Cars and Tuning

In this section we will try to put engineering datas and other things that help you in the task of “meter mano” to your car.

Tables of conversion of measures.
Basic concepts of power, torque, etc.
Basic slight knowledge of electricity.
Like determining the center of gravity of a vehicle.
Calculation of unitary piston displacement, volume of the combustion chamber and the index of compression.
Other calculations that are important.
Etc, etc and but etc.

ADVANCE PAYMENT: “Cálculo of the volume of the combustion chamber - Index of compresión”

Calculation of the unitary piston displacement:
V = 0,7854 x D² x C
where unitary V = rolled, D = diameter of the cylinder, C = race of the piston.

Calculation of the volume of the combustion chamber:

V
vc = ——–
IC - 1

where vc = volume camera combustion, unitary V = rolled, IC = compression index.
(This formula allows to know the volume the combustion chamber knowing the compression index; or to know as must be this volume for a certain index of compression).

Calculation of the compression index:
V + vc
IC = ——— -
vc
where IC = index of compression, unitary V = rolled, vc = volume of the combustion chamber.

CONVERSION OF MEASURES

1 cm = 100 mm 1 meter = 100 cm 1 meter = 3.281 feet
1 meter = 1.093 yards 1 0.03937 cm = pulg. 1 pulg. = 2.54 cm
1 foot = 12 inches 1 yard = 3 inches 1 mile = 1.609 km.
1 cm² = 0.155 pulg² 1 pulg² = 6.452 cm² 1 pie² = 0.0929 m²
1 m³ = 35.31 pies³ 1 cm³ = 6.6102 pulg³ 1 pie³ = 0.0283 m³
1 liter = 1dm³ 1 liter = 0.2642 American gallon 1 liter = 0.22 imperial gallon (ingles)
1 gallon American = 3.79 liters 1 gallon imperial = 4.545 liters 1 dot = 0.473 liters
1 kg = 35.27 ounces 1 kg = 2.2046 pounds 1 ton = 1,000 kg.
1 Kg./cm² = 14.22 lb/pulg² 1 lb/pulg² = 0.0703 Kg./cm² 1 kgm = 86.786 lb/pulg.
1 kgm = 7.233 lb/pie 100ºC = 212ºF 0ºC = 32ºF

1 kCal = 1,000 lime 1 kCal = 427 kgm 1 kCal = 4,184 Joule
1 kCal = 3 BTU 1 0.252 BTU = kCal 1 CV = 0.736 kW
1 CV = 0.987 HP 1 736 HP = 1.014 CV 1 CV = Watt
Fractions of pulg. = mm lb/pulg² = Kg./cm²
1/8 = 3,175
1/4 = 6,350
3/8 = 9,525
1/2 = 12,700
5/8 = 15,875
3/4 = 19,050
7/8 = 22,225
1 = 25,400
1 ½ = 38,100
2 = 50,800
1 = 0,07
5 = 0,352
10 = 0,703
15 = 1,055
20 = 1,41
30 = 2,11
40 = 2,81
50 = 3,515
100 = 7,03
500 = 35,15

Power = HP or CV Torque = kgm rpm = RPM
CENTER OF GRAVITY::::
Like determining its space location (XYZ) single with a meter and a balance.
We must take some measures in (mm):
EE: Wheelbase measured between the centers of the wheels front and back of the same side.
TR: Trail or distance measured between the centers of the bands of bearing of the wheels of the same axis.
RA: Radio of the wheel measured between the center of the wheel and the ground.
We must make some pesajes in (kg.) with a balance or appropriate scale:
PT: Gross weight of the vehicle.
DH: Weight of On guard horizontal the front train.
LI: Weight of On guard horizontal the left side.
I GAVE: Weight of the inclined front train - the height of the back train will have to be the fourth part of the wheelbase, will give an inclination approximated of 14º30″.
For the pesajes (except first) to consider that if the surface of support in the balance or scale is different from the level of the ground, will have to lean the wheels that are in the ground on which it places them at the level of the balance, and for inclined pesaje also it will be necessary to have it in account.
Having the measures and weights we determined positions XYZ of the Cg in (mm):
X: Distance of Cg with respect to the back axis.
X: DH*EE/PT
And: Distance of the Cg with respect to the left side.
And: LI*TR/PT
Z: Distance of the Cg with respect to the ground.
Z: ((((I GAVE - DH)/PT)*EE)*3.873)+RA
That it means that the motor “respire mejor”
When saying breathing we talked about the capacity that has the motor to receive combustible air mixture in the cylinder and also to evacuate exhaust gases after the combustion. And this has direct relation with the yield.
As they can appreciate this subject also it is related to the admission manifold and escapes, with the crossing of the distribution, the diameter of the valves, etc.

