89 replies to this topic

[Lola5000]

 

Nice James,

 

I wondered who led the build of Garrie's in-house Chevs. I guess his two Repco-Holdens went out the door in the sale of his MR5B and MS7: Edmonds and Kostera from memory. 

 

Eight-into-one howled during the 78 AGP weekend, for a while…
 

 

Alan Hamilton had a pair of VDS Chevs that went into the back of the Lola T430 and later the M26 McLaren, as here. 535bhp so the talk had them. His CFO told me they were flown home to Indianapolis for a birthday each year, expensive rebuilds!

I doubt very much in the period the Hamilton cars (T430 and the M26 ) had over 500bhp.

[Sterzo]

Fuel injection was only allowed in either the USA or the UK, I can't recall which...

 

That possibly changed over time, but it was the case in 1971.

Vitesse2 can probably clarify that, having posted in an earlier thread: "...fuel injection was legal in European F5000 in 1969 only. Weber 48 IDA carbs were mandatory for 1970 - this was a cost-cutting measure."

 

(Post 18 in: https://forums.autos...d-regulations/)

[rl1856]

By the mid 70's F5000 engines were providing +/- 525hp,,, or about 40-60hp more than a contemporary F1 car.  There was an approximate weight difference of about 200lbs, with F1 being lighter.   I would have thought that 50hp would be enough to compensate for 200lbs.  The difference in qualifying times between the respective tops of the grids generally had F1 cars about 1-2 sec faster.   So why were F1 cars generally faster than F5000 cars at the same tracks ?

[Lola5000]

By the mid 70's F5000 engines were providing +/- 525hp,,, or about 40-60hp more than a contemporary F1 car.  There was an approximate weight difference of about 200lbs, with F1 being lighter.   I would have thought that 50hp would be enough to compensate for 200lbs.  The difference in qualifying times between the respective tops of the grids generally had F1 cars about 1-2 sec faster.   So why were F1 cars generally faster than F5000 cars at the same tracks ?

Rear end engine weight ?

[Ray Bell]

And way better braking...

[opplock]

I seem to recall Frank Gardner saying in his Castrol book that the F5000s higher centre of gravity meant they'd never outperform F1 cars. Lost my copy decades ago so unable to check.

[MarkBisset]

Yes, the weight of the cast-iron stock blocks was/is the issue.

 

Let's say a Chev is about 500lbs, the DFV is 370lbs. The 5-litre donks sat relatively high in the chassis compared with engines in GP cars. All that extra bulk has to be accelerated, stopped and persuaded to change direction.

 

I had a crack at the F1/F5000 speed differential a while back: https://primotipo.co...er-f1-or-f5000/

 

Let's come back to John McCormack's McLaren M23 Repco-McCormack-Irving Leyland (aluminium) V8 later...

Edited by MarkBisset, 17 January 2025 - 00:04.

[Lola5000]

Yes, the weight of the cast-iron stock blocks was/is the issue.

 

Let's say a Chev is about 500lbs, the DFV is 370lbs. The 5-litre donks sat relatively high in the chassis compared with engines in GP cars. All that extra bulk has to be accelerated, stopped and persuaded to change direction.

 

I had a crack at the F1/F5000 speed differential a while back: https://primotipo.co...er-f1-or-f5000/

 

Let's come back to John McCormack's McLaren M23 Repco-McCormack-Irving Leyland (aluminium) V8 later...

Mark,Super Macs M23 was also an F1 car ,so perhaps the Leyland sat lower ?

[Lee Nicolle]

Mark,Super Macs M23 was also an F1 car ,so perhaps the Leyland sat lower ?

But it had less power! And that is from people working on it and replacing rivets

[Lee Nicolle]

Yes, the weight of the cast-iron stock blocks was/is the issue.

 

Let's say a Chev is about 500lbs, the DFV is 370lbs. The 5-litre donks sat relatively high in the chassis compared with engines in GP cars. All that extra bulk has to be accelerated, stopped and persuaded to change direction.

