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350 CHEVY MOTOR NOT RUNNING PLEASE HELP!!!

  
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350 CHEVY MOTOR NOT RUNNING PLEASE HELP!!!

 
Buick83 Buick83
New User | Posts: 4 | Joined: 03/13
Posted: 03/13/13
07:52 AM

Hello to all!!!

I'm new here so please somebody out there I need help here is my problem:
I have an older block from the 70's 350 chevy motor. I have fresh fuel coming in no bad gas or anything like that.  I have spark as well giving out even checked the timing which is set as well had carb completely rebuild with guaranteed from a local shop.  Motor turns but will not stay on everything is pretty much all new or replaced.  What am I missing that is not making the car stay on?  I really want this car to run already! Confused please anybody out there that could help please let me know I really don't want to bring it to a shop.  I did all the work myself checked everything before I started and nothing is happening. What I did notice was gas is not sucking into carb but when I pump carb gas goes right in so what gives? is there vacuum? I have a 650 holley street fighter avenger please let me know what you think I'm doing wrong or should be doing?  

Bobs427 Bobs427
New User | Posts: 7 | Joined: 02/13
Posted: 03/15/13
02:24 PM

Try this first:

1.Spray carb clean lightly over the carb while a friend cranks the engine.

2.If the engine keeps running as long as your spraying the carb clean, then I would say you have a fuel related problem.

3.Check for a plugged fuel filter, faulty fuel pump, or a very low float level in the carb. Not allowing fuel to come into the carb to get to the engine.

4.PLEASE NOTE DON'T OVER DUE THE CARB CLEAN. Just short bursts of the spray over the carburetor will keep it running, long enough to diagnose your problem....

Sure sounds like a fuel related problem...

Bob aka-pepsi1  

Bobs427 Bobs427
New User | Posts: 7 | Joined: 02/13
Posted: 03/15/13
02:25 PM

Try this first:

1.Spray carb clean lightly over the carb while a friend cranks the engine.

2.If the engine keeps running as long as your spraying the carb clean, then I would say you have a fuel related problem.

3.Check for a plugged fuel filter, faulty fuel pump, or a very low float level in the carb. Not allowing fuel to come into the carb to get to the engine.

4.PLEASE NOTE DON'T OVER DUE THE CARB CLEAN. Just short bursts of the spray over the carburetor will keep it running, long enough to diagnose your problem....

Sure sounds like a fuel related problem...

Bob aka-pepsi1  

Buick83 Buick83
New User | Posts: 4 | Joined: 03/13
Posted: 03/21/13
08:53 AM

Thanks Bob aka-pepsi1

I will try it that way! I'm just getting anxious to have it fired up! I also wanted to mention the motor has the headers on so its not running on a full exhaust.  I know it will be loud but will it effect the carb from turning over?  Also I put in roller rockers on and I know I have to adjust them as the motor turns but can compression be the issue as well? The fuel I'm running is premium gas the expensive gas I also had bad gas in the tank which I drain but I didn't clean out the fuel cell so when I put new gas in seems like the gas was very dark could it be that the tank needs to be cleaned out?

Thanks for the response too  Grin  

Bobs427 Bobs427
New User | Posts: 7 | Joined: 02/13
Posted: 03/22/13
05:04 PM

The open headers should not stop it from starting. You may need to choke the engine a little. Headers when they are open IE on a race car the engine will go lean. Because you have NO Restriction on the exhaust or back pressure.
  If you can get the Rocker adjusted properly. If they aren't set-up right you may not be making enough compression to fire the cylinders. Each cylinder needs compression to make power.

So you need to do these things.

1.Set the valves correctly. Adjust the rockers. Its time consuming this way but you will have the valves set correctly.

2.Disarm the ignition, pull the power lead out of the cap, or remove the ignition fuse.

3.Remove all the spark plugs

4.Working on one cylinder at a time. #1 Bring it up on the compression stroke.

5.You can put your thumb over the plug hole, or use a compression gauge. Your thumb would be faster. Have a helper tap the starter until that cylinder pops.

6.Then loosen the intake while spinning the push rod between your fingers. Now with the adjusting nut, turn it in CW until you get drag on the push rod. Now adjust the nut CW 1/4 to 1/2 turn in. Then lock the center allen head screw down.

7.Do the same on the Intake Valve. Then finish the other 7 cylinders. Don't forget the power to your distributor. Gap the spark plugs at .032 to.035.

