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Corvette Starters - Crank And Hope

Cantankerous Starting-Problem Solutions

Wayne Scraba Jun 28, 2009
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When it comes to turning over, it always seems that Corvette starters tend to dislike two things: Compression and heat. Increase the compression ratio and the starter isn't happy. Increase the temperature and it gets grumpy. Mix high temperature (engine and ambient) with a higher-than-normal static compression ratio and the starter becomes downright cantankerous. To make matters worse, whenever the thermometer really rises, you too can personally approach the boiling point, particularly if you have a Corvette that refuses to crank over, let alone start. Sound familiar? If it is, then you need to check out the following pages. It's a look at modern starting systems, aimed directly at modified Corvettes that, appropriately, have added heat under the hood (as you know it's an all too familiar saga--adding horsepower adds heat). And it's jammed with real cures for hot starting headaches. Take a look. You won't be sorry.

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The latest mini-starters deliver a whopping 50 percent more torque to the flywheel (or flex plate) than a conventional original equipment Delco starter. Internally, the starter features a number of special features, including heavy-duty bearings. This design not only allows for long service life, it is also less susceptible to heat (or cold) problems.

Geared Reduction
Why is it that starters give up at the worst possible moment--such as when you're at a car show or cruise night and you jump into your Corvette to profile and for the lack of a better term, to show off? And why is that an 800-plus cubic inch Mountain-Motored drag race engine combination (complete with a 15+:1 compression ratio) has no problem turning over, but your 11:1 compression ratio 350-inch small-block-powered Corvette fails to spin at even the slightest hint of heat soak?

Those are tough questions, and they've been addressed in countless magazine pages by way of a plethora of quick fixes (rewired starters, Ford solenoids, heat shields, header wraps, etc.). But the real answer is the starter that's bolted to the side of the block. Let's back up a bit: Decades ago, racers discovered the gear reduction starter--a design that was initially popularized by the old Chrysler Corporation. Those Mopar-based gear reduction drive starters worked. But the trouble with the Mopar system was (and still is) weight. That starter was a very hefty piece--try bench-pressing one a few times and you'll know exactly what we're talking about. And to add to the troubles with the Chrysler-configuration starter is the inherent complexity of the unit. Sure it will start a hot, large displacement engine with ease, but if you use one, the (considerable) superfluous mass is on the wrong end of the Corvette. Then racers and manufacturers noticed something: Many Japanese vehicles are also fitted with gear reduction starters. In-line four cylinder engines power many of those cars. It's been said that the firing order arrangement of an in-line engine can actually create more difficult starting problems than those associated with V8 power plants. Just as important, those "off shore" starters proved small, light and durable. Bingo. Lights went off.

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In terms of overall size, a mini-starter such as this model from McLeod is considerably smaller than something like a stock Corvette Delco starter. Overall weight is approximately 10 pounds less than a conventional starter and yes, it's almost 40 percent smaller. When compared to an iron nose HD Delco Corvette starter, the weight savings are even more impressive.

Increasing Starter Torque
What was really needed was a lightweight, simple gear reduction starter that combined the best of the vintage Mopar designs and the later Japanese configurations. Given this situation, several aftermarket companies came up with a new starter design (such as the McLeod "Mini Hy-Tork" starter shown in the accompanying photos). This starter design relies upon a gear reduction format: With a gear reduction of approximately 3 3/4:1, the motor can turn easily at a significantly higher RPM. Why is this important? Typically, a starter motor will draw higher electrical energy loads at low turning speeds. The gear reduction format solves that problem. Loads are decreased, windings are not as likely to become overheated and far less current is demanded from the battery. In the end, a starter such as the McLeod only requires roughly 250 amps of current to function (that could be as much as half of the draw found with a conventional starter under this condition). This leaves a considerable amperage reserve for the ignition system to supply spark to the turning engine.

But just as important, these mini-starters also deliver a whopping 50 percent more torque to the flywheel (or flex plate if your Corvette is automatic-equipped) than a conventional original equipment starter. Internally, some of the mini-starters on the market include full ball bearing construction. This small starter configuration not only allows for long service life, it is also less susceptible to heat (or even cold) problems.

