5 litre 1967 Tasman engines were ‘640 Series’, a combination of the ’67 heads and the 1966 modified by Repco, Olds F85 blocks. The first 700 blocks were used in F1, not the Tasman Series. In fact the early ’67 F1 engines used by Jack were 640’s as well. Denny used 620’s early on in ’67, as mentioned above just to add to the confusion!

My point is that the all new Brabham BT24 Repco won 4 races and took the ’67 drivers and manufacturers titles beating the all new Lotus 49 Ford which also won 4 GP’s- Graham Hill was winless in the other 49 that year. (I’ve ignored the 49’s guest drivers in this analysis)

BT24 sans Hewland DG300 during the German GP weekend. Elegant simplicity of the design laid bare. Spaceframe chassis, rear suspension comprising single top link, inverted lower wishbone, coil spring/damper, twin radius rods and an adjustable roll bar. Eagle eyed Aussies may note the ‘Lukey Muffler’ tipped exhausts (unattributed)

It could also be said that the 49 chassis design was not really all new- the 1966 Lotus 43 is identical in layout inclusive of suspension and using the BRM H16 engine as a stressed member, as the Ford DFV was.

So whaddam I saying?

That the spaceframe Brabham BT24 Repco combination was ‘newer’ than the monocoque Lotus 49 Ford which was really the 43 chassis design, suitably lightened and modified to carry the DFV, a much lighter and fuel efficient moteur than the sensational but corpulent, complex BRM engine. Let the correspondence begin! Here is a link to my Lotus 43 BRM article, form a view yourselves.

https://primotipo.com/2015/02/17/jim-clark-taking-a-deep-breath-lotus-43-brm/

Tell me in a conceptual sense how the 49 chassis and suspension differs from the 43? There was plenty of Ford funded PR hoopla around the Lotus 49, we have all seen the footage. It was hardly going to be the case that Chapman said of the Lotus 49 chassis ‘we needed a known platform to bolt the new engine to, so we used the BRM engined 43 chassis design with minor mods to suit the much lighter, smaller DFV’. Much better to tout the whole lot as ‘all new’- no drama in that, its all fair in a corporate bullshit sense, its just not quite true and largely a myth perpetuated by many over time. Time after time!

Lotus were not the first to use the engine as a stressed part of the car either, although that is widely attributed to Chapman. Jano did it with the D50 Lancia, Ferrari with the 1512 and BRM the P83 H16.

In any event, lets give the Brabham BT24 Repco ‘740’ V8 the respect it deserves but seldom gets.

Clark in the Mosport paddock 1967, his eyes well focused on the fashionably attired young Canadian missy, despite having just bagged pole. Lotus 49 Ford (unattributed)

Canadian GP Mosport- 27 August 1967…

This first Canadian F1 GP was in many ways an exemplar of the words above. Clark and Hill qualified 1-2 with Denny sharing the front row on Q3.

Clark led from the start to be passed by Hulme, Denny’s flat, fat Repco torque curve was more suited to the slippery wet conditions than the DFV which was notoriously abrupt in its power delivery early in its development. Bruce McLaren’s BRM V12 engined M5A was up to 3rd at one point. As the track dried Clark worked his way into the lead- which he kept after rain started again until lap 68 when the engine cut out. Jack won from Denny with Hill in the other 49 4th and Canadian driver Eppie Wietzes a DNF during a Lotus 49 guest drive with the same ignition dramas as Clark.

Maybe the truth is that the difference between the Lotus 49 and Brabham BT24 in 1967 was that Clark sat aboard a Lotus not a Brabham? For sure Jimmy would have been lightning fast in the light, chuckable BT24. Faster than Jack and Denny for sure.

Graham Hill quizzing Jack about the pace of his BT20 ‘640’ at the Silverstone BRDC International trophy in April 1967, Mike Parkes Ferrari 312 took the win from Jack. Red car is Bruce McLaren’s McLaren M4B BRM (Schlegelmilch)

A further point is around car preparation. The 1962/68 World Champion, Hill G, still at the peak of his powers was effectively neutered from the time the 49 appeared by the unreliability of the chassis he drove- of his 9 Lotus 49 starts he retired 7 times. Three of those were engine failures, the others due to driveshaft, suspension, gearbox and clutch problems. Clark retired 3 times in the same 9 races with ignition, suspension and ZF tranny dramas.