 

I had a crack at the F1/F5000 speed differential a while back: https://primotipo.co...er-f1-or-f5000/

 

Let's come back to John McCormack's McLaren M23 Repco-McCormack-Irving Leyland (aluminium) V8 later...

With a Chev it depends on the spec. An alloy headed magnesium intake injected engine would have been near 100lbs lighter than an iron head engine on Webers with alloy intake. Webers are decidedly heavy. I bought several today. Very efficient carb though

Edited by Lee Nicolle, 21 January 2025 - 02:16.

[MarkBisset]

 

 

The Chaparral Boys looking a bit dejected at Mosport on June 18, 1976.

 

Pole was 'as usual' for Brian Redman but eighth come raceday wasn't. Alan Jones won in a Yip T332.

 

Engine is a Chaparral Chevy, Franz Weiss was the primary engine builder in that outfit?? T332C HU56 according to ORC.

Edited by MarkBisset, 18 January 2025 - 20:37.

[Ray Bell]

Calder in 1980 would have been a good opportunity for the M23 Leyland IMC to show its worth...

 

They'd had time to get things sorted and Mac knew what he was up against. Of course that was all blown apart by the road crash that prevented him getting there.

 

As for the CoG thing, the alloy heads on the Chevs would have done a lot to help out there, crankshaft height was surely similar?

[Lee Nicolle]

Calder in 1980 would have been a good opportunity for the M23 Leyland IMC to show its worth...

 

They'd had time to get things sorted and Mac knew what he was up against. Of course that was all blown apart by the road crash that prevented him getting there.

 

As for the CoG thing, the alloy heads on the Chevs would have done a lot to help out there, crankshaft height was surely similar?

I cannot see how crankshaft height would change from a DFV to a Chev, to a Holden, to a Leyland. All relevant to the suspension

[Ray Bell]

Or to gearbox input height...

 

In the ultimate sense the shorter stroke of the DFV would allow it to run a little lower, but not much.

[GreenMachine]

Or crankshaft weight?  A priori I would have thought that a crank for an engine designed for a racecar would be lighter than one for a production car. 

[Ray Bell]

Certainly a crank for a 5-litre engine will be much heavier than a 3-litre...

 

Longer throws, bigger journals, heavier counterweights, then there's the larger rods as well.

 

But a decent F5000 engine will have these bits in a much lighter form than you find in a road car.

[Lee Nicolle]

 

 

The Chaparral Boys looking a bit dejected at Mosport on June 18, 1976.

 

Pole was 'as usual' for Brian Redman but eighth come raceday wasn't. Alan Jones won in a Yip T332.

 

Engine is a Chaparral Chevy, Franz Weiss was the primary engine builder in that outfit?? T332C HU56 according to ORC.

I keep seeing pics of Chevs with OEM tin rocker covers. How did they get them over the rockers? I have never seen a Chev roller rockers that goes under a factory cover. Tin rockers?? They would have failed often at around 8000 rpm. More so with roller cams with over 600 lift.

[Lee Nicolle]

Certainly a crank for a 5-litre engine will be much heavier than a 3-litre...

 

Longer throws, bigger journals, heavier counterweights, then there's the larger rods as well.

 

But a decent F5000 engine will have these bits in a much lighter form than you find in a road car.

Maybe not,, it seems that many 5000 engines used factory steel crank and rods.  I have seen them. Both I am sure well heavier than Cosworth R1 stuff. 

At the end of the period the best engines would have had aftermarket cranks and rods.. Still heavier than F1 though.

With the plethora of parts and prices available today I doubt anyone would ever bother race prepping those components these days. Labor is expensive!

A dozen years ago I had some Cleveland heads converted for screw in rocker studs, supply and fit Ferea valves, cut the seats etc. Price? Cant remember but was not huge. Priced getting screw in studs fitted recently and it was well over a grand. Then I still had to buy studs and valves and PC seals. I bought new medium quality alloy head assemblys which will outflow any OEM head and they were about $2300.

