Putting a FocusSport/Cosworth Head on a Zetec...

[Al Navarro]

I have the Caterham USA Zetec "Supersport" package...which came with throttle body fuel injection and supposedly a hotter cam.

I may pull the head soon to see if any of my little "cooling hose" mishaps (3 to date, all months apart) may have caused damage to the head gasket. (Or I may just get the fluid tested for exhaust gas.) And I figured...IF I'm going to pull the head, why not put a hotter head on?

I'm sure the TBs and injectors would be up to it, with a little ECU tuning. Is there anything else I need to worry about? Am I stupid for thinking of doing this? Has "Power Envy" clouded my judgement?

[11Budlite]

Hi Al,

If it were me, I'd check the coolant for exhaust gases, make sure the radiator cap and thermostat are functioning properly, and if everything's ok leave it as is for now (maybe come up with a better clamping arrangement). If you need more than 202hp come this winter, then change it out then!!

As far as the head you have on there now, it looks like they've raised the C/R, upgraded the cams (don't see the lift/duration), but I didn't see anything where they ported the heads. Seems like you have a pretty stout motor for the street/autoX already. If you were planning on doing some track events it might be worth it to upgrade further. Best to check with people who are much more knowledgeable with the Zetec motor than me...

I know you were looking into getting a Raceline water rail...I have one on my zetec and it REALLY cleans up the mess at the back of the head.

Bruce

[Al Navarro]

Bruce...thanks for the input. Did you retain the stock 2.0 Liter waterpump wiht the Raceline water rail? And no worries about not having an easily visible coolant level?

[11Budlite]

Hi Al,

I have a ZX1 engine and I think it's the 1.8 water pump because it doesn't have an idler pulley to reverse the rotation. I haven't run my car since I put the water rail on, but I think I'm just going to use a standard overflow tank fed from the 1/4" outlet on the thermostat hsg. Probably not ideal, but I can always change it if it doesn't work properly.

Bruce

[stevet]

Al, is this all because I signed up for Autox lessons... you can tell me, it's OK, I feel your pain. :rofl:

[slngsht]

:rofl:

[locostv8]

Al
You could always go the Mazda route.:d

[yellowss7]

Al, don't let them try to psych you out! Sunday is going to be a nice day for an autox especially compared to 2 weeks ago. This one is at the Boeing helicopter plant just off I-95 just an exit past the Philly airport. Smaller lot but will be fun. If you don't drive the 7, the offer is still open to ride with me and I may be able to convince an instructor to let you take a run in mine. PM me if you need more info. I run in the 4th heat which should start around 2:30-3:00 PM. Hope to see you there. If not May 6th is another one at the Warminster location. Tom

[Al Navarro]

I'm adding to this thread, mostly to bump it up...but also to see if anyone has tried the Cosworth/FocusSport Zetec head. For a Cossie massaged head, it doesn't seem like a bad deal.

Anyone? Anyone? Bueller?

[drew...]

Is the SVT head and the Cosworth/FocusSport Zetec the same thing? With the SVT head, variable cam timing and the varied length induction I acheive a 0-60 in 3.8 seconds with two people in the car.

[Al Navarro]

The SVT head is actually different (and a rare bird to find salvage, I've been told)...it's got bigger valves BUT has the ports is different locations...meaning my TBs wouldn't be a simple bolt on. And considering I've already cut a hole in the bonnet to fit them...

Drew...how did you get that 3.8 time? Using a Traqmate or something?

[roll a 7]

The SVT head is the only one, to my knowledge, that was designed for the zetec, from scratch, by Cosworth. The other is, I suspect, a variant of the standard head reworked, or, at best, the Ford Racing head revisited.

Your throttlebodies can be fitted to the SVT head with some fettling. DougL on the CCC website can tell you just what to do. He did it.

I bought an SVT head on FocusFanatics a while back and still believe that they can be found if you really want one. It's likely a less expensive AND better alternative, in my opinion. It has the biggest valves on a zetec and Cosworth designed porting, which is what I think that you are trying to get. With a stock zetec head gasket it will even raise your compression a few tenths, if you are going powermad.

