So I am reaching out looking for some help, advice, with this engine. Here is what we have to work with 302 Ford, rebuilt Chevy style HEI dizzy conversion At top dead center Proper firing order / older style cam When cool it is hard to fire. acting like the timing is off but will start with some fussing. When it runs for a few mins it starts to stutter then dies, as if it was starving for fuel number 3 and number 6 cyl get hotter then the rest. I tested this with my IR gun. we are not talking huge temp differences, but notable If allowed to sit for five or so mins after all this, it fires right up, but will die again with the same symptoms. if I try to re fire it right away, it back fires up the carb. The gas in the tank is high test and new, plugs are the proper ones and gap is correct. I have had the valve covers off and turned the engine over by hand to be sure all the valve train is operating properly. Everything is moving as it should and I have seen no binding. Any one have a thought as to what it might be??? I'm getting a little frustrated with it all. Thanks in advance.
I thought about the firing order as well. So I gave it a shot. that's not it. It is an after market cam though. Not really big, but enough to rumble at idle. Has any one had any experience with these Mallory Chev HEI dizzies that are converted to run in a Ford?? I had this thing running well, then....... I changed the dizzy, plug wires and took a carb spacer out. I changed it from the stock Dizzy to this Chev conversion. Slick unit, but I have never used one before.
I thought that as well. I tried it both ways. It won't run with the newer firing order at all. I took the cap and rotor off this dizzy, to check and see if anything looked out of place. I noticed the weights on the vac advance didn't touch the same way, unless I pressed it back together. It didn't need and pressure, just a little help. However, the one weight will not stay in that "closed" position at all unless held there. Could this be something?? Or am I on the wrong track. I am hoping I don't have to pull this thing apart.... It's in my dads truck and it's taken soooo long just to get it to this point.
What year motor and post a good picture of the distributor cap o run the same set up with no problem ...I actually like the h.e.i, set up very easy to tune with . Posted using the Full Custom H.A.M.B. App!
Sounds like you're doing everything right, but the newly installed HEI has you concerned...how much trouble to throw the stock, previously used, or another borrowed dizzy on the engine just to confirm the ignition system?
Missing spring on distributor's centrifugal weight sounds about right. Might be detached at just rattling around, causing the intermittent problems. But first, do a plug wire check: Once it starts acting up, pull one at a time, but remember to ground it to the block. If the symptom doesn't go away but runs worse, that cylinder and wire isn't the problem. If you pull a wire and there's no change, you might have found the bad plug wire. Change it out and see if it solves the problem. If not, and you've gone through all eight wires, take apart that dizzy. If that isn't it, I'd think you have a carburetor choke closing, a float or needle valve sticking, or some foreign material in the carburetor (look first in the bowl). Anyone else have some ideas?
I have no pics at this moment. I'll get some as soon as I can. Boutlaw, the conversion removes the entire stock ignition system from the truck. Meaning there is no more ignition box or coil from the original Ford set up. It's possible, but will take a day to change back over. I really like the HEI set up. It should be easy....
osage orange. That sounds like a good idea. I'll try that next time I'm at the shop. If there is a dead wire, the cyl won't fire, causing the symptoms I'm having
I have a 302, with the HEI set up..I've run into seveal issues with vac advance and timing...once those things were dialed in I ran into the proble that the rotor bushing snapped... You might want to take the top off the Dizzy (not the plug cap) but the middle part that houses the coil wires once that is off pull out the spring and make sure the rotor bushing is in tacked and is making good contact with the rotor...hope this helps
I have a msd on my 302 and had the same problems that your having , found out it was the magnetic pickup . Good luck
Does it make a burbling sound when you try to put a load on it? I had a similar issue, turned out I had two of the wires swapped (3 & 6 IIRC) might check for that, as I had checked the firing order several times, made sure I hadn't wired it backwards (for the rotor turning the other way) or any other weirdness. If nothing else, worth a shot to just try. Best of luck, at least it's not an intermittent problem.