We go by parts:

- Angulo of seat of the valves

This angle has certain advantages and disadvantages depending on its value:
- For angles of 45º (but used in series motors) valves of greater thickness in the area of the seat can be used being able to use the material manufacturer of intermediate quality, and managing to make a closing of the combustion chamber of safe form in spite of the high temperatures, but this value also sets up greater obstacle to the passage of gases or the mixture.
- For angles of 30º a better flir of gases or the mixture is obtained, but the closing of the combustion chamber is debilitated since the valve will have little thickness in the area of the seat, and this with the high temperatures can cause deformations and breakage.
- Then the ideal is to adopt angles of 30º for the admission valves, that better are cooled, favoring the filling of the cylinders; and to use angles of 45º in the escape valves in order to support the high temperatures.
(the angle of pitch is taken with respect to the plane of the head of the valve, for that reason for angles of 45º the seat in the cover of cylinders will be of 45º also, but for angles of 30º in the valve the seat in the cover of cylinders must have 60º).

In this of the breathing the section of the conduits is very important by where they respectively enter and they leave the mixture and gases, as these conduits are of trunkated cone surface we can use to determine this section the following formula:

For angles of 30º > > S = 3.1416 (0.866 xs I gave to + 0.375 xs h)

For angles of 30º > > S = 3.1416 (0.707 xs I gave to + 0.353 xs h)

(S = section of the conduit/I gave = inferior diameter of seat/h = height of rise of the valve)

To the calculated section it will be necessary to reduce the section to him of the piston rod of the valve.

As we see one of factors that but influences in the formula is rise that it has valve, but as we know that this can bring prepared other problems, is preferable to modify the profile of the levies to be able to improve the filling of the cylinders without having to increase the rise more good, or still diminishing it since to high regimes of turn the inertia and the pressure of the means cause vibrations being this in bad operation and until breakage.
Considering the previous thing we can determine as to calculate whatever the raised one of the levy will have to be diminished:
When the valve is commanded directly by the camshaft the diminution in the rise is proportional to the diminution in the raised one.
But when the valve is commanded by balance beams it can use this formulates:

ba
RL = rh ———
bb

(RL = Reduction in the radius of the levy/rh = Reduction wished in the opening/ba = Length of the arm of the balance beam in contact with the camshaft/bb = Length of the arm of the balance beam in contact with the valve)

The subjects related to this are: Means of Valves - Valves - Distribution - Admission and Escapes

valve overlap or overlaps

This subject is directly related to the subject valves, but we will give some basic concepts.
The distribution talks about the drive of the valves, when and whichever time they open or they close, this has direct influence on the engine efficiency, like which we looked for is greater power we have possibility of modifying the camshaft, or to place one or designed by specialists with varied designs and results, we can buy a camshaft that us of speed or other that us of push to an average regime, also varying the profile of you weigh can obtain other properties.

Classic diagram of distribution.

As general concepts we say that the diagram of the distribution can be represented easily in a circle, knowing the setting that has the camshaft that we have, but if we want it to modify we will have to represent it with the values that we wished.
What matters in this it is the valve overlap or it overlaps or as they want to call it, we will call crossing to droughts; this crossing is the sum of the angle of opening advance admission AAA, with the angle of lag of closing of escape RCE, as these actions occur in the same turn of the crank produce a direct influence on the power and the regime of turn (rpm) improving the breathing of the motor, since during this time the two valves are open simultaneously.
The volumetric efficiency of the motor is the relation between the volume of mixture that enters the cylinder and the volume of this one, then if we increased to this yield the pressure of compression will be greater and will give greater power. The amount of mixture that enters the cylinder depends on the section of the conduit and the valve of admission, but also of the time that the valve is open to the maximum, for that reason whichever greater more effect is the regime of turn of the motor have these values of crossing.

