Category: Lt1 ignition

The Chevrolet small-block engine is a series of V8 automobile engines used in normal production by the Chevrolet division of General Motors between andusing the same basic engine block.

Engineer Ed Cole is credited with leading the design for this engine. The Generation II engine is largely an improved version of the Generation I, having many interchangeable parts and dimensions. Later generation engines have only the rod bearings, transmission-to-block bolt pattern and bore spacing in common with the Generation I and II engines.

Introduced as a performance engine inthe went on to be employed in both high- and low-output variants across the entire Chevrolet product line. Over the years, every American General Motors division except Saturn and Geo used it and its descendants in their vehicles. Finally superseded by the Generation III LS in the and discontinued inthe engine is still made by a GM subsidiary in Mexico as a crate engine for replacement and hot rodding purposes.

In all, oversmall-blocks have been built in carbureted and fuel injected forms since as of November 29, The small-block family line was honored as one of the 10 Best Engines of the 20th Century by automotive magazine Ward's AutoWorld.

In February a Wisconsin businessman reported that his Chevrolet C pickup had logged over 1 million miles without any major repairs to its small block V8 engine. Source: The Flint JournalFebruary 17, It quickly gained popularity among stock car racers, nicknamed the " Mighty Mouse ", for the then-popular cartoon character, later abbreviated to "Mouse".

The was adopted by other Chevrolets, replacing the V8s. Installed in everything from station wagons to sports cars, in commercial vehicles, and even in boats and in highly modified form airplanes, it is the most widely used small-block of all time.

Though not offered in GM vehicles sincethe series is still in production at General Motors' Toluca, Mexicoplant under the company's " Mr. Goodwrench " brand, and is also manufactured as an industrial and marine engine by GM Powertrain under the " Vortec " name. Of the three engines in this family, two of them, the and thehave gone down in automotive history.

The first of this family was theintroduced in Cole's design borrowed the valve train design scheduled to be used at the time in the Pontiac V8. Internal GM rules at that time were that once an automotive division had introduced a technological innovation no other GM division could use it for a period of two years.The ignition module of your vehicle is the heart of your entire ignition system.

The ignition module has a direct impact on the performance of the engine.

lt1 ignition

The module resembles a small electrical box with a wire harness. It is usually located on or in the distributor housing in domestic vehicles, and on the firewall or wheel-well in foreign vehicles. Like all automobile components, the ignition module will eventually deteriorate and break.

However, you can anticipate and prepare for the failure. These tips will help you recognize the two most common symptoms of ignition module failure. Overheating is a common indicator that you could be having an ignition module problem. Ignition modules that are overheating will soon completely cease to function and in the meantime can cause cause electrical shorts, engine stuttering, lower gas mileage, power loss, stalling, and gasoline odors in the exhaust.

lt1 ignition

You can test for overheating while the car still runs. Idle the engine for 30 minutes, and then tap the module with a screwdriver. The car may stall, which would strongly suggest that ignition control module may be the cause of the overheating you're experiencing. If you are caught with an overheated module in an emergency situation, you can cool it down with ice water, engine coolant, or refrigerant fluid. However, this is a temporary solution only to be used as a last resort until you can reach repair facilities.

If your vehicle stalls unexpectedly during operation and will not start again, it is likely because of loose or corroded electrical connections in the ignition module. In this case, check the switch, clean oxidized terminals, and replace broken wires if necessary.

If you cannot start the car, you need to test the ignition control module using a light timing tester to check the output of the module. Connect the timer to the positive terminal of the battery and check the continuity of the black output wire while cranking the starter.

If the light blinks, the module is good. If the light is blank or constant, the module is bad. Before you attempt to replace the control module, you must rule out other ignition system components.

The module is expensive and replacing it is a laborious process. Check the ignition coil for a spark. Examine the wires at the cap, rotor, and spark plugs. We welcome your comments and suggestions. All information is provided "AS IS. All rights reserved. You may freely link to this site, and use it for non-commercial use subject to our terms of use.

View our Privacy Policy here. Toggle navigation Login Register How-Tos. Written by Robert Miller. Reviewed by H. Overheating Overheating is a common indicator that you could be having an ignition module problem. Sudden Failure If your vehicle stalls unexpectedly during operation and will not start again, it is likely because of loose or corroded electrical connections in the ignition module.