And Clevo stuff is rarer and more expensive than Windsor or Chevrolet parts. I can buy those heads for under $2000

[Bob Riebe]

Back in the day forged small-block Chevy crankshaft weighed approx.45-50 lbs. where a DFV att that time weight approx. 32 lbs.

 

How much race engine builders modified crankshafts is a question.

 

Nowadays, many speed shops, will remove weight, and rebalance, from factory cranks , usually for less windage, if asked to do so.

[MarkBisset]

Apropos Lee's comments on factory cranks and Bob's on crank weight.

 

The designers of the Repco-Holden F5000 engine were Phil Irving - lead - and Brian Heard - support.

 

Phil had the to say about the crankshaft in his autobiography.

 

'The crankshaft needed a lot of work. A specially manufactured racing crankshaft was ruled out as being too expensive, and we had to adapt the production Holden crank. I did not feel happy about its oilways and modified the big-end oil supply to be similar to that used on the Repco-Brabham V8s. The basic Holden item was a nodular iron casting and quite high quality for a production item. We arranged to have the finish grinding done at Repco, where we could apply racing standards of finish, and this also allowed us to use a larger fillet radius. Combined with careful balancing and special heat-treating we were eventually able to get a racing life of around 16 hours from the essentially standard crankshaft - which was handling nearly double its production power and revs.'

 

The final-development-phase flat-plane-cranks were steel; circa 520bhp.

 

REDCO both sold and leased engines to customers. I wonder how many, if any, purchasers of the engines had made a steel crank for their motor?

[Lee Nicolle]

Apropos Lee's comments on factory cranks and Bob's on crank weight.

 

The designers of the Repco-Holden F5000 engine were Phil Irving - lead - and Brian Heard - support.

 

Phil had the to say about the crankshaft in his autobiography.

 

'The crankshaft needed a lot of work. A specially manufactured racing crankshaft was ruled out as being too expensive, and we had to adapt the production Holden crank. I did not feel happy about its oilways and modified the big-end oil supply to be similar to that used on the Repco-Brabham V8s. The basic Holden item was a nodular iron casting and quite high quality for a production item. We arranged to have the finish grinding done at Repco, where we could apply racing standards of finish, and this also allowed us to use a larger fillet radius. Combined with careful balancing and special heat-treating we were eventually able to get a racing life of around 16 hours from the essentially standard crankshaft - which was handling nearly double its production power and revs.'

 

The final-development-phase flat-plane-cranks were steel; circa 520bhp.

 

REDCO both sold and leased engines to customers. I wonder how many, if any, purchasers of the engines had made a steel crank for their motor?

For a Holden unless it was true custom order from Europe or the US noone. Still no aftermarket Holden cranks even now. They do break after a while. 16 hours even in a 5000 engine seems quite conservative. I would have doubled that or worked out the harmonics

The only fast Holden I had anything to do with had a 350 Chev steel crank. Probably still in use 40+ years later

[Lee Nicolle]

Back in the day forged small-block Chevy crankshaft weighed approx.45-50 lbs. where a DFV att that time weight approx. 32 lbs.

 

How much race engine builders modified crankshafts is a question.

 

Nowadays, many speed shops, will remove weight, and rebalance, from factory cranks , usually for less windage, if asked to do so.

My Forged True that I bought in 2000 was 42lbs. It had lightning holes through the rod throows. Nice piece then for a $1000. The factory steel crank was full of cracks. My fault, the steel balancer I used was too heavy and large. 18lbs of flywheel and clutch on the other end

Edited by Lee Nicolle, 25 January 2025 - 06:25.

[Lee Nicolle]

My Fored True that I bought in 2000 was 42lbs. It had lightning holes through the rod throows. Nice piece then for a $1000. The factory steel crank was full of cracks. My fault, the steel balancer I used was too heavy and large. 18lbs of flywheel and clutch on the other end.

Yet the cast crank originally used is still in use even  now.Used the same balancer too.

[MarkBisset]

Thanks Brian,

 

Would you mind posting that Car and Driver article, I'd love to read it?

