New distributor, now Surging 350

[edwardgonzalez]

I've been driving myself crazy with this. Truck was running ok before I installed a new accel distributor. It always ran really rich so I wanted see if a new distributor would do the trick. I have an 81 c10 with a junkyard 350. Like I said engine always ran ok since I put It in back in 2007. It has an edelbrock 650 cfm manual choke also an edelbrock intake other than that it is stock. It ran well but I got tired of smelling unburnt gas so I decided to try and fix that. Found out that edelbrocks don't like too much fuel pressure so I fixed that by installing a Holley fuel pressure regulator. I have it set at 5 psi. Worked a lot better but still smelled like gas. Changed plugs, wires, control module, new msd coil. So I figured it would be the distributor. I bought the accel hei distributor. Found tdc on cylinder one using a vacuum gauge in the spark plug hole and put the distributor in. Truck turned on but now it surges a few times and dies out. I push the throttle and it hesitates before it revs up which was never a problem before. Also shakes a lot more than before. I can't time it because the timing mark seems to jump all over the place and the flashing from my timing light isn't consistent. Almost seems like it's not getting spark all the time from cylinder one. Or my gun isn't working anymore. It's possible it's an old timing gun. Any ideas on why it's surging, or why it was running rich all the time before? I tried timing it before but it seemed like nothing helped I went from 8-14 degrees and also played with spark plug gap. I'm so frustrated I almost want to give up. Any ideas guys?

[lindstromjd]

I use .60 gap ACDelco spark plugs. And I've never heard of finding TDC the way you described. I always have a friend bump over the engine with the #1 spark plug out and my thumb covering the hole, or take off the valve cover and watch the valves. As soon as the intake closes, you're near the top of the compression stroke which is the one you want. The relation of whether the rotor is pointing at the #1 cylinder has no bearing on setting the timing as long as you get the spark plug wires hooked up correctly, then the firing order is 1-8-4-3-6-5-7-2. Soooooo... I would re-set your distributor. Take it out, ignoring where it was and where you think it should be. Find TDC compression on #1, and set it in. If the oil pump doesn't fit right, just spin it with a long flat-head screwdriver until it does. I have found that setting the timing at 10-12* BTDC works pretty well for me.

I think your biggest problem with running rich is that Eddie-brock carb. First off, it's a square bore carb on a stock 260-ish horsepower engine. It's just dumping too much fuel for what the engine wants. Personally, I like the Quadra-jets.

[enaberif]

.040-.045 is the gap you should use for most Cheys using HEI.

To find TDC just stick a piece of tissue paper in the spark plug hole and turn it over... It'll pop out when your on the compression stroke.

[Chaplain]

Good feedback.

[lindstromjd]

Originally Posted by enaberif

.040-.045 is the gap you should use for most Cheys using HEI.

To find TDC just stick a piece of tissue paper in the spark plug hole and turn it over... It'll pop out when your on the compression stroke.

My truck says it wants .060 gap, so that's just what I've always used. I know the newer systems like smaller gaps, but I figured that the HEI's can burn a little better with a bigger gap.

[4x4k30]

its sounds like you have a burnt valve or dead cylinder the rich mixture is caused by the cylinder loading up fuel but not firing I would run a compression test on all cylinders

[enaberif]

Originally Posted by lindstromjd

My truck says it wants .060 gap, so that's just what I've always used. I know the newer systems like smaller gaps, but I figured that the HEI's can burn a little better with a bigger gap.

Out of curiosity where does it say this? Even the newer trucks which were being gapped at 0.060 have started going back to .045.

It takes a heck of a system to properly run a 0.060 gap and a HEI system seems to like 0.40-45 as when I got my plugs it was gapped at 0.030 and it ran like a dog.

[lindstromjd]

Originally Posted by enaberif

Out of curiosity where does it say this? Even the newer trucks which were being gapped at 0.060 have started going back to .045.

It takes a heck of a system to properly run a 0.060 gap and a HEI system seems to like 0.40-45 as when I got my plugs it was gapped at 0.030 and it ran like a dog.

Right on the radiator support where it calls for timing and spark settings. And the ACDelco ones I bought were even listed as OEM setting at .060

[Titomars]

HEI systems back in the 70's were spec'ed for 0.60 gap plugs. But it was changed to the 0.040 to 0.50 range due to the extreme spikes in voltage being so high it would burn through the rotors and plug wires. now a days it is an accepted norm to go with 0.45 gap.