New Engine Won't Start

Looking for advice/hints

Just installed my rebuilt 401 and it won't start. Turns over fine, but not even a pop. Gas is feeding into the carb and I checked for spark at a couple of plugs and have spark, but it just won't fire.

I checked to be sure the distributor was in correctly twice. Rotor is pointing at number one plug wire and timing mark is aligned with zero on cover. Since I had the valve covers off to check for oil to the rockers when I pre-lubed the engine I verified that number one cylinder was at TDC and valves were closed. Even if I was off on installing the distributor, I expected to at least get a pop when trying to start, but there is nothing. Spinning distributor in either direction did not make a difference. No points to play with as I am running an MSD distributor. The motor ran with the distributor before the rebuild. The only change I made was to change the springs and bushing to set curve.

Verified fuel flow by removing line from carb and placing in container. Also, was able to see fuel in throat of carb and plugs were wet. The carb is the original 4GC which was on the car when it ran before the rebuild. I have made no changes to the carb, since the engine last ran

At this point, I have spun the engine over quite a bit, so I am contemplating removing the intake and valley pan to re-lube the cam lobes. Also, going to order more break in oil and drain what is in the engine, as I am concerned about the amount of raw gas that went into the engine.

Just looking for any advice so I don't have a repeat the next time I attempt to start the engine. The only thing I can think of is that I have spark, but not enough to start the engine. What is the best way to check for good spark, besides by eye? I am pretty sure I am not starving for fuel; at least it doesn't look and smell like I am.

Thanks
Doug

 

Thanks Joe
Will check wiring to coil. I thought I put it back just like it was removed. Would I still get spark if it was wrong?

No points, running MSD distributor

 

if there+ and- were reversed u woud have a weak spark. you must have adjustable rockers are the valves opening and closing when you look at the valve springs. yes msd I should have read your post better lol. your getting gas, got to be spark or comp.

 

Yes, valves were opening when I assembled. I will pull covers and double check.

 

Gas air and spark all present? Pull #1 plug and put it in the plug wire and set it on the plug hole in the head and turn over the engine with the key trying to get the spark to ground. If it kinda fires off put it all back together and try again . Maybe a bad / no ground strap from engine?

 

when u turn the distr all one way it must turn over hard? after checking what moleary said. you can run a jumper wire from + battery to + coil.

 

Thanks Mark

I checked spark at #1 and #8 as you described and saw spark between electrodes of plugs. There are two engine ground straps. One on each head to firewall. I will remove and check for good contact as everything is freshly painted

 

Still Try the test I described. I have encountered this in the past and for whatever reason it might fire with a spark plug grounded then reinstall and off it all goes! I bet I have done that three or four times in my life when an engine wouldnt fire for some obvious.

 

Mark, now I understand. You want me to see if engine fires with one plug out - will do

Joe, will try the jumper to the coil as well

 

Hows the health of the battery?

 

Check cranking voltage - ask Ken @ Everyday about that. I think he goes by Techg8 on this board, and just went through this.

 

I questioned the battery as well, so I pulled the battery from my tractor, but it made no difference

Rhett, I will reach out to Ken

thanks

 

Sounds like you done most of it already. Hmmm.

Probably a silly question but when dizzy and lifters show TDC is the timing mark on the dampener lined up with the pointer. Doubt it would happen but could crank be misaligned with cam ie: did they set cam up correctly?

MSD dizzy? Do you have a ballast resistor on the coil? If heavily flooded I'd pull all the plugs and let it 'breath' then try again.

Damn it's hard to guess the problem when you're not bent over the actual engine
Pass me that hammer ....

 

To install the distributor I lined up the mark on the dampener with 0 on the timing cover and checked to make sure the valves were closed, then dropped in the distributor so the rotor pointed at the number 1 plug wire. This is always how I had done it, is that not correct.

I am running the MSD Pro-billet distributor (part# 8525) for the Nailhead. I am not running an MSD box or a ballast resistor. The distributor is wired per the instructions: orange wire to coil negative; red wire to coil positive; black wire to ground.

Here's a question - I am running TA's roller timing set with adjustable timing gears. The cam was installed 2 degrees advanced so it would degree out to match the cam card. Would advancing the cam change my distributor install procedure? First time I have ever needed to do this - previously all cams were installed straight up

Thanks

 

Doug,
Fresh build, won't start. If you have convinced yourself that the timing, spark and fuel delivery is OK......... pull all the spark plugs and run a compression test. If OK, GO BACK.

Cam timing and spark timing anywhere in the ballpark would fire if you have compression. If it won't even pop or backfire, you don't have compression. Valve may be held open, even .010 to .020" would dump all the compression.

 

Exactly the way I did my dizzy, always have so no problems there.
2 degrees shouldn't make a major difference, we put together my friends blown alcohol small block like that two weeks ago and it fired first time.
What I was asking is if it was possible the cam was installed on the wrong stroke, 360 degree crank rotation wrong so the cam was completely out of synch.
Crank turns twice for every one turn of the cam so it is possible, although not likely. Just another thought as most else doesn't seem to be helping.

What cam? lifters? pushrods and rockers? All stock?

 

During cranking, 12v is supplied to the coil via the yellow wire from the starter. You could bypass that with a jumper from the + terminal on the battery to the + on the coil, ensuring you have full voltage there.

You could take that one step further and determine if the cam is installed right... Rotate the engine by hand while watching the #1 cylinders' valves and the crank timing mark. Watch the exhaust valve open and then close. The intake will start to open just before the exhaust closes. The mid point of exhaust closing/intake opening should be at TDC (of the exhaust/intake stroke). Now rotate the crank one revolution back until the TDC marks line up, and your dist should be in the #1 firing position.

Also, wet plugs often won't fire at all. make sure they're dry before trying again.
Good luck with it!

 

I am pretty sure I have the distributor installed correctly. I can spin the motor with the starter while watching the valves on #1 move with the #1 plug out and grounded. Exhaust valve opens and closes, intake valve opens and closes, plug fires (proving I have spark). I will find a volunteer so I can spin motor by hand and watch valves as Walt suggested.

I am keeping a list of all the suggestions and will run through them all until I find the problem. I need to order more break in oil (current oil has a faint smell of gas from attempting to start so many times yesterday), so I have some time.

Thanks