What ended the flathead engine?

[Sunny 4 Acres]

I was wondering what happened to the flathead engine ( valve in head). Is it not practicale to build or work on? Do they still make a kind of flathead that is hard to find or real expensive? Just curious. What was the ast year they made them?

 

[Anonymous-0]

Ford stopped making the flathead in 1952 or 1953. I believe cooling was the key issue in dropping the design. Too much heat in the block vs the push rod engine.

 

[Donnie Baker]

Ain't a flathead a (valve in block)? but anywho I think they have breathing problems, that is there downfall is they can't get the air in and out of the cylinders efficiently but I could be wrong, I gotta go

 

[Anonymous-0]

The last Ford car flat head engine was 1953. My dad's first new car was a 1954 I block over head valve 6.

The biggest limitation with a flat head engine is that its hard to get a high compression ratio and it takes a higher compression ratio than the typical flat head engine to get efficiency and performance.

Lots of flat head ford blocks were raced with Offenhauser over head valve heads. 4s and V8s.

I think Briggs is still making some flat head engines.


Gerald J.

 

[BobReeves]

Chrysler made a Flathead inline 6 up till sometime in the 60's. No expert but would guess the breathing issue is the main reason for the design being replaced.

 

[ben brown]

not sure why they went but was watching horespowr tv or speed not sure whitch the other day some company is building a flat head block same as the ford with all the new thing aviable they said it was going to have around 500 to 600 hp. its to be put in roasters lke was build in the 50s

 

[Anonymous-0]

What happened to them? They became some of the most common and popular engines in the world! They sell them at Wallmart under the the name Briggs&Stratton. At least a few companys had the sense to stick with a good thing!

 

[Bob]

Don't forget (nowadays) meeting emissions standards would be impossible with a flattie.

Even small air cooled engines were forced, for the most part, to go to OHV to meet emissions standards.

 

[Janicholson]

I'll add some to that said below.
All multi cylinder flatheads (and T heads) have issues with uneven heating of the block due to the exhaust gasses passing through the water jacket. Cracked blocks, and burnt valves were issues. The flow of gasses (now called computational fluid dynamics, and computer simulated pretty well) into a flat head was forced to turn a 180 to get into the cylinder (energy and momentum lost). They also had large surface to volume ratio causing quenching of the burning flame front in the combustion chamber. Thus the unburned fuel caused efficiency (and pollution) problems. Adjusting the valves (on a V8 ford) was painful and often not done in time to save them. Nothing is very exceptional about them except the serious numbers that were produced by almost every maker. GMC was one of the first to abandon the flat head. JimN

 

[Jerry/MT]

Overhead valves heads have a higher volumetric efficiency especially in a cross flow configuration. That translates into more airflow per intake stroke and more airflow means more horsepower, all other things being equal. The same displacement with equivalent compression ratio will develop more power with overhead valves that a comparable flathead.

 

[Anonymous-0]

Some motor designers coulden't make up their minds so they made engines with exhaust valves in the the block, and intake valves in the head. I think they called it a f head engine. Jeep had a engine of that design.Stan

 

[Anonymous-0]

1955 Chev Mousemotor

 

[MarkB_MI]

The end of the Ford flathead V-8 came when Oldmobile introduced the overhead valve "Rocket" V-8 in 1949. You just can't get the performance out of a flathead that you can an overhead valve engine. But the flathead design lived on for many years in low-performance engines, particularly small air-cooled engines and marine engines like the Gray Marine (Chrysler).

I believe the main reason that small engine manufacturers are these days going to overhead valve engines is to comply with emission standards, rather than to improve performance or reliability.

 

[Bus Driver]

Cadillac had a flathead V-8 until 1949. Flathead engine blocks are wider than those for OHV. Putting exhaust and intake on the same side of the block is tricky with a V-8. Making passages through the block in order to put intake and exhaust on opposite sides of the block increases bulk of the block and makes for poor flow through those passages.

 

[CJ3b_jeep]

When I was in the air force back in the 80s-90s, we had "Coleman" tugs that still had flathead chrysler straight sixes in them. I agree with what everyone is saying, an overhead valve engine breathes easier because it's a straigh shot for the air to come into the cylinder and back out again. I have one of the jeep engines with 1/2 overhead and 1/2 f-head. Rolls-Royce had a simillar design back in the 1950s.

 

[Anonymous-0]

We had a '56 Dodge 1 1/2 ton truck with a flathead engine. If it sat outside over night and if we had a heavy dew or fog that darn thing would not start, moisture settle in around the spark plugs and it would not start, had to get the hair dryer out and dry the plugs.....not good for the marital vows when you wanted to load out hogs.

 

[02XLT4X4]

Anymore you can't hardly meet emissions with a OHV either. OHC's both single and dual seem to be taking over, and they can put out some pretty mean numbers as well.

 

[Mike (WA)]

Of course, no discussion of flatheads would be complete without mention of the mighty Hudson Hornet. Hudson came out with a 308 cubic inch flathead 6 in 1951, with dual carbs (and an optional "7X Severe Usage" package that arguably made it the first "muscle car"). Hudson simply ate everybody's lunch on the NASCAR circuit until 1954 (including the Oldsmobiles). Probably a combination of the engine, and the low and wide car itself- the V8's were competitive on the straight stretch, but the Hudsons were far superior on the turns. The first performance modification is to make it breath better- with porting and releiving around the valves, headers, cam, etc. The valve cooling problem is solved by an innovative water manifold that channels the coolest water directly to the exhaust valve area. Hudson still has a huge following, with a very active national club with local chapters, and a bunch of us are still running those old flatheads at 75 down the freeway, and loving it.

