4 valve Norton Manx

Whats the story on Andy Molnar's 4 valve Manx? Supposed to get 70 HP at 10,000 RPM (supposed)

Will it be legal? - they are arguing about it now.

I remember when this thing came out about 40 years ago and it bumped the HP up to 60 HP back then. There was some mention and a photo I saw in the late 60s or early 70s I think showing a 4 valve Manx (not Andy's)

Never mind the legal bit, how do they get it to survive at 10,000 rpm ?!!
Unless its been shortstroked, a lot ?

BTW, where are they discussing it - a racing forum someplace ?

Hi

It came up with us at the CRMC . Basically the Classic Manx/TT allowed Andy to build a 4 valve head as he (I think quite rightly said that a Manx wont live with a Paton (or MV,Honda4 etc) The design is Andy's own & he must have spent a lot developing it. ie this is not an eligible bike under classic rules.
It is not the Mularney Manx that was raced in the period (the 350 engine was the 500 was not) However both of these bikes (350 & 500) have been given eligibility by the CRMC & have been raced very successfully by Bob Newby.
Cant see Andys bike ever being raced outside the IOM. Although it would make a cracking track day bike.
There are photos of the cambox & the engine & Andy put up a clear post before the AGM last year to the committee & the members stating why he thought he should be allowed eligibility. I will try & find some of the story / links.

Chris

http://www.cmrf.co.uk/smf/index.php/topic,5667.0.html

10 pages Hopefully the gist of it all is clear.

Chris

Needs a username and password.
I'll think about joining...

Thanks for the good summary though,
probably all we need to know as a general intro.

It is mentioned elsewhere that 2 valve manxes have still done faster laps at the IoM,
so 70 hp and 4 valves aren't everything !?
(And a G50 has lapped fastest of all ?)

Molnar's 4 valver is way short of 70 bhp , it's just about on par with a good 2 valve engine, i.e 60 ~ 62 rwhp.
It is a well engineered job, but has been plagued with reliability issues to date. When these niggling problems are sorted it will undoubtedly be a formidable tool in the hands of a top flight rider. I can't imagine where the 10000 rpm came from - possibly from a well known individual notorious for his bragging claims (not Molnar)

The bore size is 95 mm. This is about as big as one can go without seriously jeopardizing the cylinder rigidity, and also clearing the cylinder long holding down studs. Cams are driven off the intermediate cambox gears, which effectively halves the original 2 v engine's included valve angle. From the outside nothing indicates a 4 valve engine, and the workmanship that is in evidence is surely a tribute to Molnar's skill and expertise. All his other engines go well enough, and for this one it's surely just a matter of time.

Chris said:

Hi

It came up with us at the CRMC . Basically the Classic Manx/TT allowed Andy to build a 4 valve head as he (I think quite rightly said that a Manx wont live with a Paton (or MV,Honda4 etc) The design is Andy's own & he must have spent a lot developing it. ie this is not an eligible bike under classic rules.
It is not the Mularney Manx that was raced in the period (the 350 engine was the 500 was not) However both of these bikes (350 & 500) have been given eligibility by the CRMC & have been raced very successfully by Bob Newby.
Cant see Andys bike ever being raced outside the IOM. Although it would make a cracking track day bike.
There are photos of the cambox & the engine & Andy put up a clear post before the AGM last year to the committee & the members stating why he thought he should be allowed eligibility. I will try & find some of the story / links.

Chris

Click to expand...

There is something wrong with the rules if similar existed back in the era and it is prohibited now, especially when you consider things such as the Katana engined XR69 Suzukis. Seems there is a decision to be made between close replicas and original bikes, and whether historic classes are to continue as 'development classes'. If it is not allowed in historic races, WHERE IS IT ALLOWED ?

Wasn't the 4 valve manx after the historic period though ? (pre 63).

There are classes for everything to race in these days.
Didn't I see mention the other day of period 6.
No idea what that actually is, but they looked to be having fun.

