Inliners International Forums General Discussion Bench racing What is the ultimate inline six?

Just want to kick a few ideas around here...

I can think of some that I really love, but there have been literally thousands made over the years... so what about you post the name, capacity etc of the inline six you like the most, details like bore/stroke hp standard, hp screwed out of them modified, what sporting successes they might have had, that sort of thing?

If nothing else, it will give us all a chance to mentally hear the unmistakeable and incomparable howl of the best sounding type of engine ever built!

Come on now! I'm sure we could have some good inline sixes enumerated here... maybe the reasons why you like them, the fun you've had with them?

Someone?

OK, I'll start: 300 Ford

7 main bearings
4" bores
forged cranks
12 port heads
takes SBF trans
7 million built
billet racing head

240 lb-ft / 155 HP stock
700 lb-ft / 650 HP @ 9000 RPM extreme NA on gas

numerous NHRA / IHRA world championships and class records by dozens of different racers

Greg, you've sold me on the power potential of the Ford 300! When are you going to write the book on it? We need that guide!

Inline development for power has hitherto been the province of those pesky furriners. We may remember the various permutations of Jaguar's inline twin-cam and the Mercedes 300SLR, to name two. In America the several inlines designed by Fred and August Duesenberg, and their technical descendants, the Offenhauser twin-cam fours, dominated American racing from the 1920s through the 1960s.

God's Peace to you.

d
Inliner # 1450

Ah... you're getting off the track there, Don!

The 300SLR was a straight eight, this discussion is about sixes, and I have a reason for that.

How about I throw one in to keep the topic going?

The Repco-Holden engine, the darling of the midget racer set here in Australia from the late fifties through the early seventies.

Based on the Holden 'sideplate' six that came out in 1948, it was rather like a scaled down Chevy, 4 mains, originally 3 1/8" stroke, 3" bore and capable of delivering an effortless 75bhp. Standard, that is, before Repco started work on them

The 'Repco' part of the equation was an aftermarket head cast in iron but formed with care... looked great with a rocker cover similar to the early 'Spitfire' Poly Dodge engines, but most of all it sounded fantastic!

Repco bought a Raymond Mays Zephyr head to study as they went into this project, but I suspect that more of their input came from the Maybach engines they were constantly upgrading for Stan Jones (Alan's father) in his quest to win the Australian Grand Prix and from things like the Chrysler Hemi and Peugeot 203/403, as these all had similar valvegear.

At full cry in a midget hustling round the 1/4 and 1/3-mile ovals, it really sang... a howl you never forget, the howl that has endeared me to inline sixes forever.

They were also used in boats and road race cars, principally to replace Bristol engines in the Cooper-Bristols that struck trouble here. The got bored out to 3 3/16" or 3 1/4"...

In short, a great little performer built out of a solid but mundane basis. Whether it was in fact based on some discarded plan for a small Buick or Cadillac (I doubt that...), it became the staple base engine for Australia for a decade and a half, Repco's contribution turned it into an inspiration.

Americans almost always think that "there is no substitute for cubic inches." The little Repco/Holden started out as a 2.2 litre six (132 cid), so it needed to breathe in order to make rpm and power. Those midget races must have sounded like a nest of angry wasps.

Among the furrin inline sixes, surely the various Jaguars and BMWs would hold our attention. Earlier, we might think of the Bentleys. There is nothing like them in American cars until quite recently.

God's Peace to you.

d
Inliner # 1450

Keep 'em coming... eventually we'll get a few together...

Aston Martin, Maserati, Citroen, Alfa Romeo, Volvo 164, Buick Silver Anniversary, Ferrari, Mercedes 220 to 300, Rolls-Royce, Austin-Healey 3000, there's lots more... which one do you like and why?

And don't forget the ones more prominent (but perhaps less exotic...) from mundane cars. After all, most of those listed would be 'mundane' if we lived where they were more common!

