Rings. Id bet they did not get seated right upon break in. You can wash the oil out of the cyls by flooding it with gas. Would create the rings getting hot, and either they swelled up and wore off, or they got hot and lost their "spring" and lose contact with the cyl wall. excessive blowby out the valve covers is the dead give away, also, if your running 10 to 1 compression, you should be running a higher grade fuel than your plain jane pump gas,, it sounds like marbles jiggling in your hand when it detonates, and you can break ring lands off the pistons, etc etc etc. Id consider pulling the heads back off, (you can do this all in the car) pull the pistons out and have a closer look. I fought a 400 Chevy for 3 weeks at 11 to 1, it finally broke the ring lands off the pistons. Took out the 11 to 1s and dropped in 9 to 1s and it ran so much better,,, could run cheap gas in it too. Low compression, is valves, rings, headgaskets, bad lobes on the cam, (but youd see shavings or chips in the pan or filter) Since the heads are new, or newer,, Id point to the rings or a damaged pistons,, it does not take much to break them if it pings too hard. Worst case scenario, is your out a set of head gaskets, intake gaskets and a oil pan gasket if things check out. PS ,,, on the 400,, I was able to straighten out the new rings in a straght line without breaking them,,, thats how hot they got and lost their ability to spring against the cyl wall. Just my .01 worth. ChadS
i have been running nothing but super in it and still probs, i started pulling wires and 3,2,5,8 are firing sparaticaly, the others are steady. i have changed the ignition module, and still nothing, the wires are new also, two of the 4 plugs were soaking with gas, the other two were black. the 4 that are firing good are a nice tan color. the four that arent firing right are fed by the right side of the carb. i took the carb apart yesterday and gave it a good cleaning, it was a little dirty but not really bad at all. i checked the jet,rod and springs to verify they are stock and they are for the 600cfm edelbrock. is there anything obvious that i may be missing or does it sound like my carb is the culprit?
Are the cyls wet, on the same side or on opposite sides? If they are onthe same side, check and make sure the primary jets are the same. Sometimes, you can get one that is bigger than the other. Ive seen where new plug wires are junk, especially from autozone, put a new set on on our old 1 tom ford laid a cresent wrench on top of the cap and they leaked spark right to the wrench. Id look into a hotter plug, the IGN box. fires 2 sparks instead of just one, so it you see more than one spark, or it pulses, its supposed to do that. Also, you may have a tang in the pick up thats worn and have more gap than the others,, might create a miss,,, Ive also pulle the spark plug wire half way off the plug and got plugs to fire,, but if they have been gas soaked, they are fouled and need replaced. Im a fan of autolites, so wallymart has a god price on em in sets of 2 or 4. If you get it to run on all 8, set the idle up to about 2500 and let it run for about 30 minutes, if this thing has little milage, I belive your fighting break in,,,, sometimes, you just have to force them to run on all 8 and let it run till the parts get broke in, then start tweeking it better. Too many adjustments off the bat can screw it up quicker than the original problem. Also, if you go a hot aftermarket coil, try another stock style coil, may not be comaptible with your Duraspark (if thats what you have) is the coil getting hot? is the module getting hot? do you have a full 12 volts at the coil, and to the red wire of the module? red wire to the +coil, white goes to start on solinoid. If they are switched,, I wonder if it would throw things out of whack,, till then, Id look a the IGN,,, sufficient power, new plugs at the proper gap, a coil appropriate for the electronic IGN, firing order,,, (not the same as a 302) make sure the valves are closing,, too tight on the rocker, may hold it open while its running and lose cyl pressure,, but close enough to build pressure when its cranking,,, try loosening up the rockers a bit,,,, see if the presuure comes up,, sometimes, if a cyl head has been milled, it can throw off the geometry of the valve train, it can hold the valves open, if its milled alot,,, mismatched heads can do it too. Chad
http://cgi.ebay.com/ebaymotors/FORD...008QQitemZ180112194137QQrdZ1QQsspagenameZWDVW this is the dizzy i have, also it has a switched 10ga wire to it for power, the spark plug wires are the universal accel 8mm wires, they didnt have the msd 8.5s at the time. i dont think it is loosing spark because it was doing the same thing with the last set of wires also. i am running autolite 26 plugs in it now, i have put about 100miles on this engine since its been fired all the rocker arms were adjusted dry to the t following comp cams directions.
