Ok, I have a few questions:
1. what is a long/short block?
2. what is a "tall" deck?
3. How exactly do open plenum and closed plenum intakes differ?
4. What are the planes in single+double plane intakes?
5. What are angle heads?
6. why don't the newer engines use solid cams?
Thanks!!! I really appreciate it!

 

youll learn the basics in time, im still learning :D never be afraid to ask and anyone please correct me if im wrong on something.
1. a long /short block is how I would describe what you get when you order a crate motor. there are short block motors, which are essentially bare blocks with all bearings installed and rotating assembly(crank, piston, rods, etc) installed. a long block has everything a short block has but aslo includes full heads, oil pan, cam and lifters, essentially everything that is inside the engine block itself. then theres turn-key engines which have everything the long block has but also includes the things "outside" the engine such as intake, carb, fuel pump, valve covers, air cleaner, wires, spark plug, oil filter etc. the main accessories if you can call them that.
2. a "tall deck" refers to the deck of the engine, which is essentially the flat surface on the top of the cylinder bank that you bolt the heads to. a taller deck will allow for a longer stroke in the engine by providing a taller cylinder.
3. not too sure about how the plenums will change engine performance. cant help ya here
4. again im a little fuzzy on what the planes are. as far as i understand its sorta like a horizontal divider, but i could be totally wrong. the single plenum is usually better for a race application, ie high rpm and high hp and the double is better for lower rpm and more torque
5. angle heads are heads that bolt to the block of the engine at an angle, such as 18 degree or 23 degree, etc. by changing the angle you affect the way the valves flow into the cylinder and also how the spark plug is angled.
6. imho the newer cars dont use solid cams because of noise/reliability/convenience.
please someone correct me if im wrong on these. thanks! :smash:


[Modified by Yellow79, 3:58 AM 12/16/2002]

 

I dont think newer cars do use solid lifters. mabey only a few but im not sure. All the engines ive dealt with on newer cars were hydrolic.

 

Short block is a block with all internals (crank, rods, pistons, etc.) with no heads, and a long block comes with heads.
A tall deck refers to basically the length of the bore and a taller deck allows you to run a longer stroke.
As far as I know an open plenum has no divider plate under the carb seperating the left and right bank of cylinders where as a closed plenum does.
A single plane intake like the edelbrock victor junior has a straight shot from the carb to every cylinder where as the dual plane is basically like a 2 story house (2 planes). The single plane will give you a lot more upper rpm power where the dual plane will give you more torque (more street friendly).
When you look at a cylinder head if the spark plugs stick out at a 90 degree angle they are straight plug heads where as angle plug heads have the spark plugs at a 45 degree angle.
Solid cams make a lot of power but with that they are high maintnance, as in they need to have the valves adjusted a lot more frequently compared to hydraulic setups and on top of that solid cams will set off the knock sensors on newer EFI cars.

 

You did a pretty good job Yellow79... kudos!

I'm also a little fuzzy on #4 with dual & single plane intakes. Every group that I have contacted has told me to go with a single plane intake with this engine set-up(Dart included), but I'd like to know the difference too. Hopefully there are some carburator/intake experts to answer the question. If one does answer I have a question about porting/polishing.

Do you also polish the center bowl or just the runners? When I ported/polished my intake on a Super Gas car I also polished the center section. Did that semi-defeat the purpose since G-Force would just push all that fuel to the rear cylinders that much quicker with it being slick?



[Modified by bgrice, 4:15 AM 12/16/2002]

 

1. short block is a block with internal components (pistons, crank, etc) installed. May or may not include the cam and cam chain.

2. long block includes the short block plus heads, pan, and timing cover. in some cases, the intake manifold and other pieces are also included.

a tall deck block is taller than a standard block. taller than standard blocks were often used in heavy duty trucks to allow for longer strokes and longer rods and are popular with racers for the same reasons.

3. an open plenum intake (aka single plane) has one large plenum that feeds both cylinder banks. A closed plenum intake (aka dual or double plane) has two separate plenums, one for each bank.

4. planes refer to the plenum(s). on a typical manifold, one plenum is above the other, hence the term "plane"

5. angle plug heads? heads who's spark plugs go in at an angle as opposed the the more traditional straight in. They also make SB Chevy heads that have narrower valve angles than the standard 23º.

6. solid cams require more frequent adjustment and are noisier than hydraulics. Long maintenance intervals and less noise are selling features for new cars.

 

garagedweller2,

There is a pretty good description of the various types and benefits of intake manifolds in "Rochester Carburetors" by Doug Roe, pages 102-108. This paperback is in print and should be in the chain bookstores (might try the library as well.)

When the intake manifold moves the fuel/air mixture from the carburetor to the cylinders, one job it has to do is maintain the velocity/turbulance of the fuel/air mixture in order to keep the fuel droplets in suspension. If the velocity of the fuel air mixture is too low, then the fuel droplets in the air separate out and deposit on the surface of the manifold. If this happens then the Air/Fuel mixture is not optimal and engine performance suffers, as some cylinders get the proper air/fuel mixture, while other cylinders run "too rich" or "too lean".

Another function of the intake manifold is to keep cylinders from "robbing" each other of air/fuel. If two cylinders are close together, and the firing order is one right after the other, then the first cylinder will "rob" the second cylinder of air/fuel. For example, on a Chevy V-8 the firing order is 1-8-4-3-6-5-7-2. Cylinders 5 and 7 are adjacent to one another in the block. Without proper manifold design, 5 robs 7.

The different manifold types are used to optimize engine performance in a particular application. A two-plane manifold is generally better for the street where MOST of the demands on the engine are at low and moderate engine speeds. The two-plane manifold passage is a more restricted design, and keeps the air/fuel mixture moving at speeds such that the fuel droplets remain in suspension.

Remember, if the mixture slows, the droplets come out of suspension and the air/fuel ratio is not optimal. When the passage size is increased, the air/fuel mixture slows down. This is why a single-plane intake manifold (large passage sizes) generally does not have good low and mid range performance. This is also why a single-plane intake manifold generally has better high end performance, as the carb and manifold maintain optimal air/fuel velocity without the flow restrictions that a two-plane manifold has a high rpm. Your choice of manifolds depends on the engine's intended use.

This is also why modern cars use computer controlled fuel injection. The computer delivers the optimal fuel/air ratio to each cylinder at any engine speed.

Lots of other factors on manifold design - excellent question - hope this helped.

 

thanks, I'll try to manipulate what you said!

 

Bgrice: thanks!