User Tag List

+ Reply to Thread
Results 1 to 21 of 21

Thread: New Down Draft Alloy Pinto Head

  1. #1
    Spanner Monkey

    Join Date
    Dec 2003
    Location
    birmingham
    Age
    42
    Posts
    189
    Thanks
    0
    Thanked 7 Times in 5 Posts

    New Down Draft Alloy Pinto Head

    Hi all

    As some of you may have seen about 12 months ago I created a 3D model of the pinto Cylinder head which I then ported and 5 axis machined.

    http://www.turbosport.co.uk/showthread.php?t=292325

    Since then I've been adding more detail to my model, and I think I've now got all the detail to make a had from scratch

    But as there is already a standard alloy pinto head I plan on redesign the ports, raising both inlet and exhaust for better flow, but still keeping all standard bolt on parts.

    The biggest issue I'm having at the moment is deciding how to have the casting cast. A few options included


    • lost foam casting from machined foam pattern
    • 3D sandprinting
    • make proper patterns for sand casting

    They all have pros and cons depending on volumes.

    Anyone got any helpful info regarding alloy casting of cylinder heads in low volume

    Thanks for any help

  2. #2
    Racer Decade Plus User

    Join Date
    Mar 2010
    Location
    Edinburgh
    Age
    46
    Posts
    3,641
    Thanks
    68
    Thanked 234 Times in 230 Posts

    Re: New Down Draft Alloy Pinto Head

    Speak to Roy Millington re. the casting, I think he's casting big cc blocks for QED.

  3. #3
    Racer Decade Plus User

    Join Date
    Mar 2010
    Location
    Edinburgh
    Age
    46
    Posts
    3,641
    Thanks
    68
    Thanked 234 Times in 230 Posts

    Re: New Down Draft Alloy Pinto Head

    And if it works well I'll buy one.

  4. #4
    Racer Decade Plus User Forest_rallying's Avatar

    Join Date
    Feb 2013
    Location
    Derbyshire
    Posts
    2,438
    Thanks
    92
    Thanked 393 Times in 348 Posts

    Re: New Down Draft Alloy Pinto Head

    Grainger and Worrall are the company that Cast Heads for the likes of Millington and Smith & Jones.

  5. #5
    Spanner Monkey

    Join Date
    Dec 2003
    Location
    birmingham
    Age
    42
    Posts
    189
    Thanks
    0
    Thanked 7 Times in 5 Posts

    Re: New Down Draft Alloy Pinto Head

    Thanks for the links, all very good ideas, but this is something I'm trying to stay away from, as at the moment this it just as a engineering project for myself, all be it a complect one. I'm not doing this as a business venture, but if they end up as good cylinder heads I will more then likely turn it into a business. So I don't really want to involve and of the big boy as it'll cost me a small fortune.

    Was hoping there may be people around here with casting experience or complex pattern making experience.

  6. #6
    Racer Decade Plus User

    Join Date
    Mar 2010
    Location
    Edinburgh
    Age
    46
    Posts
    3,641
    Thanks
    68
    Thanked 234 Times in 230 Posts

    Re: New Down Draft Alloy Pinto Head

    There no real cheap way to do casting, especially alloy, to make it viable i would say that you need to do a decent production run of 10, a one off would be pricey.

  7. #7
    Racer Decade Plus User

    Join Date
    Mar 2012
    Location
    Belgium
    Age
    56
    Posts
    2,118
    Thanks
    7
    Thanked 197 Times in 169 Posts

    Re: New Down Draft Alloy Pinto Head

    No direct idea what the casting price will be for the fist one but prices did drop a lot over the years thanks to 3D sand printing. I can only tell you I had to pay approx 4000€ for a Porsche inlet manifold. Was cheap (?) because the 2 flanges are in line. I once asked a company what it would take to produce a cylinder head from zero (including the expensive 3D design) and was over 25.000£. I do believe it can be done a lot cheaper.

