primotipo…

Introduction…

As Brabham, Tauranac and Denny Hulme scanned the competitive landscape as 1966 unfolded, they formed the view that a similar formula to ’66 stood a good chance of success in 1967. A small, light, responsive chassis, this time designed around the engine. Remember that Jack’s successful ’66 mount, BT19, was an adapted, unraced 1965 GP car Tauranac designed around the stillborn Coventry Climax Flat-16. Ron’s ’67 BT24 was and is a superb car; its race record we shall review in an article about Brabham Racing Organisation’s (BRO) successful ’67 season.

In terms of the engine, keeping it simple and light had paid big dividends for Repco Brabham Engines Pty. Ltd. (RBE) in the first year of the 3 litre formula.

The fortunes of Ferrari, BRM, its H-16 engine, the antithesis of the Brabham Repco’s in terms of weight and complexity and the Maserati V12 were well covered in my article on the ’66 season. Dan Gurney’s Weslake V12 engine showed promise, but reliability continued to be an issue. The Ford Cosworth DFV didn’t race until the Dutch GP in June 1967. Brabham’s needed more power of course; too much power is rarely an issue, but they figured they needed less power than most others on the grid. If Jack and Denny started the season with a reliable, just quick enough package, BRO could retain their title as others sought to make what were ultimately potentially quicker, more sophisticated multi-cylinder, multi-cam cars reliable. Click here for my article on Jack’s successful 1966 season: https://primotipo.com/2014/11/13/winning-the-1966-world-f1-championships-rodways-repco-recollections-episode-3/

They were an intensely pragmatic group of racers in this Brabham/Repco senior mix…

Repco’s Charlie Dean, Phil Irving, Norman Wilson (designer of the ’67 RBE740 Series V8), Brabham and Tauranac all built winning cars (and bikes in Phil’s case) themselves, as in, built with their own hands. Dean created the extraordinary series of Maybach Grand Prix cars. Look at my Stan Jones article for much detail about this series of racers built by Charlie and initially raced by him, and then later by Stanley with much success. Norman Wilson built a Holden-engined special in his youth, covered in brief at the end of this article. Tauranac and his brother Austin built and raced the ‘original’ Ralts before Ron joined Jack in the UK in 1961.

Dean, Wilson, Tauranac and Brabham had been/were drivers. They knew what it took to win races. They understood winning was as much about torque as power. Handling was essential, the circuits then were all far from just requiring top-end power, what was needed at Monza was different to the blend of corners and contours at Brands. All had driven cars and lost races due to unreliability. They understood a balanced package was critical, that whatever power they had needed to be put to the road. The point I make is that these guys were practitioners, not theorists, on ‘an engineering jolly’.

The RB group were about the application of sound pragmatic engineering practice; they didn’t have to think deeply about this stuff it was part of their DNA given the ‘build and develop it yourself’ school from which they came. These guys weren’t ‘university engineers’ (which is not to say they lacked formal qualifications) but very practical chaps. Let the others chase ‘engineering perfection’ as they saw it; ‘an evolution of what we have is probably enough to do the trick’ was the correct thinking.

It was a whole different ballgame they confronted at the same time in ’68, but this was mid-’66, the game-changing DFV was still a distance away…

1967 Engine Design Deliberations…

Ex RBE Engineer Nigel Tait; ‘By July 1966, the World Titles had already been ‘wrapped up’ for the year, so the team were already thinking about the engine for 1967. Phil, Jack and Ron were all keen on the idea of getting the exhausts out of the airstream to clean up the car in terms of better aerodynamics and also for ease of plumbing the exhausts, which otherwise had to negotiate the tubular chassis frame. The 1966 BT19 championship-winning chassis did not present a very effective frontal profile, its exhausts well out in the breeze.

Colin Chapman was far from the first chassis man to be prescriptive about design elements of an engine, as he was to Keith Duckworth in relation to the Ford Cosworth DFV, particularly in relation to its integration with ‘his’ chassis.

