I can't really decide which this is , since both head types (bike engine heads and pushrod crossflow head) are claiming similar power outputs (in non turbo form) for similar costs (with machining and fitting as opposed to orriginal purchase) is the 7 port a really super efficient design or are the 16 valve dohc engines under utilised on a mini block ? It just seems to me the 1960's tech is matching the 80's tech pretty much . Either that or is it the combo of continued A series camshaft design with the crossflow head against fixed bike camshafts (is anyone looking into cam development for the bike heads to make them more suited to an A series application ?) . Just seems they are all getting to the same place by different means and I'm not sure which is better ....

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Howdy,

In regards to power yeah they make similar on the surface... but:

The crossflow heads pulls from down low up to 7000-7500rpm
While the bikes make power at 9500-10500rpm
The Elder head will make more torque. 20-30ft/lb than the bike heads will...

Torque is what you feel! Torque is what everyone is chasing!

I know what i would get... its simple.

Pete

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Click here for the Turbo Conversion Thread!

You got it right Ian about the cam development, the 7-port is designed and matched for the A-series in both port/chamber size and shape and it's ability to match it with cams designed for the motor.

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Starlet Conversion:
http://www.ausmini.com/forums/viewtopic.php?t=15484

Interesting comment. Now I am only a pig-iron polisher and I am dumb as dog sh*t so PLEASE explain the reasons for your comments

1 What is exactly "TORQUE" and can you calculate it or do you "just feel it"

2 Why do bike engines develop power at a much higher rev range compared with a "A"series

3 why do the elder heads "make more torque" than a bike head

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Research is the difference between speculation and investment. Anyone who copys some one else will always be second
www.minisprintgt.com

OK now you have two cam shafts that are exactly the same construction in
1 duration of effectiveness
2 giving the valve exactly the same travel
3 exactly the same profile shape
4 timing relationship for v/v movement

One is set-up as per a std "A" series engine, and the other is in a twin cam head. The only difference then is one head has 7 ports with 8 valves and the other has 8 ports with 16 valves.
What you are saying is if the ports and combustion chambers are EXACTLY the same shape and size for both heads and the cams are EXACTLY the same then the engines would they be the same in terms of power and torque

_________________
Research is the difference between speculation and investment. Anyone who copys some one else will always be second
www.minisprintgt.com

I think it boils down to the fact than nobody is developing cams (yet) to suit these twincams on an A series motor, where you need more low down torque and a lower rpm ceiling..
Modern bike motors are all designed to do a zillion rpm reliably, an A series just is not, even if you do fill it with all the shmick racing bits.

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

so in closing............. we have to develop a camshaft profile to suit a bike head on an a-series engine?

Maybe get 2 turned up from scratch from a billet?

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BMW K-series --> only 987 cc...

Max Power--->90 hp (66 KW) at 8,000 rpm

Max Torque--> 86 Nm / 63.42 ft lb at 6,000 rpm

Compression Ratio--> 10.2 : 1

It`s a really "Little" motor boys & girls,,, it`s "NOT"-->"""designed to do A Zillion Revs""" ,,, but Doc you are right in one respect with the cam designs,,, they are not a perfectly suited profile (YET),,, they have not yet been "perfected" to suit a mini engine "YET"... but isn`t that exactly what GR is doing??? ---> In fact still trying to perfect cams to suit the mini engine???