 

In this part of the world Frank Matich had success with Traco-Chevs: two rounds of the 1970 Tasman including the NZ GP. He could have had the series with more luck. 

 

He won many races in the Traco-Oldsmobile powered Elfin 400 and Matich SR3 including an Australian Tourist Trophy in each in 1966-67.

​

 

(Jack Brabham with Doug Nye)

Maybe it was the Traco-Buick in the back of Lance Reventlow's Scarab RE that was the most influential though. Jack Brabham was impressed by the pace of Chuck Daigh during the 1962 Sandown International, won by Jack's Cooper T55 Climax.

 

He looked long and hard at the 3.9-litre, pushrod, aluminium, Weber fed engine during the weekend, by 1964 he'd convinced the Repco board to agree to a simple Tasman 2.5 V8 based on the Buick's relative, the Oldsmobile F85 block. That 620 Repco 2.5 V8 never won a Tasman race but the design did win a world Championship of course!

 

 

(John Ellacott)

Edited by MarkBisset, 22 January 2025 - 22:17.

[Ray Bell]

I sincerely doubt that Tasman and Gold Star racing was the main target of the Repco-Brabham development...

 

With a shortage of engines for the upcoming Formula One, I believe Brabham - and Repco - were looking that way with the 2.5 engines being a decoy and a side-issue.

[MarkBisset]

 

(Bob Mills)

 

Here is Matich's 4.5-litre Traco-Oldsmobile V8 in the back of Elfin 400 #BB662 coming together at Elfin Sports Cars in Adelaide in 1965.

 

Perhaps the engine was imported cheaply to Australia in the boot of one of Laurie O'Neil's cars ex-US...so the story goes.

 

The specs I found a few years back: Eagle roller cam, stock rockers but fabricated steel rocker stand or pedestal, JE pistons, Warren machined H-beam rods, Moldex steel crank, four 48IDA Webers, conventional Delco Remy distributor and coil ignition, Traco inlet manifold, McLaren supplied exhausts. Circa 350-365bhp @ 6,500rpm.

Edited by MarkBisset, 22 January 2025 - 22:41.

[Ray Bell]

That's the way I do it, Brian, though I use a camera...

 

But phones have pretty good cameras these days. If you put the magazine on the floor and shoot one page at a time it should be fine, in good daylight but not in the sun.

 

Sorry, mate, I wasn't thinking, you don't have much sun this time of year, do you?

[MarkBisset]

Thanks Brian,

 

That’s chockers with information and I love the way Gordon H Jennings writes. More, more, more on the tuners I say! 
 

m

[Lee Nicolle]

No doubt Ford were keen for him to use one of their engines...

 

But as you say, the weight of the Cleveland was against it apart from the lack of experience getting big power out of the 5-litre version.

 

I do recall John Goss saying he wasn't keen on the shuttles used in the Repco-Holden to reduce the pushrod length as he felt they were an impediment to further development.

Those weird pushrods used in early Repco Holdens were WHY?. Someone had their rocker arm geometry screwed up. I know they were removed by teams in the quest for reliability.   James Rosenbergs Torana Sports sedan saw 8000 rpm too often, Never had a pushrod problem. Headgaskets oh yes!

Fitting the Yella Terra alloy heads resolved that. Holden V8 pushrods are quite short in comparison to a Chev. Some use 3/8 even 7/16 pushrods. I have always used 5/16 and never bent one. Att to detail in rocker geometry is what is required For those building common V8s Crow have them in 020 increments

A Clevo being turned over 8000 would be a mass of oil on the road. Boss 302 has everthing far lighter in reciprocating mass and better oiling. Personally I would NOT use those 29kilo each  Boss Clevo heads. Too big and always will be. In the US and UK they were making very good power from OEM heads with a LOT of grinding and even IF they made a little less power the power spread would be better and the engine lighter.

As someone mentioned Goss had a Boss 302. And never used it.

[Ray Bell]

Why?

 

Because the full-length pushods bent.