Between the Vee exhausts had been raced successfully by BRM with its P56 1.5-2 litre family of V8’s in recent years. Ferrari also chose the same approach with its ’67 3 valve V12, its fair to say it was an F1 design trend of the time. In some ways, Ferrari’s approach was better than Brabham’s as Ron maintained outboard springs and shocks on both the front and back of his ’67 BT24 chassis. Ferrari, as they did in 1966, used a top rocker and an inboard front spring/shock, presenting less resistance to the air at the front of the car at least. Ferrari went outboard at the back like Brabham. (and the rest of the grid)

Conceptual Design of the Heads…

RBE Chief Engineer Norman Wilson: ‘ It would have been Jack’s idea to put the exhausts in the centre (of the Vee). Jack asked if it could be done. I remember when I started designing them, I spent a lot of time, probably 3 or 4 days, just drawing one cylinder up to try and prove that you could fit everything in. Since you have got a whole row of head studs, you have got to have water passages between the ports. The whole idea was to prove that you could get the inlet port in, the exhaust port and all the head studs. That was a giant task to figure out in a way.

‘It meant putting the outer row of studs underneath the exhaust ports. I don’t think I have the layout now, but I remember spending a huge amount of time, and finally I went to Frank Hallam (RBE General Manager) and said I think we can do it. And that’s how the 40 Series heads started. ‘To manage to get everything on one side, and the thing is, unlike most engines we built, we wanted big ports. So to fit all these big ports in, plus the port wall, plus the bolt bosses, was a major task. I think it took about three days’ work for me to fit everything in a rough layout.

The ’40 Series’ Between the Vee 1967 Cylinder Heads Design Detail…

‘…the new cylinder heads retained parallel valves, but they were now in line with the cylinder axis (instead of at 10 degrees to the axis as on the ’66 20 Series heads and were flush to the head face,’ said Wilson. ‘The 40 Series heads used the Heron head design. In this design, the cylinder head is flat, and the piston has the combustion chamber at the top of the piston (a bowl in the piston arrangement). The other feature of the 40 Series head is that it has a tall inlet port. It had a fairly long, relatively straight section there on Jack Brabham’s suggestion. He had received some highly secret information from Honda that this was the way to go. In hindsight, I don’t think so. All these things are better in hindsight, but that’s how we did it’

‘The Heron head, I think everyone agreed, had to be the way to go because the Cosworth SCA (F2 engine) was 1000cc and was putting out 120bhp. At the time in F2, it was winning everything. I think it puts out 123bhp. Now, if you are looking at a 3-litre engine, that’s 369bhp. And at that time, that would have been looking for us a fairly exciting sort of figure. The other point about the Heron head is that it allowed us to have a single camshaft, which we wanted to have the low weight, simplicity and ease of manufacture.

‘The 40 Series head was purely made for the car. No other reason. It put the exhausts down the centre of the Vee… that’s what Ron wanted, he made the car, so why not get what he wanted.

‘The highest output of the 740 Series 3-litre was only a bit over 330bhp. This horsepower rivalry between the different engine manufacturers at the time, the horsepower numbers were really irrelevant. At the time, Maserati claimed about 500bhp, but they were adding on about 100bhp to make up for the exhaust gas pollution in the test cell. But really, it’s about the area of the horsepower curve. ‘If they had 500bhp, they would be leaving us behind a lot quicker than they are leaving us behind!’ was a quip Rod Wolfe recalls Jack making to the boys in the RBE engine assembly area on one of his trips to Australia in 1967.

‘One of the philosophies was for the engine to always have a wide power range and good power at the bottom end of it, which suited the light car. So if ours was 330bhp, there was no way other cars had 400-500bhp claimed. Our power was distributed much more evenly across a wider range of revs. Thus, Denny Hulme would say it was great to drive a Repco Brabham because he could overtake competitors in the corners as if they were ‘tied to a fence’.

There were some problems with 40 Series head porosity during ’67, as ex-RBE machinist/storeman Rodway Wolfe recalls: ‘Norm did a fantastic job to even succeed with the casting, and it proved to be a great engine in larger capacity too, bigger valves etc…we were able to fit very large valves without too many seat problems. The 40 series did have a lot of porosity problems with the ports, some we scrapped as the ports actually broke through when we were porting them, and there was not the welding equipment available that we have nowadays to repair them. Porosity, a big drama, as I say, one of my jobs was to send the castings to ‘Nilsens Sintered Products’ in Richmond, where they placed the heads in a vacuum and impregnated them with hot resin. Vacuum impregnation solved some of these problems.