It is not as simple as to cause that the crossing angle is greater, but than will have to study for the specific case of a motor and what it is expected of him.

Here we presented/displayed habitual values of crossing in series motors:

Normal motors Motor expresses
Advance Opening Admission - AAA 5º To 10º 7º To 15º
Retardation Closing Admission - RCA 20º To 35º 35º To 55º
Advance Opening Escape - AAE 30º To 35º 35º To 55º
Retardation Closing Escape - RCE 5º To 7º 7º To 15º

As final consideration we can say that the camshaft agrees to make modify it by somebody of experience, or in its defect to buy one already modified with settings that have well-known effects; attention that a high crossing can cause that the motor very badly works to losses rpm, then if calle” is “de; an intermediate crossing is recommendable so that it has power in all the regimes of rpm and to walk but even.

This subject has much to do with:

The breathing
The completion
The distribution
We are in that and the subject is already ready
“Resortes of válvulas”
Of flat head
Of head of tulipa
Of spherical head
The three basic models of valves

VALVE MEANS

But hard, but soft or double?

Function: The mission of the means of valves (in ahead simply “resortes”) she is the one to maintain supported the valves in his seats of effective way when these must be closed.
Characteristics: They must have the sufficient force stops:
To maintain closed the escape valves compensating the depression in the cylinder in the admission stage that could be taken from 0.6 Kg./cm2 (approx).
In order to avoid “rebote” between the valves and the elements that drive them considering the alternative movement which they have, and the speed of this movement.
But their characteristics must avoid that bounce of the valve against their seat at the time of the closing, which in addition to incorrect operation at high speeds, brings as consequence the accelerated wearing down of several elements affected by the effort which they make these means.
It must be then of special characteristics, not simply means, to have all these virtues.
Material: They must be of resistant material to the torsion of high frequency; generally facts of wire of carbon steel stretched in cold, or alloys of silicosos steel mangano or to chromium silicon with heat treatments.
Double means: Each means have by its material and construction an own frequency of vibration (own frequency) and generally is much greater to the operating frequency that it will have installed in the motor; but in certain conditions it can have vibrations in low frequencies but, harmonic calls that are submultiple of “propia”, and they cause resonance at certain engine speeds, this resonance produces that the valves drive randomly and until they can break the means if at the moment for taking place the extension of the means receives the shock of the levy or balance beam. By the saying previously he is that two means of different diameter and values from tension can be installed, causing that one cushions the vibrations of the other, placing the means with the direction of rotation of the opposite turns.
Another advantage is that if means are broken, the other will avoid that the valve falls within the cylinder, having avoided important breakage. (the positioning of two means never is for obtaining but force).
Others are saying that the means must be in square so that the valves have a route without lateral efforts through the guides.
Knowing the height that must have the means when the valve is closed, will be necessary to measure once placed it and if the measures do not correspond is necessary to calculate the difference and to place a spacer, of commercial sale, between the means and the cover of cylinders whose thickness will be the difference between the real measurement and the necessary one.
This difference occurs mainly so that the valve seats with more depth in its seat causing that the piston rod across has greater length of the cover of cylinders.
A solution would be to rectify the piston rod of the valve to reduce to its length according to the difference between the necessary length for the means and the measured length; but he is not recommendable since the end of the piston rod has a very fine layer of hardened material, then when the sizing can be in the end of the enough but soft material valve, causing a wearing down accelerated and until possible breakage at high engine speeds.
In the covers of light alloy cylinders it is recommended that the means do not touch the cover, interposing between a these steel washer cemented of 0.5 mm of thickness, to avoid that the means can deform or wear away the material of the cover of cylinders.
Finally it will be necessary to place oil detents in all the valves to avoid the entrance of oil to the cylinder by the guides, specially in those of admission, by the depression that is generated in the cylinder in this stage of the cycle, although also by the escape valves oil will enter the cylinder if detents are not placed; this in addition avoids that the compression fugue to Carter by the valve guides.
(the detents lose their properties when the motor undergoes a heating excessive, and nonsingle those of valves but all)

To maintain the temperature in normal values.