While a hei is a great distributor, if you purchased yours off the internet ( ebay ) it's probably a cheap offshore version,they look good, but not the same quality as the ones your old gm had.that's why they sell so cheap.with that being said,,, I think I would check for a fuel related problem, most back fire problems are caused by a lean condition.. good luck.
Do you have a good 12+ to the distributor with no resister wire in line? I have run a wire direct from the battery to the cap to test for this before. Of course you will have to disconnect the wire to kill the engine.
So it ran well before you fixed it? Is the distributor new? If there is a spring off or a centrifugal advance weight is sticking, the base timing at idle will be off. If it is a new unit with that problem, it needs to be returned. If it is used, it could be other bad parts like a module or pickup. Make sure there isn't any metal dust or shavings on the reluctor magnet.
Ok. So it is a Mallory unit. Says it's made in Australia. There is two springs, one on each weight, so I don't think there's anything missing there. I haven't gone any deeper into the dizzy then there. So I could dig deeper and see if there is anything else broken. Earlier, Lorodz asked the year. The block is a 1968 with stock iron heads with larger valves. The vacuum advance was loose in the base so I tightened it up, would it need to be adjusted? It looks like the housing could be moved deeper into the dizzy or further out. Will this change the vacuum advance? It's just about centered in the slots now. Now about the pick up. Anyone know if a stock pick up will fit? I would think so, but got to ask. As for any "burbling" sound, I haven't been able to get it to stay running long enough to try putting it in gear. Engine man. Yes, after the pushrod was repaired it ran well. But then the truck build took a wild right turn and we swapped a lot of things including the chassis. At this time I rewired the truck and installed the engine into the new chassis. Sounds silly to change things when they were working well, but it was a necessity to the owners level of comfort and drivability.
That sounds like a "pro-comp" with a Mallory cap. Get an early 5.0 carbed engine dizzy [ approx. 1985 ] and convert that to HEI for about $12 Can be done with a module and spade terminals
I had similar problems with my 302 with an HEI style dizzy (Pro Comp). I replaced the module and it was fine. You might just assume that everything in the cheap distributors is junk and plan to replce it.
Are you sure the valve adjustment is not over tightened? since you have the 289 heads and an aftermarket cam do you have stud mounted rocker arms? I also have the HEI on mine over 4 years,no issues.
#3...#6...hotter than the rest... On a 302 that would be the 3rd cyl back on each side... You removed the carb spacer... My bet is a vacuum leak !....a big enough leak so it won't idle... I had this exact same problem on a 390 about 20 years ago. Tore my hair out trying to solve it...it happened when I installed a lumpy cam and edelbrock intake on a good running engine. Thought it had the cam incorrectly timed...and tried a bunch of other stuff to no avail ! The carb spacer gasket did not seal at the manifold ..it would do the same thing you describe... 2 weeks of messing around...Man..did I feel stupid when I found the problem.. Dave
Interesting Dave Lewis. I'll look into that as well. I hope to get out to the shop this weekend. Ordered a new module today so I'll try that as well. Thanks for all the input on this. Great to be able to ask such a knowledgeable group. This place rocks. Always great support.
Hello everyone. I want to take a second and thank everyone that replied here. It has been a while since I got back to the truck to try the suggestions given here, but yesterday I finally got back at it. I tried everything again, keeping all the great suggestions I received here in the back of my mind, and using this info we actually got it fixed!!!! Turns out there was a few things wrong with the truck. First, the plug wires were not all good.... Secondly, the new fuel pump wasn't pushing more then 2 psi.... Third, well third was the culmination of all the attempted fixes.... In the end though, the info and suggestions here got us through. My dad drove his 50 Merc pick up for the very first time in nearly 12 years!!!!! What a day. He took it around the block four times and I'm betting that grin won't get wiped off his face any time soon!!!! Thanks again to all the people that offered suggestions. It all payed off!!!
Hot damn! I'm so happy for you and your dad. I had a good day in the garage, too. Bump that beer bottle up against the screen and we're toasting a great day.
Well actually it would be the third cylinder back on the left (passenger) side and the second cylinder back on the right (driver) side. If you have a dual plane manifold both of these cylinders will feed off the same primary manifold runner. The Ford numbering system is 1234 5678