427 SOHC experiment?

[Nightmist66]

While were hashing on the SOHC right now, here's some more. I have heard conflicting stories about the location of the spark plugs while developing. They had the spark plugs moved to the bottom of the cylinder head in some testing. One story I read said they moved it for combustion, but it didn't make any difference, so they moved it up to the top for ease of maintenance. Another story says that they were experimenting with trying to stuff two intake valves in it and use a fork rocker to actuate them, thus relocating the plug. I wouldn't doubt they tried two intake valves like they actually did for the Calliope 427. Does anyone know the real reason for this?

[Autoholic]

I've read the story about relocating them to see if spark plug location made a difference and it didn't, so they kept them up top for ease of maintenance. Given that the SOHC is a hemi, I would believe this story over that of dual intake valves. Ford went with the SOHC layout over that of a DOHC one for complexity reasons, a DOHC adaptation of the 427 would be harder and how many valves you want to use is largely what separates the two. With all this said, I'd like to know if the other story has some merit.

I am reading the SAE paper now, maybe it will cover this. Not the easiest read, it's full of engineering talk and requires a bit of thinking along the way.

[jimeast]

The first version of the SOHC (maybe a prototype or pre-production version) had the intake and exhaust valves off-center from each other, and a casting or set of castings came up on ebay several years ago that had the valves like this.  I think the spark plug holes on this set must have been in a different location than the final production location.  I do not know if the spark plug location changed once it was decided to have the valves centered on the chamber like they were in final production.  I also had a set of heads that might have been prototype heads or very early heads that had several cast features identical to the heads mentioned above that the production run of crate engines did not have. these heads had the spark plug location the same as the final production heads.

Does anyone know if the picture above with the engine in the car is a Ford marketing photo or one from an owner of an SOHC?

[Nightmist66]

From what I understand it was a 64 Galaxie used for testing.

[Autoholic]

I believe that was a Galaxy 500 used as a show piece, before the 1964  Indy 500. At the time, Ford had not said that the engine would make it to production.

Here is an article from Motor Trend in October 1964... It's hard to make out, but at the time of this writing Ford apparently had no intention to produce the engine for sale. I can transcribe the whole article if need be.

[jimeast]

That supports my thoughts on the spark plug holes.  Unless someone has more information, I suspect all the heads that were part of production runs or "sold" had the spark plug hole in the upper location.

From what I understand it was a 64 Galaxie used for testing.

[machoneman]

The upper plug holes went hand-in-hand IIRC with a revised exhaust port. The 1st iteration had a real dog-legged port and it was down on hp from what was expected. The new raised roof port and the plug location as worth about 100 more hp. I'll try and find the Ford tech write-up on this little factoid tomorrow.

[Autoholic]

The first series head had the spark plug by the exhaust, going to the center of the chamber. This meant the exhaust port was offset. It caused a few problems, couldn't have an entirely machined chamber, caused a water jacket bump around the exhaust port that caused poor circulation that resulted in high temps, longer spark plug wires and harder compression ratio control due to machining problems. This was corrected with the series 2 which is the production head. This comes from the SAE paper. The second series head did make more power but there are a few factors as to why. The porting was improved, the cr was improved, cooling was improved and the lift was increased .05". All this will have a decent increase, around 20% from the tech writeup.

[Autoholic]

Here is a pic that has two different pieces of info between the first series and the second. It would seem that there never were dual intake valves.

[machoneman]

Yes, those are the pics of Ford Engineering's drawings I noted and remembered seeing long ago.

[jimeast]

I don't think the first series you show was ever released for sale or to race teams.  If someone has seen these in use, let us know.  This is the style I mentioned seeing on ebay years ago.  I think it was a beat us rusty unused head if I recall

 

Here is a pic that has two different pieces of info between the first series and the second. It would seem that there never were dual intake valves.

[Autoholic]

That's correct, it wasn't. It was used during testing. The second series is what went to production.

[machoneman]

Interesting seeing the port locations again. I've oft wondered with today's flow bench technology how much better the head would be today give relocation/sizing/port volumes. Jay does have the higher intake port version of the aluminum head that required a sheet metal intake IIRC but don't remember if the exhaust was similarly re-worked, save for reversing the "D" shape. Interesting too that a modern re-work to accommodate those 'new' ports and raising the cam tunnels or otherwise modifying them for higher ratio rockers would produce x more hp!

Easier said than done....Hah! 

[Nightmist66]

That picture seems to clear up the mystery, thank you Jason and everyone else for the insight. Looking at the original port contours, it appears the intake has a nice straight shot, whereas the final had a sharper bend at the end of the roof and the bump over the water jacket. I think the original intake probably flows a little better, but the final has better cooling. I like the combustion chamber shape and exhaust port better on the final. The picture is very interesting to see what they were trying during development, very cool!

[Autoholic]

I'm in the process of reading the SAE paper, it's like 29 pages long. Lots of interesting things and you have to slow down and think about what they are saying. They cross drilled the crank for example to get better oil flow. They did talk about relocating the main oil gallery to the side, so there could be some truth to the sohc being the reason why the side oiler block exists.