A typically pragmatic decision to the heads was made in relation to the 1967 Repco block…

Remember that the ’66 engine used a heavily adapted version of the Oldsmobile F85 aluminium block. Repco still had a swag of unused blocks sitting in Rod Wolfe’s Repco store at Maidstone. The blocks had been successful, a world title proof enough of their effectiveness, but the machining and adaptation required to make them an effective race tool meant they were expensive but still sub-optimal. But it wasn’t all plain sailing with the block, however much it may have seemed so from the outside, Tait; ‘For much of 1966 we had serious blowby issues due to distortion of the dry sleeves, and it was not until almost the end of that year that we went to wet sleeves. The F85 Olds blocks came with dry sleeves in situ’.

Repco’s race engine commercial ends were to be served by building and selling engines for Tasman use and for Group Seven sportscars, burgeoning at the time globally; 2.5 litres was the Tasman Formula capacity limit, and the F85 ‘maxed out’ at 4.4 litres, which was the capacity used for the sportscar engines. Repco’s first sale of a customer engine was the 4.4-litre 620 Series unit sold to Bob Jane for his Elfin 400.

So Repco decided to ‘have their cake and eat it too’. The new bespoke ‘700 Series’ block would allow all of the F85 ‘600 Series’ bits and bobs to attach to it: heads, timing case, sump, the lot. So Repco could gradually use its stock of F85 blocks for Tasman and sportscar use whilst ‘700 Series’ blocks were used in F1 for 1967 and more broadly in capacities up to 5 litres subsequently. As engines were rebuilt, the 600 blocks were replaced progressively by 700 series units. 600 blocks ceased to be used when there were none left. Typically practical, sensible and parsimonious, Repco!

Whilst the ‘700 Series’ block design decision, to allow 600 hardware to be attached, was a ‘functional’ pragmatic decision, the aluminium block itself was also improved, being redesigned to increase rigidity. The new block design was commenced by Irving, he and others say, before he departed from RBE, but the completed block is his replacement as Chief Design Engineer, Norman Wilson’s design.

Phil Irving’s departure by resignation or sacking by RBE GM Frank Hallam is an important part of the RBE story and will be dealt with in a separate article. I explore not just the difficult relationship between these two characters but also the broader issues of the leadership of Repco, CEO Charles McGrath’s key enduring support of the RBE program and the appointment of Bob Brown as the Director responsible for RBE instead of alternatives, including Charlie Dean at the project’s outset. The antipathy between Hallam and Irving was partially about personality but also about politics and legacy in terms of who is responsible for what of the RB620 design and build. More on this topic very soon.

For now, let’s just focus on the RB740 engine, which in no way, shape, nor form was negatively impacted by Irving’s departure…whilst noting that there probably would have been no 740 had it not been for the success of Jack and Phil’s RB620, JB as the engine’s conceptual designer and PI as its detail designer and draftsman…

Norman Wilson: ‘When I went there (to RBE from Repco Research), John Judd (who had been seconded to Repco by BRO in the UK) had done a new crankcase. So I asked to look at it, and John showed it to me, and I said we can’t make it. It was impossible because it was the basis of a whole new engine. It became a mutual decision (by the design team) that we make a crankcase that went underneath, on top of and behind exactly what we had. ‘We couldn’t have made a crankcase, head and timing case all at once. So we made a crankcase, and then we did the 40 series heads. We had to have a timing case with the heads, but it meant we didn’t have too much to do at once, and we just kept progressing.

Wilson: The new crankcase was designed from scratch but was also designed so it could accommodate the 20 series cylinder head if we wanted to. It was critical, being a fairly small outfit, that we had the maximum amount of interchangeable flexibility between all the components that we made. So the 700 series crankcase was designed to overcome the problems that we had seen or experienced with the Oldsmobile F85 600 series crankcase. It had wet liners, which in part was because it was easier to cast the cylinder block with a wet liner design in that it simplified dramatically the coring required for the casting of the block.

‘The Oldsmobile engine showed it had main bearing problems, so we altered the main bearing arrangement to be much more rigid. We extended the studs up through into the centre of the Vee with nuts on top to take some of the load up through to the top of the block. The unfortunate part of that was that the design was right, but people would always do the nuts in the top up tight. And of course, what would happen was that the cylinder block, being aluminium, would expand more than the stud and would eventually break it. What they should have done, and no one would listen, was to do them up at a much lower torque so when the engine got hot it would put the right load on the stud’.