So there might be someone out there who just loves the old Hudson Terraplane, the later big Hudson 6s or the Oldsmobile or Chrysler or Pontiac side-valvers, or the ohv units from Chevrolet, GMC and AMC.

I've got one up my sleeve that enraptures me whenever I think about it... but what about this one?

Fiat 1800... 1960, 1796cc or 109.6 cubic inches.

This darling had inclined valves and a crossflow alloy head over an iron block, 86bhp @ 5000rpm and torque maxed out at 105ft lbs @ 3000.

Bore... 72mm (2.83") Stroke 73.5mm (2.89")
Compression 8.8:1

Released in 1959 and powering a 4-door sedan, I reckon it was right out of its class. It should have been in something really sporty, given a bit more comp and allowed to rev a bit more.

Do you think that would snarl?

It wasn't the smallest post-war production inline 6 I can think of (anyone remember the Triumph Vitesse?), but it was a much nicer thing. That it got chunked out to 2100 and then 2300cc (ultimately fitted to the 2300 coupe... very nice!) is in a way a shame. But inevitable.

Next?

In high school, I had a 1960 Austin Healy "BugEye"
Sprite and bored and stroked the motor to a 1375CC monster. Now a 1.4 motor may not seem huge to a 4.8 292, but with racing pistons, dual webers, and a hot cam, and a 2200lb weight this car would smoke new Mustangs, Fairlaine GT's, and 340 Dusters like nothing else! Not to mention out handle them. I had a gearhead friend who was heavily into road racing and autocrossing and he helped me "Tweak" this car to it's full potential. Then I bought a 1962 Austin Healy 3000 MKII with the Omlogato engine(3-carb).This was a fast and fantastic handling car! I couldn't keep a muffler on it and who cared?
Long live the Import inlines! They have a distinct advantage over the long stroke US motors.
Watchout for the GM Ecotech 4 banger. These motors scream. I also have some inside info that a prominent car builder in the MidWest is building a SaltFlat racer with a late 60's Cuda body and an incredible inline motor that plans to go 275+MPH! It's one half of a 426" Hemi that's Turbocharged! They are predicting 500+HP from this 213 CI motor! I've seen it too....very interesting motor.

RapRap
1940 ChoppedChevyCoupe

Yeah, those big Healeys were great things... but ground clearance was a problem!

The strangest thing is that in competition, their most successful outings were in rallies!

But BMC was like that, start with a lemon, pour boundless energy into it and turn it into something sweeter that still gives off the aura of a lemon.

Did you know they made alloy heads for them? These engines started life with a simple head with a cast-in log manifold (like early Falcons) and twin ports on those to take either a single downdraught on a bolt-on manifold or twin SUs.

Then when they put them in Healeys, they built a 12-port iron head, but they were still 2639cc. They were enlarged to 2915 (is that right? 177.7ci, I recall) in the sedans late in '59 and Healeys then got them in this size and introduced the '3000'...

One very rapid one in our road racing circles here was out to about 3.3-litres and winning everything. The owner then bought an alloy head and fitted it, dynoed it and found it was short 20hp compared to the iron head.

The driver dropped his bundle when he heard this. Despondent, he was encouraged to try it at Warwick Farm... remembering that this had a 60lb or so weight saving high up at the front of the car. He improved his lap times by nearly two seconds!

Contrary to a lot of popular belief, this engine, the C-series, was not a truck engine. In fact, they were only ever used in the following cars:

Austin A90 six
Austin A95 and A105
Morris Isis
Wolseley 6/90
Riley Two Point Six
Austin-Healey 100/6

...and in 2.9 litre form:

Austin A99 and A110
Wolseley 6/99 and 6/110
Austin-Healey 3000
Princess Vanden Plas 3-litre

They were related, I believe, to the 7-main bearing unit used in the MG C and the Austin 3-litre Deluxe (with lengthened front and rear on Austin 1800 bodyshell... and front engine/rear wheel drive).

