Ported Big Valve Cylinder Head

Well, I finally got around to completing this project and updating my web page.  This was one of the longest lasting projects that I have done on my Ford 2.3 turbo powered XR4Ti.  It all started out with an interest to pull the head on my 86 Merkur XR4Ti parts car and see what the cylinders looked like.  I had bought the 86 as a parts car knowing that the engine had a loud knock.  The engine noise definitely sounded like it was coming from the bottom end (piston slap + maybe rod bearing knock), but I was also curious how the cylinder head looked.  The engine was a relatively low mile (~50K) Ford re-manufactured unit, so I was hoping that the cylinder head was in good shape for spare parts.  About this same time, I started dreaming about upgrading to a big valve head....  then, I was looking into different cams.... started to research porting some more....  One thing led to another, and I ended up going all out and having "the works" done.

When I pulled the cylinder head out, I could see that it looked good, so my plans proceeded further.  I had called around to several local machine shops and talked with them about getting a 3 angle valve job and machine work for bigger valves.  One place stood out among the rest - not because he was cheaper, but because he really knew what he was doing.  I ended up choosing a guy named Mike at "Precision Head and Block" in Orlando, Florida.  He had 20+ years of experience and had worked with the 2.3 head before.  He also had extensive experience with racing engines.  In fact, during my time in his shop, I saw him working on a normally aspirated Ford 2.3 for a local circle track racer.

The next step was to drop the head off at the shop and have Mike clean and Magna-Flux it.  During this time, I was concerned that Mike would call back and say that he found cracks which made the head useless.  It is very common for there to be cracks (sometimes hidden to the naked eye) - especially around the exhaust seats.  I was relieved when I heard that there were no cracks found.

Just a side note regarding the cleaning process Mike used.... most shops hot tank their parts, but Mike uses a different process that does not involve any solvents.  He actually "bakes" the parts in a high temperature furnace and then shot peens them!  The baking time in the furnace is quite long, and then the parts are allowed to gradually cool in the furnace.  Apparently, this baking process can actually help normalize the parts and relieve internal stresses - this is good for preventing future cracks.  His furnace is big enough so that an entire engine block can fit inside.  He also has a special jig for spinning the parts while shot peening them.  I thought this was an interesting way of cleaning the parts.

After I found out the head was in good shape, I gave him the go ahead to proceed with the next step of my plans.  He installed hardened exhaust valve seats, and made rough cuts for bigger intake (1.89") and exhaust (1.59") valves.  At the same time, as much as possible, he machined out the valve bowl ares to match the bigger valve seats.  In addition, I had him use a fly cutter to unshroud around the valve seats in the combustion chambers.

If you look closely at the photo of the chambers below, you can see a shiny semi-circular ring around the valve seats.  This was the cut that was made to unshroud the valves.  Mike cut as much as possible, without getting too close to the fire ring sealing area.  In fact, as you can see in the photo, I kept the old head gasket in place while I was working on the head - to protect the head sealing surface.  One slip with a die grinder and the head could be reduced to scrap if the fire ring sealing area was damaged.

Cleaning up the combustion chambers

In the photo above, you can also see a progression of my combustion chamber work.  Unfortunately, the photo is a bit out of focus.  Even so, you can see that the chamber on the left is untouched, the chamber in the middle has a set of old valves in place (used to protect the rough cut valve seats), and the chamber on the far right is completed.

The photo below is a little better showing the surface finish in the chambers.  It also shows the valve bowl areas and the port work I did there.  Since this was my first cylinder head porting job, I took my time and was very careful.  I spent 20+ hours porting the intake & exhaust ports, bowl areas, and combustion chambers.  I did the porting on a few different occasions, but I pulled one final "all-nighter" to finish it up.  I used grinding stones in a lot of places where I could have used carbide cutters because I wanted to remove the material more slowly.  I didn't want to mess anything up.  I did use some carbide cutters, but I had a couple close calls in the bowl area.  A couple times, after several hours of continuous porting, my hands began to fatigue.  The carbide cutter kicked back and began to "richocet" around in the bowl area until my hands got it back under control.  One of those incidents was VERY close to one of the exhaust valve seats.  Fortunately, it just missed the critical seat sealing area.  Needless to say, this close call was enough to wake me up!  After that all-nighter, my hands were wiped out!  One side of my right hand index finger went numb.... some sort of nerve damage from the vibration and constant pressure.  After a few days passed and my finger was still numb, I was beginning to wonder if I did some permanent damage.  Fortunately, the feeling came back after about a week.

