I think what people forget is that some people want different things from a cam. I am willing to trade 50HP total for the ability to slip off the clutch slowly at rpm and take off and not stall. I know cliff is a fan of some other grinds that he has seen make “more power” and the has seen the stock manifold make “more power” than the performer even though Jim hand showed it made a tiny bit of difference for him. The thing is, “more power” to you guys is like 10hp! As a pontiac HOBBYIST on a site about street performance, i can’t be bothered to chase down every last 5 hp at the cost of decent right of idle performance, and vacuum, and fuel economy. If i wanted that, i’d head over to pontiaczone or something more drag and road race related. I just don’t have the heart to run my pontiac over rpms, why do i want a cam that goes further for street use? FWIW i had the same setup with my headed , you dished the pistons for compression as my ‘s were, but i was still a bit higher.
Everything You Wanted to Know About Vacuum Advance and Ignition Timing
A minimum of 1. External rub rails will not be permitted. Threaded rods will not be permitted. All weights must be painted white and clearly labeled with the car number on it. Any weight s must be securely attached to the frame below the body decking.
Mar 28, · How to hook up vacume lines to a holley P/N s carb. mounted on a edelbrock P/N intake. Posted by Anonymous on Mar 28, dont know how to hook up carb. As long as the distributer is vacuum advance and for a it should be able to work. The main difference will be the firing order on the truck engine may be different.
Installation of ZZ4 Crate Engine in C3 Corvette After 30 years and 75, miles, my original L engine was still very dependable and running solid. I also wanted to keep my numbers matching engine so that the car can be restored back to original at some point. After many hours of research, I decided to purchase a new ZZ4 crate engine from GM with specs as follows: GM part number – ZZ4 Crate Engine, Generation I long block, includes 4 bolt main caps, nodular cast iron crank with one piece rear seal, Passenger side dipstick and center bolt valve covers.
Preparing the ZZ4 engine for installation in a C3 is not a major deal but there are some things of which you need to be aware and I will discuss these in this documentary. One of the things that you will want to know is ‘what parts from my old engine will fit on the new one? The ZZ4 comes with a long water pump which of course is not correct for a C3. The timing cover on the ZZ4 is a composite material and one of the bolts retaining it must have the head ground down to clear the back of your original pump.
In my case, I did some research on water pumps and I found out that Edelbrock make an aluminum pump for the ZZ4 application in C3 Corvettes. It is the Victor series with part number It also has the correct shaft diameter for your clutch fan and the indentation to clear the problem bolt on the timing cover.
How to Hook a Vacuum Gauge to a Quadrajet?
Theory Overlap is the portion of the engines rotation for which the exhaust valve is still open right at the end of the exhaust stroke, and the intake valve is also open to give a head start to the incoming charge. The exhaust gas is whistling out of the exhaust port at the same time the intake charge is starting to trickle past the intake valve. If you have more than about degrees of overlap, you’re looking at something more like a race cam than a street cam. Lobe centre angle, on the other hand, is the number of degrees between the point where the intake valve is at maximum lift and the point where the exhaust valve is at maximum lift.
This angle is commonly in the degree to degree range you mentioned, which is why I think you’re really interested in LCA, not overlap.
B) Hook up your tach and follow step (3AA) – you are looking for the highest smooth steady idle speed on the tach this time. The needle will behave in the same fashion as the vacuum needle if you go too far in one direction or another.
Gift Shop Technical White Papers It seems this time every year I get questions on tuning and, in particular what to do with a vacuum guage. So here we go with another white paper. I will attempt to cover the normal diagnostic indications, some tuning and maybe a trick or two some may not have used. The vacuum guage is very useful for tuning and diagnostics and I consider it a must have for performance tuning. There are undamped and damped guages available, and while the damped guage may be easier to use for someone who is new at it, I recommend the undamped type for reasons to be explained as we go.
As always, I assume no liability for any attempts on your part to hurt, maim or kill yourself or damage your car while using one. To use one, you must warm the engine to proper operating temperature and hook it to an unported full time vacuum fitting on your engine, Hooking to the intake directly is best, but the carb is fine. If you are hooking to the carb, the unported is the lowest fitting if there are more than one.
First, the common indications that come from the manual with most guages with added commentary if I see the need. Steady needle, at Engine in good condition.
Vacuum Advance question
Your mechanical advance is working – it’s why the spark moves to 25 BTDC when you rev the engine. That’s what it’s supposed to do. Your vacuum advance is probably working as designed as well. It just doesn’t come into play under the conditions you describe.
Apr 18, · After installing new plugs, wires, and distributor, good ole basic tune up. I went to set timing, plugged the ported vacuum advance, set idle at RPM, set timing 6 degrees BTDC, well she idled real smooth, sounded great.
