engines of yesteryear

F Head engines.
I have had experiences with three different F head engine types.

1/ the Willys hurricane motor used in CJ jeeps from 1954 to 1972.
I have driven and repaired extensively both the Willys Go Devil side valve and the later development of that motor the Hurricane.
Willys were looking for a way to increase the out put of the Willys side valve motor and successfully done it by converting the block and head to overhead inlet.
Horse power went from 54 to 72 horse power.
In the bush I like both motors very much for the long stroke torque which only a side valve can deliver........both versions of the motor sounded and drive very much the same.
The hurricane F head just had a good spread of power from top to bottom.
They have good interchangeability of parts......the inlet valve was very large and was subject to some wear due to the fact it formed a great part of the combustion chamber and therefore pressures.
The hurricane is heavy and likes to drink fuel if it is pushed hard.

2/ the Rolls Royce B series motors made in 4/6 and 8 cylinder versions and used mostly in military vehicles, but was also extensively used in civie vehicles including Rolls Royce cars which also included the most exclusive rolls of the lot .....the phantom 4.
The 8 cylinder motors are sort after by people to hot them up to make Bentley specials....racing sports cars.
80% interchangeability of parts thought out the engine series.
Originally designed as a tuff military truck only engine in the days before diesel took hold it was designed last 100,000 miles before rebuilds with another 80% life after that with successive rebuilds.
Designed to run at full power for days without signs of wear after strip down running on 80 octane unleaded fuels.
In some applications it would run with boiling water cooling system over heat at full power with out failure .
It was designed to be started in minus 50c and run to plus 50c temps ...again without failure or wear.
I know in the straight 8 cylinder motor it has a extremely wide power spread and while on paper out put is not that great.......the way the motor delivers that power makes it punch above its weight in many ways.
Available in wet or dry sump and some versions were designed to run up 2 mtrs under water......not bad for spark ignition motor.
The Rolls Royce cars fitted with this motor were noted for performance and smooth running for there day.
3/
Rover 4/6 cylinder motor.
My personal experiences is of the 2.6 litre motor as fitted to series 3 landrovers.
I found nothing wrong with this motor, but did notice a great difference is build quality from the factory.....some would go hard and others not.
They delivered the power Ok , but did not have the robust construction of the 2.25 litre OHV 4 cylinder motor.

F head motors were used on Harley Davidsons and a few other brands of early cars.
They nearly all suffered from large combustion chamber surface areas which leads to poor fuel economy and heat release into the cooling system.
The location of the exhaust valve usually near the side of the cylinder would distort the cylinder at high power loadings and limit the power that could be produced( much like full side valve motors)......other wise a reasonable design if done right.

Willys Hurricane motor.
Tall and much heavier than say, a Holden red motor.
It is a fantastic motor for the bush.
https://www.aulro.com/afvb/images/im...017/08/310.jpgfheadr by john smith, on Flickr

https://www.aulro.com/afvb/images/im...017/08/311.jpgfheadl by john smith, on Flickr

These pic below are the Rolls B series
https://www.aulro.com/afvb/images/im...017/08/312.jpgF-head-RR-B60 by john smith, on Flickr

https://www.aulro.com/afvb/images/im...017/08/313.jpgrolls royce B81 by john smith, on Flickr

Note the head gasket design
https://www.aulro.com/afvb/images/im...017/08/314.jpgB81 head gasket by john smith, on Flickr

The Rover F head 6 cylinder.
https://www.aulro.com/afvb/images/im...017/08/309.jpgF-Head-Rover-3-litre by john smith, on Flickr



If you want to know more ...here is a good link.

Automotive History: The Curious F-Head Engine

Ron

The 'F' head was used for various reasons by different manufacturers and at different times.

In early engines, with non-detachable cylinder heads, overhead valves meant you had to remove the block to do a valve grind - and in those days valve grinds were frequently well under 1,000miles. This rapidly led to the popularity of side valve engines, where you could have a removable pug above each valve, one of which usually sported the spark plug. But this meant the inlet and outlet valves were competing for space both for the valves and their manifolds etc. You could have them on opposite sides, and some did, but this meant two camshafts with all the costs of that.

Manufacturers rapidly woke up to the fact that you could put the inlet valve in the plug above the exhaust, enabling you to have both valves larger, and separating the manifolds more easily. This is the setup I first encountered, with a Reo from the early twenties.

As detachable heads became more popular from Edwardian times onward, the layout became a popular scheme particularly for UK manufacturers, where the use of RAC HP rating for tax purposes encouraged long stroke engines. The corollary of long stroke is small bore, which means lack of space for valves regardless of whether you put them both alongside or both in the head. So quite a few did both, as far as I am aware, invariably with the exhaust side and inlet overhead.

Rover's unique design, by thinking outside the square and having a tilted junction between the head and the block, with the combustion chamber shape defined by the shape of the block around the exhaust and the top of the piston, was able to achieve what is effectively a a crossflow hemispherical combustion chamber as well as the turbulent mixing from the piston to head clearance of almost zero for half the piston area.

