All Small Six Aluminum Cylinder Head update 2/8/2023

[akidwithacar]

Matt Cox gave an hour long interview to the YouTube channel "Engine Gremlins" giving updates as to why the production has slowed, and when production will continue, as well as much more.
According to Matt the last thing tying up full production is waiting for the foundry to finish calibration on their 3D printer. As soon as they finish that the head will be on full production.
Watch the full interview here:

 

[Kritas]

This is great news. I expect that it'll be quite a while before demand is fully satisfied. I've been waiting on this development before setting a long-term direction for my engine. I think keeping a six and rodding it is more interesting than a V8 swap for me since I've done all of that before. The six is a new direction. I can work on other areas of the car while this development gets sorted.

 

[bmbm40]

Great video, thanks.

The discussion included comments on the design flaws in the log head including the Siamese 3 and 4 exhaust ports. I don't suppose we will ever know why Ford did that, not that it is important now.

 

[clochard68]

Great video, thanks.

The discussion included comments on the design flaws in the log head including the Siamese 3 and 4 exhaust ports. I don't suppose we will ever know why Ford did that, not that it is important now.

My theory is that with the larger siamese port the velocity and therefore scavenging of cylinder 3 and 4 is reduced. That would have an effect during overlap. Since cylinder 3 and 4 have the best fuel supply, Ford made the exhaust scavenging in these two cylinders slightly worse to get all the other cylinders (in relation) more even regarding cylinder filling.

 

[Kritas]

Great video, thanks.

The discussion included comments on the design flaws in the log head including the Siamese 3 and 4 exhaust ports. I don't suppose we will ever know why Ford did that, not that it is important now.

Probably not, I always suspect cost-cutting from what I've heard about Ford culture at that time.

 

[bmbm40]

I had always assumed it was related to cost but the only scenario I could imagine was it made the casting process easier and faster somehow if that is a possibility.
The theory from clochard68 is fascinating and makes sense to me as well.

 

[aussie7mains]

Most likely reason for the siamesed centre port is that of cold weather running, by combining the two ports more heat is available to heat the pad under the carby to improve cold weather running and economy. The 2v kept this feature and added a choke pull off tube for the WW stromberg with auto choke. When the crossflow came along this was lost, but they did add a water jacket to the intake manifold which was now on the opposite side of the engine. The crossflow has 6 identicle exhaust ports and much lower restriction. The EFI crossflow 250 was rated at 150bhp (much more honest rating) and could just about outrun the Australian cleveland 302. The sohc and and dohc were better still. The Argentine SP head has 6 exhaust ports with the manifold flange much closer to the head than the 2v. The main problem with the siamesed port is that you cannot separate the engine fully into two groups of 3 pots. However the header flange used on the factory 2v was divided, this seems to have NOT affected the power.

 

[bmbm40]

Yep that too, carb heat would also be a possible concern by Ford engineers. Especially since it was highly unlikely they could have envisioned the current level of performance modifications made to these motors today and any possible negative affect the siamese port would have made for someone reasonably assuming 200 hp output from their built 200 inline six.

 

[aussie7mains]

Yep that too, carb heat would also be a possible concern by Ford engineers. Especially since it was highly unlikely they could have envisioned the current level of performance modifications made to these motors today and any possible negative affect the siamese port would have made for someone reasonably assuming 200 hp output from their built 200 inline six.

200bhp from a 200ci, even with the 2v head is pretty unlikely, unless really well developed, the 250-v would have been about 135 or so genuine engine dyno BHP. The USA people never developed the inline six any further than the log head, we however went a lot further to where the 4litre could develop better than 1bhp per ci in emissioned form and to DIN. The last barra was 192kw, 310 in turbo form. If you take the point that the six started out as 144ci, grew to 250ci, went from pushrod to dohc 4valve, almost quadrupled it output, met emissions, lasts to 400,000km easily, and kept the bore spacing and head bolt pattern throughout, its a tribute to the engineers that did it.

 

[drag-200stang]

aussie7mains is right, it is for heating the intake manifold just below the carb for faster warmups and better fuel economy. That is why the roof of 3-4 exhaust head ports and the bottom of the intake below the carb has radiator like fins.
I say it all the time, that is where the port divider shines, it covers up the fins and puts distance from the intake. But they say there is no proof that it works. But they never get a timed run with and without and tuned for it. You cannot tell by the seat of the pants if it works, but that little difference can be half a car length or more at the end of the 1/4 mile and make you the winner or pass the car when maybe you should not have tried.

 

[bmbm40]

My mention of 200 hp was meant to be humorous and to emphasize the leap from engineer's original intent of the 144/170 use as fuel efficient cheap power units for basic transportation and what we want to use them for today.

 

[78_200_C4]

Has anyone flow tested the 3 + 4 exhaust ports?
I have an eBay header that I have thought about about blocking off either the 3 or 4 tube to reduce the flow.
This might help air fuel distribution to the other 4 cylinders.
Some headers for V8's with siamese center ports only have 3 tubes per side.

 

[bubba22349]

I believe that some of the old Stock Class Drag Racers used to make / fit and weld in a divider plate on the header Flange. That plate would extended into and sealed off the center between the two exhaust ports, so when the header was removed the head is still stock.

 

[aussie7mains]

I have fitted a divider to a 2v engine many years ago and made a gasket to work with the new flange. It sounded different, but power wise????? Without back to back test your never going to know, I would say the difference would be very slight. I have sketched up a design to header to work with the 3 4 centre port, it only used 5 pipes, its very simple and is basicaly a streamlined version. Its much like those exhaust headers seen on 1940s racers. Tube diameters in mm, lengths dont matter much. IMO this would work as well if not better than any tube headers.

 

[Cox Custom Mechanical]

Just out of curiosity are we any closer to an actual date of production or cost?

 

[powerband]

"... some of the old Stock Class Drag Racers used to make / fit and weld in a divider plate on the header Flange. That plate would extended into and sealed off the center between the two exhaust ports, so when the header was removed the head is still stock."


... these showed up on local CL from another ill fated V8 swap:

. . .

have fun

 

[Kritas]

I believe that some of the old Stock Class Drag Racers used to make / fit and weld in a divider plate on the header Flange. That plate would extended into and sealed off the center between the two exhaust ports, so when the header was removed the head is still stock.

I have a new set of Vintage Inlines headers for installation and was thinking of doing this. It would be a simple mod, but the jury seems to be out on whether port dividers are effective according to what I've read. I have about a month before the rest of my exhaust system arrives and the headers will be installed. There doesn't seem to be a downside to modifying the headers, so I'll probably go for it.