Power Loss and Poor Gas Mileage. Vehicle Repairs. Popular Articles. How to Replace an Ignition Coil. By Carol S.Sure, they eliminated the whirling mechanical device that spins a rotor that aims high voltage to the plugs. But then the OEs had to purchase eight expensive ignition coils—one for each cylinder. When buying millions of these units every year, the piece price is ridiculously low, but it's still an investment. Let's take a quick look at why they went this route.

Distributor technology goes back to a man named Charles Kettering not long after the first internal combustion engine made noise. Today, with a simple crank and cam sensor, the computer knows exactly where the engine is in the firing order and can very accurately trigger when the spark should occur.

With this increased accuracy, the next biggest limitation was coil energy at high engine speeds. At 6, rpm, the engine is firing all eight cylinders 3, times per minute or 50 times per second. This leaves 0. As a result, spark energy is drastically reduced at higher engine speeds. Of course, this was acknowledged back in the '70s when capacitive discharge ignition systems first became popular with drag racers. See our sidebar on inductive versus CD ignitions and the relative advantages of each.

Small Block Chevy Engine So what does this have to do with building a stronger street engine? Imagine if you could convert an original small block Chevy engine over to DIS. What advantages would there be for the average enthusiast? Sure, you'd have a much more accurate spark that's not affected by backlash in the cam drive system and all kinds of issues with distributors.

You'd also have a much hotter spark at higher engine speeds because now you have a single coil for each cylinder, so it has plenty of time to recharge and fire a much stronger spark to the cylinder.

In actuality, your engine misfires hundreds of times in just one pass down the dragstrip and thousands of times just driving down to the auto parts store for an oil filter.

Chevrolet small-block engine

You may not feel it as a dropped cylinder, because a misfire is actually defined as incomplete combustion, meaning a spark initiates combustion, but the cylinder never achieves complete combustion.

The result is reduced power from the combustion event. But what if you could produce a stronger spark delivered at precisely the right moment throughout the engine's entire operation range? Would it be possible to make more power? DIS ignition is partially responsible for the LS, new Chrysler Hemi, and Ford mod motors making more power per cubic inch and being more fuel efficient than their year-old cousins.

So why not use LS engine technology to give a leg up to older engines to make more power? His company makes a conversion system that uses either the 24x or later 58x crankshaft trigger wheels to indicate crankshaft position within the engine. In either case, a spinning shutter wheel on the crankshaft is read by the crankshaft position sensor to indicate engine rotating position.

Because each piston arrives at TDC twice within the four-stroke cycle, the computer needs to know which of these two events represents the power stroke. That's the job of the camshaft sensor.When GM went looking for a new ignition design for the LT1, they went with a somewhat unlikely source — Mitsubishi.

They bought an optical distributor system that was already in use in many Mitsubishi, Chrysler, Subaru, and Nissan applications.

LTCC LT1 Coil per Cylinder Converter

The stock ECU uses the slot ring to determine crank angle and the inner ring of eight slots to identify the cylinders.

This writeup covers using the stock ignition module for controlling the coil. If you would prefer not to use the Optispark, check out our page on crank triggered ignitions.

This can be used for either a distributorless ignition or using the Opti strictly as a distributor. These ECUs will need a few resistors in the wiring, but no internal modifications. Wire spark output A gray connector pin 27 to the stock ignition module trigger wire.

These have a stepper IAC motor control that can drive the stock idle air control valve, which is one feature MegaSquirt-I does not have. For those looking to build this on a budget and who want to figure out another route to control your idle speed, we also have a write-up covering MegaSquirt-I.

We will need a 12 volt pull up on the ignition input. Wire spark output A MS3X pin 14 to the stock ignition module trigger wire. Alternatively, MS3 allows you to use the Optispark to trigger a distributorless ignition. For the ignition input side tach signal into the ECUwire the low resolution input signal from the Optispark pin A this is usually either black with a red stripe, or red with a black stripe to the MegaSquirt pin LT1s used a stepper idle air control motor.

MS3Pro units use pins 30, 31, 32, and 33 on the gray connector. Fuel pump: Fuel pump output is standard on all MegaSquirt versions, but the GM fuel pumps used a high side driver while the MegaSquirt output is ground triggered. You will need to rewire the fuel pump relay coil so it connects to a switched 12V source and the MegaSquirt fuel pump output pin. Cooling fans: These cars generally had two cooling fan control outputs. See here for a picture of an installed relay control mod kit.

