minispares arden head - dyno testing

[guru_1071]

here is a bit of raw footage of the new arden head been thrashed on the dyno

turn it up loud!

https://www.youtube.com/watch?v=Jt9xbc1 ... H0j6Peiik=

[Astro]

Hi,

does anyone know the diameter of the throttles?

[ivor badger]

Wot only 140 bhp, what happened to the 180 everyone else claims to get?

Why are the exhaust down pipes black when doing all these revs?

[pad4]

whats the difference with the new head compared to mine - 2005 minispares arden head

whats the engine spec on that, just interesting to compare it with mine

pad

[guru_1071]

Wot only 140 bhp, what happened to the 180 everyone else claims to get?

Why are the exhaust down pipes black when doing all these revs?

ivor, the 140 was made on this engine (it gave more once it had the full race cam in) on the engine dyno that was used, im sure minispares could have climed more power for bragging rights..... the guy doing the development has worked extensivly with ardens and has a very good understanding of them and the power that they give. he is very happy it.

once the car is finished this engine (with a different cam) is going to vist various rolling roads, so we will see what sort of varience in power it will have depending how far south it goes.....


as to the colour of the pipes, i dont know, ive never used an engine dyno, maybe you should ring mbe and tell him he is doing his job wrong

[guru_1071]

whats the difference with the new head compared to mine - 2005 minispares arden head

whats the engine spec on that, just interesting to compare it with mine

pad

pad, the differences are huge, but the best features are:-

thicker, so a larger chamber can be run without compromising the valve seats etc, it was always a compromise before when used on big motors.

far better, cleaner casting so the postition of all the internal structures are known rather than guessed

the valve seats have moved and the material thickness has altered around them for improvements in heat removal etc

the race version runs longer valves to help with the new cams and the lifts involved

better guides

proper pushrods, so no messing

proper head to block stud kit, so no messing

proper set of roller rockers, so no messing

they have spent an awful lot of time (and money) making sure that this head is as perfect as it can be with very very little compromises on any area of it.

the spec of the engine used on the dyno was a 1460 using as many minispares products as possible. its done a good few hours been thrashed with (from memory) three castings, one gave its life (it was thrashed and cut up) and the other two where sold on as 'pre-loved' heads to customers, one is racing already (and making more power than the owners original mowog alloy head), the other will be running in a week or so. once the engine is refreshed, it will be getting a milder cam and another head, then will be fitted to keith dodds mini.

i think its good to see a period item have serious money and time put into it to make it a viable product for people who want such a thing, and want to be able to buy an item thats warrentied and accountable from a known supplier.

[251 ENG]

Can we have it on our rollers ?

[ivor badger]

Wot only 140 bhp, what happened to the 180 everyone else claims to get?

Why are the exhaust down pipes black when doing all these revs?

as to the colour of the pipes, i dont know, ive never used an engine dyno, maybe you should ring mbe and tell him he is doing his job wrong

Only had an engine on a rolling road once and the centre down pipe was almost white. any other photos of engines on dynos have glowing exhaust pipes.

I will be interested to see the results from using different dynos. I remember at one time it was considered that Cosworth horse powers were better fed than most.

[Astro]

Don’t forget. For FIA historic competition use, you will have not more than 1293ccm and forged 1.3 rockers. That means far less power.

[pad4]

yes but i believe MBE were seeing somewhere just over 130 bhp when he built my 1293 which has also forged rockers , although were running with a trick exhaust manifold and hugh amounts of lift from the cam, its very drivable when your going but a wee agressive from standstill

[ivor badger]

Jim Whitehouse garaunteed customers 131bhp from 1300cc

[Astro]

Which carburation?

[pad4]

(just spoke to keith who i got the car from)and it saw 135 on mbe's dyno, mine has twin 40s on long manifolds (rally spec engine)

i guess the new minispares head can only be a good improvement on whats already a good thing - might even be tempted to run one on my other motor

[ivor badger]

Which carburation?

iirc, Lucas fuel injection, possibly TJ, but definately fuel injection. With those with access to Motorsport magazine from 69 to mid 70, there is an article on the developement of the Arden head.

