Thread: 350 sbc wont start

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just bought a 86 camaro swapped tpi 305 for a carb 350, guy had it running so he says, had a cam swap it ran then shut off, cranks very very slow, so new battery was put in. i pulled the distributor put it on #1 tdc put it back in, still cranks slow pulled all plugs still slow, so app its something in the motor. any ideas on what it could be? bad bearing, cam, both who knows any info guys thanks!

You're on the right track... with no plugs in it, it isn't a question of compression. I'm thinking a bearing on the crank... can you drop the pan easily?

im not to sure, ill put the car up on some ramps today and get under there see if i cant get that pan off easily or if ill have to jack up the motor, are crank bearings hard to install? i know im not to sure on how to do cam bearings either. thanks for the help!

If you have bad crank bearings the crank will have to be pulled and checked. Depending on what you find by pulling the pan you may be looking at pulling the engine. Good luck

Before you tear in to the engine you might want to check all the grounds.

Ground was my first thought

heres the ground situation, guy has ground coming from battery to alternator bolt, the from battery to strut mount, (was thinking of moving this to the fender). Then he doesn't have one from the block to the firewall, that i can see and i looked pretty hard. Or from the intake to the firewall i should say. should i move the one from the strut mount to the fender? and then add one from the intake to the firewall?

Originally Posted by camaro8484

should i move the one from the strut mount to the fender? and then add one from the intake to the firewall?

Welcome to CHR!

The main ground from the battery needs to be to a clean bolt on the block, not on the alternator and close to the starter is best. One of the starter bolts is an ideal place for it. The ground to the strut mount is to give things in the cabin a good ground, as would a strap from the firewall to the block.

Have somebody with an avr and check starter draw or put a tq wrench on the font of crank before you start tearing this thing apart....ted

Both the positive and negative battery cables need to be at least 6 gauge, preferably 4 gauge or larger, especially the positive since it has a longer run.
On the front of the block there are bosses drilled and tapped and the bottom one is a good place to hook up the ground. Clean it to bare metal and use a good washer and lock washer. The block needs to be grounded to the frame and yes the block should be grounded to the firewall.

while you still have the plugs out, check to see how much torque it takes to turn engine over from the from crank bolt


then check starter draw with a guage and/or the cranking volage drop


while cranking the motor use a timing lite to see where #1 is firing


one your past these three items reinstall plugs

The very best way to test the ground or positive circuits is a voltage drop test.
Set your multimeter to 12 volts DC. Connect one lead to your neg. battery post (not the battery cable terminal) connect the other end to a clean bolt or such on the engine block. Now have someone try to start the car while you watch the meter. Any reading of less than 10 percent of 12 volts or 1.2 volts is acceptable and tells you the tested circuit is good. This test works the same for the positive side also. So if your ground side tests good do the same test from positive battery post to starter lug. Just remember to hook your meter to the battery post and the starter cable bolt, not the battery terminal or terminal that hooks to starter and the circuit must be energized.

so pulled timing cover marks were way off, got it right. pulled plugs cranked strong. put plugs back in was still cranking good, checked distributor was still on pointing to #1 at tdc put wires on checked twice cranked slow and back fired through the exhaust. i mean louder then i ever heard? still timing or valves to tight?

Did you replace the timing chain, if not you'll have the problem again? Timing is still off.

timing chain was like new, i don't think the car ever ran after the kid had the cam put in even though he said it did. it didn't have much slop in it at all.