The Stovebolt Site Forums The Shop Area General Truck Talk what the heck is an L6??

When my uncle, a Chevy mechanic used to refer to our ol' stovebolts he just called it a "6". Everyone knew what that was, all the way up until the 80's a Chevy 6 only meant one thing, an inline 6-cylinder motor. Then, when the V-6's came along (I know about the early GMC's) I guess there had to be some way of differentiating between the two so it was called the I6. I just assumed that meant an Inline 6. Now, I see people reffering to them as L6. Where does that come from, and what does it mean?

inLine

I am pretty sure it means longitudinal 6.

Sean

[QUOTE]Originally posted by 1969c10:
I am pretty sure it means longitudinal 6.

Sean [/QUO
There is that $10 word,longitudinal ,I remember it now from way back there, a GM tech school instructor used it in the early-mid-'80s, they were still using them in trucks at the time,Brian

O.K., now, lets see, where did I put that dictionary?

As I recall, a flathead engine was called a 'L' head engine. If you have a L-6, it would be an old flahead Chrysler or Willys (4) or who ever, but not a Stovebolt or any other overhead valve engine.

The cylinder to valve relationship makes an inverted 'L'..hence the name!

Stuart

Come to think of it, I remember that L-6 designation for the old flathead sixes. So, is calling a 'bolt an L-6 a misnomer?

The 235 is referred to as an L-6 in the original shop manual. At least in 1960.

I was just at the Towe Auto Museum in Sacramento and I belive that the old Chryslers (I could be wrong about the make, but it wasn't any GM brand) had "L" heads, which seemed to refer to the cylinder valve relationship. I believe that this was not restricted to only 6 cylinder engines, but was also used in reference to straight 8's. Now I gotta' do some internet surfing to find out for sure, or I won't be able to sleep tonight.

I've always known them as 'straight' or 'inline' sixes.. altho Chrysler, just to be different had a 'slant' six.. which looked like a regular straight 6 kinda tilted to one side.

Buick had that straight 8 or 'fireball eight'.

"L" means linear as rather than V-shaped or opposed. Flat heads could be "L", "T" or the hybrid "F" configuration. The engine was not called by these letters without being followed by the word "head," ie. L head engine, T head engine or F head engine.

O.K. Here's what I found on the internet.

"L-head (flathead) refers to the pushrod valvetrain configuration in which the valves are placed in the engine block beside the pistons. The design was common on early engine designs, but has since fallen from use."
"The line of intakes along the side of the engine lead to the name L-head, due to the cylinders having the shape of an upside-down L. This configuration is also known as sidevalve, as the valves are located beside the cylinders."
"Although L-head inline 4 and 6 cylinder engines were frequently used for automobiles, tractors, etc., the best known L-head automotive engine is the early 20th century Ford V-8, which has both sets of valves (intake and exhaust) located on the inside of the "Vee," and which are all operated by a single camshaft located above the crankshaft. A serious concern is that the exhaust follows a more complicated path to leave the engine. This virtually guarantees that the engine will need an unusually large radiator to avoid overheating under sustained heavy use."
"Due to the heating and efficiency problems, L-head engines fell from high power uses such as aircraft engines fairly quickly, prior to World War I. They lived on for some time in the automotive world and were used in the World War II Jeep, for instance."
I also found that L-head type engines including V-8's were used in Cadillacs at least through 1929.

I love this site! It's like going back to school only the classes are fun! Thanks for all the input. Something bigmacdaddy said in this thread got me to looking at the old manuals in the tech tips section of this site. Sure enough, in the 1960 supplement, the 6 is referred to as an L-6. No explanation as to what that means, but there it is, right in the official Chevy manual. I like "linear". Anyone else?

Cadillacs V8s were L-heads until 1949.

i remember reading about what baldy said the L, T, and F valve configurations in a old auto manual years ago. best i remember the L head had become the most popular and was what was used most. this was a OLD manual.

I could go with linear


Sean

If the question was about an L7, we wouldn't have as hard a time figuring out the answer.

I don't know about anyone else, but that describes me describing my truck to anyone who isn't familiar with stovebolts or old trucks.

I'm voting for linear, its what my 63 and 66 manuals refer to it as. It also calls the L-4 diesel "linear."

Here is how I have always thought it worked.
The term L head refers to the valve configuration and the shape of the combustion chamber in relation to the cylinder bore. L head, I think, refers the the shape of the chamber with the intake and exhaust on the same side... valves both on one side of the cylinder. Hence the vertical arm of the letter L is the cylinder bore and the lower arm of the letter is the shape of the chamber.
Flat head: ie old Ford V8s, early Chrysler 6 cylinders, Model A and T Ford 4 cylinders and many others, were L heads too.

A hemi V8 has a half ball shaped chamber, usually (early Chrylser) one central cam and very long exhaust rockers to activate the exhaust valves. A double overhead cam engine has the same chamber and valve relationship with no rockers but almost direct contact between the cam lobe and the valve stems. One cam for intake and one for exhaust.(Many European and Japanese engines)
An F head (I think early Jeep engines had these) had an overhead valve (intake I beleive) and an in block exhaust valve.
Please don't think I am presuming to be an expert.... this is just the way I understood it over many years and I could be very wrong.
Comments?
Ter

Ok,L,T or F head I understand.What about the Buick V-6 "nail head".Any Harley riders remember Pan Head or Shovel Head ?

That's what happened to your head if you didn't wear a helmet.

What about the knuckle head? That was my fave.

Hey HevyHauler,

If we're talking Harleys then we forgot about pan heads and shovel heads. LOL

Sean

Don't know anything about Harley's but I thought the Nail Head Buicks were older V8s of the 50's, 60's and the name was describing their small valves ie: like 'nails'??
Ter

Thanks Ter,Never knew why they called them "nail heads". I thought they were V6's not V8's, but don't remember.
Brendan M,I thought that was called "road rash" lol

I always refer to them as a straight 6. gotta remember chrysler had a slant 6 in the 60's