Fullauto head before and after comparisons (2014)

[Fast Eddie]

This one piqued my interest:

Mine too...

It's a tough call in some ways. I had been considering this approach too, still am actually. But I'd want to be sure I wouldn't be getting into any clearance issues with the bigger valves.

The advantage of the FA though is knowing that you have a band new, very well made and engineered head, whereas a RH10 is a 40+ year old part made down to a price on worn out machinery etc !!

 

[worntorn]

.....whereas a RH10 is a 40+ year old part made down to a price on worn out machinery etc !!

Kinda like the rest of my Commando :mrgreen:

 

[acotrel]

No problem, I agree with you(and comnoz) that raising the powerband on a road going Commando is the wrong way to go, but easy to get sucked into.
For this reason I purchased a good RH10 head and plan to send it to Jim for the conversion. It is my understanding that from a performance standpoint,in the normal Commando powerband, a converted Full auto would be marginally better than a converted rh10, however the big valve RH10 comes close and should produce a little more oomph than an untouched Full auto,if I understand the info on the head thread correctly.
Of course the RH10 won't be as pretty as a Full auto is, which won't matter when I'm riding :mrgreen:

Glen

Fast Eddie's comment:

'So, there are differences that absolutely should lead to tangible performance benefits.'

That is the theory - what is the practice ?

Once you increase the standard head inlets size you have pretty much committed yourself to raising the usable rev range, and there is no easy way back. Tapering the inlet ports and fitting larger carbs doesn't drop the gas speeds. The whole design of the commando engine is about delivering torque, perhaps we should build on it's strengths ? I'm interested in whether the Fullauto head increases the torque output i.e. will the bike pull higher gearing at the same revs after you fit it ?

 

[yves norton]

The FA head was one the best change I did on my Seeley, no porosity, powerfull and machined with care.
Before puting the head on my engine, we put the head on a flow bench, the owner of the bench is a head specialist here in Belgium and he say that the flow was close to perfection
The gain in power is depending from a lot of other changes of course, and don't believe those that says that you will ad 10HP only with changing just one part on the engine, if you wish to find 10HP more and keep the engine reliable you will need to give the big money and change everithing.
And don't say that you will lost the initial caracter from the Commando, no, you will have a Commando force 4
Great thanks to Fullauto
Yves

 

[worntorn]

Once you increase the standard head inlets size you have pretty much committed yourself to raising the usable rev range, and there is no easy way back. Tapering the inlet ports and fitting larger carbs doesn't drop the gas speeds. The whole design of the commando engine is about delivering torque..... ?

Alan, the big valve conversion Jim has developed keeps the power in the same old spot, just more of it:


by comnoz » Wed Nov 27, 2013 11:20 pmI really don't like raising the powerband of a Norton motor. It is really about as high as is practical on a longstroke motor as it is.The big valve conversion will be felt throughout the same powerband that you had before, if it is a stock or mild can then mainly from 4 to 6000 rpm. The cam and exhaust system will do more to influence the rpm range than the valve size will as long as the intake port diameter is not changed. Jim

 

[WZ507]

No problem, I agree with you(and comnoz) that raising the powerband on a road going Commando is the wrong way to go, but easy to get sucked into.
For this reason I purchased a good RH10 head and plan to send it to Jim for the conversion. It is my understanding that from a performance standpoint,in the normal Commando powerband, a converted Full auto would be marginally better than a converted rh10, however the big valve RH10 comes close and should produce a little more oomph than an untouched Full auto,if I understand the info on the head thread correctly.
Of course the RH10 won't be as pretty as a Full auto is, which won't matter when I'm riding :mrgreen:

Glen

From the previous thread that Glen cited, here is a portion of the chronological flow progression reported by Comnoz for large valve fully developed RH10 and FA heads. At one point it appeared the RH10 and FA heads were essentially identical (1st plot), but when the modification that boosted the RH10 airflow was applied to the FA head, the FA head ultimately nudged it for 1st place (2nd plot). I believe Comnoz made an additional incremental improvement to the RH10 after these plots were posted (the one Glen referred to above that "piqued his interest") but in general I believe the flow topped out ~ 150 cfm at 28" WC.

Whether the difference in flow between the RH10 and FA heads would result in measurable differences on a dyno, IMHO is debatable, but regardless, both heads are spectacular performers and extraordinary jewels to crown your Norton engine with.

And as Comnoz said and Glen cited, the larger valves simply increase airflow through the existing port (at higher velocity, which is even better) and more power is generated throughout the useful rpm range. To Alan's point, of course if you ultimately flow more air through the same port, this will support higher rpm operation, but it is not necessary to explore this high end operation regime because the engine will make plenty of power throughout.

 

[acotrel]

' To Alan's point, of course if you ultimately flow more air through the same port, this will support higher rpm operation, but it is not necessary to explore this high end operation regime because the engine will make plenty of power throughout.'