We started off saying that the greater index of compression and the regime of high turn cause that heat is generated but in the combustion chamber, therefore is advisable when modifying a motor also modifies the refrigeration mainly in the cover of cylinders, since this one cools off by the passage of the water from the block of cylinders, where already received heat of the shirts; then a solution would be to also increase the diameter of the water conduits in the cover of cylinders and in the block. It will be necessary to have present that after modifying the previous thing there is to the same do in the meeting of cover of cylinders increasing the diameter of the corresponding orifices.
If the modification in the motor is not very important can be solved to the subject placing in the water pump a pulley of slightly smaller diameter, this will imply greater rpm of the pump with respect to the motor having produced a greater water volume in the same period of time.

If the modification in the motor demands but refrigeration, having done the previous thing already, it is possible to be placed in the cover of cylinders, without jeopardizing the oil conduits admission and escapes, communications with the water conduits directly connected with the pump, from this form the cover of cylinders will receive water of the pump directly without it previously receives heat of the block of cylinders.

It will be necessary to analyze for each type of motor the modifications that can be made on this subject, since an excess of refrigeration also is bad for the operation of the motor and its parts.

A separate chapter represents the motors that of series are not cooled to water, like some Citroen or VW for example, also some Porsche and Chevrolet.
In this type of motors the objective will be to increase the volume of air, mainly in la/s tapa/s of cylinders, but without also neglecting the refrigeration of the rest of motor. Generally this type of motors has systems of refrigeration for the oil different from the cooled ones by water, then it will be necessary to analyze as to increase the cooling of the oil in proportional form to the increase of the temperature.

The refrigeration of the oil treats in the section Lubrication, and it is possible also to be adopted for cooled motors to water.

Possible and/or necessary modifications

The block along with the cover of cylinders is the structure that contains and where all the elements and accessories of the motor pay attention, the main function is the one to contain the cylinders where the pistons generate the power with their different phases from the cycle.
There are different types from motors as far as the number of cylinders:
2 - 3 - 4 - 5 - 6 - 8 - 10 -12
and of the disposition of these:
in line, in V, opposite horizontals (to boxer), and in H.

Most of the motors of but of 6 cylinders they are not in line although also they exist motor in line with but of 6 cylinders; those that has 6 or but cylinders generally are in V since it allows to a short motor but and better conditions of operation; the motors to boxer allow to reduce to the weight and the dimensions of the block and also the vibrations and compensate the torsion efforts; the blocks in H are until the single moment made for competition; and on the motors with but of 8 cylinders we can say that there is as much in line as in V and they made for today old cars of series or the competition or some special models makes for.

When improving a motor the block of cylinders will have to adapt to support greater exigencies of yield, the modifications that can be made are the following ones:

To disassemble per to us and asparagus, the water corks and oil.

Polished of the interior of the block

Reinforced of the main line of large stone bench

Rectified of the superior plane (like an option to increase the index of compression)

Threads or modifications in the spirals where it fits the cover of cylinders and in the large stone benches of the crank

To disassemble or to reacondicionar the cylinder linings

Positioning of new shirts (according to the case)

To increase the lubrication in the main line of large stone bench and to reduce the volume in the high part of the motor.