[Lee Nicolle]

Why?

 

Because the full-length pushods bent.

Why did they bend,, as I said I feel the rocker geometry was all screwed up. And I know teams that used that engine went to one piece. They are actually quite short so no reason the bend

[Jon Saltinstall]

Jackie Epstein’s ShellSport squad fitted carburated rather than injected Oates-prepared Chevrolet engines to its Lolas for some races in 1974. I believe these were originally Alan Smith prepared units, but I don’t know any more about Oates.

As for the “challenging” handling of the F5000 behemoths, Epstein’s crew chief Jeff Hazell reckons that they were as keen on changing direction as “a sock with lead in it.”

(Based on interviews conducted while researching Lella Lombardi’s F5000 campaign for her forthcoming official biography.)

[Sterzo]

As for the “challenging” handling of the F5000 behemoths, Epstein’s crew chief Jeff Hazell reckons that they were as keen on changing direction as “a sock with lead in it.”

A term worthy of the Technical Thread. Unfortunately they looked that way from track-side at Brands where nothing is straight or level, although they appeared less uncomfortable at Silverstone. Not to say they weren't quick, as Gethin demonstrated by beating F1 cars at Brands. And they provided good, affordable racing. But this spectator always found them bread pudding compared with the ratatouille of Formula 2.

[FlyingSaucer]

Thanks Brian,

 

That’s chockers with information and I love the way Gordon H Jennings writes. More, more, more on the tuners I say! 
 

m

 

It's you task now Mark to produce a piece for your site, talking about the F5000 engine tuners. Tbh, it could be a really interesting series for a site, splitting tuners by region (EU, US and AUS/NZ).

 

The door is open, its up to you to get in 

[MarkBisset]

Cheers Lorenzo,

 

I think most of us that have grown up with F5000 carry the names of the top engine builders in our heads. It's not a long list.

 

The only one that has published detailed information of EXACTLY how the engines were built and developed and evolved that I've seen, is Repco. I did an article about the Repco-Holden engine years ago.

 

Peter Molloy was the Australian engine builder 'gun' - amongst his other talents - of his generation but I've never seen anywhere here a detailed article about any of the engines he built: BMC, Lotus Ford, Chev F5000 or the 351 Cleveland Group C tourer engines.

 

It's a fun thread but there is little of use for the article I think would be interesting.

 

m

 

 

 

 

 

Brett Lunger’s Morand-Chevy powered Lola T330 during the April 1 1973 Mallory Park Euro F5000 round. Q4 and 14th in the race won by McRae’s GM1 Bartz-Chev 

Edited by MarkBisset, 27 January 2025 - 21:17.

[Ray Bell]

I think you'll find that Molloy got his Chev gig going by refining Bartz (Baartz?) engines while in Niel Allen employ...

[Ray Bell]

Gary Campbell's T330 (T332?) had an Alan Smith engine in it...

 

Whether or not that was transferred from his ex-Gardner T300 I don't know, but I do know that it never left the country with the car after its carreer-ending crash, that went to Murray Bingham for his hillclimb car - the Porsche-chassised device - and a dud old 327 went for the sea voyage.

[Lee Nicolle]

I think you'll find that Molloy got his Chev gig going by refining Bartz (Baartz?) engines while in Niel Allen employ...

Al Bartz was a well known engine builder for these engines in that period. Somewhere sometime I read an article about him.

[MarkBisset]

I think you'll find that Molloy got his Chev gig going by refining Bartz (Baartz?) engines while in Niel Allen employ...

 

agreed Ray,

 

I think the Elfin ME5 copped a 5-litre Bartz-Chev which may well have then been popped into the M10B.

Molly also freshened his share of Chevs when the furriners lobbed in Sydney from NZ so I suspect he saw the privates of quite a few of his competitors.

 

m

[Ray Bell]

He did, yes...

 

I recall him telling me that a spate of engine failures was caused by engine builders lightening Forgedtrue pistons by relieving the gudgeon bosses.

 

He had a hand in a lot of rebuilds.