Duratec head swap

[boss351]

I am switching out my 2.0L head to a 2.3L (from Ford Racing), I'd like to shave a little off the new head to leave me about 10.6 compression ratio.



1 - has anyone done this

2 - how much is needed to be shaved off



Also putting in Crower Stage 2 cams and matching springs.

Cheers.
Adam

[athens7]

It doesn't take long for upgrade-itis to set in, does it?

[Doug Liedblad]

What kind of power increase can you get by swapping the heads?

Can Ford Racing give you a clue?

[boss351]

What kind of power increase can you get by swapping the heads?

Can Ford Racing give you a clue?

I guess I will figure it out the hard way.. On extra power, we'll have to wait and find out.. Guessing 20+HP.

[moosetestbestanden]

Supposedly the head flows about 15% better.

[boss351]

What I am doing is a cross between the R400 and R500 setups. The R500 gets this head but not sure which cams. I am going with stage-2 cams that I believe is what the R400 gets. I am also sticking with the Caterham intake and single throttle body for now. The tuner thinks I am inline for 30+ hp increase (similar to the increase in going to an R400 setup with multiple throttle bodies), going to be interesting finding out..

[Doug Liedblad]

Check out this link

http://www.focusfanatics.com/forum/showthread.php?t=242338

Tom as in 1turbofocus says he has done this since 2006 or so.

Also shaved .025" off the head and that other Caterhams are running his tunes.

I don't know how much that raised compression, he might tell you if you send him a PM.

I've dealt with him for my SVT engine and he's been helpful.

What intake manifold are you useing? Tom makes that point that you may need to increase the flow there the manifold to really see the increase in performance from the head swap.

[boss351]

Check out this link

http://www.focusfanatics.com/forum/showthread.php?t=242338

Tom as in 1turbofocus says he has done this since 2006 or so.

Also shaved .025" off the head and that other Caterhams are running his tunes.

I don't know how much that raised compression, he might tell you if you send him a PM.

I've dealt with him for my SVT engine and he's been helpful.

Tom is the tuner I am using! Where we are mystified is with the chamber volume the machine shop that the head is at measured. I am trying to get the volume from Ford racing now to see if what they measured is a mistake or if they really opened up the chamber basically so much it will drop the compression ration by a full '1' or more (ie 10.2:1 to 9:1).

[slomove]

Maybe I am stating the obvious but depending on the piston shape and how much it is pocketed and/or protrudes into the chamber as well as the head gasket compressed thickness the number will change.

I measured head volume and piston-related volume separately for my Zetec (using a plexiglass plate and a syringe) to find out if the engine builder had already shaved the head or not.

[boss351]

Maybe I am stating the obvious but depending on the piston shape and how much it is pocketed and/or protrudes into the chamber as well as the head gasket compressed thickness the number will change.

I measured head volume and piston-related volume separately for my Zetec (using a plexiglass plate and a syringe) to find out if the engine builder had already shaved the head or not.

That's basically my plan (me measuring when I can get to it). The machine shop measured without a plate and tried compensating for the fluid convex that appears from surface tension, not very accurate. My head is still on the block but I have the respective volume measurements, and they calculate back to 10.2:1 that is correct for the engine.

[slomove]

That is indeed not very exact. A small surface bulge of only 20/1000 will give you an error of 0.5 in the compression number for a 4-cyl 2-l engine.

I made a simple spreadsheet for entering the measured numbers with a retracted piston if you need that.

[Doug Liedblad]

You cannot measure the volume correctly unless you have at least something like this:

http://www.steigerperformance.com/products/sp90005.html

As Gert says you need to allow for the piston shape.

http://www.csgnetwork.com/compcalc.html

[JohnCh]

According to Ammo at Raceco, who is one of the authorities on this engine, the stock early head is good for about 220hp. There is a small tumble in the exhaust port that is easily removed which ups this to about 235hp. The stock later head is good for about 250hp. Given that the Ford Racing head is a further development of that one, I imagine it should flow to well over 250hp.

Looking at the specs for the Crower stage 2 cams, they seem to fall midway between the Kent D-TEC10 and D-TEC20, which reportedly make 210-225hp and 225-240hp respectively when run with DTHB and proper exhausts. I’m curious if the higher flowing head will result in any improvements with the Crowers? I’d also love to see if/how the shape of the torque curves change with each head. Any chance I can convince you to build and test two different versions of your engine? ;)

-John

[boss351]

I finally ran in to some good info (though still waiting for confirmation from Ford Racing). There is a TurboRanger Forum and one of its members seems to have all kinds of measurements made, here's an excerpt:

Well I cc'd the volume of the ports and chambers of the 3 heads I have. All 3 heads had combustion chamber volume of 43.2cc.

'03 Ranger 2.3 (same as 2.0 focus) head
intake 155.0 cc exhaust 102.4 cc

Stock 2.3 head
intake 165.5 cc exhaust 102.0 cc

FRPP cnc head
intake 172.4cc exhaust 107.6 cc

I came to the conclusion that the exhaust ports are the same between the 2.0(2.3 ranger) and 2.3 head but the intake ports are larger on the 2.3 which I have already previously verified with a caliper and it is easy to see in a side by side comparison.

Sorry, I'd love to have multiple projects but time is the biggest problem for me, this is it for now! In the future the next possible upgrade would be to individual throttle bodies..

[boss351]

I got the head back and cc'd it correctly myself at 43cc with the spark plug installed. I also got a clal back from Ford Racing today and they said the measurement is 42.2 +/- 0.9. So essentially, the head has the same chamber volumes. Besides the cnc-port the head comes from them with a 3-angle valve job.

Found another machine shop to work with, once I pull the existing head off the car and confirm the volume in the cylinder when piston at TDC I'll figure out exactly how much to shave. My guestimate, since knowing the area of the chambers is not easy, is taking 0.025 off will result in bringing the compression ratio up to 10.8:1.