Fuel or ignition or what? Need some help

[70stroker]

Alright guys i have a 460 bbc with a 177 weiand blower on it. I am having some issues with it dieing and needing some advice. I appreciate anyone who reads this long post and gives me a few ideas because i am at my wits ends.

About a year ago i droped a valve in my bbc and pulled it for a rebuild. Put a scat bottom end in along with alot of other goodies. When i was building this motor a buddy of mine had a nice new hei in his shop he said i could use, so i did. Anyhow i got it running back in june. Between june and july i put about 200 miles on it and never had any problems, It needed tuned a little but i was going to do that soon. Then he tells me he is ready for his distributor back so i order a summit hei. Anyhow i got busy for about a month and half and the truck just sat in my shop awaiting the hei. So last weekend i went out and put it in and timed the motor.The truck starts nice and easy with one pump of the gas. You can sit there and let it idle all day long, however when you go to drive it you get about a mile or so and it acts like it empty on gas and spits and sputters till it dies. You then start it back up and it wont hold a idle and just keeps dieing. You let it cool down about 30 min or so, then you can fire it back up idle it or drive it about a mile untill it does it again. IT was about 100 degrees the day i put the dizzy in so i thought maybe vapor lock, however last night it was about 70 here and i took it out and it did the same thing.

I dont know what to even look at, electrical? Fuel pump? which is mechanical. Perhaps a bad dizzy? even tho its new.

Any how i did rewire the whole truck with painless while i rebuilt the motor, so i could be electrical, however if it is why did i get 200 miles out of the motor running fine with the other dizzy?

Could it be the dizzy?

Could it be a fuel pump with a cracked diaphram leaking internally and starving for fuel?

Carb?

Any i deas on what to check? Thanks in advance

[70stroker]

anyone?

[kwhite4]

I dont know for sure but if it were me I would start with the dizzy, it sounds like its the only thing thats changed. You never know it could be getting hot and going nuts, then I would make sure there isnt some trash floating around in the carb bowl (if it has a carb)if trash gets in the needle and seat she will not be happy. After that I would check my fuel pressure and make sure I have the correct current to the dizzy.
Make her do her thing, pull the fuel line off and see if your getting enough fuel if not then you know its a fuel prob.

Good luck
Keith

[Marv D]

I had a similar issue with a buddys blown 454 with old oval port heads. We had put a set of normal plugs in the thing for the motor (n/a) They were overheating and turning to 'glow plugs' with any real cylinder pressure. But unlike your situation,,, as soon as it started up it idled fine,, but would sputter under load.

I'm wondering if possibly you have a combination of issues.
Plugs fresh and right heat range?
Is fuel pump keeping float bowls full when it won't run?
and the biggest suspect,,,,, the slummit, jeggs and most of the other discount no-name brand distributors are made in China, and have a cheep crap module made in South America (believe it or not a Chinese made module would be an improvement!)

Even if the module isn't the issue right now, I'm betting it WILL BE in the near future. Order a new AC-Delco module for your distributor and if it doesn't correct the issue, then look at plugs and fuel.

Just as a BTW,, I have 2 of the Jeggs small body ECM controlled HEI distributors. One in a 94 4x4 and one in my 67 El Camino. As of last weekend, I've had to replace the module in BOTH within less than a year of it being new.

[70stroker]

thanks for all your help guys. I called summit and sent the dizzy back and payed the difference for a msd unit. Should be getting that soon.

on another note i went ahead and replace the fuel pump and put a pressure gauge inline. running 7 psi of fuel and its still doing the issue, so hopefulley its the dizzy.

Also marv what heat range do i need to look at? I would like something i can pick up at a parts store. Right now i just put new ones in and they are champions i believe, not sure on the heat range.

[Marv D]

Not any forced induction expert by a LONG shot, and I'm guessing your not making a lot of boost with the 177. I do know blower motors like a lot of early advance, and even fixed timing,, so I would suspect the heat range would be relative to how much boost, and how much timing you run. Just as a shot in the dark,, but I think I'd start with a ACdelco plug about 1 to 2 steps colder than stock for the heads and their original application. I would chase the head casting # to find what they were originally installed on (assuming here that they are GM production castings???) Pick the plug configuration (gasketed or taper seat? reach, etc.) , then if original called for a R(x)14Y(C) champion, step down to a 12, or even a 9 and see if the plugs stay burning clean.

In most plugs, as in champion, as the number gets lower, the easier the plug expels heat (is colder)

In NGK, same deal, a xxxx-8 is colder than a xxxx-11

Autolite,, 3942 is colder than a 3944

ACdelco has a BUNCH of crazy codes, but generally the same deal,,, a FR1LS is colder than a FR3LS

But you need some idea of what was correct for the heads, in it's original engine, comparison to what compression / cylinder pressure you have now, boost, and more info than I am willing to make any assumptions and recommendations on.

Best I can say is treat boost like Nitrous. Start with a RICH mixture, cold plugs, moderate advance, and low boost. Work up SLOWLY from there until you start hurting parts (LOL).

[70stroker]

marv i did some research, i couldnt find what the original heat range was for these heads, they are 781 gm heads.

I did however start thinking about waht you said. Before i had the issue with the swapping dizzys i had a bosh platnium in it which was a heat rang 9. THen i bought some cheap plugs (which was my first mistake) champions which are a heat range 12.

do you think this could be cause?

I still havnt recieved the dizzy from summit so as of now i am just tryin to eliminate any other possiblities while i wait for the package.

thanks

[Marv D]

Don't know if this helps. A Bosch WR8 and WR9 is the same heat as a Champion J12 in the cross reference chart I have. If I were going to change heat ranges, I think I'd try a Champion xx9xx or the Bosch xx6xx (substituting the proper thread, reach and electrode)

THATS where the head casting number should lead you,, to what type of car the heads were installed on originally. Then you can make sure of the taper / gasketed seat, projected or rectracted nose, etc. I guess when your stuffing air through the port, flow and those sorts of considerations really don't matter. As long as your not making a 'glow plug' out of them,, probably not a big issue. your going to have plenty of heat to keep them burning clean.

My guess is the distributor is going to tell the story.

[70stroker]

What in the distributor would cause this kinda of symptom?

[cableguy0]

A bad ignition module will do exsctly what your describing. My bet is on the distributor being bad. Champion plugs belong in dodges and lawn mowers. Put either ac delco or ngk's in that thing. Bosch are just trash in the first place.