350 SBC. . .barely cranks???

[atomicjoe23]

I put a used 350 SBC into one of my projects. . .it ran before I put it in and all I did was pull the heads, intake and oil pan; then I replaced the hydraulic lifters, intake manifold (Edelbrock Performer), carburetor (Edelbrock Performer), all the gaskets, plugs, and wires. . .

I reset the valve lash and installed a TH350 behind it and now it barely cranks over.

Is there anything, besides a bad battery, that could cause this?

I charged the battery overnight and I get the same results. . .I just don't want to spend the money on a battery if there is something else I can check before I drop cash.

It's a brand new aftermarket wiring harness as well. . .

. . .I'm getting ready to check the battery voltage but I haven't quite yet because I've been chasing some other stupid gremlins on other parts of the truck up until now.

Thanks!

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[atomicjoe23]

OK. . .I just checked the voltage across the battery terminals and I got 12.5V so I'm pretty sure that means the battery isn't bad.

What else could cause problems rotating the engine. . .besides the "you're screwed and need to pull the engine" response?

[Chris Tobin]

Sound like too much timing to me... pull the advance back some and try it again... Make sure the distributor was not stabbed 180* out, and check all the plug wires for proper firing order while your at it. 12.5V is actually low for a battery that charged overnight especially. Typically a battery should be at 12.6V or higher at rest...

Hope this helps...

[bitter sweet]

You need good cold cranking amps, not just voltage! Check that first, then if good pull your plugs and spin it over. Any better? Those new hydrolic lifters need to be primed if you did not do so. Also check dist timing agian, if its 180 deg. out it will pop and backfire on ya! Also if correctly adjusted your rocker arm nuts will be approx. 3 threads down the stud. good luck!

[FABRICATOR]

Any time you do major motor work you should bar the engine over by hand. This is best done before the spark plugs are installed. This can be done at the front from the harmonic damper bolt (if it won't go don't force it cause it ain't a very big bolt) or from the rear with a B/A screwdriver on the starter ring gear teeth. There are actually tools made especially for these tasks but you can usually squeak by without them. If the crankshaft won't go two complete revolutions without hanging up, YOU SHOULD NOT TRY TO START THE ENGINE. A starter motor alone is powerful enough to destroy internal components. You must stop and find out what is causing the tight spot.

[idealer]

Sounds like timing to me too... try turning over with ignition off to see if it turns more freely...

[scottm]

Agreed, check the timing, but cranking it with the plugs out is a great idea too. I remeber you were having trouble setting the valve lash a few months ago - are you sure its right?

[ProFORMANCE]

Joel,

There are a lot of people on these forums that are more than willing to through their 2-cents in to aid you with your problem. But, to get the full benefit of those with the knowledge and eliminate a lot of chasing your tail, you need to be more specific in your description of the problem outside of "It Barely Cranks".

Does this mean it spins free and then spits back through the inlet manifold?
Does it begin to crank then abruptly stop?
Does it start to crank slowly and then speed up but never start?
Does it start to crank fast and then slow down?
Does it crank slow regardless?
Does it crank slow with plugs in and fast with plus out?

Your problem could be mechanical or electrical.

I'll address the electrical side since this is what I'm known for

1) You may have a bad battery. It may have voltage at no load, but with cranking load, drop below an acceptable state, approx 10.2V. Put a volt meter on your battery and check the voltage at the battery under cranking. Or, take it to an auto parts store and have it checked. Your battery must be fully charged to perform a proper test.

2) You may have an issue with a bad starter and/or too small of wire size from your battery to your starter.
If you have a current meter, check the current draw of your starter. Current draw should be in the area of 200 - 225 amps. If it is above this, your engine may have mechanical issues creating excessive load on the starter. If you do not have a current meter, you can calculate current by using a DVM and the attached link. Check the voltage drop to the starter motor by placing the Pos. lead of your DVM on the battery and the Neg lead on the starter. The reading on the meter while cranking the engine will represent your voltage drop to the starter. Next, identify what size (gauge) wire you are using from your battery to your starter and it's total length. Enter all these values into the calculator on the attached link, and you can estimate your current draw (enter current draw values until "your" voltage drop displays). If you calculate out that your starter is drawing in excess of 225-amps, your engine may be tight. (If your starter is drawing less than 200-amps, you may have a bad starter.)

3) Also, while on the website, verify from the calculator that you have an adequate size (gauge) wire from your battery to your starter. You should see no more than 10% volt drop from the battery to the starter with the proper size wire.

The above tests, if performed properly, should allow you to identify if a slow cranking issue is a mechanical, battery, starter or improper wire size issue.

LINK--- http://www.nooutage.com/vdrop.htm

[JEFFRPM]

Did I read you Installed a turbo 350 trans behind said motor? If so was the converter installed correctly? meaning not stacked up on the front pump splines? if so their is your "drag" issue.

[CADTech]

is the motor grounded to the frame with a strap or cable?