Years ago I did a beautiful Hemi transplant into my 70 Challenger. Had all the good stuff in the engine. I had run the Mopar distributor that was for the cable driven tach and no provision for VA. That dist had the light weight springs and advance was all in by about rpm. I had set idle advance some wheres around 12 deg, Car idled at rpm. Big cam and it liked being there. There wasn’t much advance left in the distributor.
But man did the car ever run. Pulled like a jet.
Vacuum Diagram for 78 quadratoilet
I originally ran my vaccume advance to ported vaccume on my edelbrock carburetor and then in switched it to full manifold and could never get it to idle right and when i’d put it in drive the vaccume would drop so much that the dash would start shaking and vibrating so i switched it back to ported vaccume. All cars used to use manifold vacuum to control spark advance, for better mileage and drivability. Ported spark advance was brought into use during the smog era for emissions control.
Rochester Quadrajet Vacuum Advance Port to hook the vacuum gauge up to the distributor advance signal port of the old 1bbl The Holley on the Ramcharger got replaced with a Rochester Quadrajet and it. The Edelbrock Performer 2-O (left) for oval port heads is sized to work.
In trying to get the headlight door motors, I ended up taking out the whole damn front end – grill, bumper, etc. There was just no easy way to get to the door motors. I probably removed 50 bolts out of the front of the thing. Eventually I had half the car in the back of the truck just to get a couple pieces of trim and the headlight door motors, but there’s nothing wrong with a few spare parts. I have heard since then that if you remove the horn it’s easy to pull the motors right out the top, though the shop manual says you can pull them out the bottom, which is impossible.
June the work began.
How to hook up vacume lines to a holley P/N 80457s carb. mounted on a edelbrock P/N 2701 intake
Gift Shop Technical White Papers Allright,,, I don’t mean to be confusing or vague but the little picture machine in my head seems to outrun my mouth and fingers, plus I’m lazy so I suppose Dave gets his wish These are the screws on the sides of the blocks on Holleys and the two screws on the front of the rest. These are the screws on the side by the throttle arm. There are three common methods of doing this- with vacuum guage s , with a tach, or by ear. Of the three, the most accurate is the vacuum guage method, best to have one for each carb, but it’s not absolutely necessary.
Pick one of the 3 below:
Jan 02, · * Ported Vacuum – Hook your vacuum advance for an emissions setup to this * Manifold Vacuum – hook your brakes, cruse control, TH modulator and HVAC vac line to this. You can also plug your vacuum advance to this if you’re not concerned about emissions.
Larger carburetors can make morepower on a dynamometer, but this can also result in slower accelerationand lower efficiency of fuel atomization. Where should I hook up my vacuum advance? The most detrimental effects of using the wrongport is an increase or decrease of rpm and poor idle characteristics. Generally the distributor vacuum line goes to the timed port.
The accelerator-pumpsystem consists of three main components: This is the carburetor system that is mostresponsible for having good, crisp, off-idle throttle response. Itspurpose is to inject a certain amount of fuel down the throttle boreswhen the throttle is opened to smooth the transition between the idleand main circuits so that no stumble, hesitation, or sluggishness willbe evident during this transition phase.
A History: ’s Word of the Year
Distributor advance It doesn’t matter what kind of ignition you have, if the advance curve is not set properly it won’t make any power. The ignition is advanced so you reach peak cylinder pressure right after TDC top dead center. If the spark comes too soon the burning fuel will try to push the piston back down the cylinder before it reaches TDC, resulting in a loss of power and possible engine damage.
If the spark is too late you will not reach full power and get poor gas mileage. There are two major factors that effect how much advance is required, engine speed and load.
Carburetor Tune Up Guide. previous page: Shortcuts in Trouble Shooting VACUUM GAUGE. TESTS WHILE ENGINE IS RUNNING. For a normal idle, with throttle stop screw adjusted for a minimum of 7 miles per hour in high gear, the hand of Vacuum Gauge .
Carburetor Technical Information Rochester Quadrajet Quadrajets were used as original equipment on many vehicles from to Over million have been produced. QJets have a maximum airflow of from cfm. Because the secondary side of the Qjet opens according to the airflow requirements of the engine, the same basic carburetor size can be used on a large range of engine sizes. For example, on a mild Chevy the air valve will never open all the way – because the motor can’t use more than cfm or so.
M4MC Quadrajets have an integral choke and a different airhorn design; also, the throttle shafts are longer than in 4MV carbs. Starting in carb numbers were stamped on the driver’s side, near the back. Identification There are three basic types of QJet: All QJets had automatic chokes, of which there are two basic types – integral choke coil on the carb and remote choke coil on the manifold.
An M4MC carb has a choke coil on the carb; and M4ME carb has the same type fo choke coil, but with an electric heater element in the choke coil.