351Wmav2 - Answer the following questions and i will see if I can help. My 351W in my Bronco was doing the same thing and as of this moment it seems to be doing fine. It seems bizarre that your carb is causing your 2,3,5 & 8 cylinders to be wet as that does, for the most part, point to an improperly tuned carb. In other words, you are obviously VERY rich on that side of the carb and it needs adjusting. 1. What carburetor are you running? 2. How far out do you have the idle mixture screws? (Right and left) 3. Have you set your #1 cylinder at TDC on the compression stroke and aligned the distributor accordingly? 4. Are you using the 1-3-7-2-6-5-4-8 (351W) firing order http://www.carmemories.com/cgi-bin/viewzoom.cgi?image=2055 or the 1-5-4-2-6-3-7-8 (221-302) firing order http://www.carmemories.com/cgi-bin/viewzoom.cgi?image=2056 ? 5. Have you removed the resistor wire from your harness and ran a full, switched, 12V to the coil in the cap? (HEI type ignitions require a full 12V!) Check the voltage here and make sure you have the 12V required to eliminate this as part of the problem. Doubtful it is, but I have seen the resistor wire be the culprit before. (As I own a Che$%^& with an HEI myself that has been converted over) 6. What gap are you running on the plugs? I bet you are using .035. That is too close for an HEI to run properly. It will fire the plugs, but not all that great. With the HEI you can run up to .065 but a .040-.045 is a safer bet for you, regardless of compression ratio. 7. Any loose vacuum connectios? 8. Is your vacuum advance connected to the proper port on the carb? (It should be connected to the one on the carb that has no vacuum at idle but has vacuum when the engine is revved up - a.k.a. - ported vacuum) If you are connected to the wrong one, and you set your timing, you could be setting it with the timing already fully/partially advanced due to vacuum being present at idle on the improper port on the carb. Check your PMs for my contact info.
Ok ill answer these in order... 1. 600cfm edelbrock performer 2. i have them set at 1-1/2 turns out 3. i have no timing tab, but it is set at #1 tdc 4. i am using the 351w firing order as listed on compcams website for my cam, there is a link to it on page one of this thread for specs 5. there is no resistor wire it is a new switched 12v to the dizzy, i have verified 13.6v while running with multimeter 6. i have them gapped at .045 7. no vacuum leaks, just dizzy and tranny lines, both are new hoses 8. the vacuum advance is on the passenger side port.
is this the dizzy your gonna run, or you got this one now? Do you still have the stock Dizzy that you took out of it? with the duraspark box? Hers my take on custom dizzys, they got to work, and ive seen alot of good parts, by name, not assembled right from the get go, not saying they are junk, but if something cant be done to correct it, and a different dizzy solves the problem, Id be leaning towards looking for things, defects, or assembly mistakes. It does happen, with aftermarket parts. One way to check, if the electrcal is good is to pull both valve covers, pull the plugs, and put each cyl on TDC when its firing, look at the rotor and see if its pointing to the right tower, or possibly off by a degree or two, I bought a dizzy a while back, custom custom custom, put it in, followed the instructions, would not run. pu the stocker back in, run like a racer, had a closer look, the rotor wasnt no where close to where its supposed to be, like putting a chevy cap on a Ford. Might be just a glitch, by design, or by fate, but if the stock dizzy dont change it, just gotta rule out every possibility, but its just whats happend to me before. (it why I went to FORD) learned it young, but now I get to work on a few. Parts swapping is the easiest diagnosis sometimes. test and test.
How old is the carb? It sounds like you need to pull it off and clean it out. Regardless, it sounds to me like you have some debris in your metering rod jet and it is causing it to flood out on your 2,3,5 & 8 cylinders. Look real close at the drivers side metering jet as that is the one that feeds those cylinders. When too much gas gets in the cylinder it will not allow the plug to fire and basically it "blows" out the spark and will not allow the mixture to ignite. I would recommend 2 1/2 to 3 turns out from the bottom for the carb adjustment on both screws just to get you started. As for the timing tab, why don't you make one out of a piece of wire and bolt it on the front of the block and align it to the TDC mark when you have the #1 at TDC. You do have the vacuum advance connected to the proper port on the carb too.
Check the head gasket torque. Bolts come loose from gaskets swelling and shrinking from heat when new. May have popped a fire ring, and it can do it very easily if you find a few head bolts loose.
ok i gapped 4 new plugs at .055 and put in to replace the affected cylinders last night and swappwed the carb from my brothers truck ( a known good one) ran like a champ, then started to run like crap, started pulling wires and it was the other 4 plugs not firing. stuck in 4 other plugs gapped at .055 and swapped my cleaned up carb. ran awesome but made a siren like sound, started feeling around and it is leaking at the base of the carb on the passenger side. i will be replacing the gasket today. do i need an adaptor plate or something? also will a vacuum leak fuel foul the plugs? it ran 10times better than before even with the vacuum leak
also the old dizzy was a single points type unit not a dura spark. and that is the unit that is in the car now. it is basicaly a stock chevy hei unit on a ford dizzy shaft. the carb has been on 3 or 4 different rigs. i completely dissassembled the carb and it was just a little dirty inside, i even replaced the main metering jets with new ones just in case. i went to town with carb cleaner and a toothbrush this thing is just as clean as a new one now.
Wow. This thread started on 2006-07-30. 'Glad to hear you're finally zooming in on the problem. Better luck in the future.