Brabham Racing Organisation prepared beautifully consistent cars in 1967 powered by very reliable Repco engines. Factory Brabhams took the championship F1 startline 22 times in 1967 for 4 DNF’s, all due to 740 Series engine failures- Jack’s broken rod at Monaco, both drivers at Spa and Denny’s overheating at Monza.

Clark was far and away the quicker of the two Lotus men- Jim started from pole in 6 of those 9 races, Hill from pole in 3 of them. As I have said before ‘if yer aunty had balls she’d be yer uncle’- but IF Hill had won a race or two that Clark did not, the manufacturers title would have been Lotuses not Brabhams. Because the lads from Hethel did not prepare two equally reliable cars the title was Brabham’s not Lotus’, surely a fair outcome?!

Denny Hulme in his ‘brand spankers’ Brabham BT24 Repco ahead of Chris Amon’s Ferrari 312 during the 1967 French Grand Prix, Bugatti Circuit, Le Mans. Jack won from Denny, Chris retired on lap 47 with a throttle linkage problem. The Ferrari 312 was a big car, the sheer ‘economy’ of the little, light, BT23 F2 derived BT24 shown to good effect in this shot. Note the air-scoop used to cool the fuel metering unit in the Tasman and some of the ‘hot’ races in the GP season (unattributed)

Denny’s 1967…

Didn’t he have a ripper season! In addition to the F1 drivers title he could easily have won the Can Am Series in Bruce McLarens M6A Chev, the first of the wonderful ‘papaya’ cars too. He went back to Mosport a month after the Canadian GP and won the Can Am race in addition to wins at Road America and Bridgehampton. Bruce just won the title with a smidge more reliability than his Kiwi buddy, 30 points to 27.

Denny didn’t have great reliability in the Tasman Series at 1967’s outset but then again the Brabham main game was engine development in advance of the GP season’s commencement. The cars were match fit for the World Championship partially due to development work done in Australasia by Jack, Denny and Repco in January and February whilst Tauranac beavered away on his new BT24 chassis design back in the UK- which is about where we came in!

Michael Gasking in grey coat and Roy Billington in shirtsleeves fitting a 2.5 litre RB640 V8 at Repco Maidstone during the 1967 Tasman. Cars raced in the ’67 Tasman were BT22 ‘F1-1-64’ for Denny and BT23A ‘1’ for Jack. The latter car is very much the F1 ‘BT24 prototype’ being a modified F2 BT23 frame to which the RB640 engine was adapted. Not sure which car is being fettled in this photo. It looks as tho they are about to fire her up- you can just see the end of a white ‘Varley’ battery by Roy’s foot and a red slave battery alongside. The motors Bosch distributor cap is missing but not a big deal to fit. The sound of those engines is oh-so-sweet! Not sure who the other two dudes in shot are, intrigued to know (Gasking)

Who Says Ron Tauranac designed the Brabham BT24?…

The BRO lads based themselves at Repco’s Maidstone headquarters in Melbourne’s western suburbs during the Tasman Series to fit engines before the Kiwi rounds and before/between the Sandown and Longford rounds in Melbourne and Tasmania each year. These two events were traditionally the season enders.

During these trips Jack, Denny, Roy Billington and others out from the UK operated from Maidstone both preparing the cars and spending time with the guys who built their engines. The Repco fellas all have incredibly strong, happy memories of these times.

The sketch below was made by Jack and Denny in the Maidstone lunch-room during a break in the days proceedings on the ‘1967 tour’.

Michael Gasking recalls that in between tea and bikkies the ‘guys were explaining to us what the ’67 F1 car would look like and its key dimensions’- so there you have it, Jack and Denny’s conceptual thoughts on the ’67 F1 car! The funny thing is, at that time, early March 1967 Ron Tauranac may not have been too far advanced with the ’67 chassis, the first didn’t appear until Jack raced BT24/1 at Spa on 18 June.

In the interim Ron was busy at Motor Racing Developments pushing F2 Brabham BT23’s out the door- far more profitable work than knocking together a few F1 cars for Brabham racing Organisation!

In any event, what a wonderful historical document! JB’s rendering of the RB740 engine is sub-optimal mind you, but its clear the guys have taken the time to carefully draw the car in pencil, and then add the dimensions in ink, or ‘biro’ I should say!

