Ford Drag Race engine development

[Maki]

Good day to everyone, few years ago I took some lessons from this forum on preparing the ford CVH head. Now I'm about to do the same to the Ford Zetec head. It will be used for the drag rasing only on a turbo charged engine.

Here are some pictures for you to know what am I talking about. It's a 2,0 litre head of an ford mondeo produced in 1996. The main concernes I have for now is the combustion chamber. It is smaller than on CVH head, so by putting this head to my old bottom end I get higher CR (aim is 7,5:1) So was wondering, maybe I could win some CC in the chamber by removing squiche area and other bits that make the chamber not round?

Thanks for your viewes on this
M.

[WhizzMan]

Do you have a spare head you can destruct to find out where the water channels are and how much "meat" you can work with? It can be a warped or cracked head, because it will never be used again. That way you can find out if you have enough metal left after you have removed the squish areas. You could saw it in pieces to reveal "hidden cavities". I think that the bumps around the spark plug are a prime candidate for removal as well. If you have enough metal, you could radius around the valves a bit more. With a little luck you would also get a better flow from that.

[Maki]

I would remove squish no problem without breaking into the water chanels, the question is if it's worths doing, and maybe I would destroy something important by removing them, they have to have some kind of purpose there? Or is it important only for NA engines?

[robert kenney]

The proper way in my book is to leave the quench band and install a dished piston.

This is how I have always done it and successfully too. I have built my share of blown drag race engines and all have some quench. Guys have played with taking away the quench band and have struggled to eliminate detonation while staying competitive.

One example of one I built for hot street/strip use, 8.5:1 CR and 16 pounds of blower and 34* timing fixed with no advance. Always run good fuel but never have detonation issues.
Also my current drag race car. on methanol 27 pounds of blower and 12.5-1 compression

[Maki]

One example of one I built for hot street/strip use, 8.5:1 CR and 16 pounds of blower and 34* timing fixed with no advance. Always run good fuel but never have detonation issues.
Also my current drag race car. on methanol 27 pounds of blower and 12.5-1 compression

34 degrees? that's mad. I'm running 12 degrees at boost, but still had some detonation last time as my upper ring began to loose metal.

[robert kenney]

That is an odd manifestation of detonation damage. More likely corrosion damage without seeing the piston crown up close that is my guess.

What ring end gaps are you running? May increase the lower compression ring gap to 20% larger then the top ring.

You run 12deg total timing?? Never would think that is normal even for a force fed engine. Might think about more or better fuel and or less manifold pressure.

Hope you have a good time racing. I do quite enjoy the rush of adrenalin and satisfaction of a good meet.

[WhizzMan]

The proper way in my book is to leave the quench band and install a dished piston.

This is how I have always done it and successfully too. I have built my share of blown drag race engines and all have some quench. Guys have played with taking away the quench band and have struggled to eliminate detonation while staying competitive.

One example of one I built for hot street/strip use, 8.5:1 CR and 16 pounds of blower and 34* timing fixed with no advance. Always run good fuel but never have detonation issues.
Also my current drag race car. on methanol 27 pounds of blower and 12.5-1 compression

Yours is an 2 valve per piston engine. I don't think you can compare that to a 4 valve per piston engine with different valve angles just as easy as you are doing here. The head discussed here is to be placed on top of an engine that already has dished pistons, so your proposed solution will most likely require shorter con rods.

[Maki]

Yours is an 2 valve per piston engine. I don't think you can compare that to a 4 valve per piston engine with different valve angles just as easy as you are doing here. The head discussed here is to be placed on top of an engine that already has dished pistons, so your proposed solution will most likely require shorter con rods.

No I'm using NA pistons with no dish at the moment. And I know that people do dish out them, so that will work fine. Got some news from people with experience on these heads, and they say to leave alone those squish areas.

[robert kenney]

The proper way in my book is to leave the quench band and install a dished piston.

This is how I have always done it and successfully too. I have built my share of blown drag race engines and all have some quench. Guys have played with taking away the quench band and have struggled to eliminate detonation while staying competitive.