‘The front bearing panel of the block was made stronger because this had proved to be a weakness with the Oldsmobile block. The back of the block was made with the same stud pattern as the Olds block so that all the existing gearbox adaptors could be used. The block was made with the idea of making it as light as possible, and that was one of the critical things in the design. In the end, Frank suggested we put some diagonal ribbing on the 700 series crankcase walls to strengthen them. ‘The sidewalls of the crankcase were actually bolted to the main bearing caps… cross-bolting (and strengthened the crankcase considerably). So I felt the diagonal ribbing was really quite irrelevant. …Frank wanted it and, you know, he was a pretty good boss to work for, so that’s what we did’.

‘The other thing about the block was that later, when we made the 4.2-litre Indianapolis engines (760 Series DOHC, 4-valve V8 in 1968/9) we could alter the sealing arrangements; in fact, the later F1 engines (’68 860 Series) were the same, so we used Cooper rings instead of head gaskets. Cooper rings sealed the combustion chamber, and O rings sealed the water passages. But we also then had a groove around the outside of the Cooper ring joined with a shallow slot to the edge of the head, so if one Cooper ring leaked slightly, there was no way it would pressurise the cooling system.

‘With the Indianapolis engine (760 Series 4.2), those grooves came out of the inside of the Vee. So you could run your engine in the pits, and you could put your finger over the end of each groove, and you’d know if any of the Cooper rings were leaking slightly. The 700 block was the same height as the Olds F85 block. And the 800 block (860 F1 and 830 Tasman 2.5) was a (1.5 inches) lower one to make the engine smaller.’

The 700 Series block, apart from being stronger, was also 15 Kg lighter than the F85 ‘600 Series, Norman Wilson again; ‘The F85 block was designed to be diecast on a diecasting machine; it was perhaps a bit thicker in spots just to make it easier to cast. We got rid of a considerable amount of aluminium around each cylinder…The Repco block didn’t have all the bosses down the centre along the block for the cam-followers. It didn’t have the cam bearings for the centre camshaft (of the F85). We didn’t have the stiffener plate on the bottom. The bearing caps were bigger, but they were done a bit better, and they were probably no heavier than what was there. And in all the places where strength was not required, we just skinned them down as much as we could’.

Most of the components for the engine were made by Repco subsidiary, Russell Engineering, few were contracted out.

Wolfe: ‘Most of the RBE engine components were made at the Maidstone factory. The pistons and rings, however, were from other Repco companies, and the crankshafts were from Laystall in the UK, but no other F1 engine constructor made their own pistons and rings in 1966; even Ferrari used Hepolite pistons, so Repco were unique.

Harold Clisby’s engineering business in South Australia cast many of the heads. Kevin Drage, the senior engineer at Castalloy, the Clisby subsidiary that made the heads, recalled that around 120 cylinder heads of four types-30, 40, 50 and 60 Series were cast by the company over the period of the RBE program.

The 30 Series head was detailed by John Judd and was two-valve with inlet and exhaust ports on either side of the head, ‘crossflow’ inlets between the Vee and exhausts out the side. 40 Series (the ’67 championship winner) heads were detailed by Norman Wilson, which had inlet and exhaust ports on the same side of the head, between the Vee exhausts.

Drage recalls that the two-valve 30 and 40 Series heads were soon followed by the four-valve 50 and 60 Series designs. John Judd drew these up with the 50 Series design having diagonally tangentially ported inlet and exhaust valves resulting in 16 inlet trumpets and 16 exhaust pipes, the 60 Series design having siamesed inlet and exhaust ports.’ The 50 Series heads, which were built and dyno tested, and the 60 Series 1968 F1 4 valve, DOHC design are the subject of a future article. The fact that RBE persevered so long, at GM Frank Hallam’s insistence, with the 50 Series heads delayed development of the 60 Series design, to RBE and BRO’s cost during the ’68 F1 season.

The Commonwealth Aircraft Corporation at Fisherman’s Bend, not too far from RBE’s Maidstone factory, made the alloy crankcases and timing covers; note that Wilson went to double-row timing chains with RB740 compared with the single chain of RB620.