[Astro]

Thanks but this is too difficult for me. I'll continue with the Weber’s and will continue to miss some horses.

[AMCO72]

I presume these hp figures you guys are quoting are flywheel hp rather than @ wheel hp. We have just built up a 1360 here using one of Jim Whitehouse's original heads. This was on our race car in 1972, and required a lot of repair and work to get it usable again. We are running 13 to 1 compression, Avgas, and 40 dellorto's. Flywheel hp was 153 with 120 ft/lbs of torque. Pretty good we think. Dont know what that would equate to @ wheel hp....close to 140 I would think. I see on the dyno test you have a water take-off from the plug [heater-outlet] on the back of the head. We have this also, running through an auxillary radiator to try and keep the whole thing coolish!!! All very well on the dyno, but under racing conditions where high revs are maintained for a lot of the time, cooling becomes rather important. Have you guys learned any other tricks to keep temp under control?......around 200 degrees F. The car certainly has some get-up-and-go, and with 120 ft/lbs of torque can really haul-arse. Interesting reading all this about the original Arden head, they seemed to be fine on the original 970 engines but when placed on the 1275 and bigger, there seems to be a few problems, not the least finding a good head gasket.

[guru_1071]

I presume these hp figures you guys are quoting are flywheel hp rather than @ wheel hp. We have just built up a 1360 here using one of Jim Whitehouse's original heads. This was on our race car in 1972, and required a lot of repair and work to get it usable again. We are running 13 to 1 compression, Avgas, and 40 dellorto's. Flywheel hp was 153 with 120 ft/lbs of torque. Pretty good we think. Dont know what that would equate to @ wheel hp....close to 140 I would think. I see on the dyno test you have a water take-off from the plug [heater-outlet] on the back of the head. We have this also, running through an auxillary radiator to try and keep the whole thing coolish!!! All very well on the dyno, but under racing conditions where high revs are maintained for a lot of the time, cooling becomes rather important. Have you guys learned any other tricks to keep temp under control?......around 200 degrees F. The car certainly has some get-up-and-go, and with 120 ft/lbs of torque can really haul-arse. Interesting reading all this about the original Arden head, they seemed to be fine on the original 970 engines but when placed on the 1275 and bigger, there seems to be a few problems, not the least finding a good head gasket.

the 13:1 compression will certainly help with the power! one of the biggest problems with the original head was that the chamber was too small for bigger engines, this has been resolved with the new casting, along with far more efficent and bigger water areas.


dont forget that the engine in the video is running a far more restrained cr as it will be going in a road car and the testing was more for a reliability test than a super dooper balls out final hp figure

[guru_1071]

(just spoke to keith who i got the car from)and it saw 135 on mbe's dyno, mine has twin 40s on long manifolds (rally spec engine)

i guess the new minispares head can only be a good improvement on whats already a good thing - might even be tempted to run one on my other motor

your engine was also running the fancy expensive bunch of bananas exhaust manifold, which releases a few more hp and helps with the torque.

[ivor badger]

Whitehouse brought out a better exhaust manifold in early 71, £100+ at that time. The 131bhp was on the original manifold. Interesting that the combustion chamber is considered too small as Steve Neale's car was 1293.

[guru_1071]

Whitehouse brought out a better exhaust manifold in early 71, £100+ at that time. The 131bhp was on the original manifold. Interesting that the combustion chamber is considered too small as Steve Neale's car was 1293.

i think the manifold that was on ebay the other week was probably a whitehouse one, it had a pair of 'y's half way up the block - so it looked like a pair of downturned tuning forks, the new minispares one has far longer primarys (as can be seen in the pictures of pads rally car, this manifold makes, normally about 5bhp on mbes rollers over a standard maniflow set up.


the original chamber was ok on a 1293, but once the engine grows to 1380 and above it starts to become an issue, dont forget that most old heads have had a good few skims over the years, which further reduce the size. the problem with the old heads was that the seats could only be moved 'so far' up to give more area for skulling out, but compromises had to be made of valve seat thickness etc, which would normally show its self as a problem by dropping the seat if the head was cooked

the new head was made far better in this area, so a higher quality seat can be fitted, in the correct place with a much better location around it.