(Gasking)

Its hard to compare all of the BT24’s publicly reported dimensions with Jack’s sketches level of detail but the total height of the car at 34 inches tallies, whereas Ron’s final wheelbase was 94 inches rather than Jack’s 91.5 inches.

Re-engineering Jacks total width from tyre to tyre outside extremities at the rear of 69 inches- to a rear track dimension, using his 12 inch wide tyres, gives a rear track calculation of 57 inches for Jack whereas Ron’s was 55 inches.

The little air-ducts either side of the nose and in front of the driver didn’t make it, the steering wheel diameter agrees at 13 inches mind you these were trending down to what became the 10 inch norm. The outboard suspension layout all around is spot on of course, as is the use of a V8 engine…

At the end of the lunch, Michael scooped up the drawing which is now, 50 years later shared with us, many thanks Michael! Wonderful this internet thingy, isn’t it?

(Max Millar)

Related Articles…

On the Repco RB740 engine

https://primotipo.com/2016/08/05/rb740-repcos-1967-f1-championship-winning-v8/

The 1967 Repco Brabham season

https://primotipo.com/2015/09/03/life-magazine-the-big-wheels-of-car-racing-brabham-and-hulme-30-october-1967/

Hulmes 1967

https://primotipo.com/2014/11/24/1967-hulme-stewart-and-clark-levin-new-zealand-tasman-and-beyond/

Tailpiece: 1967 wasn’t all plain sailing, Brabham, Monaco…

(Getty)

Jack looking intently at the sight of his RB740’s Laystall, steel crankshaft. He can see it thru the side of the engines block, an errant connecting rod has punched a hole in its aluminium casing! Dennis Jenkinson’s MotorSport Monaco ’67 race report records that JB started the weekend with an RB640 engine fitted, and popped a new 740 in- which had circa 20bhp more, which he ran-in on Saturday and then qualified with, on pole.

Bandini got the jump at the start with the rod failing on the journey to Mirabeau, whereupon Jack spun on his own oil, travelling backwards all the way to the Station Hairpin, in the middle of the jostling pack. But the robust engine continued to run on 7 cylinders for the journey back to the pits, where this photo was taken, the great Aussie inadvertently trailing oil all the way around the course, the lubricant having an easy path out of the moteur via a not insignificant hole!

The rod problem was quickly fixed by Repco who fitted Carrillo’s- drama solved. The chassis is BT19, Jack’s ’66 Championship winning frame. Brabham first raced a BT24 at Spa on 18 June, Denny did not get his until Le Mans on 2 July. So you might accurately say the ’67 drivers and manufacturers titles were won with a mix of 1966 and 1967 chassis’ and engines!

Bibliography…

 ‘Brabham, Ralt, Honda: The Ron Tauranac Story’ Mike Lawrence, GP Encyclopaedia, Michael Gasking, ‘History of The GP Car’ Doug Nye, Garry Simkin

Photo Credits…

 Ron Laymon, Michael Gasking Collection, Sutton, Getty Images, Max Millar

Postscript: Jochen Rindt driving the ring off the BT24 at Kyalami, South Africa on 1 January 1968- he was third behind a Clark, Hill Lotus 49 1-2. Clark’s last F1 win sadly…

 

 

 

 

Comments
  1. Jim Culp says:

    Great article! The BT24 was such a great car and it’s too often overlooked. One of my favorite memories is of Dan Gurney tossing a BT24 through the rain at Zandvoort in 1968. https://www.flickr.com/photos/jimculp/16083006581/in/album-72157663089370913/

    • markbisset says:

      Yes Jim,
      He had that guest drive didn’t he- back amongst his old Brabham mates!
      Hindsight is a wonderful thing- in some ways maybe Jack should have run Jochen in the BT24 in ’68 not the BT26 until it was sorted, which of course the engine never was in ’68. For sure Jochen would have put BT24 into the points.
      There was nothing wrong with the speed of BT26 when it stayed together mind you, he put it on the front row three times.
      Hindsight- I’m good at that!!
      Mark

  2. Gray Chandler says:

    Seems the ” little grey cells ” respond well to tea and bikkies . Some of the best ideas come from jotted notes , sketches etc on table napkins .