Ex-Repco engineer George Wade is often given credit for the camshafts, but Rod Wolfe says, ‘We made the camshafts for all of the engines, George Wade profiled them to various specs, but we turned the billets with a mimic tracer on our Tovalieri lathe. The very first 620 cams were cast iron but were changed to steel in 1966’.

Lucas fuel injection was of course again used, as well as a Bosch distributor.

Summary of RBE740 F1 3 litre engine specifications/suppliers…

Bore/Stroke; 3.5X2.55 inches, capacity 2996cc. Power 330bhp@ circa 8400rpm, weight 350 pounds

Compression ratio 12:1, valve sizes 1 13/16inches inlet /1 1/2 inches exhaust, valve angle vertical, valve lift .40. Valve timing 50, 70, 50, 70

Pistons, rings and main bearings by Repco, big end bearings supplied by Vandervell

Lucas fuel injection, Bosch coil and distributor, Champion plugs, Esso fuel and oil and Borg and Beck clutch

Racing the 640: 1967 Tasman Series…

The first race of the 1967 GP season was the South African GP at Kyalami on January 2. Jack and Denny raced 620 Series V8’s; the 740 was running late due to delays in patterns being made for the 700 crankcase. It’s an interesting observation given that Hallam told Brabham by letter dated 23 September that the 700 patterns were half finished. In any event, the engine was late so it made its debut in the Tasman Series, or more specifically, 640 Series engines did; the new heads atop the 600 Series/F85 Olds blocks.

RBE staff numbers during the Christmas/New Year 1966/7 period swelled to 37, with 23 engines being assembled during this period. Frank Hallam records that due to the great amount of dismantling, assembly and experimentation that took place, only four 2.5-litre motors raced in the Tasman Series. The 640 series 2.5 litre Tasman engines gave circa 265bhp@8500rpm.

Brabham’s full ’67 F1 season i will cover in a separate article, here we look at the Tasman races for the 640 and early season F1 races of the 620 and 740.

If you take the view that the ’67 Tasman was a warm-up for the ’67 World Championship, then it was a success for Brabham and RBE. The 40 Series heads were thoroughly race-tested during the annual Australasian summer contest.

Equally important was Jack’s mount, his car designated BT23A was an adaptation of Ron Tauranac’s very successful new 1967/8 BT23 F2 design, which won dozens of races in Ford Cosworth FVA 1.6 litre F2 spec. The Tasman BT23A was effectively the prototype of the BT24, which went on to win the ’67 titles, so the Tasman ‘blooded’ both the chassis and engine well before the F1 season. The reliability which flowed from this development process won RBE and BRO the ’67 championships, the Lotus 49 Ford Cosworth DFV was well quicker but had not had the development miles the Brabham Repco’s had…

Jim Clark took the 1967 Tasman title in an F1 Lotus 33 fitted with a stretched to 2-litre Coventry Climax FWMV V8 engine, a quick, reliable, well-proven combination. Clark took 3 wins, and Jackie Stewart 2 in a similar F1 BRM P261. But the stretched to about 2.1 litres P56 V8 stressed the BRM transmission to its limits, the ‘tranny its weakness that summer. Jack was equal 3^rd on the points table to JYS with 1 win.

Jack and Denny contested all rounds of the championship with the exception of Teretonga, the last Kiwi event. Jack took a win at Longford and Denny 3^rd at Wigram, his best. Brabham had a lot of unreliability, but the problems weren’t in the main engines; for Denny, a radiator hose at WF, gear selector at Sandown and electrical problems at Longford and for Jack, a driveshaft breakage at Teretonga and ignition dramas at Sandown.

At that stage, Repco hadn’t sold customer Tasman 2.5 engines of any type; the engines were made available later in the year in time for the commencement of the domestic Gold Star series (640 & 740 Series 2.5 V8s). In the meantime, the more important business of getting the 3-litre ‘740 Series’ V8S into Tauranac’s exquisite little BT24 was the priority.

The first F1 event of the European ’67 season was the Race of Champions at Brands Hatch on 12 March.
Dan Gurney won both heats and the final in his Eagle T1G Weslake. Jack was 9th in a ’66 spec 620-engined BT20 with Denny DNF, similarly equipped.