Bob  

nitrostreet57 nitrostreet57
New User | Posts: 3 | Joined: 03/13
Posted: 03/23/13
08:06 AM

I think we would first need to get a little info about your motor and how you got here like:
Was this motor running (did you witness it running) and did you just change a few things and now it doesn’t?
Or: Did you completely rebuild this motor and now it won’t fire up?
Or: You’ve never seen this motor run before
Because that will change what you need to look at, if you’ve never seen it running you’ll need to determine if it actually will run, and if you rebuilt the entire motor you’ll need to determine whether you’ve got things done right like ring gap, cam to crank timing (timing chain), distributor clocking, ect.
If it's just a motor that you’ve just changed a few things and now it won’t run we just need to determine everything you changed and how it all needs to be set to run, if you’ve changed the rocker arms they’ve got to be set right or the motor will not run, if they’re set to tight or loose there’s a possibility that they could bend valves, pushrods, break springs, punch holes in the piston tops, ect., so you’ve GOT to get the rockers set right (also need to determine first if it’s a hydraulic cam or a solid cam) but everything else that was done also needs to be listed, or there would be no way to correctly diagnose the problem.  

Buick83 Buick83
New User | Posts: 4 | Joined: 03/13
Posted: 03/27/13
06:23 AM

Thanks Bob

I will try these things first to see I will get back to you on the results wish me luck  Grin  

Buick83 Buick83
New User | Posts: 4 | Joined: 03/13
Posted: 03/27/13
06:40 AM

I've had this motor for a couple of years before I pulled it out of car and had it rebuilt completely so yea I had a running car and know what I have for a motor. Motor was originally from a chevy k5 blazer. So now it won't fire up after I just put motor back in car. A friend of mine has been helping me with the adjustment of the rockers.  I have a solid cam in the motor. We adjusted the timing checked to see if have spark I went over it many times the only thing I plan to do is remove the spark plugs to see if maybe they are wet and try again this weekend. Any suggestions you have I would appreciate  Grin  

68scott385 68scott385
User | Posts: 51 | Joined: 07/09
Posted: 03/27/13
09:40 AM

IMO, you need to check, recheck, and possibly triple check that the valves are adjusted correctly. If they are too tight, they won't close and the motor will not start. You need to make sure you have the distributor in the right way. They are very easy to install in the wrong direction. Make sure all the plug wires are going to the correct terminal on the distributor cap.  
68scott385 68scott385 68scott385

nitrostreet57 nitrostreet57
New User | Posts: 3 | Joined: 03/13
Posted: 03/28/13
06:52 PM

Since you have a solid cam I've found this is the most accurate way to adjust the valves, first figure out what your valve lash is, sometimes it's different on the intake and exhaust valves

1. Hand turn the engine in its normal direction of rotation while watching the exhaust valve on that particular cylinder. When the exhaust valve begins to open, stop and adjust that cylinder's intake valve. (When the exhaust is just beginning to open, the intake lifter will be on the base circle of the lobe, so the intake is the one we can now adjust.)

2. Use a feeler gauge, set to the correct valve lash, and place it between the tip of the valve stem and rocker arm. Adjust until you arrive at the proper setting and lock the adjuster in place.

3. After the intake valve has been adjusted, continue to rotate the engine, watching that same intake valve. The intake valve will go to full lift and then begin to close. When the intake is almost closed, stop and adjust the exhaust valve on that particular cylinder. (Again, when we see the intake valve almost closed, we are sure that the exhaust lifter is on the base circle of the lobe.) Use the feeler gauge and follow the procedure described before in step 2.

4. Both valves on this cylinder are now adjusted, so move to your next cylinder and follow the same procedure again. In the future you may find shortcuts to this method, but it still remains the best way to do the job correctly.

After you get the motor started up and run it for the cam breakin period you'll need to go back and adjust the valves warm.

I don't know if this forum will allow links but heres an article about setting valves like I've detailed above with some pictures that might help:  
http://www.dragzine.com/news/how-to-set-and-adjust-valve-lash-like-a-pro/

Also double check your distributor, it's real easy to get it in 180 degrees off, the easiest way to tell would be to take all the plugs out and then find number 1 cylinder, then ( I always use my finger but some will say not recommended LOL) stick something larger than the spark plug hole where the #1 plug was and spin the motor over until you get the whoosh of air coming out, that means you're getting ready to come up to the top dead center of that cylinder. If you then look at the distributor rotor it should be pointing towards the #1 plug wire with the cap on.
If it is the distributor is close enough that you should be able to get it fired and then set it with a timing light after it's running.
Good Luck  

68scott385 68scott385
User | Posts: 51 | Joined: 07/09
Posted: 03/29/13
05:27 AM

http://www.dragzine.com/news/how-to-set-and-adjust-valve-lash-like-a-pro/

nitro, you have to be in the right screen to use the link feature and then it's crap shoot, the forum won't allow links to some sites and there doesn't seem to be a pattern...  
68scott385 68scott385 68scott385

nitrostreet57 nitrostreet57
New User | Posts: 3 | Joined: 03/13
Posted: 03/29/13
07:24 PM

Thanks Scott,
At least it didn't remove any of the address so it was unrecognizable LOL