    About the head, I would not start producing the one you have build. If you go into so much trouble I would at least do more testing and put the port higher I the head. Otherwise you will end up with a head just as the one from Burton. Only little more power over the original.

    The biggest problem with the Pinto compared with for example the BDA is selling price. You can sell anything for a Pinto, lot of ask, as long as prices are very low. There are already companies building downdraught Pinto heads starting from the original. Prices round 4000 - 4500£ and that's the reason you will only sell a hand full of them. BDA heads sell a lot easier. Different public.

  8. #8
    TURBOSPORT SPONSOR Turbosport Subscriber
    Turbosport Moderator
    Turbosport Administrator
    Graham's Avatar
    My Race Car
    My 1st Project
    Join Date
    Feb 2006
    Location
    Ely, Cambs
    Age
    56
    Posts
    25,099
    Thanks
    310
    Thanked 2,476 Times in 2,250 Posts

    Re: New Down Draft Alloy Pinto Head

    if you really want a downdraft head to work you need to redesign the valve as well as the port angles. with a pinto the air shoots straight across the back of the valve, downdrafting without changing the valve angles or moving the guides will merely slam the mixture into the back of the valve.

    talking to dave the other day we were reminiscing about pintos and got onto this subject, way back when both he (and im pretty sure roland hayes also) tried downdrafting by bring ports up through the cam cover so pretty dramatically downdrafted, the gain was zero power increase over a conventionally modified head.

  9. The Following User Says Thank You to Graham For This Useful Post:


  10. #9
    Racer Decade Plus User

    Join Date
    Mar 2010
    Location
    Edinburgh
    Age
    46
    Posts
    3,641
    Thanks
    68
    Thanked 234 Times in 230 Posts

    Re: New Down Draft Alloy Pinto Head

    I guess if you were casting a head from scratch it would make sense to design the combustion space with a more hemi design and valve angles to suit a more downdraft style of port?..

  11. #10
    Spanner Monkey

    Join Date
    Dec 2003
    Location
    birmingham
    Age
    42
    Posts
    189
    Thanks
    0
    Thanked 7 Times in 5 Posts

    Re: New Down Draft Alloy Pinto Head

    Thanks for all the ideas. I've already spoke to a could of foundries about 3d sand printing, and they want about £2500 per casting. So that's out the question. Been looking at the head more and more. And I think my plan is going to be something as follows

    main body of casting will be traditional green sand
    resin set core to produce inlet & exhaust runners
    Resin set core to produce spark plug cut out
    3D printing core for water jackets.

    The design I've got at the moment includes
    Moving the inlet up about 30mm but still allowing standard inlet manifold
    Moving the exhaust port up about 10mm and back about 4mm to remove the exhaust port dog leg.
    Both valves have been moved away from each other by 0.25mm and rotated 0.25 deg to increase the gap between vales by almost 2mm


    As suggested be a few people the head could be drastically redesigned, but this then would require everything to go with it to be custom made parts, and before you know it a complete head would be over £10K, and a lot of dev work. I havn't got the spare time or money for that.

  12. #11
    Spanner Monkey

    Join Date
    Jan 2011
    Location
    nl
    Posts
    210
    Thanks
    0
    Thanked 32 Times in 25 Posts

    Re: New Down Draft Alloy Pinto Head

    I couldend find the pictures anymore so I took them out of a book , these where taken at the company where I worked in the late 80's
    The Pinto was based on a Holbay rollercam engine and as I recall correctly did over 220 Bhp
    Attached Thumbnails Attached Thumbnails 001small.jpg‎  

    002small.jpg‎  


  13. #12
    Racer Decade Plus User

    Join Date
    Mar 2010
    Location
    Edinburgh
    Age
    46
    Posts
    3,641
    Thanks
    68
    Thanked 234 Times in 230 Posts

    Re: New Down Draft Alloy Pinto Head

    Quote Originally Posted by duel View Post
    I couldend find the pictures anymore so I took them out of a book , these where taken at the company where I worked in the late 80's
    The Pinto was based on a Holbay rollercam engine and as I recall correctly did over 220 Bhp
    Tricky inlet angle for carbs, you would prob need a custom inlet manifold too that flattened out, or downdrafts.