The Willys engine is an interesting case. Faced with the need for a more modern engine as the US awoke in the 1950s to the fact that the rest of the world was mostly using overhead valves, but lacking in capital, they managed to convert their 1930s side valve engine into an IOE engine and retain the same block casting, as well as quite a few other bits. I doubt the fact that the Landrover had used an IOE engine since its inception had anything to do with it - Willys was probably only marginally aware of the Landrover's existence, justifiably, in one sense, as there was little trade between dollar and sterling currency areas.

Quote:

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Not MG, but I suspect the same engine, a friend of mine's father had an OHC Morris six built around 1950, and I know there was a Wolseley version as well.

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Yes there was. The whole family was like some inbred tribe! Wolsey, Morris, Austin, Riley, and then Lord Nuffield and his merry band of men. There were OHC engines in 4,6 & 8 cylinder guise. But none of them retained the vertical drive dynamo. At first they employed a straight shaft, and later a chain drive.

Quote:

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Originally Posted by JDNSW

The 'F' head was used for various reasons by different manufacturers and at different times.

In early engines, with non-detachable cylinder heads, overhead valves meant you had to remove the block to do a valve grind - and in those days valve grinds were frequently well under 1,000miles. This rapidly led to the popularity of side valve engines, where you could have a removable pug above each valve, one of which usually sported the spark plug. But this meant the inlet and outlet valves were competing for space both for the valves and their manifolds etc. You could have them on opposite sides, and some did, but this meant two camshafts with all the costs of that.

Manufacturers rapidly woke up to the fact that you could put the inlet valve in the plug above the exhaust, enabling you to have both valves larger, and separating the manifolds more easily. This is the setup I first encountered, with a Reo from the early twenties.

As detachable heads became more popular from Edwardian times onward, the layout became a popular scheme particularly for UK manufacturers, where the use of RAC HP rating for tax purposes encouraged long stroke engines. The corollary of long stroke is small bore, which means lack of space for valves regardless of whether you put them both alongside or both in the head. So quite a few did both, as far as I am aware, invariably with the exhaust side and inlet overhead.

Rover's unique design, by thinking outside the square and having a tilted junction between the head and the block, with the combustion chamber shape defined by the shape of the block around the exhaust and the top of the piston, was able to achieve what is effectively a a crossflow hemispherical combustion chamber as well as the turbulent mixing from the piston to head clearance of almost zero for half the piston area.

The Willys engine is an interesting case. Faced with the need for a more modern engine as the US awoke in the 1950s to the fact that the rest of the world was mostly using overhead valves, but lacking in capital, they managed to convert their 1930s side valve engine into an IOE engine and retain the same block casting, as well as quite a few other bits. I doubt the fact that the Landrover had used an IOE engine since its inception had anything to do with it - Willys was probably only marginally aware of the Landrover's existence, justifiably, in one sense, as there was little trade between dollar and sterling currency areas.

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The Rover motor tried to over come the side valve draw back of the exhaust valve and port heating up the side of the cylinder wall and distorting it under high power out puts.
By canting the exhaust valve over tended to lesson the effect of uneven heating of the top of the cylinder.
Doing that limits the size of the exhaust valve and causes other problems.
Mercedes played with many experimental slanted head inlet over exhaust designs similar to the Rover engine.
The B series Rolls got over the problem by having the water jacket between the exhaust valve and the cylinder.........but that lead to a very long combustion chamber and high fuel consumption though heat loses to the cooling system........fuel burn didn't worry most Rolls Royce owner or the military.
The Willys motor used the same exhaust valve as its earlier full side valve version.
It never appeared to have any major precautions for the higher power out put other than a exhaust valve rotator.
Both full side valve and IOE versions could crack the block......may be a sign of the extra power and cylinder/ block uneven heating and expansion.

It is interesting to note both the Rolls and Willys motors have water heated manifolds and I think the Rover 2.6 litre at least did too.( 3 litre I think was different manifold)
The Rolls and Willys to me to drive are true side valve motors because they behave as such and deliver the torque down low where it is needed off road and around town to save gear changes.
The Rover motor to me never delivered that sort of power, but behaved more like a over head valve motor.
All three could turn at reasonable revs for their day too.

You guys have some fantastic knowledge of motors/history,, thanks for sharing.
Wish I'd been able to read this before I went to the Rob Roy hill climb yesterday.
There, there were some pretty awesome looking old pieces of machinery running around, including quite a few old MGs and Lancias (??), very strange looking units, but geez, some of them could move [biggrin]

I presume the Lancias you refer to were Lambdas. These had a narrow angle V4, not really a Vee engine in the usual sense, but with alternate cylinders angled a little so that they can be closer together, so as to make the engine more compact.

These cars were also pioneers in other areas - they were probably the first car built in significant numbers with independent front suspension, and also the first with integral body and chassis.

John

John I'm not sure to be quite honest,,, one was rather weird looking, rather tall I thought, with what seemed to be a domed top/head section. It was specifically a racing car, a replica in this case, hopefully Tom (Greyghost) will remember some more specifics of it as he was with me, I'm not sure if Kyle (alien) was with us at the time.
Im sorry, but like always, I had a camera there, my phone was with me, but just got carried away chatting, looking, and being a bit gob smacked to remember to take pics. [bigwhistle]

See Lancia Lambda - Wikipedia