Found a used head up in Colorado Springs as I was passing through - first junkyard I called! Supposedly a 74 dart. Casting number 2843169-2 an looks to be in excellent shape. Here's some pictures of the before and after - just started today. Left valves in to protect the seats, however do plan on putting in enginebuilder larger intake valves. My guess is the seats ARE hardened - I see very little carbon buildup in the head so presume unleaded was run for many years, zero signs of any burned/sunken seats/valves. The first two pictures are of the head after just a wire brush, and the head was just pulled off the motor as I waited. Look at the big "cup" the valve seats are in. That shrouding and sharp edge must really be a big restriction on airflow at low lifts - and with the piston speed of the 225 - I bet it's extremely important to get flow going as soon as the piston starts racing down the bore.


So, I started the basic grinding to eliminate the ridge of the cup that shrouds the valve and the lumps near the cylinder edge. A smaller cutting stone will be purchased and the areas will be blended, then the oversize intake valves will be installed. Obviously I'll do some porting after the valves have been removed then a three angle cut. Here's the start of the porting:

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Tom
'86 Alfa Romeo Spider, red "Dinsdale"
'10 Corvette, red "" (no name yet)
'95 Ferrari 348, red "Zoom"
'04 Maserati, black "Evil"
'05 Aston Martin DB9, green "Bond, Treasury bond."
'82 Dodge W150 Power Ram, yellow "E. Valdez"

OOps. Guess no spaces between the img markers.

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Tom
'86 Alfa Romeo Spider, red "Dinsdale"
'10 Corvette, red "" (no name yet)
'95 Ferrari 348, red "Zoom"
'04 Maserati, black "Evil"
'05 Aston Martin DB9, green "Bond, Treasury bond."
'82 Dodge W150 Power Ram, yellow "E. Valdez"

If you touch the valve seats, you'll also take out the hardening.........

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Ed
64 Valiant 225 / 904 / 42:1 manual steering / 9" drum brakes

Yeah, have to figure out how to protect the exhaust seat once I remove the valve . . . . Figured there was enough to lap in a NOS valve, but a slip with the cutter and I'm in trouble city. Maybe a thin piece of sheet metal (really thin) with a hole cut in it, a brass mallet to form fit it and a c-clamp to hold it in place. Or put some light light oil on the entire area, put a cardboard sleeve in, pour some JB weld in the "ring" - let harden and remove. A few drops of super glue to hold in place at the edges, then break it off when done porting.

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Tom
'86 Alfa Romeo Spider, red "Dinsdale"
'10 Corvette, red "" (no name yet)
'95 Ferrari 348, red "Zoom"
'04 Maserati, black "Evil"
'05 Aston Martin DB9, green "Bond, Treasury bond."
'82 Dodge W150 Power Ram, yellow "E. Valdez"

He's meaning with the valve job. The valve job will wipe out the hardening in the seats when you cut them for O/S valves. But to protect them from the porting grinder, just stick in an old intake and exhaust valve in that chamber as your doing it.

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There's no such thing as too much cam....only not enough engine!

The grotesque valve guide bosses are the worst part of the heads. I now bore out the guide first for SBI inserts then completely remove the guide boss from the intake port. I premake the replacement guide in my lathe tapering the in port ends nicely leaving a bit of flat at the end so the end isn't temped to break away or crack. I cool them then using Sunnen Br200 or some other extreme lubricant for press fit install them from the top of the head into position. I wind up with essentially the same length of effective guide but the big ugly boss is no more. Flow rises nicely and turbulence is reduced. When doing this mode I take the oppourtunity to go to the .343 valve guide /stem size. If it is a race only engine I go to 5/16 or .312 guide OR use the Stainless valves that many make for SB chevs with the in port stem reduced to .312 although the main stem is .343 . Summit for one has these valves. I reduce the valve face diameter to whatever I decide I need . Usually 1.84 and 1.50 although I have run a 1.88 in times past. I also unshroud the valve in the chamber as you have mentioned. Usually I cut .070 from the head. I make the valve pockets as deep and straight as practical. Seat hardening is deeper then you might think and should not be a concern unless you are going nuts and there is no room for nuts in these heads.
don

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8 cylinders are for folks who cant make HP

Thanks everybody for the info. Will look at the guide issues and will be leaving the exhaust valve the stock dia so as to preserve the hardening. Intake, which runs cooler, shouldn't be a problem. That I've got enginebuilder OS valves for. Been a long time since I've seen these heads and had forgotten how bad some of the things (like the shrouding in the CC) are. The engine in the Alfa Spider was designed in the 1950's and is still fairly modern - hemi head - good for power, bad for emissions though. Will be working on it today and will hopefully have the valves out so I can remind myself of how bad the guide bosses are. Will link to more pictures later.

