Thread: what the heck is this

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Ok guys I've never seen this before maybe one of you can lead me in the right direction. I have a fresh BBC with a solid cam a torquer 2 intake and a 750 holly and hooker headers. Here's the problem cylinders 1,3,5,and 7 spark plugs look good maybe one jet size lean. Cylinder 2 is so rich it fouls the plug 4 is a little rich 6 and 8 are scary lean. The valve adjustment has been checked 4 times as has the spark to all the plugs. Any ideas?

Check your float bowl. It sounds to me like its sticking on one side and as such, you have a cross mixture.

This may sound crazy but check and make sure all the intake runners are clear....... the only reason I bring this up is I bought a new Offy manifold once took it to be plumed for N2o and they found one of the runners still packed with sand from when it was cast

just a thought

MM64

Are the wires are good or what kind of plugs are you using?
I've had some bad problems using Accel spark plugs.
What kind of distributer, dual point or what? Are you
sure your getting spark to those cyclinders that are
running rich. It could also be a cam problem or valve
adjustment problem. Sorry to ask what seem like stupid questions but some time thats what it is, Some thing stupid.
Not even necaessarly our falt, some times just defective
new parts. Sucks but it happens.


~ Vegas ~

Sometimes, the plugs or wires are a problem, in a case like this, and they are the easiest things to check. What I'd do, is change the plugs, just out of hand; don't try to second guess them. Or, at least check the resistance on all of them and make sure they are all pretty close to each other; large differences could cause a problem. Same with the plug wires; they have a spec for resistance, and should be within the spec, and pretty close to the same on all wires. There will be a slight difference because of the relative length of each wire, but I think you can get my drift. Next is the distributor cap and rotor, and if you run points and condenser, examine them all really well, or just replace them with new, and check the new stuff well, too. With the Torker manifold, I believe you can see down the runners from the carb base with a light and a small inspection mirror; lift the carb, and take a look. If you have access to a borescope, use that, and look all the way to the valves. Sometimes, surprises hide in the dangdest places. The carb may be unbalanced, or there might be a stuck needle or clogged jet, or a bleeder port thats not "bleeding" right. Did you recently overhaul the carb? Get an incorrect gasket in the incorrect place? That can block things that should not be blocked. I've run across all of these things, in so many combinations, over the years, that I can't remember them all. And most of them were the result of something I did myself. I had a newly rebuilt four banger one time, that had been running well, before it ate a rod bearing. I put it all back together, and fired it up, set the timing, and took it for a little spin around the block; everything was "hunky-dory". I decided to drive it to a business conference to give it a bit if break in, and the first hill I pointed it up, it almost quit running, it was breaking up so badly. Since I was in a suit and tie, I eased my way to the meeteing, and back home, and cussed everything in the world, the whole way. Next chance I got, I started looking, and lo, and behold; the plug wires were shot. They had not been shot before the thing broke, but apparently the handling of the distributor and wires during the rebuild, caused them to go bad. So, I try not to discount anything, anymore. Good luck.

Thanks for all the replys. To narrow this down some this is the third set of plugs and the second set of wires. It is also a new cap, rotor, points and condensor. I'm leaning toward the carb it's just that i've never seen one or two holes run rich and the rest run good.

I've been ponderin' on this problem for a few days, now, and I sure don't have any more suggestions. I went to the Edelbrock pages, and took a look at that manifold; I was wrong in my thinking, that you could look down the runners from the flange. Iwas thinkin about one of those straight runner "X" type manifolds. I also noted that that manifold has no plenum dividers in it, so the intake turbulence should help keep the charges to the cylinders fairly even. I would sure be interrested to know what you find out about this. Keep us posted, if you don't mind.

In addition to this I would run a vacume guage and make a note of what the needle is doing at different engine revs. Is it low vacume ? Is the needle fluctuating ? (moves back and forth) It should be a handy tool in pointing you towards the problem.

Hey! POW/MIA, you still around? Did you ever get this upset figured out? Inquiring minds would like to know.

I've got to say this quiet, I dont want the carb to hear this but i think i might have won this battle. What I think was happening is that there were a few different things working aginst me. Number one being my general lack of carburetor tuneing ability. I think what was going on was that the carb came off of a stock engine and with the amount of cam in the new engine the power valves were open at idle. This was allowing fuel to trickle through the transition slots in the base plate. At idle this would foul those plugs, when you hammer the throttle these plugs would clean up and it would run like a raped ape. What I did that seems to have it under controll is I replaced both power valves with 2.5's and opened the secondary's a small amount so I could close the primary's and not have so much of the transition slot exposed. This is by no means perfect but it seems to have cured the worst of it and can be fine tuned from here.

Fuel trickling into the intake is bad by any standards. Not a bad temp fix. Good job

Thanks for the reply. I'll file the info away for a possible "rainy day".