First thing I would do is check intial timing and total timing. See what rpm it is all in by. Is this a stock balancer(age)? If so it may have slipped a few degrees. Do you have the right pointer for your application some use a 10 o'clock others use an 11 o'clock. You need to find top dead center. The easiest way with out tearing a head off is to use one of those whistles you screw into your spark plug hole(it whistles when the valves are closed and stops when it hits TDC). If this checks fine, I would next check fuel pressure and volume just before the carb inlet. If you have a weak spark the car would feel as if it running rich not lean. Result equal fouled plugs on all cylinders. If it is cylinder specific a Plug inspection after cranking it to 4k and hearing it ping or pop, and then shutting it down and pulling the plugs(immediatly after shut down) will give you a clue as to what is happening. Popping is different from pinging. Popping may indicate ignition crossfire or lifters pumping up as a result of a slight over adjustment at the higher rpm. Also vacuum leaks at the carb base or intake runners can cause alean condition. Spray them down with some carb cleaner and if the engine rpms idle up you have a vacuum leak(advice before this test spray the igntion wires cap with water from a spray bottle this will do two things indicate a wire shorting to ground/bad cap and insure the carb test won't blow up in your face if the igntion were to ignite) Keep a water hose handy:evilsmile I've only had one in about 500 catch fire but it can. Scary stuff. Concerning the power valve in the carb, personally I doubt it's the culprit as it would likely show more symptons just off idle. Same with the accelerator pump. That would give you a bog not popping or pinging. IMO the best way to tune a carb is to use a air/fuel meter it doesn't lie and fills you in on the A/F from idle to wide open. Your Carb should be big enough,but my holley XP is limited, I much prefer demons. Easier to tune IMO if you get the Street/Mighty/King demon. If all the stuff checks fine then it's almost gauranteed it's carb related. Is it a newer carb? or just something you slapped on or rebuilt? Sorry to give you so many things to check but if you wantit fixed and donlt want to just throw parts at it this info should get you in the right direction. I pMed you my number if you want to give me a shout to pick my brain Lance
Are the valve springs up to snuff, had a similar problem with a car with the wrong valve spring pressure for his cam. Just an idea to check
I am running Autolite 32's with a .030 gap I believe. The last time I pulled the plugs they looked a little better, but there were some black specs on them still, I haven't pulled them in month or two now. The dizzy was used, the cap is the new later model cap and a new rotor. The wires are 9mm Ford Racing wires. The coil is a 45,000volt pertronix flamethrower, it has a ballast resistor inline with it to bring the ohms down to the level spec'd by pertronix. It is a used ford balancer, had some cracks in the rubber but it was all I could afford at that point, I have considered buying a replacement one for $50 now. This is definately a popping, not a ping, especially heard when the header plugs are out. The valve springs were matched to the cam by my engine builder, I believe they are 125# at the seat and around over 325# open. I gets off the line GREAT, but once I hit 4k, it's over. I think that was everyone. Originally I had a rebuilt 600 on this thing, but I never got it to work correct (it went CRAZY lean at 2k rpm, never figured out why) so I bought a brand spanking new 600 vac. 2ndary with the auto adjusting needles and seats. The new carb seemed to help, but it was definately LEAN, so I jetted up until I got it to smooth out until about 4,000rpm. The maverick is my only car, so I have to drive it like this no matter what. I try and keep it below 3k rpm until I can figure out the problem. Then, when I get enough good ideas to try, I tear into it for a weekend. My folks recently moved to Arizona and left me behind in IL. As soon as their house sells, I will not have a garage to work in. I'm getting a little frustrated but I can't give up. My car is my life, without it I would have trouble getting to work and school, so I WILL figure this out.