Only one guy can win in every race, of course.
Even if they are only racing postie bikes, that guy will still win. ?

Harking back to what went on in the 'era', I recall there were very few owner/riders who were content to race their machines as purchased from the factory. The amount of private development and modification that went on was amazing for the range of ideas tried out, and the skill and ingenuity of the individuals carrying out the work. Development never stood still then, and it's hard to understand the logic behind the view that it should do so today. Even men like Bob MacIntyre were making special parts, frames, cams, pistons etc, Roland Pike was scaling down a 350 Gold Star engine to make a special 250. Ray Petty, Bill Stuart, Steve Lancefield, Francis Beart, Jim Smith, Geoff Monty and a whole lot more were working towards squeezing a bit more out of their machines than the opposition. Some even made their own complete engines, Dennis Jones and Bob Geeson being two that come readily to mind. And to cap the best efforts of private endeavor there were the Gilera's, Mv's and Benelli's skimming off the wins and top placings. What's changed ?
My own opinion is that the problem lies not with Andy Molnar's interpretation of the rules, but the incompetence of the rule makers to administer what rules there are(were) with fairness and impartiality.
There is an old saying among engineers that a camel was intended to be a horse, but unfortunately was designed by a committee. This could well be the case with CRMC. Perhaps the rule book should be re written, and rule 1 should be 'There are no rules'.

Hi Al

In the original rules, an original one off bike ie the Mularney Manx was allowed (350) No replicas.
I am aware that Norton built a 4 valve head & a desmo. What would occur is reverse engineering. ie modern design but unless you have the drawings & can prove the bike was raced it is not eligible. Plenty of things have slipped through. Nearly all the modern Manxes are based on factory works bikes.
All Andy did is build his head for the classic Manx & try to get it into the CRMC as the committee had updated eligibility rules & dropped the original wording that would have stopped it. They did not cover themselves in glory attempting to change the rules again but then this development is not in the "spirit" of classic racing. There were plenty of garden shed designs (and better) that were built 4 valve G50 4 valve dohc Daytona, even Percy Tait looked at getting a 4 valve head designed for the triple but they are still one offs & can not be replicated.
When Andy gets the bike right I am sure it will compete with the Paton at the Manx however rose tinted classes on Is it not the same as running bandit engines in X69's Hondas that have bigger engines than they had in the day. Wont people in the future believe a Manx can compete with a Paton even though it is Andys view of a 4 valve Manx. Do you open up a subclass of period one group1 for specials ie what the factory might have come up with.
Would the rest of the modern Manxes Molnar summerfield Norton Works dwindle from the grids? I think the club should have done that when the first lot of Modern Manxes came in 20 odd years ago. Maybe? the Landsdowne series would be within the club (I don't believe that) People will always walk away if they feel uncompetitive, If the risk & cost of running an original bike so hard to be competitive cant be justified especially if you are running with new bikes that are not original.
I cant see that it will ever be granted a place in Classic racing outside of the Island but you have to be impressed that Andy has gone ahead & done it.

Chris

I would think that if a fellow were to carefully build an advanced component entirely from verifiable period materials, using only verifiable period tools and equipment, he should be allowed to have it scrutineered and accepted as a "period modification" if absolutely verified.

...especially if it's an older guy FROM that period...

grandpaul said:

I would think that if a fellow were to carefully build an advanced component entirely from verifiable period materials, using only verifiable period tools and equipment,

Click to expand...

Just where are you going to find all these "verifiable period materials" ?
And just how do you enforce that "verifiable period tools" ??
(And just what real purpose does imposing this limit on technological advances do anyway ?)

If there is one thing that is terribly apparent about modern motorcycles and their manufacture,
it is that modern metals are soooo much better than decades ago,
and modern machining and production methods have come a looooong way over the past few decades.....

