Editing Basic modifications for newbies

'''There are numerous sources of information to assist the untrained individual in the rebuilding or repairing of specific components of a vehicle, but there needs to be a place where he/she can learn what to do and what not to do in the modification of their vehicle(s). This article will attempt to fill in the blank spaces in their education concerning these modifications.'''

==Verifying Top Dead Center at the damper ring with the motor assembled==
The first thing I would do with an unknown motor is to verify top dead center on the damper ring at the pointer. With age, the ring can slip on the elastomeric material that is used between the ring and hub of the damper, rendering futile any further attempts to time the motor with a light. 

Verification is mostly labor, with the only expense being a top dead center piston stop tool and a degree tape for the ring. Measure the outer diameter of the ring so you can get the correct tape.
You'll also need a device to determine for sure when the piston is heading back down the bore such as a length of small diameter wooden dowel, a wooden pencil or an old popsicle stick split in half lengthwise to make it skinnier. 
[http://store.summitracing.com/egnsearch.asp?Ntk=KeywordSearch&DDS=1&searchinresults=false&y=5&N=+115&Ntt=piston+stop+tool&x=24 piston stop tool]
[http://store.summitracing.com/egnsearch.asp?Ntt=timing+tape&x=28&y=6&searchinresults=false&Ntk=KeywordSearch&DDS=1&N=700+115 timing tape]


Remove the fan and all belts. Remove all spark plugs to make the motor easier to turn over by hand. It would also make it easier to do this with the water pump removed (just gives you more room to get in there), but I have done it in some cases with the pump in place. Completely degrease the damper ring with solvent, then hot soapy water. Dry completely. With a socket and long bar on the damper retaining bolt at the crank snout, rotate the motor clockwise as you're standing in front of it. Have a buddy hold his thumb over the #1 spark plug hole (driver's side, closest to radiator on a Chevy, passengers side closest to the radiator on a Ford). As you rotate the crank, your buddy will begin to feel pressure build as the piston comes to TDC on the compression stroke. Watch the timing mark on the ring as it comes up to the pointer. Your buddy can help you out here by sticking the wooden stick down in the spark plug hole and probing to determine piston position. Do not rotate the crank while the wooden probe is in the hole, just have him stick it in and pull it out as you rotate the crank and stop for him to probe. He can tell you when the piston has reached top dead center and then started down in the bore. Rotate the crank about another inch at the damper/pointer. STOP. Insert the piston stop tool and just snug the inner rod of the tool against the piston crown. Don't force it, just thread it in by hand until you feel resistance. Make a mark on the damper ring at the timing pointer on the front cover. Sometimes I put a piece of masking tape on the ring and mark it at the pointer with a ball point pin. Leave the tool alone and rotate the crank around another revolution (Go easy) until the piston comes up against the stop again. Put another piece of tape on the ring at the pointer and mark it with the pen. Now, you should have two marks on the ring about 2" or so apart. With a dial caliper, measure the exact width between the two marks. Halfway between them will be TDC. I usually punch that into the ring with a center punch. Now you can install the timing tape with the tape TDC mark affixed exactly at the punch mark you made and you're good to go to time the motor with a light.

If the forces of nature have aligned and the factory TDC notch on the damper ring just happens to line up with the pointer at TDC, you should run right out and buy a lottery ticket.


==The first modifications to be made to your vehicle==
It is usually cheaper and easier to begin making mods to the motor and that's where most everybody starts in their quest to make the vehicle faster/quicker. 

The problem with this approach is that you're starting at the wrong end of the vehicle. Unless you're starting with a scratch build, you're probably modifying an OEM vehicle which was engineered at the factory to provide good gas mileage (numerically low ring and pinion, (probably something in the 2.70 to 3.00 range) and a tight torque converter (maybe somewhere around 1,200-1,400 rpm stall).
This vehicle was designed for all sorts of people, the vast majority of whom expect good fuel mileage and quiet operation. The cam, intake manifold and other parts that came stock in the vehicle were matched to the ring/pinion and the torque converter to accomplish this goal. When you begin changing parts on/in the motor, you are upsetting this balance of parts that were built into the vehicle at the factory.

The first things that a newbie usually changes are the cam, intake manifold and carburetor (if working on a pre-efi motor) in an effort to make the ol' hoss a world beater.

First things first. The cam must be matched to the static compression ratio of the motor. The OEM's have super computers that tell them exactly the timing points to be ground into the cam to match the c.r. and make power at the rpm's the public expects. This is usually idle to around 4,000 rpm's or a little higher. Any cam that you bolt into the motor will have an operating range of roughly 3,500 rpm's. In other words, it will be efficient from idle to 4,000 or 1,000 to 4,500 or 2,000 to 5,500 or 3,500 to 7,000 or whatever, depending on the valve opening and closing points ground into the cam when it is manufactured. It will also have a wide Lobe Separation Angle (max lift intake point after top dead center added to max lift exhaust point before top dead center and divided by 2) for good manifold vacuum to properly operate power brakes and other vacuum operated accessories and contribute to a smooth idle (Grandma doesn't want the motor going RUMPETY-RUMP when she's on the way to bingo). An OEM cam might be measured at 114 to 118 degrees LSA for instance.

Now, the newbie comes along and decides that the motor needs more cam. In most cases, he has no idea what the static compression ratio of the motor is or the piston deck height or the squish clearance or anything else about the interior of the motor. All he knows is that he wants the RUMPETY-RUMP that he heard coming from the Super Comp motor he heard at the drag strip. What he may not know is that the motor in that car has upwards of fifteen to twenty thousand dollars invested in it and is maximized for racing. It idles like that because the cam has to be very agressive to work with the 14.0:1 to 16.0:1 static compression ratio that is built into the motor. It may have been designed to make power from 4,500 to 8,000 rpm's for instance and will be coupled to a very loose torque converter that stalls at around 5,000 rpm's for instance. 

I'm just throwing these numbers around to show you that the cam in the Super Comp motor will not work in your street-driven 350 Chevy. 

I've gotten a little off track with my explanation. We need to go back to what a newbie should do  to his vehicle FIRST. 

Number one is a new rear gear. A good compromise between mileage and acceleration in a street car is somewhere around 3.70:1 ratio.   

To be continued.....