The Stovebolt Site Forums The Shop Area Engine Shop 327 snc no start

Got a real stumper on a 68 327 sbc I installed for a friend. It ran beautiful when installed, then a month later it started to miss. He horsed around with his timiming a bit, took his cap and coil off to inspect and it hasn't started since. Then he called me, I rechecked cap, rotor, coil. Took distributor out put on #1 compression, reinstalled no start. Verified 12V @ coil, cleaned spark plugs, they were a bit fouled and wet (accel shorties)rechecked firing order... no start. Because it stopped starting after he messed with coil thought it might have gone (accel super spark), he purchaced a whole new dist, cap, coil. Installed no start, replaced plugs with AC delco brand new... no start. The new cap is the clear platic I can see it distributing spark as it turns, he has a plug tester, it lights up as the distributor turns. Ran a wire from the positive terminal to distributor.. no start. Voltage on live wire @ hookup is 11.7V, all grounds hooked up, no vacuum leaks, put my thumb over spark plug hole and compression "blows" my thumb off. Also when I say no spark I mean no kick, backfire nothin... just nananana! Lastly spark plug wires are brand new MSD brand. Sorry for the long read, just wanted to give all info, any input or ideas would help.

Thx

It sounds like you've eliminated electrical,now check the fuel system.

Demon carb gives a good sqirt @ jets when accelorator it pushed.

Change the spark plugs. Yep, I know they're new- - - -doesn't matter! Once some plugs have been fuel-fouled, they just don't work. Why is he wasting money on all that hotrod stuff? All he's buying is the name. Original-equipment AC parts are as good as it gets. Buying race parts for street use is like pounding sand down a rathole!

Edit: If he simply insists on trying to re-use the fouled plugs, at least pull them and get the tips red hot with a torch to burn the fuel fouling away. SOMETIMES a fuel-fouled plug can be salvaged that way, but don't count on it.
Jerry

One more thought, See what that Demon is squirting.
It wouldn't be the first time if it turned out to be gas contaminated with Diesel fuel or water.One won't start on poor fuel.
If it were mine it would get a good squirt of starting fluid to see if it would respond.
Also check for strong spark at the plug by holding a wire to make it jump to the PLUG in the engine.A weak spark may jump an air gap outside the engine but be too weak to fire the plug under compression.
I am reading that this is an HEI type coil in cap distributor--it wasn't stated.

Hey Hotrod just to clairify you are suggesting I replace the new AC's I installed? I have had them out since I've tried to start it and they still look good. They are gapped @ 0.43". He bought the shorties as he is running headers and it is close clearance, and the coil was on the car when he got it. If it was a matter of new plugs I would do it, just want to be sure.

hey enginenut, that never thought of that. It was after a trip to the gas station this started to happen. I'll try a splash of good gas in the carb and see if it does anything.

Also today I'm gonna install his distributor on my truck to verify the coil is emitting a hot enough spark.

Also yes its an HEI set up. Thanks for the replies so far!

Pump a little of his gas into a container, toss it on the ground, and drop a match into it. I've seen gas go so stale it won't match-light in a month or less, and if he's gotten some Diesel fuel onboard, it definitely won't start!

If the plugs have gotten fuel-soaked, it's possible they have a conductive path down the porcelain, no matter how new they are. Edit: I re-read your original post, and I guess I missed seeing you'd already done a plug swap. If they're fuel-soaked again, at least heat them up with a torch. It's possible the carb is flooding so badly it's soaking the plugs at every starting attempt.

Just an observation- - - -Demon carb, headers, Accel ignition, high-dollar wires, and probably a lot of other go-fast stuff just isn't necessary for street use. It sounds like somebody is more interested in bragging about all the expensive accessories the engine has than actually building in reliability. I spent a lot of years building NASCAR race engines, and I didn't use half that stuff to win races pretty consistently. My engines ran 7K RPM + on stock-appearing parts and easily outran most of my competitors.
Jerry

Hotrod I know what your saying, thats why one of my first suggestions was for him to switch to the AC delco plugs. This afternoon I had him bring his new distributor to my house. I installed it in my truck and no start. Then I put my cap on his distributor and again no start. I believe it is the magnetic pickup in his distributor. Will swap it out and reinstall the distributor in his car. I'll let y'all know how it shakes out. I do believe the accel plugs caused him original miss and started this whole thing.

You might want to double check that you have # 1 plug wire in correct location on distributor - seems to me there were ( 2 ) possibities depending on engine ??

I confirmed #1 britcon thx 4 the suggestion

There's a quick way to check the magnetic pickup. Disconnect the 2-wire connector from the pickup to the module and connect an AC voltmeter to the wires. Spin the distributor by hand, and the pickup should produce about 1/2 volt AC as the shaft spins. You can also check out the entire system by installing the cap & coil assembly and leaving the top cover off the coil. Don't forget to connect the wire harness from the module to the coil. Clamp the distributor housing in a vise and connect a 12V battery to the ignition coil + terminal and ground the negative battery post to the vise. Spin the dizzy shaft by hand, and sparks will jump from each spark plug terminal back to the coil housing. It takes about 50K volts to make that jump, so that's more than enough to jump even a wide plug gap. It's also possible to have a hole burned into the rotor which allows the spark to jump directly to the distributor shaft and never get to the plug wires.
Jerry

Thanks for the tip on how to check the voltages Hotrod. Problem was two fold. #1 when it stopped starting the first time a bad coil was suspected. He was gonna buy a new distributor anyway so this pushed him to buy one. The one he bought had a bad pickup (off craigslist... prolly the reason it was for sale in the first place). It wouldn't fire in my truck. So he installed in his car after installing a new pickup and nostart. #2 really the only reason... bad gas, I tried some out of his lawn mower and it kicked right away. He had half a tank so we syphined off as much as we could, added a bottle of seafoam plus $20 bucks new gas now it runs like a million bucks. Thanks for all the helpful replies he is very happy now.