FE Head Temp

[FrozenMerc]

I can't speak to FE's, but I have done this exercise on smaller engines (single, V-Twin, and Inline Twin two and four strokes) in the past.  I would drill and tap dozens of holes into the water jackets around the cylinder and throughout the heads and install thermocouples.  It wasn't unusual to have 12 to 16 thermocouples mounted in the cylinder, and another 8 to 12 in the head on these engines.  This was almost always done on prototype engines, or new designs to make sure there wasn't any problems during initial run-in and fuel mapping.  Generally speaking, there wouldn't be more than a few degrees difference between the thermocouples, once the engine was up to temp.  Warm up would show a bit of difference, especially with the thermostat closed. 

The one engine that would show a large temperature difference would be the direct injected two strokes.  The fuel was sprayed through a window in the piston towards the transfer ports.  The spray pattern would hit the opposite side and keep that cylinder wall considerably cooler.   Took a looonnnng time to figure out how to properly cool the piston on that design to keep it from splitting along the window and sticking in the bore. 

[Falcon67]

Not sure when Ford got around to addressing the problem on the 351C 2V type heads.  The 70-71 heads have the better exhaust port, then this 75 thing.  That's going by casing numbers BTW.  I think I magged like 8 heads before I found a good replacement.  Ported, the set ran around 254 cfm intake / 200 exhaust at around .550.  Conversely, I have not found the same exhaust issues with any of the 351C 4V heads I've owned and magged.  I wonder if the problems only showed up post 1974 production.  Looks like Cat converters showed up in 1975 - that would have really heated up the exhaust head temps I'll bet.  The 1993 F-350 460 is also known for overheating the exhaust manifolds and either cracking the manifolds or causing bolt problems.  No head issues, just the bolted on parts.

[WConley]

... The 1993 F-350 460 is also known for overheating the exhaust manifolds and either cracking the manifolds or causing bolt problems.  No head issues, just the bolted on parts.

That's why they specified cast stainless exhaust manifolds on those 7.5L truck engines.  I remember dynoing those at Ford and oh man you could cook some nice marshmallows just holding them near those glowing things.  It had something to do with the chamber design and cam/ ignition timing needed to meet emissions.  We had problems with 7.5L E-350 Ambulance fires for awhile    Not a good look to see a whole row of burnt out ambulances on the infield of the Dearborn Proving Grounds.

[pbf777]

Conversely, I have not found the same exhaust issues with any of the 351C 4V heads I've owned and magged. 

    I would agree with this with the exception of the later open chamber, small valve, 4v head, identified as the 'AA' casting; as we have found these to often exhibit cracks between the intake and exhaust ports seat thru seat.   

    Scott.