Possible and necessary modifications

There are several things that we must do with the cover of cylinders if “potenciamos” a motor:

To enlarge the holes of passage of the asparagus of adjustment of the cover to the block; since we increased the diameter of the cylinders or the compression index the adjustment of the cover to the block must be greater, and this is obtained with asparagus of greater section, then the holes in the cover by where they pass these asparagus must be but great; the greater section of the asparagus will be in proportion to the increase of the diameter of the cylinders and/or to the increase of the compression index, and the hole in the cover must be of approx 1.5 mm greater than the diameter of the asparagus or per to us.
Reinforcement of per us of fixation of the camshaft or the axis of balance beams, proportionally to the increase of the effort of the means of valves that settle; for this it will be necessary to increase the diameter of per to us that they fix the camshaft or axis of balance beams removing the original ones and installing others of the correct measurement, considering that will be to enlarge the holes through where they pass these in the same proportion always assuring the correct alignment the bolt at issue.
Another modification will be reduced of the surface or the face of support with the block, or to obtain that the cover is perfectly flat, and/or to increase the index of compression; clear that previously we will calculate this and the effect that it will have in the motor. (a peladita as it is said)
Something that few think is that when “hace” the motor of the car and was necessary to reduce the cover of cylinders the compression index changed, and therefore also the settings of completion of the ignition, there are less material in the cover then greater temperature and other etcéteras.
It can be necessary to modify the combustion chambers, to eliminate acute zones that will transform into producing hot spots of detonation and pre-ignition, being treated whenever they have hemisférica form, that is the one of better results; anyone is the form of the camera will be necessary to try to come near best the possible thing to this hemisférica form, considering the position and displacement of the valves and pistons, obtaining of this form to diminish the accumulation of carbonaceous remainders and the best one to flow soon of the mixture and also of the flame of the combustion.
When they send to reduce the cover agrees that they calculate and they indicate whatever want to reduce, or in their defect that the rectifier says to them whatever had to reduce so that it is flat, of there in but they will have to calculate that compression index they have left the motor and to take the corresponding collections.
Something very common occurs in the great motors (6 or 8 cylinders) that use common or normal gasoline, repairs them and also the cover of cylinders by x stoops reason, and if it reduces it has important values soon the motor has ignition problems, that are attributed to him to the carburetion or the own ignition; it is enough with using it with gasoline special or super and solved the problem. Pavada but that happens happens.
In the section Engineering datas there are some useful calculations with respect to the index of compression and determination of the volumes of the camera and the cylinder.

Lubrication

We already know that in a modified motor and/or which it will be put under efforts greater and also greater regimes of turn, it is necessary to control the temperature, but sometimes it does not reach with increasing the refrigeration, subject that treats aside, but also is necessary to act on the lubrication, these are some alternatives:

To increase the amount of oil in Carter, in order to favor the cooling of the oil and with this to guarantee that the oil film between movable parts never disappears and stays in amount and sufficient quality.
According to the previous thing the use of an oil radiator is recommendable that will have to receive oil of the pump and soon to send it to the filter already with smaller temperature. This system is used in several motors of series, but he is not complicated to install it in any motor. The cooled motors to air (by air canalization) generally have oil radiators, as for example Citroen 2CV or 3CV has it behind the trowel of the ventilator.
As they see is not nothing of the other world and it is very effective.
It is necessary to clarify that this oil radiator will have to receive fresh air or in the front of the vehicle if the motor is ahead, or to make canalizations adapted in the back part if is where it is the motor, since the distance of the radiator with respect to the motor will always have to be reduced to avoid falls of pressure by the conduits; that they will have as well to support the pressure of the pump.
Another modification that can be necessary, according to the modification degree that undergoes the motor, will be the one to increase the diameter of the conduits of circulation of the oil.
It is recommended not to increase the diameter of the conduits in more than 2 mm, since the walls of the block or another piece with risks of serious breakage could be debilitated.
The main conduits of the block of cylinders, the oil gallery of departure, and the conduits that go towards each part of the motor, in special will be modified then towards the cover of cylinders.
Also it will be necessary to modify the diameter of the conduits of the crank, the connecting rods and the pistons (without it has them), and also in the cover of cylinders and the drive of the valves.
To consider that this also is necessary to do it in the meeting of cover of cylinders, in the bearings, bushings, etc, but would not have any effect.
Since we will need greater volume oil to maintain the pressure with greater conduits, it will be necessary that the pump provides with greater volume and the limitor valve of pressure of this pump will be calibrated for the new configuration.
The ventilation of oil Carter, (well-known like vent, economizer, etc) is fundamental that he is always free to allow the steam circulation of water, fuel and oil, in order not to allow an increase of pressure in Carter.
Generally this ventilation is redirigida to the admission, has like disadvantage that more quickly soils the carburetor, but also collaborates with the temperature of the mixture that enters the cylinders, of there the economizer name.
In competition motors a system known like “de is used habitually Carter seco” that it is implemented with the positioning of more than an oil pump in series, placed between the motor and a deposit destined to contain the lubricant, one gathers it and the other sends it to the motor.
As it is not the case of a street motor we did not develop the subject in depth

spark plugs, distributor etc.

