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8 Port 998Cc Cnc Machined Billet Head And Collectors


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#1 Elmtech

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Posted 24 April 2012 - 06:26 PM

Hi there

We are a small Finnish company and are currently in the process of manufacturing a 998cc fully cnc machined billet head. We have a lot of experience racing Minis in the local circuit racing series. Since we're no longer racing we decided to do something else with the car, and this seemed like a good idea. This is still in the prototype stage, but since we plan on selling these heads soon I guess it's best to have the thread in here.

The head is designed to fit on the block we have which is a 998cc. It will have 33mm intake valves and 29mm exhaust valves as that it basically the maximum dimensions that will fit without pocketing the block. It will also use standard m14 spark plugs. The center exhaust port will be split by a steel plate creating 8 ports. The exhaust locations/shapes are also completely custom so it's not compatible with any standard exhaust manifolds.

So far we have produced a test piece with all the ports/chambers machined with slightly different machining parameters for each port to figure out which settings give the best finish. The next step is to machine a new head that we will test in our racing Mini. The plan is to use fuel injection. We're targeting about 135hp na which should be doable as we were very close to 100hp with a ported stock head. The injectors will be located on an adapter plate directly bolted to the head.

Because we'll have to build a custom exhaust anyway, we are going to cnc machine a 4-1 collector to give a more professional look. We will also be offering these for sale at competitive prices compared to welded versions.

Here is a picture of the test-head on our 998cc block. 3 of the front head studs need to be replaced as the head is of different thickness to make room for the spark plugs.
Posted Image
Another picture showing the combustion chambers.
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You can find more information/pictures as well as a youtube video of the machining at http://elmtech.eu/en...c-machined-head

I will keep you guys informed as the project moves forward.

Edited by Elmtech, 25 April 2012 - 03:24 PM.


#2 miniman92

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Posted 25 April 2012 - 09:37 AM

One word......... WOW!

#3 yeti21586

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Posted 25 April 2012 - 09:40 AM

Would it fit on a 1098?????

#4 Elmtech

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Posted 25 April 2012 - 11:07 AM

If it has the same spacing between the bores(and it seems like that is indeed the case) then it will fit.

Something else worth mentioning that I didn't in the original post...we designed the head for race use, so there are coolant outputs at both ends of the head and no place for a thermostat. However, if enough people are interested we can modify the design to accomodate a thermostat. Or optionally you should be able to use an inline thermostat.

Edited by Elmtech, 25 April 2012 - 11:07 AM.


#5 Carlos W

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Posted 25 April 2012 - 11:13 AM

Are there any plans to design and producea head for 1275 cc engines?

#6 TopCatCustom

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Posted 25 April 2012 - 11:30 AM

Jesus it's amazing what you can produce nowadays with a 5 axis mill and 3D software. Stunning piece of work, and as above- 1275 heads?!

#7 yeti21586

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Posted 25 April 2012 - 11:31 AM

also how much are you going to selling them for? and how much extra would it be for one with a thermostat etc

#8 Elmtech

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Posted 25 April 2012 - 01:57 PM

A 1275cc version will likely come later, the 998cc version was just a logical starting point as we can test the head on it and also got precise measurements from the block.

Regarding the price, the initial price is 1200£ +VAT for a head that includes:
-multi-angle stainless steel valve seats (ok for unleaded fuel), for 33/29mm valves
-selectable combustion chamber volume (between about 18-23cc)
-exhaust adapter from steel for the center exhaust port, with 2 round outlets
-2D drawings for the creation of exhaust/intake flanges

The head is also machined from a grade of aluminum that can be anodized, but it is not included.
The default exhaust size is 29.7mm ID, and we can also supply stainless steel 90degree bends with the same diameter.
For an additional fee we can also supply the flanges, as well as intake adapters for throttle bodies/webers etc. We can also quite easily make custom versions with slightly different valve sizes/port sizes and port finishes.

Also, because of the way the head is machined we'll be able to offer a 15% discount for group buys(5 or more heads).

#9 cooperdan

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Posted 25 April 2012 - 03:01 PM

wow got say that looks so satisfying, yum..

must say though sounds great, be something to look out for

#10 Elmtech

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Posted 26 April 2012 - 09:16 AM

and how much extra would it be for one with a thermostat etc


I did some digging, and the easiest(and cheapest solution) would just be to get an inline thermostat, like this or this. Machining a place for the thermostat in the head would be complicated and costly.

#11 mini_in_progress

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Posted 26 April 2012 - 09:52 AM

i cant see the side of the head but how about fitting a ford zetec one ? only needs 3 tapped holes on a flat surface on the side the head, and the thermostat is clipped in and the seal is an o ring on the housing too or turning a basic version of it up to fit.... easy..

Edited by mini_in_progress, 26 April 2012 - 09:53 AM.


#12 Sam Walters

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Posted 26 April 2012 - 10:55 AM

Whats the flow on these heads at say 12mm valve lift?

#13 Elmtech

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Posted 26 April 2012 - 04:39 PM

Well, it's difficult to say as we do not own a flow bench. We could always run some CFD on the heads though. But basically we have tried to "straighten out" the ports as much as possible. As can be seen from the pictures the intake ports exit right at the top of the head(any higher would be impossible as they would then go into the valve spring pockets), this gives a nice and large inner radius in the port that should flow well. We have also made sure the area of the port remains constant.

The exhausts are a bit trickier as there has to be room to drill coolant channels, so they aren't quite as nice as the intakes but should still be a large improvement over the stock head.

In any case, the head will be tested to verify it works like we expect it to.

#14 Carlos W

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Posted 26 April 2012 - 04:55 PM

I like it!

Crack on with the 1275!

#15 Sam Walters

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Posted 26 April 2012 - 07:59 PM

Well, it's difficult to say as we do not own a flow bench. We could always run some CFD on the heads though. But basically we have tried to "straighten out" the ports as much as possible. As can be seen from the pictures the intake ports exit right at the top of the head(any higher would be impossible as they would then go into the valve spring pockets), this gives a nice and large inner radius in the port that should flow well. We have also made sure the area of the port remains constant.

The exhausts are a bit trickier as there has to be room to drill coolant channels, so they aren't quite as nice as the intakes but should still be a large improvement over the stock head.

In any case, the head will be tested to verify it works like we expect it to.


I was going along the CFD route. I was supprised at the use of a splitter on the centre ex port. I thought you had yielded gains shown via CFD. But now i just question its use. Given how the firing sequence of the engine. Something to think about at the very least.

Just for refrence, a full blown race head that has no class restrictions places upon it as per the miglias.

133/112 @ 12mm on a 28" pressure drop.

Edited by Sam Walters, 26 April 2012 - 08:01 PM.





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