Cast steels used to be quite a rare and expensive commodity not that far back in time,
and now you can buy electric furnaces to almost do this in your home garage.
Aluminium alloys used to be prone to bubbles in pouring and cracking in service,
and modern alloys are way way way better than they used to be.
Why go back into the stone age ??

If these 4 valve manxs were not around in the 'classic era',
why allow them into classic era racing.
They should be in the relevant age bracket.
And if they are not then competitive, thats why they didn't develop back then either.
But, perhaps there should be an experimental class of racing ?

"Why go back to the stone age?"

My argument is go back to the technology and materials available in the years encompassed in the various classic bike racing classes, in order to assuage the anti-modernists crowd.

If somebody can make a new 4-valve head that's better than a tricked-out original, using the same machine tools and materials, it can be argued that the new part should be allowed in the classes as "period correct".

Take it even one level higher: if said new part manufacturer can produce verifiable design drawings for the part DATED FROM THE PERIOD, there should be no earthly argument against it.

grandpaul said:

Take it even one level higher: if said new part manufacturer can produce verifiable design drawings for the part DATED FROM THE PERIOD, there should be no earthly argument against it.

Click to expand...

And if they can't produce those drawings ?
Are newly made "verifiable design drawings from the period" going to be allowed. ?

This sounds like an exercise in total obfuscation.
KISS = keep it simple needs to apply ?

P.S. Anyone got those drawings of the 4 valve desmo that Nortons were said to be thinking of ?
I'd like to try that one for myself.

Anyone got the drawings for just the desmo...

PPS. Nortons have had 4 or 5 designs for 4 cylinder bikes done over the years.
Does that mean they would be eligible to race. ?

And the Nirvana V8.
Even if it was 2 Kwikasaki top ends sandwiched together...

Rohan said:

PPS. Nortons have had 4 or 5 designs for 4 cylinder bikes done over the years.
Does that mean they would be eligible to race. ?

And the Nirvana V8.
Even if it was 2 Kwikasaki top ends sandwiched together...

Click to expand...

Good points, but I'll still beat ya...

Norton had a design for a 4 cyl DOHC engine drawn up in the early 50's

A bored out Japanese home market 4 cyl 400cc engine spinning to about 18,000 rpm should do the trick. Of course, I'll get some covers cast up saying Norton, then its just like what may have been.

The featherbed frame's gonna earn its keep with that lump in it innit?!

Back to being serious for a mo, this is why the notion of 'no rules' as posted by someone is impossible with classic racing. The very notion that it is a classic class necessitates rules from the outset!

The closest you can get 'no rules' racing is modern open class racing. Which is a fine class, but it isn't a classic class.

With classic racing, there will always be arguments about where 'the line is drawn' and who has stepped over it. I agree it seems annoying to have such 'politics' in racing, but the very notion of date related classes will ALWAYS suffer this.

Nortons four an article from an old book I found somewhere



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Thats the BRM (?) designed 4 that Nortons commissioned in the early 1950s.

Note the carbs facing forward, behind the radiator. (carbs not fitted)
It was commented back then, and is equally valid now, that that meant it was breathing hot air.
Not good for efficiency - especially in a racing engine, where every bit of hp counts....

And it has elsewhere been commented that BRM did how many versions of race car engines,
before they ever won a single race. ?? !! It was said that their designer would fuss and fuss
over a single tiny detail, and lose sight of the big picture - i.e. to win races !

As can be seen from this article, a complete engine was never finished, so it was never raced.
The power output from the slave 125cc, as stated, was not even up to then manx levels,
so it would not have been a giant killer...

However the Manx inspired Vanwall did.

"The 2.0 L engine was designed by Norton engineer Leo Kuzmicki, and was essentially four Manx[1] single-cylinder 498 cc (30.4 cu in) (86.1 mm × 85.6 mm (3.39 in × 3.37 in)) engines with a common waterjacket, cylinder head (a copy of the Norton's) and valvetrain,[1] with induction by four AMAL motorcycle carburetors."
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