This latter engine was, however, a disaster. There are some who've seen it (I never have, strangely) who say that it's more like the Austin Freeway engine we had here in Australia.

This was a 2.4-litre 6-cyl version of the B-series as used in MG A etc. Maybe it was a 6-cyl version of the 5-bearing MG B engine stretched yet further to get the capacity? Frankly, I don't think so... but I'm open to new information any time.

From an appearance stand point and performance at its time, the Alfa Romeo 6C2300 motors of the early thirties are my vote. Beautiful castings and the kicked serious tail in their time.

Bang for the buck is probably the Ford 300.

Most unexplored potential may be the Vortec motor.

Even the Alfa 2600 from the fifties was a delight...

Bore 83mm (3.27") Stroke 79.6mm (3.13")

2584cc 8.5:1 compression, 130bhp @ 5900rpm, 139ft lbs torque @ 4000rpm

Alloy block and head, twin overhead cams, slightly oversquare and a bit revvy, it must have had some performance potential.

The 2300 might well have derived, though, from this little gem from 1928:

62mm (2.44") x 82mm (3.23") for a capacity of 1487cc. With a single Zenith carburettor it gave 54bhp @ 4500rpm, it had an iron block. Clearly this is the one that grew to be the famed 1750 of the early thirties, but was it stretched to 2300cc?

There was a series of drawings of this sort of thing published in Australian Motor Sports in the late forties and early fifties, I'm sure one of these engines was depicted in this series... must find it.

Found a picture of a Repco Hi-Power head at last... only external, but something to show:

My dad had a 60's Fiat with the 2300 6. Not very stylish but I liked the hemi 6 all aluminum except the block. Had aluminum fined brakes. The plan was to build a midget around it and stuff me in it. My mom put an end to that. Anyway how about Hall Scotts? A condemed ww1 airplane engine that found its way into trucks and buses made into late 60's, 1091 cid sohc,cross flow head and two sparkplugs per cylinder. Too big? There was a "baby scott" 590 cid same features as the big motor. Now with some firewall work maybe some front springs and a tough rearend we have fat fender hot rod that still sounds like a 6. Bring that big block v thing over here and lets see what you got If a little is good More is better And too much is just right

Found some Hall Scott specs b 5 3/4 x 7 1091 cid comp 6,5 on gas 8.1 on lpg hp 332 @ 2200 torque 960 @1200 on lpg hp 368 @2200 torque 1091 @1100 For the baby scott 5x5 590 cid on gas 6.6 comp hp 239 @2800 torque 490 @ 1600 on lpg comp 8.7 hp 256 @2800 torque 530 @1600 .These numbers may not impress but it wasn't until the 70's that diesels got near this proformance and they were turboed where Hall Scotts were always natural asperated. In fact the first high proformance cat diesels (343 /1693) were diesel copies of Hall Scotts

Thanks for bringing up that Fiat engine, Rick... it was a nice baby six...

In 1800cc form, it must have revved really nicely. John McCormack used to race F5000 in Australia, and when our new Formula 2 came in during that era, requiring a production head and block, no more than one camshaft (overhead or in block), he suggested destroking a Fiat 1800 would be a good way to go.

Later 2300 cars, by the way, had disc brakes. In fact, I think they had 4-wheel discs. And there was a 2300S coupe that was regarded by many as a baby Ferrari.

There was also a 2100 in between the 1800 and 2300.

But we still haven't got to my favourite inline engine...

In their day, It was pretty hard to beat the Hudson Hornet. 308 cubic inches. With the factory 7x racing setup, it had 225 hp. These are a Flathead engine with 12 ports, and you could get them with a two bbl, or two 1bbl carbs. There is a guy in Illinois with a bored and stroked hornet engine with Webers in a 41 Hudson coupe, that is running 12.70's in the 1/4. Hudson Dominated NASCAR and AAA circle track racing in the early 50's...