 

[Anonymous-0]

Memories of 1937 ULH Harley, 1948 Ford sedan, 1960s G HD and KHK, WRs. Flatheads had a breathing restriction over 4000 rpm- the 180 turn from intake into cylinder- but had less valve train mass compared to pushrod engines so cam profiles could be quicker opening. Heating problems noted on Ford V8 - 6 cylinder inline didn't have exhaust crossing middle of cylinder bank and water jacket on exhaust manifold would help cool- still used on marine engines. Pollution laws getting some but a dual spark plug, HEI type ignition, lean fuel mix, and improved rings and slightly tighter piston/cylinder clearance can get through most emission laws now- may not in future. Flatheads were a compact engine design, when Chrysler went to OHV 6 in late 60s to replace flathead they had to slant the engine to fit in car body designed for flathead engine- the 'slant six'. 7 to 1 compression with a slant popup piston, relieved block at valve area and 90 octane gas was working fair, 6 to 1 or so with 80 octane gas common- Ford 9N was about that. Engine casting of a simple block and a small OHC head now a bit cheaper than casting multi cylinder block with valve design next to cylinders and simple head- especially if engine expected to run to 6000 rpm. some OHC Jap engines running 8000 rpm and short runs higher. HD KRs could hit 6000 rpm easily, pulled about 1hp per cubic inch- 45- for class C racing, but these were running high octane leaded fuel and were getting toward limit of design. RN

 

[Mathias NY]

I don't think compression has been mentioned yet. People may dispute this arguement, but there is some logic to it. The the pressure the compression stroke holds the valves on OHV engine closed. A side-valve engine relies completely on spring force to seal the combustion chamber.

Therefore on a flathead engine, the higher the pressures in the engine, the stronger springs you need to hold the valves closed. On an OHV engine, higher pressures can be acheived with the same spring force.

 

[Anonymous-0]

Sure I will dispute it, because there is no logic in you statement. Pressure is equal everywhere inside the combustion chamber. Using your reasoning, if you have a flat tire and the valve stem is up, when you inflate it the tire will never come up???????????

 

[Walt Davies]

WHAT????????

Walt

 

[Anonymous-0]

I trust your answer was in response to the original question of what ended the Ford flathead V8. Ford ended the flathead with the '53 run and already had an OHV V8 in their '54s. I really think it was the other way around as Chev saw the ridiculous position they were in offering only a straight six, which Ford also offered.

 

[Ken 46]

Flatheads don't breathe as well as the OHV engines. they were efficient up to a point
Ford discontinued the Flathead in 1953, except for Canada who put them in cars and trucks in 1954.
Also the heating problem was another dislike of the flatheads

 

[ohio]

more compression = less flow because air must flow across top of block to get to the valves.

 

[Anonymous-0]

Ford flathead V8's were offered from 1932 thru 1953 model years. Henry and Edsel, after their famous day long meeting on Dec 7th, 1931, made the bold decision to go to V8 power. This was two years after Henry had ordered every V8 engine available sent to Dearborn for testing. In the six month period prior to Dec 7th, Ford had tested over 30 of their own design. All of them were rejected by Henry. Ford told Charlie Sorensen, his production genious, "Charlie, spend money until it hurts". Charlie did. Still, the thing had to be cheap enough in the long run to sell, car and all, for a price of $450-650. In order to do that, it had to be made in one piece and come down the Rouge line at a rate of up to one per minute. The spectacular pouring furnace that Sorensen commissioned was the wonder of Detroit. Problems in the first year of production were legion,cooling, lubrication, etc., but by about '33-34 the engine was pretty much the same package that the '53's used.

 

[Gene Davis (Ga.)]

When did GMC ever have a flat head??

 

[Pappy]

It would seem to me that you could open the valves wider on a valve-in-head than on a flat head, thus giving better flow.

 

[Anonymous-0]

We built a boat from plans offered from Popular Science. We built a 7X Hudson with stock Hudson performance parts - overbored it to get about 320 cubes. The hudson was a 12 port block- one port for each valve, no siamese ports. We had a lot of fun passing it off as a Grey Marine Engine. It was a cracker box design hull and would do 60-65 mph not bad for 1956.

 

[Sunny 4 Acres]

I never expected all these replys. I have a mobile ingersoll rand air compressor and a mobile hobart welder all with inline 4cyl flatheads. Never once had a overheating problem. I also have a Lull forklift with a flathead dodge motor in it and it has never overheated yet. Maybe I am not working it hard enough

 

[ken in texas]

I loved the flatheads ,but one problem with the v8 was the exhaust went throught the water jacket side of the engine.On four and six cylinder engines,usually the intake and exhaust were on the same side of the block and exhaust did not go throught the water jacket as on v8.therefore engine ran cooler ??????????

 

[Janicholson]

Some GMC trucks used the Oldsmobile flathead six in 1937 Wikipedia.
Other vehicles and farm equipment powered by GMC had their own engine series. JimN

 

[Allis chalmers 6]

Why did the flathead have trouble with oil burning. I was told most flatties did not make it past 75000 miles before they were using oil. What was the reason for that?