The svt choice is truly the most Cosworthy of the lot, I'd say. And may be the least costly.... It's advantages should give it the chance to be the best performer among the entrants. An easy decision for me....

[drew...]

Al - Passport G-Timer RR2 mounted on the windsheild.

[SR27.Seth]

For a Cossie massaged head, it doesn't seem like a bad deal.
\


What kind of price are you talking about?
I garauntee that a professional head builder could get more flow from the head on your car than the Cosworth will have And I am not saying anything bad about Cosworth- I have a picture of Kieth Duckworth over my work bench- but your still getting something 'generic'. When we have head work done by John Parker Racing, 'simple street' head work runs about $1500-2000, while race heads cost anywhere from $3000 and up.
Results are certain- Given you can tune the motor!

[Al Navarro]

When I looked at the flow charts, the Cosworth Zetec head was well beyond the Ford Racing head. I don't have them handy at the moment, but it was a substantial improvement.

You can see the prices and specs over on Focus Sport (http://focussport.com/cylhead.htm). It's in line with your ballpark costs, Seth. I think you might be suprised at how "ungeneric" it is. I also had talk with Ken over at Cosworth...

Rolla7...I do know about the SVT option, but a talk with Ben at RMSCi made me think twice. Apparently you have to fabricate a flange and weld and....more than I feel like doing. And gosh, it's situations like this when I wish we had one consolidated forum (I'd have to dig up my CCC password again). Of course, there are many ways to skin the proverbial cat. Maybe I'll just rip out the Zetec and put in an H-1 (don't I wish!!!)

I am going to find out what the Cosworth Cam is like compared to the Kent that's in my Superlight. BTW, does anyone know if it's the Focus 12 or Focus 2 (or the FZ2003)? I've put a feeler out to Cody, but heard nothing back yet.

[Cherik]

Al,

do you have one of Jon Nelson's (RMSCI) ported heads on there now? That TB/manifold he made is quite good.
The standard TB's (like Jenvey / Lumenition) have a kink that limits power >7000rpm.
Contouring the TB/head transition and gasket with a dremel tool (sanding drum / polish weheel) can solve some of that.

I doubt if the Cossy head will give more, although combined with Jon Nelson's TB/Manifold it might.
Of course, this is probably for flow >7000rpm. Not sure it'd help for Auto X. You'd want to play with gear ratio's for that :-)

As far as cooling issues - I agree with Bruce regarding the Raceline water rail. It does clean up the mess.
I use a plastic vented over flow bottle to check the water level. The filler cap has the dual vent valve in it to
prevent undue evaporation.

Cherik

[Al Navarro]

p

[Al Navarro]

Cherik (have I told you enough how much I dug the Illinois/Wisconsin posse and your cars?)...I have the head which was used on the "Supersport" Zetec setup. I don't know how ported/polished that head is...according to a few people it's just milled to bump up compression...

If that's so, then the Cossie head seriously outflows the stock (and also the Ford Racing head:

http://www.usa7s.com/aspnetforum/upload/2124883889_fshead_vs_stock.jpg


Note, I did end up going Raceline water rail....no problems so far. And, as you know, it was HOT down in NC.

[Al Navarro]

Here is the Ford Racing data...though it is NOT apples to apples (28" to 50" of water...whatever that means).

TYPICAL AIRFLOW (@ 28" OF H20 DEPRESSION) AS DELIVERED
LIFT INTAKE FLOW(SCFM) EXHAUST FLOW(SCFM)
.050 38.0 32.8
.100 80.7 74.9
.150 119.1 109.1
.200 153.7 144.6
.250 181.0 167.9
.300 193.0 186.0
.350 204.8 188.5
.400 214.0 193.1
.550 220.3 195.2


Can someone smarter somehow factor in the difference in "water" and let me know if the Ford Racing one is comparable?

[Cherik]

Al, I can't say enough how much we enjoyed being part of the magical event!

