Precat has got Wildcat

[Matthew Poxon]

Interesting one to try and predict.

I think I will go for 380BHP as my guess.

Like you say the ACR 5.0 is 398BHP with mech cam and wildcat TBs. You have said you will lose BHP on your inlet manifold, I am assuming you will lose BHP on the roller cam vs mechanical high lift ACR are using in thier race engine. BUT you have 200cc more displacement. You will certainly have more torque than the ACR 5.0 and will be much better to drive on road which is what it is all about regardless of figures.

[carsy]

I suppose a lot depends on the profile of that roller cam.

I`m guessing that with it being a roller the profile will be totally different to the average flat tappet profile.

More aggressive lift curve, valve held open for longer etc

Anthony, any more details of your cam.
.

[rev-erend]

I loved the idea of a roller cam.

They were not really available when I spec'ed my engine.

M256 with more torque sounds good to me

[Precat]

Porting, oh joy
So far I have spent fifteen hours and I've nearly finished one side (four ports) .






As shown the Wildcat inlet ports are 10mm taller and 4mm wider than the ports in the Pierburg manifold. I have to remember the Pierburg was designed for a 3.5-Litre race engine and I'm building a 5.2-Litre fast road engine.
I need the manifold capable of flowing enough air to make 400hp.
Back to porting, I estimate another twenty hours to go.
Does anyone know where I could get tea strainer type filters made to fit the ends of the manifold trumpets? Any support will be appreciated.

Edited by Precat on Tuesday 11th April 22:58

[rev-erend]

Cant remember where I found the picture though..

[Kokkolanpoika]

I also like to know specs of the cam..

I also order set of wild cat head´s, (i´m not fan of them) want to go closer 470-500hp than 418hp what STD fully ported rover head´s can support..
But i would not use that size of valves, and i will port those head´s by hand, not CNC.. CNC head´s are for line production, not race application´s..

If i will cast those head´s, i will modify that casting, they will need job..

And also i order them by valve seat´s fitted, mutch cheaper than install them here in Finland, but i make an mistage for that. Next time if need those head´s, i will wait to get them without seat´s..

I will use Eales DD manifold´s, need lot of porting, and small modifications for mounting and water outlet.. Also need some welding to get water holes in line..

[rev-erend]

I found these ..

Aldon


http://www.aldonauto.co.uk/product-detail.aspx?PID...


These migh be just what you need:

http://www.hitchcocksmotorcycles.com/amal-carburet...

[Precat]

Thanks
rev-erend

[Precat]

Kokkolanpoika said:

I also like to know specs of the cam..

I also order set of wild cat head´s, (i´m not fan of them) want to go closer 470-500hp than 418hp what STD fully ported rover head´s can support..
But i would not use that size of valves, and i will port those head´s by hand, not CNC.. CNC head´s are for line production, not race application´s..

If i will cast those head´s, i will modify that casting, they will need job..

And also i order them by valve seat´s fitted, mutch cheaper than install them here in Finland, but i make an mistage for that. Next time if need those head´s, i will wait to get them without seat´s..

I will use Eales DD manifold´s, need lot of porting, and small modifications for mounting and water outlet.. Also need some welding to get water holes in line..

Hi Kokkolanpoika
Based on your posting, I have the following questions and thoughts.
You bought a pair of Wildcat heads and you don't like them? What is it that you don't like about them? What would you do differently?
To port a cylinder head and get a good result, one has to have the relevant experience and a Flow Bench to test what works based on the final application. This takes a lot of time. Once the desired result has been achieved, to replicate the result, it is easier to use modern engineering processes like digitalisation and CNC machining.
In recent years most companies in the USA that produce Ported cylinder heads use a CNC process as this is the most commercially effective way of getting these products to market.
CNC Porting Vs Porting by hand
Pros of CNC porting:
Consistency - Every head produced will be the same
Financial efficiency - CNC process is quicker than porting by hand, therefore more cost effective
Cons of CNC porting:
Bigger financial investment in technology and CNC machines
Pros of porting by hand:
For low volume or one-off jobs it's the only practical way to do the job
Cons of porting by hand:
Inconsistency
Higher production cost
My personal ideal would be to buy CNC flowed heads and finish them by hand. That said I'm in the position where I have the infrastructure to do this. I am aware not everyone has this.
What valve size would you recommend?
You mentioned you would cast the heads differently, what would you change?
Are you thinking of producing Heads for the Rover V8? I for one would be interested.
I don't class myself as a racer, I'm just an enthusiast.
Finally what is an Eales DD Manifold?
If possible, I would appreciate some diagrams and /or pictures to help me understand.
Thanks Precat