When modifying a motor we have some disadvantages in the system in charge of producing the spark to inflame the combustible air mixture, these are:

The spark plugs must produce greater amount of sparks, receiving more heat product of greater combustions and the temperature of these combustions, all this in smaller time.
There are two general types of spark plugs: you cold and the hot ones.
For motors of regime of turn and high index of compression spark plugs are used you cold by their greater capacity to dissipate the heat that receive from the combustion chamber and the cover of cylinders; as on the other hand for motors slower and less compressing hot spark plugs are used.
The normal operating temperature of a spark plug is between 600º and 700º, if the temperature very is elevated can produce pre-ignition, and if she is low these they are soiled or they lubricated (fill with paste usually it is said). We can see as the spark plugs in the single motor with watching them are working, if they are black and with grasitud it is because the temperature is very low, if on the contrary we see ampolladuras in the insulator and corrosion in the electrodes the temperature very is elevated; if they present/display an aspect in clean general and with the insulator of amarronada coloration, whenever the completion of the ignition and the carburetion are correct.
Another subject with the spark plugs is the separation between electrodes, the recommendable thing is what the manufacturer of the spark plug says, but if we do not have good results we could begin by about 7 mm of light between electrodes and soon to be reducing after the tests, the minimum light is of about 4 mm. This takes us subject to the following.

The subject of the spark plugs is easily solutionable since different types exist from spark plugs of commercial sale, you cold or I warm up, of one or but electrodes, etc.
In competition a system of double ignition can be used lodging in the combustion chamber two spark plugs favoring the fast inflammation of the compressed mixture, but it is not the subject of this site so we left it so that they consult to some preinn friend.

The ignition coils generally have the capacity to produce spark in amount and quality according to the motor for which they were designed, if the exigency is greater will be necessary to place a prepared coil to produce them in greater amount with good quality; the spark but releases (light of electrodes) is good whenever the power of this one is the correct one, and considering that when increasing the regime of turn we demanded to the coil to produce but tipsy in the same time, can happen that the coil arrives at a point of saturation in which the tension of the spark (voltage) begins to diminish remarkably, without obtaining the power necessary to inflame the mixture with the speed and quality that is needed; let us consider that if we increased the index of compression spark will have to be then of greater power, and if to that we added to him that they must be but tipsy per minute, is obvious that we needed another coil adapted to the motor that we modified.

If we consider that the coil of a motor of 4 5,000 cylinders to rpm must produce 10,000 sparks per minute, they will see that the increase of the turn regime remarkably increases east value of sparks per minute, for example if the same motor turns to 7,500 rpm the coil must generate 18,000 sparks, that would be the maximum limit of a coil normal to produce sparks with good tension. Then to 18,000 rpm is necessary to produce a spark each 0.033 seg. and if the motor has conventional ignition of platinum and condenser, this becomes a little complicated, depending this function directly on the levy of rupture of the axis of the distributor, ordered to open and to close the contacts of platinum. For this problem levies of rupture with different profiles can be acquired, of the calls of fast opening, in which the projections that produce each opening have an angle but pronounced to make it but fast and also determining as it is the time that remains open the contacts, being possible to diminish the light of the platinum to compensate this short time that must remain open the contacts.
But if it is possible to install an electronic ignition east last problem is forgotten.

The systems of automatic advance of the ignition, or are centrifugal or of emptiness, they must be regulated in its performance with respect to the regime of turn and to the combustible air relation of the mixture that enters the cylinders considering the modifications that the motor had.