But just as important, these mini-starters also deliver a whopping 50 percent more torque to the flywheel (or flex plate if your Corvette is automatic-equipped) than a conventional original equipment starter. Internally, some of the mini-starters on the market include full ball bearing construction. This small starter configuration not only allows for long service life, it is also less susceptible to heat (or even cold) problems.

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The special mount found on this starter allows it to be used on both Corvette flywheel-flex plate sizes (153 or 168 tooth). This starter fits all conventional Chevy engines, except old models with bell housing mounts and engines with offset mounting holes (mini starters are available from various companies for those applications as well). As you can see, adapting the starter for either ring gear diameter application is rather simple. Move the starter in for the 153-tooth ring gear and out for the 168-tooth job.

According to East Coast Auto Electric (a company that offers a number of different mini-starter configurations), when the engine displacement exceeds 500 cubic inches, and when the compression ratio increases past 12:1, it may be necessary to use a larger mini-starter (which seems like a contradiction, but it isn't). By using a motor with larger field windings, a stronger armature and bigger brushes, torque increases over a conventional mini-starter can multiply by an extra 40 percent. In terms of hard numbers, a conventional mini-starter produces roughly 1.6 HP. In contrast, East Coast Auto Electric's "Super-Mini-Starter" produces 2.4 HP. The only sacrifice when switching to the higher capacity mini-starter is a minimal increase in length. East Coast Auto Electric's Super Mini is 1.0-inch longer than a conventional mini-starter.

Weight Savings & Installation
In terms of overall size, you can easily see that a typical mini-starter is considerably smaller than something like a vintage heavy-duty Delco starter. This small size allows for added exhaust clearance, oil pan clearance and in some cases, ground clearance. The added room allows for increased airflow around the starter, and that lessens the heat predicament. Just as important, the latest mini starters are approximately 10 pounds lighter than an aluminum nose Delco. Compared to an iron-nose Delco (such as the models used on countless vintage Corvettes) or a big Chrysler gear reduction starter, the weight savings are even more considerable.

What about installation? If you look closely, you'll see that a starter such the one shown in the photos comes complete with a pair of mounting holes. By mounting the starter inward or outward, it can fit small and large diameter Corvette flywheels or flex plates. Adjustment for correct pinion mesh is also taken into consideration. Included with the starter are shims to move the pinion down and another set of shims to move the pinion out. Mounting bolts are also included with the starter package.

How difficult is the wiring? If you have a look at the solenoid, you'll see two threaded (8-mm) studs and one male spade (push on) terminal. The (+) battery cable attaches to the top stud and the starter switch wire goes to the spade terminal. In some applications, an ignition resistor bypass is used. In this case, the wiring is the same, but a second wire from the distributor goes to the starter. Connect the distributor wire to the lower 8-mm stud (closer to the starter motor body). A 10 amp, 12-volt diode will have to be spliced into this wire so that feedback voltage does not reach the starter. Although the diode isn't supplied with the McLeod starter, they advise that any 10 amp, 12-volt diode will work.

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The pinion gear on this mini-starter is for a conventional Corvette application. In the unlikely event of a pinion gear failure, companies such as McLeod offer replacement components. Additionally, service parts for all starter components are generally available.

What Fits?
So far so good, but what fits what? Mini high torque starters are readily available for almost all Corvette applications from vintage C1 Corvettes all the way up to today's LS-powered models. For example, Power Master's XS starter weighs just 8 pounds and is recommended for 12:1 compression or higher LS engines. The Power Master XS mini starter is an excellent choice for highly modified Corvettes with large tube headers and big oil pans due to its small size. Like the LS-engines, LT-series small-blocks were equipped with starters that were smaller than the Delco jobs of old, but they too can readily accept today's even smaller, high torque gear reduction starters. As pointed out previously in the article, McLeod, Power Master, East Coast Electric and likely a dozen other companies offer high torque mini-starters for conventional Corvette small and big block engines. The bottom line here is the sky is the limit if you need a small, powerful, reliable starter for your Corvette.

The Bottom Line
In the end, you'll find that the newer gear reduction, miniature starters aren't frazzled by large displacement, high compression, heat or cold. They're light, small, provide more header and oil pan clearance and just as important, they're consistent from a starting perspective. For a daily-driven and modified Corvette, that could be the most important asset.