  14. #13
    Spanner Monkey

    Join Date
    Jan 2011
    Location
    nl
    Posts
    210
    Thanks
    0
    Thanked 32 Times in 25 Posts

    Re: New Down Draft Alloy Pinto Head

    Carbs on the Pinto ?
    The pre Xflow is a F3 head , the engine was tilted 30 degrees.

  15. #14
    Racer Decade Plus User Forest_rallying's Avatar

    Join Date
    Feb 2013
    Location
    Derbyshire
    Posts
    2,438
    Thanks
    92
    Thanked 393 Times in 348 Posts

    Re: New Down Draft Alloy Pinto Head

    The Pinto Engine`s photo`s certainly a Holbay Engine, with a side mounted Water pump and Water rails that come out of the top of the Cam cover for the Rad.

  16. #15
    Racer Decade Plus User

    Join Date
    Mar 2010
    Location
    Edinburgh
    Age
    46
    Posts
    3,641
    Thanks
    68
    Thanked 234 Times in 230 Posts

    Re: New Down Draft Alloy Pinto Head

    Quote Originally Posted by duel View Post
    Carbs on the Pinto ?
    The pre Xflow is a F3 head , the engine was tilted 30 degrees.
    Mechanical injection in the pics but if you did a similar style of head it would be tricky to fit carbs.

  17. #16
    Racer Decade Plus User RWD fords rule's Avatar

    Join Date
    Feb 2006
    Location
    Ireland
    Age
    39
    Posts
    3,579
    Thanks
    173
    Thanked 374 Times in 312 Posts

    Re: New Down Draft Alloy Pinto Head

    If you are going ahead with the downdraft pinto head you better give me a shout about the port shapes, I can tell you exactly what you need to make it flow really well

    First of all round ports are nowhere near optimum

    Maximum raise the short turn, which means making the port much wider and also taller

    I would use the 1600 valve lengths and seat positions, or even move the valve seats a few mm closer to the head face (which improves the short and long side of the port by creating more space between the bottom of the valve guide and the valve seat)

    Make the inlet port 50 to 55mm wide maybe more over the short turn an ideally all the way out to the manifold face which maximum raises the short turn

    Bias the port flow by tilting the port over away from the exhaust port, this makes the inlet feed the centre of the cylinder better and reduces the effect of valve shrouding

    Use 45.72mm inlets at the very least, I would personally aim for 47 to 48mm inlets with a custom head like this it will make way more CFM, torque and top end power

    Move the inlet guide a little further away from the bore line making room for a larger inlet without shrouding

    Move the exhaust guide towards the bore line

    Possibly tilt both inlet and exhaust guides clockwise looking from the front of the engine so that the inlet valve guide and port is slightly more downdraft further moving the inlet valve seat away from the bore line to reduce shrouding

    Use a 37mm exhaust valve, straighten out the exhaust port, either leave the port exit in the same place or raise it slightly, a round raised exhaust port would be ideal but way less important than the inlet port shape

    Fill in the chamber opposite the spark plug for a little extra compression

    D shape inlet ports with a wide flat port floor


    If you wanted to send me a prototype port shape for flow testing just let me know, I am happy to help optimise the shape if you are looking for 240 to 250bhp levels from this head from 2000cc which is absolutely possible

    Modern V8 race inlet port shapes will give you a good idea of the shape to aim for, maximum raised roof, floor especially and the port made much wider especially over the short turn (so that the short turn can be made much taller, flowing more air and also creating more port volume for the air to slow down and turn around the valve)