MULTIPLE And EXHAUST MANIFOLDS

First we must have in account that the manifold are extension of the conduits of valves, or of admission or escapes, and we can make some modifications:

The internal diameter of the admission tubes and escapes of each cylinder will have to correspond with the diameter of the conduit of the valve.

Simple it is polished internal of the conduits of valve and the tubes of admission and escapes for which the air/fuel mixture in the admission, and the exhaust gases do not have resistance in their displacement, improving remarkably the speed of reaction of the motor since we favor this way “respiración”.

The curves of the conduits must but smooth the possible thing, and the crossed distance or must be but similar the possible thing in all the cylinders, so that the breathing is balanced; normally in series motors these manifold is pieces that can polish easily but that they do not have that balance between cylinders, reason why there is a solution for the admission and another one for the escape.

Another option in the admission is the positioning of a manifold that if it has the mentioned characteristics, or modifying the one of series and placing another one of commercial sale; but also it is possible to be installed but of a carburetor, and tying these to manifold different.
For example in a motor of 6 cylinders in line we can install two semi-multiple to feed 3 and 3 with two carburetors; or to install 3 semi-multiple to feed 2, 2 and 2 with three carburetors. The different combinations are possible as long as also it is possible to acquire the necessary elements.

For the escape but the important one it is that there are not obstacles in the exit of gases, reason why will have to be polished and mainly to have for each cylinder the same distance or route, so that the gases of the cylinder nº1 for example, is not with a gas cork of the escape of another cylinder. There is variety of manifold of escape of commercial sale of good yield; only with the positioning of a manifold of these characteristics we can you sensibly increase the engine power without other modifications.

Speaking of breathing we are going to say that the air cleaners must like fundamental function avoid that any particle of material stranger enters the cylinders, therefore is advisable not to retire it if outside possible, since this must like aim prolong the life utility of the motor and maintain the cleaning of the fuel system. To have present which only the dust of the atmosphere that enters the cylinder acts like a paste emery in the carburetor, the valves and the cylinders, so while less strange things within the motor better; there is variety of filters of commercial sale that have very good qualities cleaning the air that enters and not setting up greater obstacle.

With respect to the escapes, they will have noticed that if the sewer, silencer or precamera are broken (hole) loses much power and reaction the motor, is possible to clarify that by but which the manifold that they equip motors of series do not have the best benefits, are designed by experts and for a determined operation, when they change these conditions simply are not acting its as correctly. Then they think that the diminution of power by breakage of the escape is approximately the gain that we can obtain placing a manifold of escape of high benefits.

In many manifold of admission there are water conduits to preheat the mixture of air/fuel, and generally such conduits in manifold of oriented design but to the yield do not exist that to the comfort.

BEARINGS

General aspects - Material - Adjustment

The bearings that are used in series motors are of materials that support in general a load of 140 Kg./cm2. Antifriction or white metal is denominated of metal. They can be of different alloys with base in the lead or tin.

For motors of high index of compression and regime of turn another type of alloys denominated pink metal is used, different alloys with base in receive-seals with lead or bronze-seals with lead, this type of alloys allow loads of the order of 250kg/cm2; generally this type of bearings is used in combination with cranks and others of greater hardness.

Also another type exists that counts previously on almost all the advantages of the mentioned ones, and are those of aluminum and their alloys, that can arrive at a 450 resistance of Kg./cm2, in this case are not necessary that the crank has a hardness outside the normal thing.

Like general information on the subject, we can clarify some properties that must have the bearings:

They do not have to wear away nor to line the surface of the axis that they support, although the oil flow is interrupted between both materials by breakage of the oil pump or another reason.

They must support temperatures superior to 150ºC without deformations that allow to displacement of the layer antifriction.

They must be the sufficiently soft thing like so that the solid particles become engraved in them that can contain the oil without damaging the axis which they support.

They must resist the corrosive action of the acid presents in the oil.

They must be of measures and forms identical that the original ones that comes with the motor.

Finally we must know clearly that if the crank or the connecting rods were modified, in wide of the trunnion or the orifices of lubrication, it will be necessary to adapt the bearings to these modifications, placing bearings of the wide one of the trunnion and/or making the orifices extra that the done modifications demand.