Like i keep saying boys & girls,,, GR is doing good things & i agree with what he`s doing,,, I`m defiantley not knocking him,,, I`m all for it & it`s exactly why i like to build really big donks with mild cams,,, effectively achieving a similar power spread as what GR is trying to achieve,,, Crickey,,, how many times have i said exactly that??? Id dearly love to have a smaller engine with the same (or better) power characteristics as my 1415cc & 1510cc engines---> Who wouldn`t?????????????

sorry if some of my pot stirring is sometimes taken the wrong way,,, i`ll back off "playing around" now, just to keep the peace,,, but If you guys just stop to think about what you`re saying with all this 10-11-12,00rpm stuff & how the mini can`t do 10-11-12,000rpms,,, well i`m sorry but the Bimmers are set up with small ports,,, small valves & run "up to" 8000rpms ,,, they are a very very mild beast indeed,,, very very drivable & smooth & absolutelky no need to rev the tits off them at all,,, just because they "CAN" run up to 8000rpms doesn`t mean they have nothing down low, nor does it mean their power spread is useless to the road driven mini,,, in fact it`s quite the opposite,,, they have a lovely power spread & soon there will be cams avaliable for them which will be far better suited,,, they`re being "Played with" now & have been "played with" for quite some time,,, (In fact by a number of different companys) just like GR has been "Playing with" (Developing) his new range of cams

the K1200 head is a totally different kettle of fish tho & yes it`s far better suited to the higher end of the rev range... but they are still VERY mild in there cam profiles

again it`s only a little engine at --> 1171 cc

Max Power--->130 bhp (96 KW) at 8,750 rpm

Max Torque--> 117 Nm / 86 ft lb at 6,750 rpm

Compression Ratio--> 11.5 : 1

Now if you just stop & do the math,,, lets now add the size of engine that GR is "Playing with" --- a 1380cc,,, sorry ,,, what was that???---> A 1380cc

OH!!!!!!!!!!!!!!!! well lets add that massive chunk of capacity into the equation now shall we??? lets now just add that massive chunk of low rev air speed increase into the mix shall we??? Now we suddenly have a far "Bigger" pump havn`t we??? We are now passing WAY more air into the engine at the same rev range yeah??? Please someone tell me i`m wrong here???? Now, so far in this particular example i havn`t said anything about increasing the revs to the moon (Just yet)

so do the math now & see what those std , very mild K-1200 figures turn into "simply" by adding that big increase in engine displacement yeah???

do nothing else ,,, just add one 1380cc pump underneath that std K-1200 cyl head yeah???,,, well---> more like 130+hp & approx 110-ish ft of torque,,, still within the same rev range, still with a stock head

Now lets "Play" with the head (like GR is doing)... & there is much we "can" do but (if you`ve ever looked inside a K head), you will see one simple problem imediately which is soooo easy to correct & adds a whole bundle of power without having to increase revs.... It`s so simple & easy to fix it`s not funny

& then lets say we "PLay" with the cams (Like GR is doing)... ok, now we see a even more improvment (just like GR is finding)

BUT,,, that`s not "REALLY WORKING" the head at all is it,,, it`s just fiddling with a fiddly little lip problem,,, there is "PLENTY" more you can do with them to help bump the power again & still remain in the std-ish revs dept,,, there`s more work with that side of things happening on many many twin cam mini heads all over the world at the moment (of which we hav`nt seen the fruit of yet) ,,,, they`re a relatively hew thing compared to the age old suffocating A series head that`s had soooo much work on it for soooo many years,,,,,, so maybe you all should cut the twinkys some slack yeah??? They`re new & it`s exciting & there`s "OBVIOUSLY" plenty more to come from all the various twin cam heads ,,, as is the same with GRs work & the Elder 7 port,,, lets all just be nice Boys & girls,,, lets stop the arguing now,,, lets just go about doing our things & it will all come out in the wash,,, I`m building turbo injected twin cam engines,,, GR is doing push rod 5 & 7 port N/A engines
... it`s not apples with apples,,, it`s not even apples with oranges

This whole discussion has gone way off topic from GR playing with 7 port Elder heads ,,, through to GRs cams for early 5 ports,,,, & now we`re back with all sorts of crap about which type of head everyone prefers,,, cool,,, but no "One Particular" cyl head is going to be fitted to "All" A series mini engines for the rest of all eternity,,, there will allways be some one finding Somthing else to fit & "Play with"

If we didn`t have a play with minis,,,, then GR wouldn`t be GR,,, David R wouldn`t be David R & i most certainly would be playing with turbo 4x4 GTR skyline running gear underneath duel cab kombi utes instead

get back to work you bludgers

& GR,,, definately no offence intended,,, & i know you know that already,,, just want everyone else to understand our relationship is good.

see you at the Hyrtericals at Morgan Pk

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No offence intended here but--> anyone writing a book about minis 30 years ago may not have experienced such worn or stuffed-with components as we are finding these days.