Difficulty Index - Wrenches
Anyone's Project: no tools required1 Wrench
Beginner: basic tools2 Wrenches
Experienced: special tools3 Wrenches
Accomplished: special tools and outside help4 Wrenches
Professionals Only: send this work out5 Wrenches

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Wiring on the mini-starter solenoid is rather simple. The battery cable runs to the top 8-mm stud while the starter switch wire goes to the spade terminal on the side of the solenoid. The text offers details for wiring when a wire from the distributor is required.

Troubleshooting The Starting SystemSix Corvette Starter TestsBackyard starting system diagnosis is pretty simple. Very few special tools are required, and for the most part, diagnosis can be handled in less than an hour. What follows could be old news to many seasoned Corvette enthusiasts. If you're stuck and can't trace a balky starting system, you might try the following:

Test One: Before you even consider a starter problem, you have to test the battery. A battery that's a dead player (or weak) can not only create starting troubles, it can make testing next to impossible. Once the battery is eliminated as the culprit, try this old mechanic's trick: Turn the headlights on and try starting the engine. If the lights go out when the starter is switched "on" and the starter doesn't spin, look for a poor connection between the battery and the starter motor. The number one cause of grief is a corroded battery terminal. The next biggest problem spot is a bad ground--especially where the ground strap attaches to either the car chassis (body) or the engine. In many cases, the problem is actually paint between the ground strap and the ground.

Test Two: If the lights dim when the starter is turned "on", and the starter turns slowly or the cranking action is sluggish, then the starter is experiencing a very heavy load. The number one reason for this in modified engines is too much initial ignition advance. If the engine has too much initial advance (or if it has mechanical advance weights and they're stuck) to start correctly, it tries to run backwards. The first thing to check is the mechanical advance. If it's stuck, free it. If the engine has too much initial advance dialed into it, reduce it. What if you need a bunch of initial advance to make your Corvette work (for example, a high compression Corvette race car with an automatic transmission)? Try separating the ignition and starting circuits. In other words, set up the wiring so that one switch (such as the key) turns the starter motor "on" while another turns the ignition "on." This way, you can get the engine turning quickly with the starter, and then flick on the ignition. It works.

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Mounting hardware and shims are included with most mini-starters. What you see in this photo are shims that are used to move the pinion out. The shims are included with the starter, but McLeod offers a complete shim pack under PN 800170.

Test Three: If the headlights on your Corvette remain bright when you turn them on, but the starter does nothing, then there's an open circuit somewhere in the starting system. The first thing to do is to hook up a booster cable from the battery + post directly to the terminal on the starter. If the starter still doesn't spin over, then it needs work. Another component to check is the neutral safety switch. If you by-pass the switch, and the starter functions, you've found the problem.

Test Four: If the solenoid (or relay) makes clicking sounds when you flick on the switch, but it starts with a direct shot of battery power (you can by-pass the solenoid by inserting a large screwdriver between the large battery cable post and one of the small switch terminals on the starter), it doesn't necessarily mean that the solenoid is healthy. Quite often, the contacts inside a solenoid can be burned. This makes it impossible for the solenoid to switch on the heavy current to the starter. The most effective fix is to simply replace the solenoid. If you've done that, and the starter still refuses to spin, it's time to tear it down for a rebuild.

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Mount bolts and conventional shims to move the pinion down round out the package. You'll note that there isn't a nose brace included (as used on many conventional Corvette hi-performance starters). The reason is simple. The starter is so light short and rigid it doesn't require extra support.

Test Five: If the starter works periodically, but with obvious grinding noises, remove it and carefully inspect the armature shaft where it engages the starter drive. Believe it or not, this problem is very perplexing since the starter will work fine (even off the bench) for a number of "starts", but then it will refuse to function. You might be astonished to find a fractured armature shaft (this is an extremely frustrating problem that plagued a low mileage truck this writer once owned). Usually, the cause is poor engagement with the ring gear.

Test Six: Finally (and we're leaving the worst for the last), if the engine refuses to turn over, even if the starter is making a bunch of noise, you could have "hydrauliced" the engine. Since liquids (coolant, oil or gasoline) cannot be compressed, they don't allow the pistons (one or more) to go through their complete stroke. The cause could be a leaking head gasket, a stuck float or even a broken block. Remove all of the spark plugs and try spinning the engine over. If it turns over freely, you'll soon be met by one (or more) of the above fluids. That should tell you what the problem area really is.



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