Completed combustion chambers

It's not my intention to go into a lot of detail of exactly how I ported and shaped the bowl areas and ports.  I am not THE expert.  I did some research and followed the advice of some knowledgeable people.  I was conservative, since I knew that improper material removal can kill the flow in a port - especially on the short side radius.  As a result, I removed as much material as necessary to blend the bowl areas into the bigger seats.  I also blended the bowl areas into the port runners.  While in there, I removed material around the valve guide knot without shortening them at all.  As you can sort of see in the photos, I gave the guide knots more of a triangular cross section and blended them back into the port walls.  I was just trying to improve the air flow around the knots without sacrificing the valve stem load bearing area.  An all out racing engine may benefit from having the guide knot completely removed, but I was also interested in longevity on my street engine.  After all, I am looking to get another 100K miles out of this head!

I spent the majority of my time on the exhaust side.  Again, I was conservative and only raised the exhaust port roof about 0.10".  I polished up the exhaust ports the most -  knowing that this would help retain more heat in the exhaust gases that could further power the turbine wheel.  On the intake side, I roughly cleaned up the ports and did not spend as much time polishing the surfaces.  The photo below is a view of the exhaust side where you can see some of the ports and also the guide knots.

Ported exhaust side

After I finished all my porting work, I gave the cylinder head back to Mike.  He did the final 3 angle valve grind, set up the valve clearances (follower lash) and did the final assembly.  At this point, it was somewhere around December and the holidays were approaching fast.  I decided that I would not do the installation until after the New Year - later in January 2000.

Completed cylinder head ready to install

Finally, January rolled around and I picked a weekend to do the cylinder head installation.  I had talked with my wife and I decided to start on a Friday night, work all night, and hopefully finish early on Saturday.  By working all night, I would minimize the time taken away from my family.  I was thinking that I'd be done some time by mid-day Saturday.  WRONG!!  The entire project took me twice as long as I estimated (what else is new?!?).

After a LOOONG weekend, I got everything back together.  I first ran the engine for about 20 minutes at 1500-2500 RPM for proper cam break in.  As of the time of this writing (with minimal tuning), I have done some preliminary G-Tech meter testing.  I found a 37HP increase over the stock head setup.  I should also mention that I installed a 0.63 A/R turbine housing (replacing the stock 0.48), and did some porting on the exhaust manifold and turbo exhaust elbow while I had everything apart.

While testing, I ran into some fuel problems.  The increased air flow was creating some very lean conditions at WOT.  My A/F meter showed that I needed to do something, so I decided to install a bigger pump.  I installed a Walbro 255lph in-tank pump that I got for a very good deal.  The fuel pump upgrade eliminated my WOT, high RPM lean condition.

A nearly 40HP increase is not bad for just putting everything back together and roughly tuning it.  I look forward to seeing the power increases once I turn up the boost and advance my ignition timing some more!

In case your interested, the parts list for this entire project is below:

Parts from Racer Walsh (1-800-334-0151)  {first number is Racer Walsh P/N}:
1470 Springs = $46 .
1476A Retainers = $35 .
1486 Lifters = $58 .
1502 Keepers = $4 .
1492 Oversize Intake Valve (1.89") = $48 for 4 .
1494 Oversize Exhaust Valve(1.59") = $48 for 4 .
1544 Cam Timing Belt = $18 .
1590-23  Head Bolts = $23 .

Wolverine Cam & Followers = $130 .
Advertised Duration (Int/Exh): 270 deg
Duration at 0.050" lift (Int/Exh): 220 deg
Valve Lift: 0.454"
(can be ordered through J.C. Whitney or AutoZone)

New solid roller Cam Belt Tensionor = $25 .
(Got it at Discount Auto - much sturdier than stock tensioner.)

Fel-Pro 1035 Head Gasket = $40 .
Fel-Pro Cam seal = $10
Fel-Pro Valve Stem Seals = $12
Federal Mogul Cam Bearings = $12
Misc parts from shop (valve seals, seat inserts) = $30

While porting the cylinder head on my Merkur XR4Ti Ford 2.3 turbo head was one of the most challenging projects that I undertook on my Ford 2.3 turbo engine, it was also one of the most rewarding projects.

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