I think eveyone has a idea of the ultimate six should be. I think my 292 build is pretty ultimate because of lots of power on small tires. There are a lot of super cool builds but the one that stand out to me is this one

Twin turbo Cummins 6,a shot of nitrous, 60lbs boost and weights 5000 lb. 10.50s in the 1/4 on street tires. Crusin around on Saturday night beating up on Camaros and mustangs how cool is that

I have to agree with mighty6, we seem to have the same perspective here.

But, I don't think those are street tires.

the mighty chrysler hemi 6.designed in the US in the sixty's(but never built there)only built in australia in the 70's.215,245 and the great 265 cu in.horsepower ranged(the 265)from a mild 203hp to a ground pounding 302hp(complete with 3 weber-factory fitted-twin choke carbs)weighing in at a mild 440lb's and able to be bored to 280 cu in and have even been stroked to 320 cu in.last year ,a naturally asperated hemi(on pump gas with weber carbs in a steel bodied sedan ran a 10.4 1/4, a turbo hemi six ran the 1/4 in the mid eight's! (full steel bodied sedan)and ran in the mid 7's(front engined rail with a blown hemi 6!)the very few 6's in oz that V8's are scared witless of!

Was it really designed in the US?

We're getting off the subject here, aren't we? Pure drag racing grunt surely isn't the province of the inline six.

Inline sixes, to my way of thinking, are engines that express themselves in finesse. They're ultra smooth, can be sophisticated.

I don't think bigger is always better with an inline six.

While it may not fit your line of thought Ray,my early 240Z was the best inline 6 I've ever owned.
It was smooth,tons of torque,, and after I dropped in a close ratio 5 speed and a LS 4:11
rear it had huge top end.Later own it became more race car then street with carb,header and chassis changes.I was middle of the pack competitive and I never changed the cam, compression or CI. I never trailered it to a track either.

What about the engine from the Ocean Liner that was posted a while back??

Several thousand horsepower as I recall.

Ha Ha. True John.Weren't the bores the size of a VW beetle?

Oh it does! Yes, a lovely thing, somewhere in the right size range for sixes. Revvy, smooth, make a great sound.

But my favourite is smaller than that, I must admit... and by a large margin.

By the way, anyone have any experience with the 1600cc version of the TR5/TR6 Triumph six? It came in the Vitesse sedan and coupe and the GT6 version of the Spitfire, as I recall.

But it was based on very old and awkward foundations... the Standard 8 and Standard 10 4-cylinder engine which ultimate got stretched out to about 1400cc for the last of the Spitfires.

Yea, something like that

The Mechanics working on it looked like ants.

I'm afraid that this thread has gone astray from my intentions...

While I am trying to direct it along a path bounded by free-revving engines, bathed in the sound of snarling inline sixes, some seem to think it's about larger and larger engines. And it's certainly not!

Even this is anathema to my cause...



So can we please think smaller?

Well Ray, for me it's been this one...



The 230 flathead six in my '50 plymouth, not that I'm biased or anything, LOL. Driving it daily, lulled along by the sweet sound.

Actually, I Think my favorite six was in the '89 Mercedes 190E that I owned for a few years. Absolutely and perfectly balanced, from idle to redline you could not feel the engine running in the car. Plenty of power, and great mileage to boot. Engineering at it's best.

Pete

Now that one descended from this one, right?



Sort of a low cost edition with more modern porting...

But a nice thing all the same. I'm looking forward to re-creating a Special that raced in the Australian Grand Prix of 1951 using that engine. One day.

Continuing the six-cylinder theme of this thread... one day I found a mention in Motor Sport of a really neat little twin-cam six. It was made by the French firm of Vagova.

It was built in 1923/24, with a bore of 49.7mm and a stroke of 64mm, it was actually smaller than the Austin 7 engine at 746cc. With twin cams and desmodromic valve operation it was a very advanced little thing and if it revved out I'd reckon it would have sounded really sweet. It also had a 30,000rpm centrifugal supercharger.