Vehicle speed output: Some Corvettes use this for features like active suspension control, and it is linked to the cruise control. Otherwise, if you have an automatic you will need to either control it with the stock GM ECU or a stand alone transmission controller. Dwell will depend on exactly which coil you are using. Cranking trigger time must be set to Calculated. Trigger angle is in the 90 degree range; this may vary depending on production tolerances, so confirm this with a timing light.

Alternately, you can manually copy the settings over from the borrowed file.What is it? The "opti" has two parts, a low-voltage optical section and a high-voltage cap and rotor section. Where is it? The opti is mounted on the front of the LT1, above the crank snout and behind the water pump. To replace it the water pump must be removed. How does it work? The optical section consists of a disk with slots in it, representing degrees of crank rotation.

In this way, the PCM knows the precise location of the crank at all times. When its working right, the opti is an extremely accurate timing mechanism. Why do optis fail? Due to its location, the optispark is subject to moisture from several sources. First, driving through high water can submerge the opti completely. Automatic car washes with undercarriage wash can also soak the opti. Secondly, if the water pump suffers bearing failure and coolant comes out the weep hole, the opti can be soaked with coolant.

To wash your motor, use a damp soapy rag and take your time. Moisture buildup inside the opti can cause the precise parts of the optical side to rust up. The bearings are also weak and prone to faliure, particularly from misalignment or a too-long cam dowel pin distorting the drive mechanism. Last, high voltage causes ozone buildup inside the cap Aftermarket ignition amplifiers make the ozone buildup worse and can significantly shorten the life of your opti.

There are four basic options.

lt1 ignition

It uses the signal from the optical section of your opti to work, so if you suffer optical section failure you'll still have to replace the opti. But, by removing the high voltage section from operation, you can significantly prolong opti life. Sponsored Links. What is an Optispark and why do they fail? All rights reserved.If you are an international customer who ships to a US address choose "United States delivery" and we will estimate your ship dates accordingly.

If you are an international customer and would like to change the currency that prices are displayed in, you can do so here. We need additional information about your vehicle to help you select the correct part.

Image is a representation of this item.

lt1 ignition

Actual item may vary. Change Currency. Loading Today Estimated International Date Check Fit. Brand: MSD Ignition. Manufacturer's Part Number: Part Type: Distributors. UPC: Computer-Controlled Compatible: Yes.

Trigger Style: Optical. Advance Type: Computer-controlled.

EFI 24x™ LT1/LT4

Ignition Box Required: No. Mechanical Tach Drive: No. Slip Collar: No. Distributor Gear Rotation: Standard. Distributor Cap Color: Red.

Housing Material: Billet aluminum. Housing Finish: Natural. Marine Use: No. Quantity: Sold individually. They feature a precision-machined billet aluminum housing that fits in place of the factory piece, a new pickup assembly, a trick timing adjustment mechanism, and a new MSD distributor cap and rotor.

The pickup is an advanced optical encoder that has proven to be very reliable and stable through extreme rpm and conditions. The rotor is bolted to a drive assembly that is indexed to the shaft, and is stabilized through the use of a large ball bearing assembly.Back to Tech Page.

Use any info from this site at your own risk. Picture or text links to auction sites ex. Ebay are forbidden. All rights reserved by shbox. This is an installed coil. I did not take any pics before I took the old, stock one off. Remove the coil wire and two other harness connectors. There are two studs holding the coil on. Take care when removing the nut where the ground lugs are. If necessary, hold the stud still with a wrench to keep the lugs from rotating and possibly tearing loose from the wires.

Lay the lugs out of the way. That is all there is to getting the coil out. Here, the coil and bracket assembly has been removed for service. At this point you, have to separate the old coil from it's mounting assembly. Exploded diagram of coil mounting assembly. Punch out the rivets.

You may wish to use a block of wood for some support. The coil assembly is a little wobbly because of it's shape. These are the pieces you will have to reassemble. Note: If you remove the ignition control module from it's mounting, there is some silicone grease between it and the mounting plate. DO NOT clean this off, unless you plan to replace the grease. It is there to provide a proper heat-sink bond between the two parts.


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