[petepetrolhead]

DD = Down Draught (or Down Draft if you're from the good ol' US of A!):



They can take TBs as well as carbs. Much cheaper than his cross-overs!

[Precat]

petepetrolhead said:

DD = Down Draught (or Down Draft if you're from the good ol' US of A!):



They can take TBs as well as carbs. Much cheaper than his cross-overs!

Duh, of course, silly me.
Thanks precat

[Matthew Poxon]

If you want to go up market then these are the ones that Singer use on thier Porches, mesh with built in filter. Not cheap though!!!

http://www.ccookenterprises.com/air-cleaners-domed...

[GlynMo]

Matthew Poxon said:

If you want to go up market then these are the ones that Singer use on thier Porches, mesh with built in filter. Not cheap though!!!

http://www.ccookenterprises.com/air-cleaners-domed...

More porn!

[QBee]

Well done Antony.

My bid, for what it is worth, is 370 bhp, assuming it still revs to 6200 rpm.
The mild cam, plus there must be a weak link in there somewhere in terms of airflow, but I do hope it's more.

Hope to see you and it on a track this summer.

[Precat]

Matthew Poxon said:

If you want to go up market then these are the ones that Singer use on thier Porches, mesh with built in filter. Not cheap though!!!

http://www.ccookenterprises.com/air-cleaners-domed...

Thanks Matthew
Looks very interesting. The Pierburg trumpets are an unusual shape. So to get the engine up and running I'm thinking of using conventional trumpets with filters, then working on a solution to go back to the original trumpets.

[Precat]

QBee said:

Well done Antony.

My bid, for what it is worth, is 370 bhp, assuming it still revs to 6200 rpm.
The mild cam, plus there must be a weak link in there somewhere in terms of airflow, but I do hope it's more.

Hope to see you and it on a track this summer.

Hi Anthony
The weak link that I'm aware of is the inlet manifold
I'm working to improve this
Apollo Coventry Ltd welded additional material to the outside of the ports and this has improved my ability to open up the ports to match the Wildcat heads










I've spent quite a bit of time smoothing and blending the outside of the manifold to give it that factory look.

[QBee]

Wishing you well

[Matthew Poxon]

Precat said:

Hi Anthony
The weak link that I'm aware of is the inlet manifold
I'm working to improve this
Apollo Coventry Ltd welded additional material to the outside of the ports and this has improved my ability to open up the ports to match the Wildcat heads










I've spent quite a bit of time smoothing and blending the outside of the manifold to give it that factory look.

That is some serious dedication right there. You must love that inlet manifold to go to those lengths!

End result actually looks spot on when it is all smoothed down. Top work that.

I agree on the trumpets - the OE shaped ones are a must long term as they are part of the manifolds identity. Not quite sure what the answer is regarding filtration other than maybe ITG sausage filters, but then you loose the look.

Looking forward to seeing what you come up with and of course the end result.

[Precat]

Hi Matthew
Years ago I saw the Pierburg manifold casing for sale and thought it would be brilliant to see it on a running engine.



So I bought it and I'm working towards that goal. Maybe it's another one of my mad experiments. The upside is it keeps me out of trouble most of the time. I'm curious about the end result too!
Precat

[rev-erend]

I had the same issue with mine. I started with the mesh idea. Have tried various filters like itg that have not fitted. Ended up building a custom Airbox.