    However far you want to go with the port shapes, the inlet ports have to be made tall wide and with a wide flat short turn, plus at least a 46.5mm inlet valve, I would personally go straight to 48mm and move the seat away from the bore line but the shape of the port is more important than the valve size, both with give pretty huge power from this engine guaranteed
    "Horsepower sells cars, torque wins races" - Enzo Ferrari

  18. #17
    Racer Decade Plus User RWD fords rule's Avatar

    Join Date
    Feb 2006
    Location
    Ireland
    Age
    39
    Posts
    3,579
    Thanks
    173
    Thanked 374 Times in 312 Posts

    Re: New Down Draft Alloy Pinto Head

    Quote Originally Posted by duel View Post
    The Pinto was based on a Holbay rollercam engine and as I recall correctly did over 220 Bhp
    That is an interesting head, Holbay were well ahead of the rest back then, although I can see the port shape is nowhere near optimum but for sure good enough for that kind of power level and a big step above anything else available at the time, even now it would beat any off the shelf head
    "Horsepower sells cars, torque wins races" - Enzo Ferrari

  19. #18
    Spanner Monkey

    Join Date
    Dec 2003
    Location
    birmingham
    Age
    42
    Posts
    189
    Thanks
    0
    Thanked 7 Times in 5 Posts

    Re: New Down Draft Alloy Pinto Head

    RWD fords rule

    Thanks for all your advice and I will definitely be taking note. But I haven't even open my cad drawing for about 2-3 months now, just been to busy working on project for JLR.

    Regarding the final design of the port shape, this isn't very important at the moment as long as I get the rough design somewhere near, the final port will be fully CNC machined which can always be changed

    One thing I want to keep with this head (if it ever happens) is to be able to use all standard pinto parts, inlet / exhaust manifold, cams & rocker gear. Main reason is to keep costs down. I know this isn't ideal for best performance, but then neither is the pinto engine, and without keeping the head pinto shaped it's not a pinto.
    Last edited by Mac; 25-07-2014 at 21:43.

  20. #19
    Tyre Kicker

    Join Date
    Dec 2009
    Location
    reading
    Posts
    25
    Thanks
    1
    Thanked 0 Times in 0 Posts

    Re: New Down Draft Alloy Pinto Head

    Great shame it's gone cold

    Question why cast a head it pushes up cost, I remember an alloy head made from bilet alloy.
    It had water ways in face of head and some drilled.
    if you got a good cnc it would probably be just as cheap if not alot cheaper.
    or make it from two slabs of alloy dowelled together.
    Then use cvh valves as there longer for better valve geometry.

    I know it's a dead thred but why not
    ps there are alloy blocks n heads already buy the cost out weighs gains for most of us ...

  21. #20
    Pit Crew Decade Plus User para144's Avatar

    Join Date
    Jan 2006
    Location
    South Wales
    Posts
    1,075
    Thanks
    75
    Thanked 87 Times in 70 Posts

    Re: New Down Draft Alloy Pinto Head

    Dave Brooks does an alloy 8v pinto head of completely his own design, he showed me one - looks very clever.

  22. #21
    Pit Crew Decade Plus User MK1_Oz's Avatar

    Join Date
    Nov 2008
    Location
    Adelaide, Australia
    Posts
    1,331
    Thanks
    96
    Thanked 42 Times in 40 Posts

    Re: New Down Draft Alloy Pinto Head

    I have often thought about designing a head from scratch. Rather than take the Pinto 1600/2000 head as a starting point or reference point could you not look at other heads of the world that already make good power and copy parts? What about making the combustion chamber a hemi design? Just seems restrictive to just try to make a better Pinto.

    I have also thought along the lines of Mr Mad in that you could use a billet and make a 2 piece head so that waterways could be machines in (would take somebody way more clever than me).

    I hope we see some more work on this soon.
    1970 Mk1 Escort Tarmac Rally Car

+ Reply to Thread

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts