Thread: Newly built 350 Chevy wont start...

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Hi, I'm new to this site and fairly new to Chevys. I have just rebuilt a 350 Chevy SB with Edelbrock Performer intake and 600 Cfm Carb, all other parts are stock (normal dist, no HEI). The vehicle is for road use at good fuel economy, as I live in Germany, where fuel is very expensive. My Questions:

What advance should I set the ignition at to get started?
What idle screw settings are a good bet for getting started?
Do i need the ported or the full time vac-advance?

At the moment, I can get the enmgine to fire, but not to start, it will run a few turns, then stop again. So naturally I vcan't set the idle speed or anything correctly, edelbrock only helps you out if your engine is actually running (even if porely), but to get the first revs out of a rebuilt engine the page doesn't help very much.I've tried all sorts of fuel settings, but without real knowledge about the carb (bought it used with no documentation, haha, stupid of me) I don't want to yank out my bearings by setting the ignition too soon or have any more carb-fires, which I found out were due to a wrongly set valve, which I have now corrected. BTW, all other engine parts are fairly new and undamaged and not worn.

Thanks a lot!

Originally posted by MadMax


At the moment, I can get the enmgine to fire, but not to start, it will run a few turns, then stop again.

Thanks a lot!

Sounds like the timing may be off. I would tighten the dist. hold down snug but so it can still be adjusted. Them move it a little at a time until you have it close enough to fire and and stay running. 6-8 Degrees should be close enough to run. You may also have a vacuum leak somewhere causing it to not stay running?

Max,

Being in Germany you may have had occasion to set the timing on an old VW Beetle using a test light or a voltmeter. You can static time the Chevy the same way. Get number one cylinder (front driver side) on top dead center, or better yet about 4 degrees advanced. Make sure it is the compression stroke. You can do this if the valve covers are off by seeing that both valves are closed; or if the valve cover is on, pull #1 plug and put your finger over the hole and turn the motor over and you should feel pressure as the piston comes up. If the timing mark comes up and you don't feel pressure, go around one more time. Now trace the #1 plug wire back to the distributer cap and make sure the rotor is pointing to the #1 wire. Now hook your volt meter or test light to the negative post of the coil. Turn on your ignition, but don't try and start it. If your test light comes on, you are right on the timing, if not slowly rotate your distributor counter clockwise until the light comes on. If the ligtht was on, turn the distributor clockwise until it goes out, then back counter clockwise till it comes on. Just to be sure pull the cap and make sure the rotor is still pointing at the right wire. That should get you timed close enough to start.

Next question is how did you adjust your rocker arms? Hopefully you did each one just snug, rotating the engine so each pushrod was in it's lowest position before adjusting.

I would set the idle mixture screws about 1.5 turns out to start with, then adjust for best rpm from there. Make sure your choke is in the closed position for initial start up, then opens at the motor warms up.

For running timing I suggest 4-10 degrees advanced finding the best range with out pinging.

Hope this helps

Pat

Have to agree with pro. Your timing is probably off. Turn the distributor until it runs and then use your timing light. You also need to set the mixture screws about 2 turns. Pat says one and a half which will work but the rule of thumb is usually two.

Originally posted by Stu Cool

Next question is how did you adjust your rocker arms? Hopefully you did each one just snug, rotating the engine so each pushrod was in it's lowest position before adjusting.

I would set the idle mixture screws about 1.5 turns out to start with, then adjust for best rpm from there. Make sure your choke is in the closed position for initial start up, then opens at the motor warms up.

For running timing I suggest 4-10 degrees advanced finding the best range with out pinging.

Pat

Hi Pat!
I set the rocker arms as said in the Haynes repair manual, I guess thats a good bet. Of course I don't know if they are set perfectly, but I guess they're within a working range. I tightened the rocker arm bolts til I felt a resistance when turning the pushrods, then a halfturn more, to seat the pushrod in the lifter. Would that maybe be too much? Or too little? I have now got it to run nicely, it will even start without the choke set, but its warm weather here. It now runs and stays running sometimes even under WOT, but sometimes, as I gradually open the throttle, there is a loudish knock, like someone hitting the engine with a small hammer, and the engine stops dead. I doesn't seem to have done anyharm, as it startedt up again nicely and on eight starts so far, that has only occurred twice, once with the engine stopping, once with a slight shudder, but the running again. Am I getting detonation? Is my ignition too far advanced? I now have it statically at 8 degrees advanced, without the vacuum advance hooked up yet, just to set the initial timing. Don't want to try around too much, might break something... Thanks for your help!

Max,

Sounds like you are on the right track. My concern with the valve adjustment was that you rotated the engine as you adjusts so that the valve was in the closed position when you adjusted. From the sounds of things that is what you did.

Without hearing the knock it is difficult to identify what it might be. Have you checked to see how much the timing is advancing as you reve the motor? Your total timing is the key. If you back the timing down to 4 BTDC or even 0 does the knock go away?

PAt

Originally posted by Stu Cool


Your total timing is the key. If you back the timing down to 4 BTDC or even 0 does the knock go away?

PAt

Hi Pat,
Total timing is set at 8 BTDC, (w/o vacuum advance hooked up) which might be a bit much as an initial advance. And yes, the engine was rotated and I guess I set the cylinders at the right time, too, otherwise it probably wouldn't run at all, and when it's running it sounds to me to be set nicely, sounds just like it should sound, with just a slight irregularity, as I have a mechanical fuel pump without a pressure-check. But it doesn't sound as if a cylinder was missing, and I have now audible valve-train noise. I'll just have a check on 4 or 6 BTDC, on 0 I didn't get it to run, it fired, but never started. but possibly that's my carb set wrong. I'll just have to play about a bit. Thanks a lot for your help, I really appreciate that, CU,
Max