When you fit E3134 race cams to an early 650cc Triumph Thunderbird you get an increase in power right through the whole rev range, even below the cam spot. If you port the head bigger you get more flow however you lose midrange torque, so tend to rev the motor higher. The better option is to keep the inlet port size standard and raise the overall gearing. Most of our old 650 Triumphs have blown up their bottom ends and not returned to racing. Standard Triumph valve gear lightened and polished, with the right springs, will cop 10,500 RPM continually for about 4 race meetings a year for a couple of years. The torque thing is very deceptive, and unless you've experienced it on a high geared race bike, it is difficult to recognise when you have it. I often wonder about torque readings off a dyno. I think most guys look for the peak power reading and don't recognise the rev limit imposed by the bottom end when you race the bike.
What have you got when you raise the overall gearing and the bike accelerates faster ? It is not what you would expect. If you've got all the gears very close, and the overall gearing very high - with lots of torque it is a real thrill, and long as you don't need a low first gear.

 

[worntorn]

The gain in power is depending from a lot of other changes of course, and don't believe those that says that you will ad 10HP only with changing just one part on the engine, if you wish to find 10HP more and keep the engine reliable you will need to give the big money and change everithing.


Yves

I'm guessing that the head alone is probably going to add maybe 3 or four horses and a bit more torque thru the range. Truth is there is not too much you can do to a Commando before you run into the kind of fragility problems encountered by Kenny Dreer.
The extra torque of the 850, 56 ft lbs vs 48 for 750, 49 for Combat, is already pushing the limits of the gearbox, designed when 25 HP and perhaps 30 ft lbs torque was Max output of a parallel twin.
I agree, to add ten or more HP with longevity expected means lots of money for better cases, crank and a TTI box, aside from the items which add the power.

Glen

 

[Fast Eddie]

.....whereas a RH10 is a 40+ year old part made down to a price on worn out machinery etc !!

Kinda like the rest of my Commando :mrgreen:

A fair point... well put... !

 

[acotrel]

It would be very interesting to make a head for a 750 Triumph which looks similar to the T110 head except for the down angle on the inlet ports, and make all the Fullauto (Norton) improvements to it - squish band, D shaped exhaust ports. Might be a market for them, a lot of Triumph heads have cracked.

 

[Fullauto]

It would be very interesting to make a head for a 750 Triumph which looks similar to the T110 head except for the down angle on the inlet ports, and make all the Fullauto (Norton) improvements to it - squish band, D shaped exhaust ports. Might be a market for them, a lot of Triumph heads have cracked.

Looked at it. No good. Norton owners spend money on their bikes. Triumph owners are notoriously tight fisted and complain about the price of secondhand stuff.

 

[Fast Eddie]

It would be very interesting to make a head for a 750 Triumph which looks similar to the T110 head except for the down angle on the inlet ports, and make all the Fullauto (Norton) improvements to it - squish band, D shaped exhaust ports. Might be a market for them, a lot of Triumph heads have cracked.

Looked at it. No good. Norton owners spend money on their bikes. Triumph owners are notoriously tight fisted and complain about the price of secondhand stuff.

And of the Triumph owners who are prepared to spend 'healthily' on new heads... they have Nourish. So that's what any new alternative would be measured against.

 

[SteveA]

For this reason I purchased a good RH10 head...............

Glen

Glen, to my mind this is the big issue.

The Full Auto is a great replacement for a poor RH4, of which it seems there are quite a few out there.

Finding a 'good RH10 head' is like winning the lottery today. There were fewer of them made, of those that survive most who own them would be wise to keep them.

Enter the Full Auto, which guarantees a certain standard from stock. Which for someone in need of a reliable solution to the poor RH4 is a good option, you know what the cost is and what the performance outcome is likely to be...'better', but of course the purpose of the thread for Fast Eddie, was 'quantify better'. Difficult, but you never really know what you are into with a used head until you get to the final test. And to my mind you have no 'guarantee' of better. Or even that the head you submit for repair will even be usable.

If you have a good RH10, or even RH4 or 750 head in hand it must be a difficult decision to make.

If like me you didn't, the decision to go FullAuto is much easier. You have a benchmark that you know can be achieved. This is true if you are looking to build a nice road bike, but it becomes critical if you want to build a decent race bike.

I am going the route Kenny Cummings went on the head. Fit standard FullAuto and get a bench mark before looking at getting more from it. In any case I am much further back with whole bike development and need time for everything from basic carburation, ignition and suspension set up to braking...and breaking (build a race bike and even the most sturdy looking brackets can fail to perform as anticipated).

With racers you never know where you will end up.

With a road bike keeping the fundamental Commando characteristics seems to provide more satisfaction. Standard stroke, reduced reciprocal weight, FullAuto head and mildish cam sounds like a good package most would enjoy. And it is repeatable.

