Flathead chamber design

[peejay]

Like this Jack?

I learn something new every day!

Didn't know this was done to the old flathead engines exhaust manifolds at one time.

It would have also been better if the center exhaust ports would have came out the top of the block to shorten heat retention due to their long path.

pdq67

So, like a Cadillac engine, then.



One of my customers had a '40 Cad that he bought after he sold his '55 Olds. (And what a hack we did on that Olds to make a modern Quadrajet work with the Hydramatic transmission. Very intricate machining work on some bracketry to get the motion ratios right)

It was a real strange sight to get the car up on the lift and look up at the engine and see NOTHING... NOTHING!! on the sides of the engine! Just straight bare iron casting.

Two things I remember about that car. One, it was a real PAIN to get it into Reverse. You had to do some funky dance maneuver with the shifter to shift into a forward gear momentarily to stop the geartrain before you shifted into Reverse, else the gears would clash horribly. I eventually learned The Secret Maneuver but it took no small amount of practice.

The second thing, was that the engine would run with thermosyphon cooling! Meaning, without a water pump. The engine would be able to idle and run in the city all day without overheating, but on the highway it would run kinda hot. Turns out the impeller had fallen off of the water pump. Idling and at low power, thermosyphon was enough motion to keep things cool. Hot water rises out of the engine, cools in the radiator, and lowers back into the engine, no pump needed.

[Ks Fats]

"Didn't know this was done to the old flathead engines exhaust manifolds at one time". It was never done in production; that was a prototype (I think Jack may of addressed that). Henry's idea on the center exhaust through the coolant was to promote winter warm-up. When the exhaust was moved into the coolant passages at both ends of the block it wreaked havoc with the efficiency of the head mounted pumps; a switch to the block mounted pumps helped.

[Pete1]

Upon returning from an absence I see one of my favorite subjects being discussed.
Port relocation and chamber design on the flathead Ford.
John Bradley and Ron Main's engines are classic examples of port relocation, Main's being far more radical.
Over the years we have done a couple simlar to Bradley's and several similar but so you couldn't tell anything had been done from the outside. These were all circle track engines.
On these engines, the old saying, more is better sure holds true.

[jed]

Can you show pictures please??

[MichaelThompson]

Upon returning from an absence I see one of my favorite subjects being discussed.
Port relocation and chamber design on the flathead Ford.
John Bradley and Ron Main's engines are classic examples of port relocation, Main's being far more radical.
Over the years we have done a couple simlar to Bradley's and several similar but so you couldn't tell anything had been done from the outside. These were all circle track engines.
On these engines, the old saying, more is better sure holds true.

Pete I think I know you from the Ford Barn. My handle over there is HenryFloored. I have learned a lot from you over the years and have always enjoyed your input.

Glad you’re here!

[Pete1]

"Can you show pictures please??"

Here is one where the engine had to appear basic configuration from the outside.

[PackardV8]

To keep all this obsolete stuff in one thread, here's today's question. In the piston pop-up going into a recess in the head, how close to the top of the cylinder do we feel it prudent to allow the compression ring?

Question two - yes, it's better to order custom forgings, but we have a old Badger cast piston with a machined recessed ring above the compression ring. How would we feel about having that exposed above the top of the cylinder bore?

[Pete1]

To keep all this obsolete stuff in one thread, here's today's question. In the piston pop-up going into a recess in the head, how close to the top of the cylinder do we feel it prudent to allow the compression ring?

Question two - yes, it's better to order custom forgings, but we have a old Badger cast piston with a machined recessed ring above the compression ring. How would we feel about having that exposed above the top of the cylinder bore?

1 - I use .200 for the top ring in all cases. That is .200 below the relief. I use flat top pistons so no recess in the head.
I think with any type of pistons, I would want the top ring .200 down.

2 - No.

[PackardV8]

Let's do the numbers. We have a customer who wants to replicate the Barron/Navarro experiments of running the piston crown above the top of the block and into a matching machined recess in the head. You say keep the rings .200" below the deck. That works perfectly, as the pistons have the top ring groove .350" below the flat top and they would protrude .142" above the deck, so the rings are .200" down.

BTW, are there any specs on differing compression heights of the early Ford flathead V8 3-1/16" bore pistons? All I've found thus far seem to be listed as 1.531".

[Pete1]

Let's do the numbers. We have a customer who wants to replicate the Barron/Navarro experiments of running the piston crown above the top of the block and into a matching machined recess in the head. You say keep the rings .200" below the deck. That works perfectly, as the pistons have the top ring groove .350" below the flat top and they would protrude .142" above the deck, so the rings are .200" down.

BTW, are there any specs on differing compression heights of the early Ford flathead V8 3-1/16" bore pistons? All I've found thus far seem to be listed as 1.531".

The only difference in early pistons, I know of, are the later Mercury with the 4 inch stroke.

As a side note, I talked to Barney Navarro several times at Bonneville in the 50's and saw the inside of one of his engines.
I never could understand why people thought they could get higher compression by popping up pistons with weird shaped domes, on a flathead engine.
Besides that, they screw up the flame travel.

[PackardV8]

FWIW, it's been ten years since Panic began this thread with:

Then why did he, nor Blair, not use "pop-up" domes (KR, some Ford), which need not interfere with this swirl pattern (but do increase static CR nicely with no transfer restriction)?

I didn't go back and re-read all ten pages, but here we are back where we began.



Not everything which supposedly worked on the late, great H-D KR works on other flatheads, but what are your thoughts on the beveled piston?

jack vines

[Pete1]

"Not everything which supposedly worked on the late, great H-D KR works on other flatheads, but what are your thoughts on the beveled piston?"

Because the piston is in the area where that bevel might be of some help, so short of a time, and the gas flow is at the lowest level, I did not think it was worth a set of pistons to try it.

Smokey said he tried it on the Hudson but it did not help.

[jed]

Speaking of Hudson does anyone have any information concerning performance levels or pictures of heads or pictures
Of the valves and transfer area.
Back in the late 70 I spent half a day boring a 308 Hudson so builder could use a 283 piston in it.

[jed]

Wouldn't a flat head/piston have less area than the dome? Even with tight squish/quench, there's a considerable area which wouldn't be exposed to the flame front.

The OEMs could have made domed pistons for essentially the same cost as flat tops, but most didn't. The OEMs researched flathead chamber design for sixty years and the best they could do exemplified by the '50s Packard I8 and '60 Studebaker Champion I6. I'll try to get some photos of those.

Jack do you rember why the Champion I6 chamber was special?

[PackardV8]

The 1960 was the last flathead and had their best thinking on chamber design; only 50 cc, for 8.0 compression. That's about all an iron flathead could tolerate.

Per John Bond, the 1939 Champion was the first US engine which would survive for hours at 5,000 RPM.

OTOH, that's another way of saying it wouldn't make enough power to harm itself. ;>)