  3. Kevin Drage says:

    Another great article on Repco Brabham. However casting of the cylinder heads is incorrectly attributed to Castalloy. The cylinder heads were actually cast by myself whilst employed at Clisby Industries.
    The contract for Clisbys to cast the cylinder heads actually originated during a visit to the new Maidstone factory in mid ’66.
    The 630 cylinder head drawing had just been completed and was about to be sent off to Stirling Metals in the UK who had produced the 620 cylinder head castings. It was estimated that working long distance with a UK based foundry it would take around six months to tool and produce prototype castings.
    Frank Hallam knew of my work with the Clisby and Globe engine castingss and asked me how long it would take to tool and produce prototype 630 head castings. I suggested that we should be able to do this in around four weeks. This was extremely attractive to Frank as it would put them around five months ahead of schedule. We achieved this timing and this gave Repco the time to re-think the design and introduce the 640 cylinder head which they believed would give more power and with the centre exhausts package better into the car. We subsequently went on to also tool and produce the four valve 50 and 60 Series cylinder heads
    In total I think we at Clisbys cast about around 120 cylinder heads of four different types for Repco Brabham Engines.
    I left Clisbys to move to Globe Products in late ’67 and I think that Clisbys had some casting problems and Commonwealth Aircraft Corporation subsequently took over the work.

    • markbisset says:

      Kevin,
      Thanks so much for getting in touch, I’ve made the correction, I should have remembered this as I saw your post to that effect in TNF a while back.
      The next Repco topic is the ‘860 Series’, I will get in touch if I may to get the ‘story of the heads’ right but am also interested to get your perspective on ‘860’.
      Other topics of interest are the Clisby V6 and the Globe quad-cam Windsor Ford engine- both of those deserve as many words as needed to tell the story in full!
      My email is mark@bisset.com.au if you wouldn’t mind sending me your contact details.
      Thanks for pointing out the error.
      Regards,
      Mark
      Ps; Your photos inspired the Derek Jolly article- I hope I did the topic justice!

  4. David Wilson says:

    Excellent website especially down under and Repco stuff. Compensation for the cr*p that passes for magazines these days. When do we get the promised feature on the Repco 860? Regards

    • markbisset says:

      Thanks David,
      Chronologically an article on the Tasman engines is probably next with ‘860’ after that.
      860 is a biggie I’ll do in two parts- the design and build, easy to say but fraught with some complexity, and then the season itself which is simpler if disappointing.
      Not to forget the Indy 760’s which are a topic on their own…
      Great to hear from you,
      Mark

  5. nig says:

    Another cracker of an article captures all the wonderful spirit of 1960’s motor racing.
    Thanks
    Nigel

    • nig says:

      Ah, I meant to mention Hulme’s talents and how he was deprived (along with Ken Miles) out of winning Le Mans in 1966, giving McLaren and Amon their win by team orders, surely one of the cruelest of loss/victory in the sport.
      Regards
      Nigel

    • markbisset says:

      Cheers Nigel,
      Sixties are a Bewdy of a decade aren’t they? I enjoy all the Repco stuff- reckon am now about half way thru the ‘Repco Racing History’!
      Mark

  6. Stephen says:

    Looking forward to the RB 860 article. As I have said on a FB page, there isn’t a lot of technical stuff or even period photos, ephemera etc etc relating to this engine.

    • markbisset says:

      Stephen,
      There is a little bit of ‘unplanned child’ about 860- mind you the 760 4.2 and 5 litre were successful as you know. The lack of 860 photos and stuff may be it was a one season only engine whereas especially in Oz the 600 and 700’s raced thru till the eighties in some cases.
      In terms of the next few Repco articles, an update on where we are.
      I’ve a piece on the 2.5 Tasmans almost done, just a swag of photo captions to do, and then we need to do the 850 radial, Nigel Tait is going to help with that as my engineering knowledge would not do it justice.
      Then 860.
      850 is really important in 860’s failure in that 850 was persevered with for too long at Frank Hallams insistence- as a consequence it was started or prioritised too late.
      I’m not saying it was the cause of 860’s failure but for sure it was a part of it.
      I’ve got a few bits and pieces you might not have seen before on 860!
      Mark

  7. Stephen says:

    The topic of who was the RB620’s designer cropped up again today on Youtube. I said the detailed drawings were Irving 100%, while another person, who claimed to be there at the time, qouted Hallam, Judd, Paul England and “Keith McCubery”. Irving apparently being “incapable”. T
    ell that to a Vincent Black Shadow owner…

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