I had a simular problem a few years back in my old 302. Would pop and breakup at about 4500rpm. Turned out to be a combo of two things. First was spring pressure..when I had the heads rebuilt they put in the wrong year of valves. Noticed this when I pulled the covers and all the intakes were at a differnt height than all the exhaust valves...and I only had 30lbs seat pressure on the intakes(could push them down with my hands). Thought that would fix the problem but it was still there. My car was orig a points car...I had converted it to Duraspark a year or so before and used the same wire(there was only one) from the ignition to power the coil and power the box. As rpms went up the box started sucking more power and the voltage to the coil would drop and cause a missfire. Tested this by running power directly from the battery to the coil...miss was gone! Not saying that this is your problem...but there are some pretty weird things that can happen....hope this helps out..but it probably won't
When the "popping is through the carb its a lean mixture - that what I thought when I first started reading the thread. When you said you heard it more when you opened the header caps then I realized... The two things that can cause this kind of problems are weak or mis-timed ignition or weak valve springs / heavy valves or valve hardware. You are running a fast opening cam with a 1.7:1 rocker so that might be a consideration but you say it only happens when you get on it hard. Weak valve train wouldn't care about how far your foot was in it - just what rpm you were at. That leaves the ignition system. Check the specks again on the Pertronics unit - See if it is supposed to have that resistor on it with a flamethrower coil. Fords use a resistor wire to the coil and if you are using the factory harness you might be using two resistors when you should only be using one or the other. Check the cap and rotor for carbon tracks (they look like cracks) and replace them if there is anything questionable. Weak spark will only cause problems when the demand for hot spark is high. That happens when you are under a high load in the higher gears more than any other time. When you check your power wire you will probably find that you are using the resistor wire and the external resistor at the same time. Remove one or the other and you will be fine.
I had the exact same problem with the 427 Windsor in my Fairlane. I removed the resistor wire and ran 12v to the Pertronix and it solved the problem. I think that the Pertronix instructions are somewhat vague and contradictory. At one point they tell you that it is OK to use the factory resistor wire, but then they make reference to eliminating it. (I am using their Flamethrower coil also)
I lean towards getting full battery power to the Pertronix at this point. I also think .030" plug gap is a little tight. Get full power to the ignition. If that doesn't help, Disconnect the secondary side of the carb and see if the problem is still there. That will either eliminate or confirm that the carb is part of the problem. Good luck Dave
I am definately running only one resistor wire, I will try the full voltage and see what happens. (I ran a trigger wire to a relay which supplys the coil with it's power initially)
I ran full power to the pertronix and it runs a little better, pulls a little harder. It is still sounding "lean" around 4,300-4,500 rpm. I am going to put some new plugs in it before I screw with the carb, what gap would you guys suggest? Also, how do I disconnect the 2ndaries, just plug their vac. line?
now that i read all the responses, this could be a problem i have. if i run my car over 5200 rpms, my engine starts to pop like crazy and it falls on its face and wont run good for the rest of the trip down the track. i thought this was valves floating. my spring pressure is 120#, and i have the complete MSD ignition system. could this be my prob or is it valves floating? i thought it might also be my performer 289 falling off as well.... but i really dont know what it is and my MSD box is wired off the factory harness, and so is the MSD Blaster SS coil. how do i run power off the battery for the ignition? im not good at electrical work, so any help would be great.
Simon the large black wire should go straight to ground and the large red wire straight to the battery. The MSD unit is turned on using your factory coil wire connected to the small red wire on the MSD or a key-on 12 volt source. The small orange wire on the MSD goes to the + side of the coil and the small black wire goes to the - side of the coil. It depends on which distributor your running on whether the unit is triggered by the white wire (points) or purple and green wire for magnetic trigger.
http://www.msdignition.com/1download.htm Got all the answers here! Read all the print, run grounds as stated and wire hots to the source. Remember to keep your box cool.
i used their directions when i installed mine a long time ago... i am using the MSD Pro Billet Dizzy, MSD 6a box, MSD Blaster SS coil, and MSD 8.8 wires i cut into the existing wires when i installed my ignition... according to the directions from MSD... but someone told me a long time ago that the fuesable wire is only 7volts, instead of 12.. never thought about it since the car runs fine. but now after reading this thread, is it possible that under hard exceleration that the voltage might not be all there??
