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-   -   Chevy SBC No Start (http://www.hotrodders.com/forum/chevy-sbc-no-start-188005.html)

david-b 11-21-2010 02:14 PM

Chevy SBC No Start
 
After some compications, got the Monte Carlo all set for startup today. Car cranks, but is not turning over. It'll back fire, but that's all. Here's what I've got going on, please help if you can...

75 Monte Carlo, SBC400 auto.
Crank pulley has marks 0, 10, 20, 30. I have 0 set on the timing mark to 8 BTDC.

Distribuator is pointing to cylinder 1, with all wires correct. Plugs brand new

Timing light shows pulses on the wires. Was too bright outside to see where it was flashing though. Even with the chaulk trick, still couldn't see it.

Demon carb is pumping fuel fine. Very visable, and bowls are filled.

Engine cranks fine, everything spinning great.

Tried cranking with vacuum advance hooked up and taken off. Feels like no change.

Rotated the distrib slightly to see if any changes. Some backfired more, some less. But no start.

Car sat for like 2 years, added some stablizer in the fuel and even tried with starter fluid, no change.


Any ideas on what's going on here? Any help is appreciated. Thank you much!

bigdog7373 11-21-2010 02:30 PM

Run a fuel line from the pump to a gas can with brand new fresh gas. You can add all the stabilizer you want but bad gas is bad gas, you can't change that. Make sure you have the wires on right. Do you know which way the rotor turns? Here's a diagram to help make sure the ignition is set up correctly. http://www.crankshaftcoalition.com/w...diagram_GM.jpg
If it is all set up right and you're feeding it fresh gas, then just advance the timing a little bit at a time until it fires. Also, make sure all the plugs are in good shape, not cracked, fouled, etc... Make sure you don't have any rockers tightened too tight and holding a valve open. Let me know how it goes.

bigdog7373 11-21-2010 02:33 PM

One more thing, make sure you have the engine on tdc of the COMPRESSION STROKE with the rotor facing #1. If it's on tdc of the exhaust stroke it will not work.

david-b 11-21-2010 03:07 PM

I have the wires in the right order for sure. I believe it turns clockwise if I'm not mistaken.

#1 was fully closed right before and just about to open when I closed her up yesterday. Is there a way to check where's it at now that's its all closed up? I dont have the whistle thing to try sadly.

T-bucket23 11-21-2010 03:18 PM

Quote:

Originally Posted by david-b
I have the wires in the right order for sure. I believe it turns clockwise if I'm not mistaken.

#1 was fully closed right before and just about to open when I closed her up yesterday. Is there a way to check where's it at now that's its all closed up? I dont have the whistle thing to try sadly.

Pull #1 plug, put finger over hole and have someone just bump the key until you feel pressure pushing your finger off the plug hole, bring up the timing mark by hand and check the distributor rotor to be sure it is pointing at the #1 plug tower. If not you will need to remove and reset the distributor.

You didnt say what you have done so far, there are lots of other possibilities but this is the most common mistake made when putting an engine back together. The other issue that could cause backfiring through the carburetor is tight valves.

david-b 11-21-2010 03:23 PM

Quote:

Originally Posted by T-bucket23
Pull #1 plug, put finger over hole and have someone just bump the key until you feel pressure pushing your finger off the plug hole, bring up the timing mark by hand and check the distributor rotor to be sure it is pointing at the #1 plug tower. If not you will need to remove and reset the distributor.

You didnt say what you have done so far, there are lots of other possibilities but this is the most common mistake made when putting an engine back together. The other issue that could cause backfiring through the carburetor is tight valves.

I will do this tomorrow to check. So when the pressure pushes the finger off, that's compression getting raised, correct?

Back fire is coming through the exhaust; exhaust isn't hooked up after the headers, so it's very obvious when it backfires and that it's coming from the exhaust.

As far as mods, I have aluminum heads with roller rockers. I don't have specs on things since I got everything when I got the car, and it was already all torn down to the block/internals. Just got it all checked out, and got it altogether.

T-bucket23 11-21-2010 04:09 PM

Quote:

Originally Posted by david-b
I will do this tomorrow to check. So when the pressure pushes the finger off, that's compression getting raised, correct?

Back fire is coming through the exhaust; exhaust isn't hooked up after the headers, so it's very obvious when it backfires and that it's coming from the exhaust.

As far as mods, I have aluminum heads with roller rockers. I don't have specs on things since I got everything when I got the car, and it was already all torn down to the block/internals. Just got it all checked out, and got it altogether.

Even though it is through the exhaust, the same things can cause the backfire. Check the distributor, it is the most common issue.
Yes you should feel the pressure push you finger off the hole. That is compression stroke starting, You can use a breaker bar and A socket to bring it up to the timing mark. The key is to have the helper just bump the key, and to stop when you are close.

crussell85 11-21-2010 05:15 PM

you can buy these at most of your auto parts stores, these make things a little easier. I agree with the above post that the distributor is not set correctly. http://www.summitracing.com/parts/SUN-CP7853/

eloc431962 11-21-2010 06:06 PM

Quote:

Originally Posted by crussell85
you can buy these at most of your auto parts stores, these make things a little easier. I agree with the above post that the distributor is not set correctly. http://www.summitracing.com/parts/SUN-CP7853/

Yep i got one it's a little older then that style but a great tool all the same. :thumbup:
And i think you have the distributer out also. JMO


Cole

david-b 11-22-2010 02:39 PM

Sounds good guys. I was watching some youtube vids and think I figured out my problem.

My timing pointer (sorry for lack of the better term) has the 0 mark, and then it goes to -10 and +6 or somewhere around there. I think I was setting that 0 on the dampener to -8 according to the pointer. Where as it should be -8 on the dampener instead. I think that makes sense.

When I get home, going straight to the car and getting it running.


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