Ok, here goes $.02 - it's not all personal opinion, there's some trial and error experience in here as well :-)

The flow numbers look very good. The 28" / 50" would translate to.... 10mtr H20 Column = 1 Bar, or 14.5 psi, so then 40" is about 1 mtr, or .1 Bar or 1.45psi.
Point of that is to acknowledge the inherent turbulence effects which make the flow numbers non-linear with the degree of vacuum.

The pics on the Cosworth website look very good. The CNC method should yield a very predictable result and with their enormous knowledge base likely a very good one.
Having said that, it's interesting to see that for most commercially available 300...400cc cylinders the .4" lift is viewed as a reasonable limit for street (<8000rpm) performance.
The graphs confirm that. But.. think about where you want to go make the power with that head. A cam with a fast rising opening profile is what you'd be looking for.

The best way to extract max performance is to consider the whole path: TB's, manifold, tract, valve profile. Then dynamically look at the opening transition (as fast as the cam drive allows) and the edge turbulence effects - these are usually quoted at or near .040" lift. This is the initiation of the stream into the chamber.
The interesting parameter to play with is the intake cam adjustment - small steps can cause big changes in torque profile.

From my past tinkering I know that small edges and steps can really spoil the flow in any intake system. Somewhat less so in the exhaust, due to the higher pressures. Intake trumpet profile is critical as well. Make sure you have at least 90dg curled flares, but better is to get the full 180dg curled intakes. Look at their flow numbers (!). Anyway, many chapters have been written on this, but in the end you have to go play with it to get the maximum.

I'd suggest to ask RMSCI if that head was ported.... I thought Jon N. quoted 220HP with his combined TB/Manifold with a slightly ported head, 270dg/9.7mm cams, and 10.5 CR, but I could be wrong.

Cherik

[slngsht]

Al, another thing you may want to consider is getting your current head bench flow tested, so you know what you have. Of course, that means taking the head off, so your car will be out of commission until you decide to put it back on, or get a different head.

[Al Navarro]

I'm going to do this project in the "off season"...so pulling the head shouldn't be an issue. My car sits from Nov to March.

Cody got back to me with some info...I may try the Ford Racing head with Kent Focus 2s...still not crazy $$, especially if someone takes my current head, which it seems like I have a few takers for.

[Cherik]

one other thing to consider is if you plan to race in a particular class - i.e. modifications: valve sizes, porting etc are limited in certain classes.
I'd check to see which classes these heads are allowed in.

As far as a build-up, used ZX3's are not expensive, a short block costs much less ($300...$750) than all the parts you're going to add.
It's a lot more fun to take your time building the new engine that way and not have your car out of commission.


Cherik

[Al Navarro]

Tx for the tips Cherik...your build site is a great read, btw.

Hey, can you tell me which of the heads (Cosworth vs. Ford Racing) has better flow from the numbers? I can't tell and didn't quite understand your explanation of the inches of water...(forgive my ignorance).

In the end the bare head is about the same price...so I'll go with whatever has best flow (I do know that the Ford Racing head has slightly larger valves than the stock head...don't know what the focus sport head valve size is yet.

[Cherik]

Al,
glad you enjoyed the site.

The "water pressure" depression is a measure of the vacuum. 394" H2O is 100% vacuum. More vacuum (50") is more flow.
However, it's not linear.... can't just multiply the numbers with 50/28 and come up with the matching flow.
All I meant to say is, a fair comparison is a bit obscured by using different vacuum levels. But it looks they are actually very similar.
Ignore the lifts >.4". You'll find most cams doing around 9.75mm lift.

However, I recall from when we recently put a new head on Graeme's engine, he compared the two heads you are looking at and we found that the cossy head uses stock size valves, whereas the Focus sport head uses 2mm larger valves and will thus flow more because of that ( at the same pressures) He decided for the Focus Sport head. (as you pointed out - similar price).

The Focus head was not skimmed however, so that had to be done separately at a local engine shop (approx $70), but we had to do the "cleanup" afterwards.

Cherik