One example of one I built for hot street/strip use, 8.5:1 CR and 16 pounds of blower and 34* timing fixed with no advance. Always run good fuel but never have detonation issues.
Also my current drag race car. on methanol 27 pounds of blower and 12.5-1 compression

Yours is an 2 valve per piston engine. I don't think you can compare that to a 4 valve per piston engine with different valve angles just as easy as you are doing here. The head discussed here is to be placed on top of an engine that already has dished pistons, so your proposed solution will most likely require shorter con rods.

I beg to differ. The general question was regarding removing the quench band only and if that was a good way to decrease compression ratio from a resultant chamber volume increase. My answer was NO.
Further it has nothing to do with rod length or anything else..

Another item. From a valve configuration/quantity the function of quench is always the same and it's purpose remains the same. The general rules for engine dynamics remain the same regardless of head one must assume maching mechanical properties.

[Maki]

Hi everyone, winter outdoors is holding me back from tunning my engine, but anyway I've counted that the piston bowl should be taken deeper by 2 mm to compensate the loss of 10 cc in the chamber after changin to 16v head. I will still have 5,2 mm thick piston crown in the dished part.
Would like to get your help about the head prep. I was told that the head is good for 350 bhp without any modifications. But still I can't look at its factory job and will at least clean all the bits, like sharp seat edges in the combustion chamber and other things that look restrictive.
The main question I have for now is, what to do with the seats? almost every seat I ever saw had enough meat to be enlarged even with standard valves. Is it what's recomended to do?
Thanks
M.

[Guy Croft]

Your head may well make 350bhp without mods but in reality all you're doing is wasting energy forcing charge through a restrictive head with higher boost than you'd otherwise need.

I've done those heads but have no pics of seat work - not unusual if I don't enjoy the job.

However the chamber has a bit in common with the Peugeot 16v so here are a couple of before-after pics. Also some of Zetec 2 liter heads - on flowtest after a great deal of hard-labour. I did two back-to back, one previously worked (not by me) and the best I got was 140cfm @10" inlet flow which I judge to be close to the limit on them really, and the other 138cfm. Gave typically 235bhp and 186lbf ft on short-circuit cams. Imagine who well it would work with some boost thrown-in...

On inlet I went for 27.5mm vertical and 26.3mm horizontal thru. On the exhaust on 138cfm head I went 41 wide and 30.8mm high with 24mm thru and got final 103cfm ex flow, giving final E/I shown which is fine. You can get a lot more ex flow by going bigger. The previously worked ex ports on one head had been (unnecessarily) enlarged and I when I finished it, it was 26.9mm thru and 44mm x 31.8mm outer section with E/I flow ratio of over 85% which is certainly not needed on an atmo engine. i didn't make it bigger, it was massive already. There is definitely no point deliberately going any bigger thru the ex port than the ex valve throat diameter (about 3mm less than valve) on any head, the throat is the controlling section.

The seat inserts should ideally be opened out to true valve diameter, though that said it depends how big they are for given valve size and you must leave a mimimum of 0.5mm on radius as a supporting edge outboard of the 45 deg contact face or they will crack. Do the cc relief first and then the seats. When smoothing the chamber make sure you don't intrude on the seat inserts or you'll never be able to cut/grind the contact face true.

As the Zetec is a downdrafted head you want:

top cut/grind: anything from 15 deg to 40 deg (because of the small valvesize the influence on flow of the top cut is modest compared with an 8v head. The main thing is to do it and get the contact face trued-up).
contact face: 45 deg x 1.5mm wide
throat: 75 deg into parallel lower section then fully blended.


The inlet splitter bores can be safely enlarged by up to 2mm on diameter and the short side radius needs to be lowered and increased (ie: the radius made bigger) and the curvature needs to be extended right to the seat insert. Hard to explain but the XE photo may explain.

Hope this helps,

G

[Maki]

Thank You, Guy, you gave me a lot to think about as not everyhting you gave here is easy to understand, but I will do my best to follow what you shared. Thanks.

[Maki]

Hello, Guy, is there any point in going for larger valves on this zetec head?

[Guy Croft]

What is your current size and engine cc?

G

[Maki]

I'm not sure how to count, but it used to be 2 litre zetec engine 1952 if I remember right, now the bore is enlarged from 84 to 86, that should give theoreticaly something around 2040?