You should put your heart & soul into everything you do.

Well said Matt.

Power and torque are two totally different things.

With power, think of an engine as just a big air pump - the more air you pump, the more power you make. You can pump more air by doing any of three things, or a combination of them - 1. Increase the pumps internal capacity (boring or stroking), 2. Increased the speed at which the engine runs at (higher redline), or 3. Forced induction (forcing more air into the cylinder than that which would be done under normal atmospheric conditions. Any of these three things will effectively make the engine pump more air.

So, a small bike engine can produce as much HP as a larger car engine, because it has a higher redline for a smaller capacity but can pump the same volume of air. However, the peak HP is moved further up the rev range because of how the engine is designed to produce that power.

Torque is a turning moment. Imagine a frozen bolt on the A-series head. If you have a 6-inch shifter, you can't get a lot of leverage on that sucker, effectively only 6 inches or 200mm worh. And no matter how much force you put behind it, you can't get it to move. Now, imagine that same bolt with a breaker-bar and extension handle applied to it, with absolutely minimal effort, the bolt comes free (or snaps off! ). This is an example of leverage, and leverage for a reciprocating engine is referred to as torque. So, imagine an engine with a large stroke (like a diesel). The distance from the crank centre to the crank pin is quite large - lets say 100mm, or 4 inches. The downward force of the piston can effectively apply 100mm worth of turning moment, or torque, to the crank. The larger the crank throw, the more the torque (but also the lower the engine speed due to larger reciprocating mass). Now, imagine a bike engine, with a crank throw of 50mm, or two inches. It would produce half the torque (ideally), but would be able to produce more power because it can pump more air (it can rev much higher).

A motorcycle engine (because that is what we are comparing here) does not need to produce much torque, because it doesnt need to. It does not have a heap of mass to move (bikes are very light), and when it does get the mass moving the inertia forces are quite small. A large family 4x4 however needs a lot of torque, not necessarily power. It needs to get large bulk off the line, tow loads etc, so therefore it has either diesel or petrol engines with large strokes, transferring large turning forces on the crank (just like the frozen bolt head).

If you take two extremes of internal combustion engines, you can get a good idea of torque and horsepower, and how they are produced. Look at large capacity marine diesel engines - some of them have capapcities of hundreds or litres, they have crank throws of metres! However, they revolve only slowly, about 1500rpm or less. But they produce oodles of torque due to the large leverage forces (but relatively low HP for their size), turning massive big propellors, driving ships through water weighing thousands of tonnes. Or, an F1 engine, small capacity (under 2.5 litres), but with very small strokes allowing them to rev their tits off (no offence to the ladies amoung us or those men who have man-boobs!) to the order of 19,000rpm. They produce bugger all torque, but loads of HP, like 700-800hp. Because they dont need to move heavy inertial loads, but they do need to propel cars at high speeds.

Camshafts, and their profiles of lift, duration, overlap etc, simply enhance an engines natural ability. You will never get a cam that will allow an A-series to rev to 10,000rpm - the engine design just doesnt allow for this. But you can design cams to move power and torque, and how much of each is produced, up and down the rev range and determine when they peak, how flat the curve is, when they start to 'come on' etc. It is application specific most times, and done with a lot of trial and error.

So, its horses for courses I'm afraid.

My $0.02

Cheers,
Tricky

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"Not Speeding Officer..........Qualifying"

And 30 to 40 ftlb extra at lower revs in a Mini will make a big difference in a road car.

Are these 7 port heads radically different from the one Mini Sport UK sells which I think comes from Denmark and is reportedly not as effective as an 8 port?

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Slide
1965 Mini Van (1360)
1970 Mk2 Cooper S (1310)
1978 Rover SD1 V8 (4.6)
1996 Land Rover Discovery V8 (4.0)

Yes they are. Absolutely no comparison. The intake ports in the AKM/Minisport 7 porter are lousy shape and too damned big.

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

Hi Matt
Go back to page one KAD engine 1380 still no big torque no port velocity you can not make big
torque with out port velocity ,now lets take an A Series with 73mm bore std stroke 3.2ins forget
about cams they only move the torque around (rpm) Ken Elder head 1.4 valve
Mean Gas Velocity through the port in ft/ sec .400 valve lift
4000 rpm 252
6000 rpm378
8000 rpm504
Now i dont know what valve sizea BMW head has but going off Davids Honda port and valve
sizes,(tell me your sizes and i work it out) they are as follows .400 valve lift
4000 164
6000 244
8000 328
As you can see the higher the RPM the higher the gas speed now the bike will keep on
reving alot higher than the mini that way they can use the breathing of the 4 valve head
but lower you go the slower it goes , my statment page one to much port to much valve
for low down torque.
Hope this makes things a little clearer
Graham Russell

See you at morgan park Friend
Very nice to talk to you to day David ill be in touch

Good to have you back Tricky, was beginning to wonder where you'd gone

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Simon

The adventures of an owner builder in the Tallarook Ranges

Hey GR, i totally understand what you`re saying (always have)

Bimmer 8V head has much the same size valve as the std "S",,, with only a 31.5mm port (Round shape,,, not oval)

1100 4 valve has 2x 26mm inlets ,,, with much the same port diam. (obviously it opens slightly to suit the 2x valves tho & yes i know what you`re going to say )

K1200 is again much the same port & valve diam,,, but has thinner 4mm stems

There are quite a few other goodies on a K1200 (obviously more suited to higher rev tho) like larger 38mm throttle bodies etc

I remember you saying that you had a Bimmer 8v head there, but hadnt` done anything with it... I`d like you too for one reason (& that`s got absolutely nothing to do with any of this discussion at all) but,,, the fact is that i have been crew chief for Bruce Ayres Litre sprint car team for quite a long time (years) & as you well know, Big broad spread torque is the name of the game in that stuff,,, bike engine cars are pretty good on wide open fast tracks but most speedway circles are just that,,, short tight ovals (well ok, except maybe Paramatta ,,,

well,,, One of Bruces engines just absolutely sh!ts all over the entire competition, including a whole swag of bike engines & a whole gaggle of car engines (early & late) ,,, but his head is sooooooo very much like the 8V Bimmer it`s uncanny & the dam thing has this Absolute Mongrell looking monster cam like i`ve never seen before & i totally expected this engine to have absolutely nothing down low,,, BUT!!!! It actually wheelstands at 2500 & still spins hard to 10,400rpms,,, now with that sort of grunt down low & still producing dam good "usable power past 9500rpms (it does drop slightly at 10,000ish) well,,, that`s where my mind starts thinking that there is more to this equation than meets the eye & i`m dealing with the whole group of people involved with the development of that engine (names withheld for many reasons,,, stay tuned for one particular twinky mini donk in the next year or 2 & no it`s not mine)

The only drama we have had in the last few years of "Playing" with this speedway engine is that it hasn`t been able to hold together,,, we`ve had it finish one feature race in about 5 years (sad i know & i hate to admit that sort of thing,,, but in my defence---> i`m not the builder of this engine) ,,, but also,,, in his defence , t`s more the parts breaking (one thing after another) that`s caused the failures,,, & yeah i know ,i know,,, you`d think they`d have done more homework to save this stuff breaking but it`s "ALL" been very experimental

So,,, for that one reason & that one reason only,,, "I KNOW" there is really good things "ABLE" to be extracted from these "Little" heads

Bruces donk is only a 1560cc,,, But trust me that if you`d had seen it run & if you`d had seen the competition,,, & if you can understand for a minute that we`re not talking back street billy carts here,,, there`s a big bundle of high dollar & big name engines that we run against, some fairly exotic stuff & some cheapo old ford x-flow stuff,,, crickey there`s all sorts thrown into the mix with the Litres ,,, But Bruces just absolutely sh!ts all over them (when it`s not actually broken) & im talking the entire Aust litre sprint car field, years & years of it.

But,,, (& again i`m sorry for the long posts) I`ve been doing this stuff with Bruce a very long time,,, i`ve got a very good appreciation for the time you`ve been doing your stuff too (& i agree with what you`re doing totally) But if you had the experiences i`ve had with Bruces engine, i really think it would open your mind up a bit more (like it has me) to what is avaliable with some (as you said with your new cam grind ,& i quote--->"""this cam is rather radical design and im still doing more testing on it """,,, well Bruce has done his testing & it works really really well,,, he just needs it to stop going Bang & i believe he will achieve this

He has had plenty of years playing with all sorts of profiles with his little 8v OHC donk & i can assure you, there is no other litre car doing wheel stands out of the corner at 2500-3000rpms & still making "Usable" power at over 9000,,, & i can assure you that it`s not just a soft rear end & the wing set way back This particular cam design that Bruce is using is the "WHY" i`m more interested in seen things actually happen with the twinkys,,, & Why i "KNOW" theres more to be tapped from them,,, Nothing to do with anything anyone has said here or in any other forum anywhere,,, it`s all first hand stuff,,,, It`s Just that for now i`ve made my bed with the turbo injected twinkys so i have to sleep in that bed first,,, finish upo the customers engines & my own few,,, when i wake up from that bed, then hopefully you`ll have sorted all your cam/head packages i`ll probably grab one off you for the Marcos,,,

But only because the Bimmer twinky doesn`t fit in the Marcos Just Kidding with ya

cheers mate, see you at Morgan Pk with one of my old 5 ports i ground when i was 16 years old

Edit for spelling mistakes

2nd Edit,,, OH & i know what anyone may now suggest with the use of Methanol in the speedway engines,,, & yes,,, one may "Normally" & quite rightfully expect & believe that most methanol cars will be running well above 14, 15 , 16 to one & upwards compression ratio & it being a "Cold" fuel etc etc etc yeah???? well Bruces has only 12.3:1,,, so there`s no real benefit to be blabbering about with that factor,,, & yes obviously that`s just another problem Bruce has to contend with but would also be another bonus "If" we could correct that & go higher,,, but we can`t,..... we`ve tried all sorts of things to achieve that purpose & the donk went backwards,,, Chamber fill & swirl & squish factors are involved here,,, & yet again that`s just another reason why i think i really am on the money with a similar donk in a road/race mini.

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No offence intended here but--> anyone writing a book about minis 30 years ago may not have experienced such worn or stuffed-with components as we are finding these days.

You should put your heart & soul into everything you do.

Hi Everyone,

Just thought you might like to see what a raw casting looks like straight out of the foundry. This is a Ken Elder 7-Port head that has been cut in half to check the casting for flaws, porosity and gas holes.

When the gas expands from the process after the aluminium has been poured in, this gas cannot escape and sometimes forms holes.

Tablets are used to help with the gassing in the core boxes when the heads are poured.

These castings are very good as can be seen there is no porosity holes in the casting.

After the heads are cast they go from the foundry to the machine shop where they are machined with a CNC machining centre. From there the valve inserts are fitted and the valve guides. Then the heads are ported and the valve seats cut. The chambers can then be milled to size.