Getting something similar from a used head is achieveable, but needs a little more luck, and by the time you have finished the budget differential may be less than anticipated. Doesn't mean it isn't a good route to go for someone who has less time pressure and enjoys the process.

And of course you have something apparently more original, but arguably, in some ways a bike that has an RH10 fitted in place of a dodgy RH4 is no more 'original' than a bike fitted with a FullAuto in place of a dodgy RH4.

 

[acotrel]

How is originality enforced in your race classes ? I've never seen any conscientious attempt by our event organisers at achieving it. And to me it seems a pointless exercise. One of the major objectives in racing is to 'improve the breed'. All this stuff about eligibility is a deterrent to development. That is not to say that when a championship is involved, the rules need to be well defined. I'd love to see 4 valve manx nortons and G50s racing, I believe that development of old British singles and twins finished too early before they reached their full potential. If you look at what they became, they are pretty good however could have become better. There is also an economic impact from this stuff. If the race classes encourage development, the resulting bikes can command a market. I'm certain the Japanese never built a single cylinder 500 as good as a G50 or a Manx. Or a 750cc vertical twin as good as a Norton or a Triumph. A 750cc Paton might be exciting ?

 

[SteveA]

Alan, as Ken has identified, it is a significant investment to copy an original part in form and fit, with a bit of improved function.

Surely it is another thing entirely to embark on the development of a multivalve head, with the clear intent of race winning reliability and performance with little concern for historic machinery. You would only do it if you were looking for a significant return on investment. And if you were successful the machines using your parts would command top dollar, whilst those that don't would lose value......or retire to museums and sheds, as many have done already....

None of this would achieve what the FullAuto head does, a part that is useful whatever your Commando interests, road, race or gravel tracks.....or 'concours level originality'.....the part looks like an original part in all dimensions, and provides a good base for race development.

Classic racing is a nightmare mix, enthusiasts remembering the machines and exploits of their youth, skilled engineers 'developing' classics or 'what might have beens', amateur unsponsored riders struggling to participate, industry sponsors and paid riders who don't appreciate the contribution of the 'amateurs' in making the events happen......and eligibility rule makers.....

Not sure where the debate takes us except that it needs something different to a debate to answer Fast Eddie's question.

What that really wants is Comnoz to take a clean standard head, a reworked RH10, a standard FullAuto, and maybe a big valve full auto and move on from the flow bench and methodically stick them all on the same bottom end using a mid range range cam and the same carbs ignition and exhaust, and apart from minor adjustments to suit each installation and atmospherics, record the results.

I suspect in the long term Fast Eddie will give us his own comparative results :wink:

Anything else is 'speculation' and even then we may not fully understand the 'rideability' of each.

 

[acotrel]

Steve, back when I was racing regularly, I always rode my 500 Triumph in an Allpowers race class. It was before historic racing happened, and the race grids were always a mix of different types of large capacity bikes and two strokes. When historic racing came along it seemed to be an extension of that type of class, however with a lot of un-necessary rules. I really like such things as Battle of the Twins. And I am certain I never want to see two stoke bikes from the fifties and sixties racing against manx Nortons and G50s, to me that is a waste of good race motors. I suggest it is important that the same types of bikes with similar tuning problems race together. If you look back, that is effectively what happened in the non-beginner race classes, without any rules needing to be applied. In the 70s, if you were a B grader or an A grader, you bought yourself a TZ Yamaha. With the commandos, there are a lot of similar bikes. To me the ones to beat with a commando are the similar capacity 851 Ducati, the BMW boxers, the big Guzzi Vtwins and the Triumphs. These days we never seem to get the situation where they get lined up together and I think that is a shame.
I don't know what the race classes are like in America and the UK however some of the racing on Youtube looks good.

 

[Fast Eddie]

985 views and 35 posts later... yet still no answer... where are all of the Fullauto users... Or are FA heads truly that good looking that they really do just get put on the mantle piece and admired ?!?

 

[acotrel]

Perhaps when most people fit a Fullauto head, it is part of an engine upgrade or rebuild and so it is difficult to attribute the performance changes to any one factor ? If it improves the torque output, unless the overall gearing is raised and the bike still accelerates the same or faster, the benefit wouldn't be obvious.
If you are developing a bike, it is important to make changes one at a time and document the observed effects. When I built my bike, from experience I had a fair idea what works, now I'm trimming and optimising. This forum helps that process.

 

[Gino Rondelli]

Just got mine before I left for the International rally in Germany, just back and not had a chance to fit it yet. It will be fitted over the winter to my mk1 850 and I'll give you all a report next Spring. Angela Hemmings told me I should get 100bhp
Meanwhile it looks cool on the coffee table!
Just looking for a head that doesn't "breath oil" on a long trip and despite it costing 3 times what my Commando cost me originally I figure I've had well over 100,000 miles of fun on that bike and it deserves a little present. It's cheaper than buying a 961!

 

[acotrel]

If you ask her nicely Angela might show you how to ride your 100 BHP commando.