Finally after many hours of suspension and engine work, I took my 72 z on its mayden voyage. Don't think I've been so happy since I beleived in Santa! Only problem is that I'm completley fouling out all my plugs after about 20 miles or so. The culprits I know to check are my vac. advance, timing, and air fuel mix. Am I missing anything? I strongly feel that the problem is in the carbs. Is there a way to tell when my air to fuel mix is set correctly without the use of a special tool such as a a colortune? If not, what tool do yall reccomend for checking the mix? I've backed out the air/fule screws 5 turns and still no cure. Maybe I'm running to lean? BTW the carbs are webber dgv's, plugs are ngk's set at .40. Any help is very appreciated, these plugs are getting a bit expencive!

Dan

If you are fouling plugs, it's one of two things: too much fuel or you're getting a lot of oil in the cylinders. Wipe your finger across one of the plugs after they foul (do it quickly so you don't burn yourself). Now you need to determine if the "wetness" on your plugs is oil or fuel. Most likely, it's fuel.

From the sounds of things, it sounds like your car is running really rich. A lean fuel mixture will not foul plugs. I don't anything about how the Weber DGV's work so I can't help you there. But I do know that our local Z club President had them on his 240 once, and he could never get the car to run any faster than 60 mph! And it ran really rich, and shot flames out of the tailpipe! Once he switched over to SU's, never had a problems again. Find yourself a knowledgable DGV person or get a book. Then do a step by step process of elimination until the problem is solved.

One other thing you might look at is your ignition system. Make sure you points are in good condition, the coil is good, and that your battery & alternator are putting out what they should. A weak spark can make fouling plugs very easy.

I'm with Kmack..

I no nothing about webers, but i think its way too rich.

Possibly really weak ignition- what's the state of that?

Do you know much about the webers? Backing out the screws 5 turns- does that lean, or richen the mixture? Wish i could help more, but thats why i run SU's- simple as a toilet!

Originally posted by AxtellZ

simple as a toilet!

Be careful how you phrase that, Jeremiah. I know people that can't fix toilets and end up calling plumbers or just live a toilet that doesn't work. Who would have thought that a toilet could be so complicated? :stupid:

Well, let me *qualify* that!

I live in a 140-some year old home. First home in this town with an indoor "water closet"! Now, the toilets here aren't THAT old, but they are probably 40 to 80+ years old. Old, simple- if i can fix 'em any fool should be able to.

As for SU's- i'll admit i feared even touching them at first! But i read alot, got Scott's first tune-up video, and dove in.

And i've found they are essentially as simple as an old toilet (insert "gas" joke here:_____________)

Man, this place is great

I had the same anxiety about the SU's also. But they really are easy once you understand them. And they're not hard to understand. They work off the simplest principles of carburetor theory! If you can understand how a simple caruretor works, you're set!

I've had people at race events ask me how hard it is to tune my sidedrafts. They are amazed (and usually don't believe me) when I tell them it takes less than 15 minutes, with no special tools (other than my flow meter).

yeah, i was thinking it was running too rich as well but i never thought to check the spark. i've tried running the carbs at just about every ratio possable and still no luck, makes sense that it would be a weak spark. btw its fuel thats fouling the plugs. i kind of thought that timing may be an issue as well, if the spark was not ingnited at the proper time couldn't this lead to fould plugs. just curious if its possable. anyhow, thanks for your help. onward to ingnition inspection.

Originally posted by mtdripo

i kind of thought that timing may be an issue as well, if the spark was not ingnited at the proper time couldn't this lead to fould plugs. just curious if its possable. anyhow, thanks for your help. onward to ingnition inspection.

Yes, double check your timing, inspect your plug wires, and points. Make sure everything is up to snuff. Process of elimination....

my first guess would be the same. Too rich or weak spark. There are many other problems that could cause this but most others would be mechanical problems that you could hear.

Also, you will never be able to keep the webers properly tuned. I bought my car with webers an quickly took them off because the backfires started pissing me off right away. The webers will make a puddle of gas in the bottom of their manifolds when you idle after driving. That puddle can do a lot more damage than just fouling your plugs