The ‘Daily Express Spring Cup’ at Oulton Park followed on 15 April, Brabham ‘cleaned up’ in BT20s; Denny won both heats and Jack the final, taking a great race win for the new 740 3-litre V8 with Denny 2nd in a 620-engined ’66 chassis.

BRO fitted its first 740 Series engine just in time for the Monaco GP on May 7.
Apart from the delays caused by late patterns for the blocks, Repco Die and Tool Co forged conrods developed faults. After being unable to establish why the Repco rods were failing, the team went the Carillo route, the team using these tried and true products…despite not being made in Oz! Rod Wolfe: ‘We did discover that the chamfer at the bolt heads did not match the bolt radius under the head of the bolt, and even when tensioned correctly, they were not seating properly, resulting in a couple of failures. ‘

The definitive RB ‘740 Series’ engined Brabham BT24 didn’t appear until Jack gave the chassis/engine combination its championship debut at the Belgian GP at Spa on June 18. This was 2 weeks after the Ford Cosworth DFV V8 took the first of 155 GP wins, the 1967 successful Brabham GP season, a Repco story for next time…

Repco 1966/7 promotional film…

Check out this great footage, the first half covers Brabham’s victorious 1966 F1 season, the other bit the ’67 Tasman season, the debut of the 640 Series V8’s, including some factory footage of the engines build.

Etcetera…

Etcetera: Norman Wilson RBE740 Chief Designer…

It’s interesting context to Wilson’s work at Repco Brabham Engines to look at the car he built as a ‘youngster’ before his ‘glory years’ as part of the Maidstone team. The car is both innovative and practical in its adaptation of proprietary parts, a combination applied in his later work.

As the cars current owner Greg Smith observes ‘the Norman Wilson Special is a beautiful study of a late fifties racing car with its Mercedes’ styling and layover engine, side vents and knock-off wire wheels’

Norman started his 6-cylinder Holden-engined ‘Norman Wilson Spl’ around 1956, aged 29/30. The chassis is a spaceframe; front suspension Wilson’s using inverted Holden uprights and wishbones, his own cross member and geometry. Steering is rack and pinion. The rear end is a ‘cut and shut’ Holden with an offset diff to lower the driver; springs are quarter elliptics with some neat locating links.

The clever bit was laying the Holden engine over at 30 degrees to the horizontal to lower both the centre of gravity and bonnet line. By the time the car was finished, Norman had moved to Repco, where it was completed and furnished with 3 large, single-throat Webers Charlie Dean bought for Maybach but never fitted to it when that car was fuel injected. The ‘box was Jaguar, the beautiful aluminium body built by Barry Hudson, who also did the Ian Mountain (Peugeot) Spl.

Norman raced the car, mainly in Victoria from 1960-63; it passed through several hands before being ‘chopped up’ in the late ‘60’s. With the interest in historic racing growing, and knowing the historic significance of the car and driver, reconstruction was commenced by Graeme Brown in Adelaide in the mid-1980s; its first run was in 1997. The car is currently being rebuilt by Victorian racer, engineer and raconteur Greg Smith to its precise period spec, from whom this history and photos were provided. There is a whole lot more to this incredibly clever car built by Wilson in his youth. We will do a feature on it when Greg is close to its completion. I’ve seen it; the thing is sensational. Smithy will race it in 2017. I also plan to write more about Norman Wilson’s career; too little is known about this fella, now 91, so important in the Repco story.

Bibliography…

Recollections of Rodway Wolfe and Nigel Tait, Norman Wilson quotes from Simon Pinder’s ‘Mr Repco Brabham’, Doug Nye ‘History of The Grand Prix Car’, ‘Phil Irving: An Autobiography’, Kevin Drages comments from ‘The Nostalgia Forum’, Greg Smith’s photos and details of Norman Wilson and the ‘Norman Wilson Spl’

Photo Credits…

Rodway Wolfe and Nigel Tait Collections, Repco Ltd archive, Autocourse, Digby Paape, David Keep, Bruce Wells/The Roaring Season, David Keep/oldracephotos.com, Automobile Year, Ellis French, David Nash, John Manhire

Tailpiece…

Jack Brabham guides his Brabham BT23A Repco into the Viaduct on his way to victory in the ‘South Pacific Trophy’, Longford 5 March 1967. He takes the first of many ’40 Series’ Repco 1967 wins…

Finito…