Oh, forgot to mention - this will be going in a truck so I want torque. The guides and seat area will be the primary considerations - I won't be enlarging the ports themselves - just removing the nasty bumpies.

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Tom
'86 Alfa Romeo Spider, red "Dinsdale"
'10 Corvette, red "" (no name yet)
'95 Ferrari 348, red "Zoom"
'04 Maserati, black "Evil"
'05 Aston Martin DB9, green "Bond, Treasury bond."
'82 Dodge W150 Power Ram, yellow "E. Valdez"

Ok, got a Dremel tungsten carbide cutter - works great! Did some more cutting to unshroud the valves and open up the "bumps" at the end of the valve pockets where they meet the cylinder head. Will put on a head gasket and see if it lines up with the marks left from the previous one. If so - will open up the head where it meets the cylinder wall on the exhaust valve to eliminate the .08" step where the head meets the cylinder. Will then blend out the scallops around the valves where the small cutter did its work. Will then measure each combustion chamber volume as the shrouds around the valve seats varied by up to almost .04" in depth - thinner on the front, deeper on the rear cylinders. Also - what is this wire thing inside the head itself? A leftover from the sand casting?

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Tom
'86 Alfa Romeo Spider, red "Dinsdale"
'10 Corvette, red "" (no name yet)
'95 Ferrari 348, red "Zoom"
'04 Maserati, black "Evil"
'05 Aston Martin DB9, green "Bond, Treasury bond."
'82 Dodge W150 Power Ram, yellow "E. Valdez"

what is this wire thing inside the head itself? A leftover from the sand casting.

Yes.

Richard

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Part of Tyrde-Browne Racing

Don't use the gasket as your guide for this, you need to put the head on the block and let the cylinder wall dictate this. Just transfer the cylinder bore diameter for each bore onto the deck surface with a scribe and don't grind beyond that. Otherwise you will create worse shrouding than what you have originally because it will create a shelf in the chamber that will overhang the deck surface.

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There's no such thing as too much cam....only not enough engine!

Thanks, yeah now that you mention it I bet the gasket is a fair bit larger diameter than the cylinder also. Will wait till I pull the head off the engine and see where the gasket is in relation to the block also. Will not be lower end rebuild unless motor is in bad shape. Got some of the valves out. Lesson learned - the top of the head spring compressors suck royally - mine kept popping off. I used to have a C clamp style - can't find it. After swearing for the last hour and a half to remove three valves - may well just buy one of the C clamp ones. Looked inside one of the intake ports. Yowza. Big undercut ridge under the seat - looks like a disaster for airflow but can see no way of fixing without adding material. See photos. Was surprised at how much valve stem/guide wear there actually was. I need to get a dial indicator to measure the exact runout but from caliper measurement it looks like .047" - wow. At first glance I was thinking there might be a very remote chance that the guides were OK as-is. Ha ha ha ha. Anyway, here's the funky ridge in the intake of cylinder #1. The black area under the seat is actually about 1/8" recessed from the bottom of the machined area creating a reverse "ring" (think upside down "J") creating a sharp pointed edge that the air needs to flow over. What a mess.

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Tom
'86 Alfa Romeo Spider, red "Dinsdale"
'10 Corvette, red "" (no name yet)
'95 Ferrari 348, red "Zoom"
'04 Maserati, black "Evil"
'05 Aston Martin DB9, green "Bond, Treasury bond."
'82 Dodge W150 Power Ram, yellow "E. Valdez"

I use kurig coffee cups...

A lot of people make that mistake and ruin their heads without knowing it, and are often disappointed by how it didn't seem to help out much power-wise. Then they get a bad rap on head porting, not realizing all along that the problem was them and not porting. I guess they think that since you use the intake/exhaust gaskets for port matching that you do the same for chamber shaping.

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There's no such thing as too much cam....only not enough engine!

Fixed it for you.

There's water real close when porting. Read the articles, and search this forum. When you hit water, your done. Oversized seats can hit water. Read.

CJ

Thanks! I read about the seat installation and hitting water so decided to not install hardened seats and keep the stock exhaust and just go with an oversized intake and no intake seat - figured the cooler intake valve should be OK. Will just clean the guide area and seat transition with no real port opening. The seat area is so bad to begin with . . . .

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Tom
'86 Alfa Romeo Spider, red "Dinsdale"
'10 Corvette, red "" (no name yet)
'95 Ferrari 348, red "Zoom"
'04 Maserati, black "Evil"
'05 Aston Martin DB9, green "Bond, Treasury bond."
'82 Dodge W150 Power Ram, yellow "E. Valdez"