But it was a non-starter at the Brooklands JCC 200miler. The Palais du Cinquentenaire was the venue for the Brussels show of 1925, and there a production version was exhibited with the same specifications.

Bill Boddy asks in that article how many might have sold... but I'd love to know if any remain...

Now this is the kind of jewel I can really appreciate!

I'm always amazed at the old engine technology that never gets the light of day anymore.....that is what I enjoy so much about that show with Bill Goldberg on the History Ch. "Automaniac" I think it is called.....Always interesting stuff. I heard him say on one episode with the gangster cars that the engines (probably inline sixes and some eights) were such low rpm torque monsters that they could just leave the tranny in 3rd gear and start no problem and not have to worry about shifting while running from the cops.

Walt, thanks for that...

And yes, the old technology, John. In 1927, I think it was, Studebaker offered an option that was a simple one-action start. Turn the key on, the engine started itself!

Then there were the British systems that kept the engine warm for you... the engine would start up once it dropped to a predetermined temp and switch off again when warm.

Found another Repco Holden engine pic...



But still nobody talks about tiny six-cylinder screamers. That's what I want to know about!

Guys:

Offenhauser built a few "tall block" 270 cubic inch inline sixes in 1937 patterned after their famous fours. I know one was built that year for Joe Lencki's "special". It's hard to imagine anything much better than an DOHC Offy Six!

back in the '60s, on the ohio river by louisville, kentucky, i watched some inboard hydroplanes practicing. one, in particular, was exceptionally loud and fast, sounding like it was making obscene rpm. when the guys began pulling the boats out of the water, in preperation to go home, i cornered the 'screamer' to see what his engine was. much to my surprise, i found out the engine was an early falcon 144, with the cast-in intake milled off and 6 amal motorcycle carbretors feeding the engine! it's been many years since that day, but if i ever heard that noise again, i'd know what it was!

OK, Ray, here's my two cent's worth. My pick for the ultimate compact six cylinder screamer is the twincam Honda 500cc six cylinder engine that was used in the GP bikes Honda campaigned in the 60's with Mike Hailwood riding them far beyond the limits of their rather insubstantial frames and winding the little monsters to about 14,000 rpm while running away from most of the competition. Honda later enlarged and civilized this basic engine design and used it in the CBX 6-cyl street bike in the early 80's.

Ok I'll say it.... the Chevy Trailblazer engine 4 valves per cyl. :-)

Hank

64 Nova man... that was one engine all right!

Not only the CBX (a friend of mine here made a packet of dough for a few years selling six-megaphone exhausts for them to the US), but there was a Kawasaki watercooled 1300 as well.

Still nobody mentions my favourite... but those are in the right size category!

Hmm, just remembered that the Toyota 2000GT had a rather interesting twincam six in it, which was largely ignored in the good ol' USA while it was in production. And shame on us for not buying them in large numbers.

Still about Mike Hailwood, it's worth to remember his 247cc six-cylinder Honda RC166 race bike (won World Championship in 1966 and 1967). I read that this little screamer sounded very unique, and unforgettable...

They were never made in large numbers, actually... they were a very limited production run, and worth a mint today!

I think it was Yamaha, but it might have been Suzuki, had a part in the engine building, but they were largely based (IIRC) on the then-current Crown 2000 motor. Which wasn't a bad thing either.

I think there's half a dozen or so of them in Australia, but that might have changed. It might be like the Honda S600... the prices or these have jumped skywards as the Japanese buy them back from whence they were once exported.

hay ray my father owned a prince skyline GT here in oz not to sure on the specs but possibly a 2 litre engine with 3 42mm webber carbs ,5 speed box not bad for 66 then he updated to 67 when it came out . not many production cars around here were as fast off the production floor???