disassembling my Oz head I have some questions

[Anlushac11]

8)

1) Did the Oz heads come with valve seats? mine has machined in valve seats. And I thought someone said the Oz heads were 1.65" intake and IIRC 1.39" exhaust. Mine has 1.73" intake and 1.49". If I can sell some Stang parts this weekend I am going to try and get some one piece stainless valves with the back cut heads.

2) Is it normal for the exhaust valves to be non magnetic? The intakes I can pick up with a magnet but the exhaust valves are non magnetic.

3) Whoever previously owned my intake ported the intake runners to slightly past the intake gaskets.

4) Can someone post some pics of a ported SB inline six exhaust port. Im kinda studying them as their doesnt seem like there is alot I can do as far as straightening or opening it up. I am open to suggestions from the experts om tips and suggestions. I am also suprised at how smooth and clean the castings in the exhaust ports are.

5) The intakes Im just going to clean up and smooth some edges and transitions but they look very good to begin with. No hogging out as that will kill low end velocity. Not trying to build a 7000rpm drag motor.

This motor is going to be redlined at 6000rpm but I will probably limit it to 5000-5500rms. Looking at a cam around 264-272deg dur and about .450" lift. Compression is estimated to be about 10:1 when done but I still have to cc the chambers before I clean them up and unshroud the valves.

My goal is to pick up about 20hp or more over a stock Oz head. I feel most of this will be picked up in the exhaust and by unshrouding the valves.

Any advice will be appreciated. Thanks.

 

[xctasy]

After 1986, all Aussie cars had to run unleaded. Pump ULP was not available before 1983. Unlike the US, the 1970- 1973 XY/XA Falcon 2V's never got induction hardened seats, let alone inserts. The iserts were fitted for the advent of unleded fuel, and most cars serviced after 1995 had to use them as leaded fuel was phased out entirely.

Valve sizes look like they are from Cross-flow iron/ pre 1985 XF alloy head. They have slightly differenent heights to the stock 2V/ Log head (non cross flow) ones. If the intakes valves are about 5.2 inches tall, they are likely to be a modification by the machinist who did the valve inserts.


Perhaps Addo, Tim or someone could comment on the exhast ports. My friend who had a 2V 250 in his Cortina found the stock log head cast iron header leaked badly.

 

[addo]

Mark, someone has been into that head already. Non-magnetic usually means stainless. Yes, 1.388/1.649 are the stock sizes - it is a 72DA casting, right?

Seats were always just cut in; never inserted. The factory valve bowls can benefit from some major work, whether or not you run high RPM.

Exhausts - I can email you pictures to compare with, but have forgotten the exact URL for posting on Al's account (I can FTP, but can't get the address right to post). If there is any erosion on the exhaust face, mill it now to save grief.

Inlets are poorly matched to the manifold and benefit from the "realigning" of a port match.

Regards, Adam.

 

[Anlushac11]

8)

OK

Both the intake and exhaust valves are almost exactly 4.25" tall, single groove valves. I placed a straight edge on top and measured from flat surface to bottom edge of straightedge. It measures almost exactly 4.25".


Also someone has been inside the intake ports with a flapper wheel or sme kind of abrasive becasue when I was looking inside the port with a flashlight there are abrasive marks like inside a honed cylinder wall. But the bowls look stock.

It also looks like someone has cleaned up the exhaust ports too. They have marks in them too but the exhausts ports have not been port matched. It looks more like someone just smoothed the surface out and removed some casting seams and general cleanup.

The casting number is ARD1OE-6049-AC.


If you could send me some pics of a stock Oz intake and exhaust bowls and ports and what modified looks like I would be very happy.

johnvarry@hotmail.com is my email address. Thanks for the help as the mystery deepens.

 

[addo]

The stock valve sizes (length) are 4.278/4.266 by my measurements. If the 2V pictures aren't much chop, I can probably try for some more in a week or so. (Looks like I may have a quick indoor contract - work is not happening outdoors with all the rain.) We can never have too much information on the 2V's!

BTW, use the "pinch" test rule of thumb for widening out those exhausts - don't thin the walls too much in that first section from the flange.

Adam.

 

[Anlushac11]

8)

Thanks for the info. I was looking at the exhaust around the flange and I noticed that opening up the sides too much will give you a hole in the side.

I was also confused because looking down onto the exhaust port bowl there doesnt seem to be alot I can do. It looks like a cylinder straight down and the port comes into the side of that. There really isnt much room to open up the bowls. The port can use some work. The intake Im pretty much going to leave stock. Someone has already gone through them.

 

[addo]

Yeah, but... Even on that s****y exhaust bowl, you can see which way it's designed to swirl (different depending on chamber), and help that a little. Plus, as I mentioned, a little foreshortening of the guides for smooth transition into the actual exhaust port can't hurt. And a bit of work on the short side radius; again respecting the swirl (which is the opposite in the Southern Hemisphere ).

Cheers, Adam.

 

[Anlushac11]

8)

Thanks for trying to send me the pics but they were corrupted. I cant even open the file.

It looks like the exhaust has been ported too. The roof and shape of the chamber is different than the pics I can find and there is no valve guide boss sticking down. Looks like the only thing I can do is port match the exhaust and blend it back into the port a bit(without grinding port wall too thin at the side at the dogleg). At this point about all I can do to improve it is get some backcut head stainless valves and a set of fully rollerized 1.65:1 rocker arms. Anyhting to boost horsepower. I want that 200hp mark.

 

[addo]

Sorry the file didn't work out. I'll try to think up alternatives.

200HP NA on a 200 is a huge ask, even at the flywheel. I have been feeding on 200 six "porn" for a few days now on one of the GM boards:

220 RWHP Worked! with triple Weber 45s
160 RWHP, 350 Holley and usual tweaks
114 RWHP, triple CD175, mild cam
125 RWKW, Garrett; 13.1 @ 95 mph (blames wrong gearing)

Consensus was that 35 pounds boost and a Garrett based kit was the pinnacle - high 9s with the right rig/driver (lighter car than a Mustang). The lowest powered NA result would be the most tractable, the first one was a weapon.

Adam.

 

[Anonymous]

I would love to have bought a head with all the work yours already seems to have had done on it. I had my 2V ported in the exhaust recently (left inlet as standard)
There didnt seem to be much you could do with the bowls (I may stand corrected). Thats is compaired to a 351 cleveland head I did the other day. The bowls on this had a ridge around the top and when removed plus a bit little more made the bowls look huge. It makes sence to do work on this area if you can especially with bigger valves.
After Adams comments I might look at it more seriously with the 2V next time.
My 2V head had the same inlet valves when I bought it as a log head but had bigger exhaust valves as a bit of a bonus.