My 427 SOHC Build..... Finally the time has come!

[jayb]

Looks like the seats did come with the heads.  Scary...

[WConley]

Machined steel does not flake apart like that.  They must be sourced powder metal (from Federal-Mogul or the like).

The original ones in my iron SOHC heads are beryllium copper.  You can still get those for some engines, but the stuff is toxic and nasty to machine.

[machoneman]

Wow, didn't know Ford way back them fooled with beryllium copper, even in engines destined for racing. Was it to improve longevity? Did the straight valve Ford FE heads on the GT-40's (II's and IV's) also have b-c seats?

I read long ago that b-c dust was highly toxic and a few firm's machinists found out the hard way with terrible lung infections.   

https://www.osha.gov/dts/hib/hib_data/hib19990902.html

[cobracammer]

I just read that they found a substitute for B-C seats by infusing copper with Nickel and silicon.  Oddly, they still make B-C seats ( Audi and Mitsubishi were 2 I found)  hard to believe you would find someone to machine them for you  LOL

[CaptCobrajet]

After looking at that, the thought came to mind that the top angle could have originally been machined to a razor sharp edge at the o.d. of the seat, which may have been slightly proud in the chambers.  Hotspots could have caused detonation to pepper the outer edges. JMO.  I try to make sure there are no sharp edges at that transition.  Sometimes it means taking another tool to knock that edge off.

[Barry_R]

I tend to agree with Blair on this one.  Looks like they chipped out from the OD.  Probably tried to blend the upper edge of the valve job to the chamber and had a proud or dead level sharp edge with no cross section.  Since we know that the engine had issues, detonation could have knocked the edges off & left something looking like that.  I'd be surprised to find a PM seat in an aftermarket part.

[jayb]

Thanks guys, I appreciate the feedback.  I'll make sure my machinist watches that particular issue on these heads - Jay

[WConley]

Bill Coon called me after hearing about this thread.  Here's the information I got:

• Yes indeed these are powder metal seats.
• The seats are installed 0.005" to 0.008" proud of the chamber surface.  The intention is that the valve seat cutter will remove all of this material, plus a bit of the aluminum chamber surround itself.  It seems this was not done correctly on Jason's head, resulting in a sharp exposed corner.
• The results of the sharp corner are just as you guys described.  Hot spots and detonation beat up the outer edges of the PM seats.

[cobracammer]

OK, so we heard back on the crank and the mains and rod journals had to get a 0.01 grind.  With that info in hand, the rod bearings and main bearings were ordered and are already on their way to Jay.  As of this moment, all is accounted for and all gaskets, bearings and etc. have been ordered!!  Next to come is the fun part!!!  Happy Holidays to everyone!

[Drew Pojedinec]

Jason, let me be the first to say:
For a 1.5 year long, $50k project, I've been watching since it began....  This is perhaps the most absurd first major engine build to take on.
Part of me shakes my head in disbelief, part of me just wants to shake your hand.  Aside from the incredibly difficult and expensive engine build you chose to put it into an incredibly expensive and difficult to work in vehicle.  I'm continually amazed that you stuck with it this entire time.
Either way, good job, the end is near, stick with it.  At the end of the day you are certainly going to have something in the garage NO one has ever seen before.

Good luck!
Drew

[cobracammer]

Thanks Drew.  Its been and continues to be an adventure!!  Happy holidays!

[Jim Comet]

Would it be possible to see a photo of the chambers with the new seats as a comparison to the pics with the powdered metal seats when you get the heads back?

[jayb]

Sure Jim, I'll post some pictures when the heads get finished - Jay

[Joe-JDC]

According to what Bill said, it should have been simple to do a new fresh valve job with a cutter that is larger than the seat material and lower it to the chamber with a simple radius.  If the original seats were standing proud, they needed to be machined down at least level with the combustion chamber.  Would require checking the installed height and adding a .010 shim under the springs.  Joe-JDC

[cobracammer]

OK, in speaking with Jay, his Machine Shop called him to let him know the Crankshaft was done and ready for pickup.  As we are still awaiting the Cams from Comp and the Heads from the Machine shop (and the cam shells from Precision), the plan is to ready the bottom end now that all of the "items" necessary have come together!  Maybe if "Dr. Brown" has an extra hand during assembly, we may see some pictures ?  LOL  And now the fun begins!