The games of adjustment of the bearings depend on the material:

Material Bearing Large stone bench Connecting rod
White metal to 0,001 mm by mm of diameter up to 50 mm.
b 0,0005 mm by mm of diameter after 50 mm 0,0005 mm by mm of diameter.
Pink metal to 0,0015 mm by mm of diameter up to 50 mm.
b 0,0013 mm by mm of diameter after 50 mm.

Alloy Aluminum to 0,003 mm by mm of diameter up to 50 mm.
b 0,002 mm by mm of diameter after 50 mm.

CIGUEÑAL And STEERING WHEEL

What we can modify and so that!

We already know that the crank has the function to transform the alternative linear movement of the piston into turn movement.
As far as steering wheel of inertia, (so that therefore it is called) is to accumulate energy to give it in times dead that there is between each combustion, of that form giving greater continuity of turn to motor (this effect loses importance when it increases the number of cylinders), this leaves us in clear why the steering wheel must be united to the crank but the firmly possible thing.
The possible modification in these elements, for the case of modifying a series motor, would be only to reduce the weight of both pieces, if the modification in the motor is but important it is perhaps necessary to modify the dimensions of the crank, worse is not but the common thing in a street or series car.
In case of these pieces, we consider movable which to the being they have inertia, that directly is related to its weight, then if we want a motor that accelerates express must have movable but light pieces so that this weight does not act like retarder of the acceleration.
It is necessary to establish whichever weight will be eliminated of the crank and that forms will have this, as far as its profile mainly of the counterbalances that are those that more material they have possible to eliminate, the ideal would be to draw the profile of the future counterbalances and to cut the leftovers, soon to finish the work with grinder and to polish best the possible thing. Another form would be to turn the counterbalances eliminating material.

Crank and steering wheel.

It is necessary to consider that will be to balance the crank, (to balance it) since any imbalance produces very important vibrations. Generally the balance of a crank is made in a specialized factory, but it is possible to be made perfectly supporting the crank by the extreme trunnions on two disc games that allow the free turn with much lightness, then the crank it will turn and leave the part but heavy downwards, to balance it is possible to be made some countersunk in the counterbalances.
The steering wheel can be turned and be made holes distributed uniformly in all the circumference, according to the amount of material that we want to remove and the weight to reduce. In order to balance the steering wheel it will be necessary to install it on the ready crank to place, and to make just like previously, of that form we can determine important imbalances.
To consider which the final balance will have to be made in a specialized factory, since the static balance can do it without problems, but the single dynamic balance is possible to be done with special machinery that the intensity detects imbalance points and of, correcting with countersunk small any defect. After this already we have a crank and steering wheel that they will want to fly.

THE CONNECTING RODS

The connecting rods, its function and what we can do to them.

The connecting rods have double function, by a side they transmit the force originated by gases of the combustion to the crankpin, and on the other hand when being united to the crank they transform the alternative movement toward the front of the piston into circular movement of the crank. Generally they are constructed in printed steel of 50 Kg./mm2 of resistance for motors little loaded and until of alloys of chromium-nickel-molybdenum for fast motors and great power. For competition motors they are constructed with printed aluminum alloys, that improve the heat transmission and reduce the weight of the pieces in movement within the motor.
The possible modifications in the connecting rods of a series motor are few, to reduce the weight on the one hand, and by the other to reinforce per to us of fixation of the head of connecting rod with the increase of the compression index proportionally.
This last modification does not represent greater problems, and it will be come as in the case of increasing the diameter of per to us of fixation of the cover of cylinders.

Lightened connecting rods and pistons.

In order to reduce the weight of the connecting rods material in the head can be cleared mainly of which generally it has but material for counterbalance, having as benefit the reduction of the weight in the zone that but movement it has, always must as much balance the connecting rods in gross weight (all must weigh the same) and of the weight of pié and of the head. This is determined supporting pié of connecting rod and weighing the head with the tapeta and placed per to us, all the heads must weigh the same, and come similarly with pié of connecting rod; the tolerance of the 2 weights does not have to be greater to gr., if outside necessary to reduce pe< <<<<<<< snip >>>>>>>>