71' Chevy truck

[Hoosier-one]

I'm having trouble finding the correct starter for a 71' Chevy truck. I have been told the engine could be a 350, 327, or 307 from 1968-1972 auto.

Can the motor casting block numbers (On the front) determine the engine? Based on these numbers I was told it was a 307 motor, but still having trouble with the starter. The flywheel appears not to be wore. Could the transmission or flywheel vary, causing the starter for this particular engine to not work?

Thanks

[silicon212]

In 1971, your only choices for small blocks are the 307 and 350. On your vehicle, both should have the large (168 tooth or 14") flexplate, so use the same starter. The starter bolts should be angled from each other - the one closer to the engine block should be about 2" inboard of the starter 'nose', where the outboard bolt should be even with it.

[bobss396]

Is the truck automatic or stick? Starters for automatics have a wide variety of housings depending if you have a Powerglide, Turbo 350 or 400. It also varies from model to model and year to year.

Double check the flywheel size, it could be a 164 tooth as silicon suggests or a 153 tooth depending if someone swapped a passenger car set up into your truck.

I would try to get an accurate decoding on the block number first, see if the motor is out of a Chevelle, Impala, etc. See what size flywheel you have. If possible, try to determine if the transmission is native to the truck.

Bob

[Hoosier-one]

This 71' Chevy has a 350 turbo Automatic Trans, but was originally manual. I did check the engine code, the number lines up for a 71' chevy 350 ci. I haven't checked the flywheel, must do that. Any suggestions on a good quality brand starter?

[bobss396]

You've made progress, so the engine might be native to the truck. The transmission could be a truck designated one too. What was the initial starter problem? Did it engage the flywheel or miss completely? You would have heard the starter spin with no mechanical engagement.

Find out how many teeth are on the flywheel first. I would look for a local electric rebuilder and take the starter that you have to him. Those guys know the truck from the car parts and should be able to help you right off. You might have to pay a core charge, which is like $10 or $15 if he has to give you a different nose casting.

Bob

[Hoosier-one]

I had the flywheel changed and a 3-bolt starter put in, that fixed it!

For some apparent reason the truck quit this weekend and will not turn over. The starter cranks fine! The gas is spraying the carburetor, but will not run?

Any suggestions?

[taillight]

Check for spark.

[Hoosier-one]

There's no spark. Could the distributor cap be cracked or the points fouled?

[silicon212]

Originally Posted by Hoosier-one

There's no spark. Could the distributor cap be cracked or the points fouled?

In 1971, the coil might get its power from the starter solenoid "I" terminal. If that is the case, double-check that it got put back on correctly.

[Hoosier-one]

I have replaced the distributor cap and still no spark? I noticed it appeared to have an electronic ignition, could this gone bad or the condenser?

[67chevypickup]

Id say the timing chain is shot the only way you get gas coming out the carb is either your valve timing is very far off or worse you have a bent or tuliped valve

[silicon212]

Originally Posted by 67chevypickup

Id say the timing chain is shot the only way you get gas coming out the carb is either your valve timing is very far off or worse you have a bent or tuliped valve

Actually, that is incorrect, as there are many more causes, although the ones you've laid out can cause the problem. Ignition timing can cause it, as can a failed cam lobe/lifter and/or bent pushrod, or other valvetrain or ignition system malady. Crossfiring ignition wires have been known to cause this malady. Check the wires for knicks, burns (silicone wires will exhibit a powdery-white appearance on a burn), or oil-soaking (they'll be swelled up and very soft).

If it's a valve timing issue, that would likely be due to a slack timing chain. That would manifest itself in a spun-bearing-like knock at the front of the engine, before the chain and/or sprocket let go. To be fair, a '71 may well have an aluminum timing sprocket with nylon teeth. Excessive chain slack, enough to cause the knock, can certainly strip the nylon off of the sprocket, which would cause the sprocket itself to fail in very short order, leaving the cam on its own. In that case, if the distributor cap is removed, the rotor will be observed to be stationary as the engine is cranked. The cranking itself will also generate a strange sound.

Looking back over the thread, I get the idea that by "the gas is spraying in it" means that he observes gasoline spraying into the barrels as he turns the throttle. This is normal behavior, due to the accelerator pump.

[Hoosier-one]

The rotor is working, as I crank the engine it rotates. Also the spark plug wires and plugs are like somewhat new.

This truck was running fine and then all of sudden it acted like it was out of gas (there was plenty), then died.

How could you tell if the timing chain is dis-engaged or not working?

At what point could I check resistance or current in the circuit?

[silicon212]

Originally Posted by Hoosier-one

The rotor is working, as I crank the engine it rotates. Also the spark plug wires and plugs are like somewhat new.

This truck was running fine and then all of sudden it acted like it was out of gas (there was plenty), then died.

How could you tell if the timing chain is dis-engaged or not working?

At what point could I check resistance or current in the circuit?

If the rotor is turning, that means the camshaft is turning. If the camshaft is turning, then the timing chain is doing its job.

If the engine has been converted to electronic ignition, make sure the battery lead on the distributor is not ballasted (the wire itself is a ballast resistor on breaker-point distributors). The HEI requires full voltage. With the engine not running, this measures at 12.6 volts with the ignition in the ON position. If you measure less than this (say 10 volts or so), then you have the ballast wire, which will need to be replaced (all the way to the fusebox/harness header) with a 10-12 gauge wire.

Likewise, if the engine uses breaker points, you MUST have a ballast resistor (the wire) if you want the points to last. In that case, the power should measure about 10 volts or so with the ignition ON.

In the case of HEI, failures typically occur in the coil, the module or the pickup/reluctor assembly. The coil is in the cap; the module is where the breaker points would be in the older system. The reluctor/pickup ass'y will require removal of the distributor to replace. You can test it with an ohmmeter while in the vehicle. Just remove its two-wire lead from the module and test resistance across the leads. It should be as near to 0 as practicable (there will be some A/C impedance but next to no DC resistance) - if you measure anything over 10-20 ohms or so, suspect the pickup. none of these parts are exceptionally expensive - the reluctor/pickup assembly is in the area of $10, the module perhaps $15 and the coil is the most expensive around $20 or so.

In the case of breaker points, make sure the points are opening when the rubbing block is on the apex of the cam. If the points are pitted/burned, they may not make an electric break in the circuit when they are 'open'. Use a dwell meter at the 8-cyl setting and if the engine starts, adjust the points (using an allen wrench) to obtain 30 degrees on the meter.

[bobss396]

Im to the point with distributors that if they're old and haven't been gone over in a long time, I get a good rebuilt unit and swap it out. A few more bucks but one-tenth of the aggravation and I hardly break a sweat or get that dirty.

Bob